It is possible to use the impedance matching concepts to construct vertical antennas substantially shorter than the 1⁄4 wavelength at which the antenna is resonant. By adding an inductance in series with the antenna, a so-called loading coil, the capacitive reactance of this antenna can be cancelled leaving a pure resistance which can then be matched to the transmission line. Sometimes the resulting resonant frequency of such a system (antenna plus matching network) is described using the construct of electrical length and the use of a shorter antenna at a lower frequency than its resonant frequency is termed electrical lengthening.

What could be coupled with an antenna to form pure resistance?

inductance

What element would this pure resistance be coupled with?

transmission line

What phrase describes the process of purposely using a lower standing antenna at a less than peak frequency?

electrical lengthening


The end result is that the resonant antenna will efficiently feed a signal into the transmission line only when the source signal's frequency is close to that of the design frequency of the antenna, or one of the resonant multiples. This makes resonant antenna designs inherently narrowband, and they are most commonly used with a single target signal. They are particularly common on radar systems, where the same antenna is used for both broadcast and reception, or for radio and television broadcasts, where the antenna is working with a single frequency. They are less commonly used for reception where multiple channels are present, in which case additional modifications are used to increase the bandwidth, or entirely different antenna designs are used.

 If your were unable to match the source frequency with the design frequency of the antenna what could you use?

resonant multiples

What is the most common application of resonant antennas?

single target signal

What antenna setup type is generally used for TV viewing?

resonant

For use with more than one channel changes are made to increase what property?

bandwidth


The amount of signal received from a distant transmission source is essentially geometric in nature due to the inverse square law, and this leads to the concept of effective area. This measures the performance of an antenna by comparing the amount of power it generates to the amount of power in the original signal, measured in terms of the signal's power density in Watts per square metre. A half-wave dipole has an effective area of 0.13 2. If more performance is needed, one cannot simply make the antenna larger. Although this would intercept more energy from the signal, due to the considerations above, it would decrease the output significantly due to it moving away from the resonant length. In roles where higher performance is needed, designers often use multiple elements combined together.

What accounts for the geometry involved in the use of an antenna?

inverse square law

How is the compactness of the signal measured?

Watts per square metre

What type of project would call for more than one element used together?

higher performance


Returning to the basic concept of current flows in a conductor, consider what happens if a half-wave dipole is not connected to a feed point, but instead shorted out. Electrically this forms a single 1⁄2-wavelength element. But the overall current pattern is the same; the current will be zero at the two ends, and reach a maximum in the center. Thus signals near the design frequency will continue to create a standing wave pattern. Any varying electrical current, like the standing wave in the element, will radiate a signal. In this case, aside from resistive losses in the element, the rebroadcast signal will be significantly similar to the original signal in both magnitude and shape. If this element is placed so its signal reaches the main dipole in-phase, it will reinforce the original signal, and increase the current in the dipole. Elements used in this way are known as passive elements.

What is a half wave dipole need to be coupled with in most instances?

feed point

What part of the current is usually strongest?

center

What does this result in?

standing wave pattern

Element used to provide support to the original signal are called?

passive elements


A Yagi-Uda array uses passive elements to greatly increase gain. It is built along a support boom that is pointed toward the signal, and thus sees no induced signal and does not contribute to the antenna's operation. The end closer to the source is referred to as the front. Near the rear is a single active element, typically a half-wave dipole or folded dipole. Passive elements are arranged in front (directors) and behind (reflectors) the active element along the boom. The Yagi has the inherent quality that it becomes increasingly directional, and thus has higher gain, as the number of elements increases. However, this also makes it increasingly sensitive to changes in frequency; if the signal frequency changes, not only does the active element receive less energy directly, but all of the passive elements adding to that signal also decrease their output as well and their signals no longer reach the active element in-phase.

What can take advantage of these elements to add more gain?

Yagi-Uda array

Does this device improve the operation of the antenna?

does not contribute

What is the name for passive elements nearer to the source of the signal?

directors

Adding more elements to a Yagi-Uda would have what effect?

increasingly directional


It is also possible to use multiple active elements and combine them together with transmission lines to produce a similar system where the phases add up to reinforce the output. The antenna array and very similar reflective array antenna consist of multiple elements, often half-wave dipoles, spaced out on a plane and wired together with transmission lines with specific phase lengths to produce a single in-phase signal at the output. The log-periodic antenna is a more complex design that uses multiple in-line elements similar in appearance to the Yagi-Uda but using transmission lines between the elements to produce the output.

What can be paired with transmission lines to create phases that would support output?

active elements

What is the most common element used to create a single in phase signal?

half-wave dipoles

What must be precise in order to create this signal at output?

phase lengths

What is a more complicated occurrence of the single in-phase producing antenna?

log-periodic


Reflection of the original signal also occurs when it hits an extended conductive surface, in a fashion similar to a mirror. This effect can also be used to increase signal through the use of a reflector, normally placed behind the active element and spaced so the reflected signal reaches the element in-phase. Generally the reflector will remain highly reflective even if it is not solid; gaps less than 1⁄10 generally have little effect on the outcome. For this reason, reflectors often take the form of wire meshes or rows of passive elements, which makes them lighter and less subject to wind. The parabolic reflector is perhaps the best known example of a reflector-based antenna, which has an effective area far greater than the active element alone.

If you wanted to somehow clone the original signal you could use?

extended conductive surface

What effect would the use of a reflector have on a signal?

increase

What allowance can be made for gaps without loss of performance?

less than 1⁄10

What is the most recognized type of an antenna that has its basis in reflection?

parabolic reflector


Another extreme case of impedance matching occurs when using a small loop antenna (usually, but not always, for receiving) at a relatively low frequency where it appears almost as a pure inductor. Resonating such an inductor with a capacitor at the frequency of operation not only cancels the reactance but greatly magnifies the very small radiation resistance of such a loop.[citation needed] This is implemented in most AM broadcast receivers, with a small ferrite loop antenna resonated by a capacitor which is varied along with the receiver tuning in order to maintain resonance over the AM broadcast band

What magnifies the small radiation resistance of a loop?

a capacitor at the frequency of operation

What is used in most AM broadcaster receivers?

loop

What is resonated by a capacitor along with the receiver tuning that maintains resonance over the AM broadcast band?

small ferrite loop antenna

When using a small loop antenna at a low frequency, what may occur?

impedance matching


Antenna tuning generally refers to cancellation of any reactance seen at the antenna terminals, leaving only a resistive impedance which might or might not be exactly the desired impedance (that of the transmission line). Although an antenna may be designed to have a purely resistive feedpoint impedance (such as a dipole 97% of a half wavelength long) this might not be exactly true at the frequency that it is eventually used at. In some cases the physical length of the antenna can be "trimmed" to obtain a pure resistance. On the other hand, the addition of a series inductance or parallel capacitance can be used to cancel a residual capacitative or inductive reactance, respectively.

Where does cancellation of any reactance seen?

antenna terminals

What is left after antenna tuning?

resistive impedance

What can be used to cancel a inductibe reactance or residual capacitative?

parallel capacitance

What is an antenna designed to have?

purely resistive feedpoint


Although a resonant antenna has a purely resistive feed-point impedance at a particular frequency, many (if not most) applications require using an antenna over a range of frequencies. An antenna's bandwidth specifies the range of frequencies over which its performance does not suffer due to a poor impedance match. Also in the case of a Yagi-Uda array, the use of the antenna very far away from its design frequency reduces the antenna's directivity, thus reducing the usable bandwidth regardless of impedance matching.

What type of antenna has impedance at a specific frequency?

resonant

What term can be used to refer to the usable spectrum of an antennas frequency?

bandwidth

What causes the frequencies outside of the bandwidth to be unusable?

impedance match

What is lessened by the Yagi-Uda design?

directivity


Instead, it is often desired to have an antenna whose impedance does not vary so greatly over a certain bandwidth. It turns out that the amount of reactance seen at the terminals of a resonant antenna when the frequency is shifted, say, by 5%, depends very much on the diameter of the conductor used. A long thin wire used as a half-wave dipole (or quarter wave monopole) will have a reactance significantly greater than the resistive impedance it has at resonance, leading to a poor match and generally unacceptable performance. Making the element using a tube of a diameter perhaps 1/50 of its length, however, results in a reactance at this altered frequency which is not so great, and a much less serious mismatch which will only modestly damage the antenna's net performance. Thus rather thick tubes are typically used for the solid elements of such antennas, including Yagi-Uda arrays.

What characteristic would be better if it were steady?

reactance

What characteristic of the conductor changes the amount of reactance?

diameter

What would be used to create a half wave or quarter wave dipole?

A long thin wire


Rather than just using a thick tube, there are similar techniques used to the same effect such as replacing thin wire elements with cages to simulate a thicker element. This widens the bandwidth of the resonance. On the other hand, amateur radio antennas need to operate over several bands which are widely separated from each other. This can often be accomplished simply by connecting resonant elements for the different bands in parallel. Most of the transmitter's power will flow into the resonant element while the others present a high (reactive) impedance and draw little current from the same voltage. A popular solution uses so-called traps consisting of parallel resonant circuits which are strategically placed in breaks along each antenna element. When used at one particular frequency band the trap presents a very high impedance (parallel resonance) effectively truncating the element at that length, making it a proper resonant antenna. At a lower frequency the trap allows the full length of the element to be employed, albeit with a shifted resonant frequency due to the inclusion of the trap's net reactance at that lower frequency.

What type of tubes are generally used for sturdier always of antennas?

cages

What effect do cages have on the spectrum of usable frequencies?

widens

How could one achieve the task of creating an antenna that can be Used over various bands?

connecting resonant elements

What is an essential for dealing with directing the flow of power?

trap's


Gain is a parameter which measures the degree of directivity of the antenna's radiation pattern. A high-gain antenna will radiate most of its power in a particular direction, while a low-gain antenna will radiate over a wider angle. The antenna gain, or power gain of an antenna is defined as the ratio of the intensity (power per unit surface area)  radiated by the antenna in the direction of its maximum output, at an arbitrary distance, divided by the intensity  radiated at the same distance by a hypothetical isotropic antenna which radiates equal power in all directions. This dimensionless ratio is usually expressed logarithmically in decibels, these units are called "decibels-isotropic" (dBi)

What is an acknowledgement of the range of possible direction for and antenna?

gain

What is another way to refer to an antennas gain?

power gain

What is the meaning of intensity?

power per unit surface area

What type of an antenna would offer the same level of power to each possible destination?

isotropic


High-gain antennas have the advantage of longer range and better signal quality, but must be aimed carefully at the other antenna. An example of a high-gain antenna is a parabolic dish such as a satellite television antenna. Low-gain antennas have shorter range, but the orientation of the antenna is relatively unimportant. An example of a low-gain antenna is the whip antenna found on portable radios and cordless phones. Antenna gain should not be confused with amplifier gain, a separate parameter measuring the increase in signal power due to an amplifying device.

Antennas with higher gain have what positive feature?

longer range

Dish network Tv takes example of what type of antenna?

parabolic dish

What type of antenna would be best if placement was tricky?

Low-gain

What is a measure of how much efficient is improved by adding a device designed to make something stronger?

amplifier gain


Due to reciprocity (discussed above) the gain of an antenna used for transmitting must be proportional to its effective area when used for receiving. Consider an antenna with no loss, that is, one whose electrical efficiency is 100%. It can be shown that its effective area averaged over all directions must be equal to λ2/4π, the wavelength squared divided by 4π. Gain is defined such that the average gain over all directions for an antenna with 100% electrical efficiency is equal to 1. Therefore, the effective area Aeff in terms of the gain G in a given direction is given by:

What must the relationship of an antenna and the receiving area be due to reciprocity?

proportional

what could an antenna with complete electrical efficiency be said to have?

no loss

hat could an antenna with complete electrical efficiency be said to have?

Another term for the effective area is?

Aeff


The radiation pattern of an antenna is a plot of the relative field strength of the radio waves emitted by the antenna at different angles. It is typically represented by a three-dimensional graph, or polar plots of the horizontal and vertical cross sections. The pattern of an ideal isotropic antenna, which radiates equally in all directions, would look like a sphere. Many nondirectional antennas, such as monopoles and dipoles, emit equal power in all horizontal directions, with the power dropping off at higher and lower angles; this is called an omnidirectional pattern and when plotted looks like a torus or donut.

A plot of the radiation behaviors of an antenna would show what?

relative field strength

What type of pictoral aid is often used to show this?

three-dimensional graph

A sphere shows what type of antennas radiation?

isotropic

Dipoles are considered to be what antenna type?

nondirectional

What would an omnidirectional antenna look like if plotted?

donut


The radiation of many antennas shows a pattern of maxima or "lobes" at various angles, separated by "nulls", angles where the radiation falls to zero. This is because the radio waves emitted by different parts of the antenna typically interfere, causing maxima at angles where the radio waves arrive at distant points in phase, and zero radiation at other angles where the radio waves arrive out of phase. In a directional antenna designed to project radio waves in a particular direction, the lobe in that direction is designed larger than the others and is called the "main lobe". The other lobes usually represent unwanted radiation and are called "sidelobes". The axis through the main lobe is called the "principal axis" or "boresight axis".

What is the term that refers to areas where an antennas radiation is zero?

nulls

What do radio waves do that account for maxima or nulls in an antenna pattern?

interfere

If you desired to project radio waves to the south, what part of the antenna would you build larger in that direction?

lobe

What is the main distinction of side lobes?

represent unwanted radiation


As an electro-magnetic wave travels through the different parts of the antenna system (radio, feed line, antenna, free space) it may encounter differences in impedance (E/H, V/I, etc.). At each interface, depending on the impedance match, some fraction of the wave's energy will reflect back to the source, forming a standing wave in the feed line. The ratio of maximum power to minimum power in the wave can be measured and is called the standing wave ratio (SWR). A SWR of 1:1 is ideal. A SWR of 1.5:1 is considered to be marginally acceptable in low power applications where power loss is more critical, although an SWR as high as 6:1 may still be usable with the right equipment. Minimizing impedance differences at each interface (impedance matching) will reduce SWR and maximize power transfer through each part of the antenna system.

What is one piece that makes up an antenna system?

radio

What is created by a portion of a radio waves energy reversing?

standing wave

A term that refers to the highs and lows of power in electro magnetic waves is?

standing wave ratio

Impedance matching makes an important difference in what antenna function?

power transfer


Efficiency of a transmitting antenna is the ratio of power actually radiated (in all directions) to the power absorbed by the antenna terminals. The power supplied to the antenna terminals which is not radiated is converted into heat. This is usually through loss resistance in the antenna's conductors, but can also be due to dielectric or magnetic core losses in antennas (or antenna systems) using such components. Such loss effectively robs power from the transmitter, requiring a stronger transmitter in order to transmit a signal of a given strength.

A measure of the power that is useable and the power absorbed by the terminals?

Efficiency

What happens to the power that is not absorbed by the antenna?

heat

What can cause that reaction?

transmitter


For instance, if a transmitter delivers 100 W into an antenna having an efficiency of 80%, then the antenna will radiate 80 W as radio waves and produce 20 W of heat. In order to radiate 100 W of power, one would need to use a transmitter capable of supplying 125 W to the antenna. Note that antenna efficiency is a separate issue from impedance matching, which may also reduce the amount of power radiated using a given transmitter. If an SWR meter reads 150 W of incident power and 50 W of reflected power, that means that 100 W have actually been absorbed by the antenna (ignoring transmission line losses). How much of that power has actually been radiated cannot be directly determined through electrical measurements at (or before) the antenna terminals, but would require (for instance) careful measurement of field strength. Fortunately the loss resistance of antenna conductors such as aluminum rods can be calculated and the efficiency of an antenna using such materials predicted.

What would need to be placed into the transmitter to create ten W oh warmth?

100 W

What factor may play a hand in lessened power from a transmitter?

impedance matching

What would need to be investigated to determine how much power was radiated?

electrical measurements


However loss resistance will generally affect the feedpoint impedance, adding to its resistive (real) component. That resistance will consist of the sum of the radiation resistance Rr and the loss resistance Rloss. If an rms current I is delivered to the terminals of an antenna, then a power of I2Rr will be radiated and a power of I2Rloss will be lost as heat. Therefore, the efficiency of an antenna is equal to Rr / (Rr + Rloss). Of course only the total resistance Rr + Rloss can be directly measured.

What can increase the feedpoint impedance of a component?

loss resistance

The addition of Rr and Rloss equals what?

resistance

What equation an determine an antennas effectiveness?

Rr / (Rr + Rloss)

What is the single factor that can be precisely measured?

total resistance


According to reciprocity, the efficiency of an antenna used as a receiving antenna is identical to the efficiency as defined above. The power that an antenna will deliver to a receiver (with a proper impedance match) is reduced by the same amount. In some receiving applications, the very inefficient antennas may have little impact on performance. At low frequencies, for example, atmospheric or man-made noise can mask antenna inefficiency. For example, CCIR Rep. 258-3 indicates man-made noise in a residential setting at 40 MHz is about 28 dB above the thermal noise floor. Consequently, an antenna with a 20 dB loss (due to inefficiency) would have little impact on system noise performance. The loss within the antenna will affect the intended signal and the noise/interference identically, leading to no reduction in signal to noise ratio (SNR).

In what type of programs would low efficiency antennas not make a difference in effectiveness?

receiving

At lesser frequencies what can account for incorrect assumptions about efficiency?

man-made noise

What is the median level for measuring atmospheric noise?

thermal noise floor

What is SNR?

signal to noise ratio


The definition of antenna gain or power gain already includes the effect of the antenna's efficiency. Therefore, if one is trying to radiate a signal toward a receiver using a transmitter of a given power, one need only compare the gain of various antennas rather than considering the efficiency as well. This is likewise true for a receiving antenna at very high (especially microwave) frequencies, where the point is to receive a signal which is strong compared to the receiver's noise temperature. However, in the case of a directional antenna used for receiving signals with the intention of rejecting interference from different directions, one is no longer concerned with the antenna efficiency, as discussed above. In this case, rather than quoting the antenna gain, one would be more concerned with the directive gain which does not include the effect of antenna (in)efficiency. The directive gain of an antenna can be computed from the published gain divided by the antenna's efficiency.

What else is also known as power gain?

antenna gain

What is used to signal toward a reciever?

transmitter

Which gain does not iclude the effect of an antenna?

directive gain

Wats divided by the antennas efficiency?

published gain


This is fortunate, since antennas at lower frequencies which are not rather large (a good fraction of a wavelength in size) are inevitably inefficient (due to the small radiation resistance Rr of small antennas). Most AM broadcast radios (except for car radios) take advantage of this principle by including a small loop antenna for reception which has an extremely poor efficiency. Using such an inefficient antenna at this low frequency (530–1650 kHz) thus has little effect on the receiver's net performance, but simply requires greater amplification by the receiver's electronics. Contrast this tiny component to the massive and very tall towers used at AM broadcast stations for transmitting at the very same frequency, where every percentage point of reduced antenna efficiency entails a substantial cost.

Small and minimal frequency antennas are know to be what?

inefficient

What is added to to increase ability for reception?

small loop antenna

How would this antenna rate in the greater scheme of things?

little effect

When talking about much larger network what effect can reduced antenna effectiveness have?

substantial cost


The polarization of an antenna refers to the orientation of the electric field (E-plane) of the radio wave with respect to the Earth's surface and is determined by the physical structure of the antenna and by its orientation; note that this designation is totally distinct from the antenna's directionality. Thus, a simple straight wire antenna will have one polarization when mounted vertically, and a different polarization when mounted horizontally. As a transverse wave, the magnetic field of a radio wave is at right angles to that of the electric field, but by convention, talk of an antenna's "polarization" is understood to refer to the direction of the electric field.

What is another name for electric-field?

E-plane

How many polarizations will a antenna have when mounted vertically?

one

Whats understood in reference of direction of an E-plane?

polarization

When is a magnetic fields right angles to a electrical field?

transverse wave


Reflections generally affect polarization. For radio waves, one important reflector is the ionosphere which can change the wave's polarization. Thus for signals received following reflection by the ionosphere (a skywave), a consistent polarization cannot be expected. For line-of-sight communications or ground wave propagation, horizontally or vertically polarized transmissions generally remain in about the same polarization state at the receiving location. Matching the receiving antenna's polarization to that of the transmitter can make a very substantial difference in received signal strength.

What mostly affects polarization?

Reflections

What reflector can change the waves polarization?

ionosphere

What will you be matching with the  receiving antenna's polarization?

transmitter

What stays the same regarding polarization state at the recieving location?

polarized transmissions

What is the name used for signals recieved following reflection by the ionosphere?

a skywave


Polarization is predictable from an antenna's geometry, although in some cases it is not at all obvious (such as for the quad antenna). An antenna's linear polarization is generally along the direction (as viewed from the receiving location) of the antenna's currents when such a direction can be defined. For instance, a vertical whip antenna or Wi-Fi antenna vertically oriented will transmit and receive in the vertical polarization. Antennas with horizontal elements, such as most rooftop TV antennas in the United States, are horizontally polarized (broadcast TV in the U.S. usually uses horizontal polarization). Even when the antenna system has a vertical orientation, such as an array of horizontal dipole antennas, the polarization is in the horizontal direction corresponding to the current flow. The polarization of a commercial antenna is an essential specification.

Whats predictable about an antenna's geometry?

Polarization

What is a more complicated type of polarization from an antenna's geometry?

quad antenna

The polarization of what antenna is essential specification?

commercial antenna

Most rooftop antenna's are polarized in which direction?

horizontal


Polarization is the sum of the E-plane orientations over time projected onto an imaginary plane perpendicular to the direction of motion of the radio wave. In the most general case, polarization is elliptical, meaning that the polarization of the radio waves varies over time. Two special cases are linear polarization (the ellipse collapses into a line) as we have discussed above, and circular polarization (in which the two axes of the ellipse are equal). In linear polarization the electric field of the radio wave oscillates back and forth along one direction; this can be affected by the mounting of the antenna but usually the desired direction is either horizontal or vertical polarization. In circular polarization, the electric field (and magnetic field) of the radio wave rotates at the radio frequency circularly around the axis of propagation. Circular or elliptically polarized radio waves are designated as right-handed or left-handed using the "thumb in the direction of the propagation" rule. Note that for circular polarization, optical researchers use the opposite right hand rule from the one used by radio engineers.

What are electrical fields projected on to?

imaginary plane

What is the imagenary plane perpindicular to?

radio wave

What is the name to describe polarization of radio waves varies over times?

elliptical

How many directions does the E-plane of the radio waves oscillates back and forth?

one direction


It is best for the receiving antenna to match the polarization of the transmitted wave for optimum reception. Intermediate matchings will lose some signal strength, but not as much as a complete mismatch. A circularly polarized antenna can be used to equally well match vertical or horizontal linear polarizations. Transmission from a circularly polarized antenna received by a linearly polarized antenna (or vice versa) entails a 3 dB reduction in signal-to-noise ratio as the received power has thereby been cut in half.

What is the best for an recieving antenna for optimum reception?

match the polarization

What loses signal strength?

Intermediate matchings

What is used to match vertical and horizontal linear polarizations?

circularly polarized

A transmission can cause reduction in what?

signal-to-noise ratio


Maximum power transfer requires matching the impedance of an antenna system (as seen looking into the transmission line) to the complex conjugate of the impedance of the receiver or transmitter. In the case of a transmitter, however, the desired matching impedance might not correspond to the dynamic output impedance of the transmitter as analyzed as a source impedance but rather the design value (typically 50 ohms) required for efficient and safe operation of the transmitting circuitry. The intended impedance is normally resistive but a transmitter (and some receivers) may have additional adjustments to cancel a certain amount of reactance in order to "tweak" the match. When a transmission line is used in between the antenna and the transmitter (or receiver) one generally would like an antenna system whose impedance is resistive and near the characteristic impedance of that transmission line in order to minimize the standing wave ratio (SWR) and the increase in transmission line losses it entails, in addition to supplying a good match at the transmitter or receiver itself.

What requires matching of the empedance to an antenna system?

Maximum power transfer

What is the desired design value for transmmiting circuitry?

50 ohms

Why would a transmitter have additional adjustments?

"tweak" the match

What is SWR?

standing wave ratio


In some cases this is done in a more extreme manner, not simply to cancel a small amount of residual reactance, but to resonate an antenna whose resonance frequency is quite different from the intended frequency of operation. For instance, a "whip antenna" can be made significantly shorter than 1/4 wavelength long, for practical reasons, and then resonated using a so-called loading coil. This physically large inductor at the base of the antenna has an inductive reactance which is the opposite of the capacitative reactance that such a vertical antenna has at the desired operating frequency. The result is a pure resistance seen at feedpoint of the loading coil; unfortunately that resistance is somewhat lower than would be desired to match commercial coax.[citation needed]

What can be shorter than 1/4 wavelength long?

whip antenna

What is the opposite of inductive reactance?

capacitative reactance

What is at the base of the antenna?

loading coil

Where is the resistance seen on the loading foil?

feedpoint


So an additional problem beyond canceling the unwanted reactance is of matching the remaining resistive impedance to the characteristic impedance of the transmission line. In principle this can always be done with a transformer, however the turns ratio of a transformer is not adjustable. A general matching network with at least two adjustments can be made to correct both components of impedance. Matching networks using discrete inductors and capacitors will have losses associated with those components, and will have power restrictions when used for transmitting. Avoiding these difficulties, commercial antennas are generally designed with fixed matching elements or feeding strategies to get an approximate match to standard coax, such as 50 or 75 Ohms. Antennas based on the dipole (rather than vertical antennas) should include a balun in between the transmission line and antenna element, which may be integrated into any such matching network.

What is not adjustable when it comes to a transformer?

turns ratio

A general matching network needs a minimum of how many adjustments to correct all components of impedance?

two adjustments

How many ohms are in are in a standard coax?

50 or 75

What is included between the transmission line and the antenna element?

balun

A balun should be integrated into what?

matching network


Unlike the above antennas, traveling wave antennas are nonresonant so they have inherently broad bandwidth. They are typically wire antennas multiple wavelengths long, through which the voltage and current waves travel in one direction, instead of bouncing back and forth to form standing waves as in resonant antennas. They have linear polarization (except for the helical antenna). Unidirectional traveling wave antennas are terminated by a resistor at one end equal to the antenna's characteristic resistance, to absorb the waves from one direction. This makes them inefficient as transmitting antennas.

What antenna's are nonresonant?

traveling wave antennas

How long are the wire antenna's that the voltage and current waves travel in the same direction?

one direction

What antenna does not have linear polarization?

helical antenna

What are undirectional traveling wave directions terminated by?

resistor

What is the resistor equal to?

antenna's characteristic resistance


The radiation pattern and even the driving point impedance of an antenna can be influenced by the dielectric constant and especially conductivity of nearby objects. For a terrestrial antenna, the ground is usually one such object of importance. The antenna's height above the ground, as well as the electrical properties (permittivity and conductivity) of the ground, can then be important. Also, in the particular case of a monopole antenna, the ground (or an artificial ground plane) serves as the return connection for the antenna current thus having an additional effect, particularly on the impedance seen by the feed line.

What is the radiation patter influenced by?

dielectric constant

The ground is important for what antenna?

terrestrial antenna

Whats another name for the ground?

artificial ground plane

What does the artificial ground plane do for the antenna current?

return connection


The net quality of a ground reflection depends on the topography of the surface. When the irregularities of the surface are much smaller than the wavelength, we are in the regime of specular reflection, and the receiver sees both the real antenna and an image of the antenna under the ground due to reflection. But if the ground has irregularities not small compared to the wavelength, reflections will not be coherent but shifted by random phases. With shorter wavelengths (higher frequencies), this is generally the case.

What is the net quality of the ground dependent of?

topography

What is the reason for the receiver seeing both the ral antenna and image of the antenna?

reflection

What frequencies is associated with shorter wavelengths?

higher frequencies

When will reflections not be coherent?

ground has irregularities


The phase of reflection of electromagnetic waves depends on the polarization of the incident wave. Given the larger refractive index of the ground (typically n=2) compared to air (n=1), the phase of horizontally polarized radiation is reversed upon reflection (a phase shift of  radians or 180°). On the other hand, the vertical component of the wave's electric field is reflected at grazing angles of incidence approximately in phase. These phase shifts apply as well to a ground modelled as a good electrical conductor.

What is the refractive index of the ground?

What is the refractive index of air?

When is polarized radiation reversed?

reflection

Besides a ground, what has these phases apply well to?

electrical conductor


When an electromagnetic wave strikes a plane surface such as the ground, part of the wave is transmitted into the ground and part of it is reflected, according to the Fresnel coefficients. If the ground is a very good conductor then almost all of the wave is reflected (180° out of phase), whereas a ground modeled as a (lossy) dielectric can absorb a large amount of the wave's power. The power remaining in the reflected wave, and the phase shift upon reflection, strongly depend on the wave's angle of incidence and polarization. The dielectric constant and conductivity (or simply the complex dielectric constant) is dependent on the soil type and is a function of frequency.

what is reflected and transmitted into the ground when a plane surface is struck?

electromagnetic wave

Who proposed this theory?

Fresnel coefficients

Is the ground has a great conductor, how much of the wave will be reflected?

180° out of phase

What depends on the polarization and waves angle?

power remaining


The effective area or effective aperture of a receiving antenna expresses the portion of the power of a passing electromagnetic wave which it delivers to its terminals, expressed in terms of an equivalent area. For instance, if a radio wave passing a given location has a flux of 1 pW / m2 (10−12 watts per square meter) and an antenna has an effective area of 12 m2, then the antenna would deliver 12 pW of RF power to the receiver (30 microvolts rms at 75 ohms). Since the receiving antenna is not equally sensitive to signals received from all directions, the effective area is a function of the direction to the source.

What is the portion of something that is reached by the radio transmission called?

aperture

What is a measure of the power of an antenna?

microvolts

What effects the function of signals received by an antenna?

direction

How much power will be delivered to the reciever if the antenna has an effective area of 12 m/2?

12 pW of RF power


The bandwidth characteristics of a resonant antenna element can be characterized according to its Q, just as one uses to characterize the sharpness of an L-C resonant circuit. However it is often assumed that there is an advantage in an antenna having a high Q. After all, Q is short for "quality factor" and a low Q typically signifies excessive loss (due to unwanted resistance) in a resonant L-C circuit. However this understanding does not apply to resonant antennas where the resistance involved is the radiation resistance, a desired quantity which removes energy from the resonant element in order to radiate it (the purpose of an antenna, after all!). The Q is a measure of the ratio of reactance to resistance, so with a fixed radiation resistance (an element's radiation resistance is almost independent of its diameter) a greater reactance off-resonance corresponds to the poorer bandwidth of a very thin conductor. The Q of such a narrowband antenna can be as high as 15. On the other hand, a thick element presents less reactance at an off-resonant frequency, and consequently a Q as low as 5. These two antennas will perform equivalently at the resonant frequency, but the second antenna will perform over a bandwidth 3 times as wide as the "hi-Q" antenna consisting of a thin conductor.

The properties of a usable radio frequency can be called its?

Q

What is a measure of the comparison between reactance and resistance?

Q

What is the largest Q that could be achieved with a slimmer band antenna?

What type of element would be used to encounter less reactance?

thick


For example, at 30 MHz (10 m wavelength) a true resonant 1⁄4-wavelength monopole would be almost 2.5 meters long, and using an antenna only 1.5 meters tall would require the addition of a loading coil. Then it may be said that the coil has lengthened the antenna to achieve an electrical length of 2.5 meters. However, the resulting resistive impedance achieved will be quite a bit lower than the impedance of a resonant monopole, likely requiring further impedance matching. In addition to a lower radiation resistance, the reactance becomes higher as the antenna size is reduced, and the resonant circuit formed by the antenna and the tuning coil has a Q factor that rises and eventually causes the bandwidth of the antenna to be inadequate for the signal being transmitted. This is the major factor that sets the size of antennas at 1 MHz and lower frequencies.

What can be added to allow for an antenna shorter than the needed height to produce desired results?

loading coil

How would the resistive impedance from this scenario compare to if the antenna was the proper height?

lower

The coil has lengthed the antenna to reach how much length electrically?

2.5 meters

What is the major thing that sets the size of antennas at lower frequencies?

reactance


Consider a half-wave dipole designed to work with signals 1 m wavelength, meaning the antenna would be approximately 50 cm across. If the element has a length-to-diameter ratio of 1000, it will have an inherent resistance of about 63 ohms. Using the appropriate transmission wire or balun, we match that resistance to ensure minimum signal loss. Feeding that antenna with a current of 1 ampere will require 63 volts of RF, and the antenna will radiate 63 watts (ignoring losses) of radio frequency power. Now consider the case when the antenna is fed a signal with a wavelength of 1.25 m; in this case the reflected current would arrive at the feed out-of-phase with the signal, causing the net current to drop while the voltage remains the same. Electrically this appears to be a very high impedance. The antenna and transmission line no longer have the same impedance, and the signal will be reflected back into the antenna, reducing output. This could be addressed by changing the matching system between the antenna and transmission line, but that solution only works well at the new design frequency.

How big would an antenna be used to with with one m wavelengths?

50 cm

How could the rection of output be adressed by?

changing the matching system

What unit is used to measure current?

ampere

What effect occurs when the signal is reflected back into the antenna?

reducing output


Recall that a current will reflect when there are changes in the electrical properties of the material. In order to efficiently send the signal into the transmission line, it is important that the transmission line has the same impedance as the elements, otherwise some of the signal will be reflected back into the antenna. This leads to the concept of impedance matching, the design of the overall system of antenna and transmission line so the impedance is as close as possible, thereby reducing these losses. Impedance matching between antennas and transmission lines is commonly handled through the use of a balun, although other solutions are also used in certain roles. An important measure of this basic concept is the standing wave ratio, which measures the magnitude of the reflected signal.

What sort of changes in material would a current reflect?

electrical

What must match between the transmission line and elements?

impedance

What technique is used to prevent unintentional decrease in signal?

Impedance matching

How is this process usually used for transmission lines and antennas?

balun


An electromagnetic wave refractor in some aperture antennas is a component which due to its shape and position functions to selectively delay or advance portions of the electromagnetic wavefront passing through it. The refractor alters the spatial characteristics of the wave on one side relative to the other side. It can, for instance, bring the wave to a focus or alter the wave front in other ways, generally in order to maximize the directivity of the antenna system. This is the radio equivalent of an optical lens.

What is used to allow one to control the function of wave fronts moving through an antenna?

selectively delay

What changes the structuak traits of a wave on either side?

refractor

What is the main purpose of a refractor?

spatial characteristics

A refractor can be compared to what type of viewing?

optical lens


The actual antenna which is transmitting the original wave then also may receive a strong signal from its own image from the ground. This will induce an additional current in the antenna element, changing the current at the feedpoint for a given feedpoint voltage. Thus the antenna's impedance, given by the ratio of feedpoint voltage to current, is altered due to the antenna's proximity to the ground. This can be quite a significant effect when the antenna is within a wavelength or two of the ground. But as the antenna height is increased, the reduced power of the reflected wave (due to the inverse square law) allows the antenna to approach its asymptotic feedpoint impedance given by theory. At lower heights, the effect on the antenna's impedance is very sensitive to the exact distance from the ground, as this affects the phase of the reflected wave relative to the currents in the antenna. Changing the antenna's height by a quarter wavelength, then changes the phase of the reflection by 180°, with a completely different effect on the antenna's impedance.

What can receive a stron signal by transmitting an original wave?

actual antenna

Where will the additional current be induced?

antenna element

What is altered because of the proximity to the ground?

antenna's impedance

what happens to the reflected wave which allows the antenna to reach its asympotic feedpoint impedance?

reduced power


For horizontal propagation between transmitting and receiving antennas situated near the ground reasonably far from each other, the distances traveled by tne direct and reflected rays are nearly the same. There is almost no relative phase shift. If the emission is polarized vertically, the two fields (direct and reflected) add and there is maximum of received signal. If the signal is polarized horizontally, the two signals subtract and the received signal is largely cancelled. The vertical plane radiation patterns are shown in the image at right. With vertical polarization there is always a maximum for θ=0, horizontal propagation (left pattern). For horizontal polarization, there is cancellation at that angle. Note that the above formulae and these plots assume the ground as a perfect conductor. These plots of the radiation pattern correspond to a distance between the antenna and its image of 2.5λ. As the antenna height is increased, the number of lobes increases as well.

What is between recieving and transmitting antenna's?

horizontal propagation

When is the emission at maximized recieved signal?

polarized vertically

Where is the radiation patterns in the vertical plane shown?

image at right

What is also increased along with the antenna's height?

lobes


On the other hand, classical (analog) television transmissions are usually horizontally polarized, because in urban areas buildings can reflect the electromagnetic waves and create ghost images due to multipath propagation. Using horizontal polarization, ghosting is reduced because the amount of reflection of electromagnetic waves in the p polarization (horizontal polarization off the side of a building) is generally less than s (vertical, in this case) polarization. Vertically polarized analog television has nevertheless been used in some rural areas. In digital terrestrial television such reflections are less problematic, due to robustness of binary transmissions and error correction.

What is another name for classical television transmissions?

analog

Buildings can create ghost images because of what?

multipath propagation

When is ghosting reduced?

horizontal polarization

What cause less problems in digital terrestrial television?

Vertically polarized analog television


Current circulating in one antenna generally induces a voltage across the feedpoint of nearby antennas or antenna elements. The mathematics presented below are useful in analyzing the electrical behaviour of antenna arrays, where the properties of the individual array elements (such as half wave dipoles) are already known. If those elements were widely separated and driven in a certain amplitude and phase, then each would act independently as that element is known to. However, because of the mutual interaction between their electric and magnetic fields due to proximity, the currents in each element are not simply a function of the applied voltage (according to its driving point impedance), but depend on the currents in the other nearby elements. Note that this now is a near field phenomenon which could not be properly accounted for using the Friis transmission equation for instance.

Where are the indiviual array elements known?

antenna arrays

What induces a feedpoint to antennas nearby?

Current circulating

What are the mathmatic useful towards?

electrical behaviour

What cause mutual interactions between the elements electric and magnetic fields?

proximity


This is a consequence of Lorentz reciprocity. For an antenna element  not connected to anything (open circuited) one can write . But for an element  which is short circuited, a current is generated across that short but no voltage is allowed, so the corresponding . This is the case, for instance, with the so-called parasitic elements of a Yagi-Uda antenna where the solid rod can be viewed as a dipole antenna shorted across its feedpoint. Parasitic elements are unpowered elements that absorb and reradiate RF energy according to the induced current calculated using such a system of equations.

a antenna element not connected to anything is circuited how?

open circuited

When is the element not allowed voltage?

short circuited

What element absorbs and reradiate RF-energy?

Parasitic

What antenna can the solid rod be viewed as a dipole antenna?

Yagi-Uda

Where can this solid rod be viewed?

feedpoint


The difference in the above factors for the case of θ=0 is the reason that most broadcasting (transmissions intended for the public) uses vertical polarization. For receivers near the ground, horizontally polarized transmissions suffer cancellation. For best reception the receiving antennas for these signals are likewise vertically polarized. In some applications where the receiving antenna must work in any position, as in mobile phones, the base station antennas use mixed polarization, such as linear polarization at an angle (with both vertical and horizontal components) or circular polarization.

What type of programmin relies on vertical polarization?

broadcasting

If you were to position your receiver closer to the ground what might be a negative of this placement?

cancellation

What is one use that would require an antenna to receive signals in various ways at once?

mobile phones

If you were to develop a signal to be used with mobile phones what would be an effective antenna type?

circular polarization.

What would the antenna you are using take advantage of to allow it to work in multiple locations?

mixed polarization


Loop antennas consist of a loop or coil of wire. Loops with circumference of a wavelength or larger act similarly to dipole antennas. However loops small in comparison to a wavelength act differently. They interact with the magnetic field of the radio wave instead of the electric field as other antennas do, and so are relatively insensitive to nearby electrical noise. However they have low radiation resistance, and so are inefficient for transmitting. They are used as receiving antennas at low frequencies, and also as direction finding antennas.

What type of antenna can be formed by a circular segment of wire?

Loop antennas

What is a loop antenna compared with to determine its beahvior?

circumference of a wavelength

If you needed to place an antenna somewhere with a large amount of interference, which type would be best?

loops small

Why would this type be good for receiving but not transmtting?

low radiation resistance

What else would be an effective application of this antenna type?

direction finding


It is a fundamental property of antennas that the electrical characteristics of an antenna described in the next section, such as gain, radiation pattern, impedance, bandwidth, resonant frequency and polarization, are the same whether the antenna is transmitting or receiving. For example, the "receiving pattern" (sensitivity as a function of direction) of an antenna when used for reception is identical to the radiation pattern of the antenna when it is driven and functions as a radiator. This is a consequence of the reciprocity theorem of electromagnetics. Therefore, in discussions of antenna properties no distinction is usually made between receiving and transmitting terminology, and the antenna can be viewed as either transmitting or receiving, whichever is more convenient.

Are essential properties of an antenna changed based on what fungtion they are performing

the same

What proposition explains the equivalency of the recieving pattern of an antenna?

reciprocity theorem of electromagnetics

Can the antenna serve more than one fungtion at a time?

either transmitting or receiving

What is one electrical trait of an antenna?

radiation pattern


The flowering plants (angiosperms), also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with about 350,000 species. Like gymnosperms, angiosperms are seed-producing plants; they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, and the production of fruits that contain the seeds. Etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term "angiosperm" comes from the Greek composite word (angeion-, "case" or "casing", and sperma, "seed") meaning "enclosed seeds", after the enclosed condition of the seeds.

What are the most diverse group of land plants?

angiosperms

How many species of flowering plants are there about?

What do angiosperms have in common with gymnosperms?

seed-producing plants

What does an angiosperm produce its seeds within?

an enclosure

What is the Greek word for "case" or "casing"?

angeion

Where does the term gymnosperm originate?

I'm not sure.

What are gymnosperms known as?

I'm not sure.

What do angeion have in common with angiosperms?

I'm not sure.

How is production of fruits distinguished from a fruiting plant?

I'm not sure.

What does gymnosperm mean etymologically?

I'm not sure.


Fossilized spores suggest that higher plants (embryophytes) have lived on land for at least 475 million years. Early land plants reproduced sexually with flagellated, swimming sperm, like the green algae from which they evolved. An adaptation to terrestrialization was the development of upright meiosporangia for dispersal by spores to new habitats. This feature is lacking in the descendants of their nearest algal relatives, the Charophycean green algae. A later terrestrial adaptation took place with retention of the delicate, avascular sexual stage, the gametophyte, within the tissues of the vascular sporophyte. This occurred by spore germination within sporangia rather than spore release, as in non-seed plants. A current example of how this might have happened can be seen in the precocious spore germination in Selaginella, the spike-moss. The result for the ancestors of angiosperms was enclosing them in a case, the seed. The first seed bearing plants, like the ginkgo, and conifers (such as pines and firs), did not produce flowers. The pollen grains (males) of Ginkgo and cycads produce a pair of flagellated, mobile sperm cells that "swim" down the developing pollen tube to the female and her eggs.

How long have higher plants lived on land?

at least 475 million years

How did early plants reproduce sexually?

with flagellated, swimming sperm

Upright meisporangia allowed what to be dispersed to new habitats?

spores

What are the nearest algal relatives existing today?

Charophycean green algae

What is the common name for Selaginella?

the spike-moss

What do the first green algae not produce?

I'm not sure.

What does the pollen of spike-moss produce for reproduction?

I'm not sure.

What does the pollen of spike-moss do to reach the female?

I'm not sure.

What suggests that confiers have lived on land for 475 million years?

I'm not sure.

What did Charophycean green algae develop to disperse by spores into new habitats?

I'm not sure.


The apparently sudden appearance of nearly modern flowers in the fossil record initially posed such a problem for the theory of evolution that it was called an "abominable mystery" by Charles Darwin. However, the fossil record has considerably grown since the time of Darwin, and recently discovered angiosperm fossils such as Archaefructus, along with further discoveries of fossil gymnosperms, suggest how angiosperm characteristics may have been acquired in a series of steps. Several groups of extinct gymnosperms, in particular seed ferns, have been proposed as the ancestors of flowering plants, but there is no continuous fossil evidence showing exactly how flowers evolved. Some older fossils, such as the upper Triassic Sanmiguelia, have been suggested. Based on current evidence, some propose that the ancestors of the angiosperms diverged from an unknown group of gymnosperms in the Triassic period (245–202 million years ago). Fossil angiosperm-like pollen from the Middle Triassic (247.2–242.0 Ma) suggests an older date for their origin. A close relationship between angiosperms and gnetophytes, proposed on the basis of morphological evidence, has more recently been disputed on the basis of molecular evidence that suggest gnetophytes are instead more closely related to other gymnosperms.[citation needed]

What did Charles Darwin call the sudden appearance of nearly modern flowers in the fossil record?

abominable mystery

What type of fossil is the recently discovered Archaefructus?

angiosperm

What fossil evidence is lacking when it comes to flowers?

evidence showing exactly how flowers evolved

From what period does fossilized pollen suggest an older date for angiosperm origin?

Middle Triassic

What relationship proposed on the basis of morphological evidence has recently been disputed?

relationship between angiosperms and gnetophytes

What was ancestors of angiosperms suddenly appearing called by Charles Darwin?

I'm not sure.

What have several groups of Archaefructus been proposed to be?

I'm not sure.

What is missing to show how ancestors of angiosperms diverged from an unknown group?

I'm not sure.

Why has the relationship between gnetophytes and gymnosperms been disputed?

I'm not sure.

What type of fossil is the recently discovered Sanmiguelia?

I'm not sure.


The evolution of seed plants and later angiosperms appears to be the result of two distinct rounds of whole genome duplication events. These occurred at 319 million years ago and 192 million years ago. Another possible whole genome duplication event at 160 million years ago perhaps created the ancestral line that led to all modern flowering plants. That event was studied by sequencing the genome of an ancient flowering plant, Amborella trichopoda, and directly addresses Darwin's "abominable mystery."

How many distinct rounds of genome duplication events are suspected in the evolution of seed plants?

two

When did the first whole genome duplication event occur?

319 million years ago

What type of event perhaps created the line which led to modern flowering plants?

whole genome duplication

How are duplication events studied?

by sequencing the genome of an ancient flowering plant

Who coined the term "abominable mystery"?

Darwin

What appears to be the cause of duplicaton of seed plants?

I'm not sure.

When did Darwin's "abominable mystery first appear?

I'm not sure.

When was the ancient plant used in the study dated to?

I'm not sure.

How are modern plants studied?

I'm not sure.

Who coined the term duplication event?

I'm not sure.


The earliest known macrofossil confidently identified as an angiosperm, Archaefructus liaoningensis, is dated to about 125 million years BP (the Cretaceous period), whereas pollen considered to be of angiosperm origin takes the fossil record back to about 130 million years BP. However, one study has suggested that the early-middle Jurassic plant Schmeissneria, traditionally considered a type of ginkgo, may be the earliest known angiosperm, or at least a close relative. In addition, circumstantial chemical evidence has been found for the existence of angiosperms as early as 250 million years ago. Oleanane, a secondary metabolite produced by many flowering plants, has been found in Permian deposits of that age together with fossils of gigantopterids. Gigantopterids are a group of extinct seed plants that share many morphological traits with flowering plants, although they are not known to have been flowering plants themselves.

When is the earliest known macrofossil identified as an angiosperm dated?

about 125 million years BP

What is the earliest known angiosperm?

Archaefructus liaoningensis

What pushes the age of angiosperm 5 million years further back?

pollen

How long ago has circumstantial evidence has been found for the existence of angiosperms?

250 million years ago

What group of now extinct seed plants had many of the traits of what are now flowering plants?

Gigantopterids

What is Oleanne, the earliest macrofossil, traditionally considered to be?

I'm not sure.

What evidence has shown that flowering plants existed 125 million years BP?

I'm not sure.

What has been found in ginko deposits of that age with gigantopterid fossils?

I'm not sure.

What do Oleanne share morphological traits with?

I'm not sure.

What are not known to have Permian deposits themselves?

I'm not sure.


The great angiosperm radiation, when a great diversity of angiosperms appears in the fossil record, occurred in the mid-Cretaceous (approximately 100 million years ago). However, a study in 2007 estimated that the division of the five most recent (the genus Ceratophyllum, the family Chloranthaceae, the eudicots, the magnoliids, and the monocots) of the eight main groups occurred around 140 million years ago. By the late Cretaceous, angiosperms appear to have dominated environments formerly occupied by ferns and cycadophytes, but large canopy-forming trees replaced conifers as the dominant trees only close to the end of the Cretaceous 66 million years ago or even later, at the beginning of the Tertiary. The radiation of herbaceous angiosperms occurred much later. Yet, many fossil plants recognizable as belonging to modern families (including beech, oak, maple, and magnolia) had already appeared by the late Cretaceous.

When does a great diversity of angiosperms appear in the fossil record?

approximately 100 million years ago

What is the appearance of a large amount of angiosperms in the fossil record known as?

great angiosperm radiation,

When did the division of the eight main groups of angiosperms occur?

40 million years ago

What were the angiosperms up to by the late Cretaceous?

dominated environments

Beech and maple had already appeared by what period?

Cretaceous

When does a diversity of magnoliids appear in the fossil record?

I'm not sure.

What is the appearance of ferns in the fossil record called?

I'm not sure.

By the end of the Tertiary, what did angiosperms dominate?

I'm not sure.

When did eudicots replace conifers as dominant trees?

I'm not sure.

When had eight main groups of Chloranthaceae recognizable as belonging to modern families appear?

I'm not sure.


Island genetics provides one proposed explanation for the sudden, fully developed appearance of flowering plants. Island genetics is believed to be a common source of speciation in general, especially when it comes to radical adaptations that seem to have required inferior transitional forms. Flowering plants may have evolved in an isolated setting like an island or island chain, where the plants bearing them were able to develop a highly specialized relationship with some specific animal (a wasp, for example). Such a relationship, with a hypothetical wasp carrying pollen from one plant to another much the way fig wasps do today, could result in the development of a high degree of specialization in both the plant(s) and their partners. Note that the wasp example is not incidental; bees, which, it is postulated, evolved specifically due to mutualistic plant relationships, are descended from wasps.

What is one proposed explanation for the instant appearance of flowering plants?

Island genetics

What is island genetics thought to be a default source of?

speciation

What did radical adaptations seem to have required?

inferior transitional forms

How did an isolated setting like an island help flowering plants evolve?

highly specialized relationship with some specific animal

What are bees descended from?

wasps

What are transitional forms descended from?

I'm not sure.

What is an explanation for the sudden appearance of fig wasps?

I'm not sure.

What does a relationship between bees and wasps result in?

I'm not sure.

What is carrying pollen thought to be a common source of?

I'm not sure.

How did flowering plants help transitional forms evolve?

I'm not sure.


Animals are also involved in the distribution of seeds. Fruit, which is formed by the enlargement of flower parts, is frequently a seed-dispersal tool that attracts animals to eat or otherwise disturb it, incidentally scattering the seeds it contains (see frugivory). Although many such mutualistic relationships remain too fragile to survive competition and to spread widely, flowering proved to be an unusually effective means of reproduction, spreading (whatever its origin) to become the dominant form of land plant life.

What are animals also a part of?

distribution of seeds

What did the enlargement of flower parts evolve to form?

Fruit

What does a plant get out of forming fruit?

seed-dispersal

What are many mutualistic relationships, thus failing to survive competition?

fragile

What turned out to be unusually effective for plants to reproduce?

flowering

What did competition prove to be effective at doing?

I'm not sure.

What did mutualistic relationships spread to eventually become?

I'm not sure.

How does a plant benefit from competition?

I'm not sure.

What reproductive method spread widely but made plants fragile?

I'm not sure.

What did accidentally scattering seeds help flower parts evolve to form?

I'm not sure.


Flower ontogeny uses a combination of genes normally responsible for forming new shoots. The most primitive flowers probably had a variable number of flower parts, often separate from (but in contact with) each other. The flowers tended to grow in a spiral pattern, to be bisexual (in plants, this means both male and female parts on the same flower), and to be dominated by the ovary (female part). As flowers evolved, some variations developed parts fused together, with a much more specific number and design, and with either specific sexes per flower or plant or at least "ovary-inferior".

What uses a combination of genes to form new shoots?

Flower ontogeny

What were plant parts like in their primitive days?

separate from (but in contact with) each other

How did flowers become bixsexual?

grow in a spiral pattern

What did some plant parts do as they evolved?

fused together

What is a term for a plant with a specific sex per flower?

"ovary-inferior"

What was dominated by the male parts?

I'm not sure.

How did flowers tend to grow when they were male dominant?

I'm not sure.

What did some plant parts do when the flower had only male parts?

I'm not sure.

During flower ontogeny, what was a plant of a specific sex called?

I'm not sure.

What do ovary inferior plants use to form new shoots?

I'm not sure.


Flower evolution continues to the present day; modern flowers have been so profoundly influenced by humans that some of them cannot be pollinated in nature. Many modern domesticated flower species were formerly simple weeds, which sprouted only when the ground was disturbed. Some of them tended to grow with human crops, perhaps already having symbiotic companion plant relationships with them, and the prettiest did not get plucked because of their beauty, developing a dependence upon and special adaptation to human affection.

How long has flower evolution occurred?

present day

Humans have effected some flowers so much they can no longer do what in nature?

pollinated

What heritage do many modern domesticated flower species have?

formerly simple weeds

Why did weeds grow with human crops?

symbiotic companion plant relationships

What feature helped flowers not get plucked?

prettiest

What has happened to weeds due to human influence?

I'm not sure.

How long has weed evolution occurred?

I'm not sure.

What was the origin of many simple weeds?

I'm not sure.

What have weeds developed a dependence on?

I'm not sure.

What characteristic caused crops not to be harvested?

I'm not sure.


The exact relationship between these eight groups is not yet clear, although there is agreement that the first three groups to diverge from the ancestral angiosperm were Amborellales, Nymphaeales, and Austrobaileyales. The term basal angiosperms refers to these three groups. Among the rest, the relationship between the three broadest of these groups (magnoliids, monocots, and eudicots) remains unclear. Some analyses make the magnoliids the first to diverge, others the monocots. Ceratophyllum seems to group with the eudicots rather than with the monocots.

What three groups were the first to diverge from angiosperm?

Amborellales, Nymphaeales, and Austrobaileyales

What term refers to the first three groups to diverge from angiosperm?

basal

How clear is the relationship between the broadest of the three non-basal angiosperm groups?

unclear

What group do some analyses seem to indicate diverged first?

magnoliids

What were the first three groups to diverge from magnoliids?

I'm not sure.

What do Amborellales tend to group with instead of monocots?

I'm not sure.

What is the status of the relationship between Nymphaeales and monocots?

I'm not sure.

What attitude is there about the first magnoliids diverging from the ancestral angiosperm?

I'm not sure.

What do some eudicots indicate diverged first?

I'm not sure.


The botanical term "Angiosperm", from the Ancient Greek αγγείον, angeíon (bottle, vessel) and σπέρμα, (seed), was coined in the form Angiospermae by Paul Hermann in 1690, as the name of one of his primary divisions of the plant kingdom. This included flowering plants possessing seeds enclosed in capsules, distinguished from his Gymnospermae, or flowering plants with achenial or schizo-carpic fruits, the whole fruit or each of its pieces being here regarded as a seed and naked. The term and its antonym were maintained by Carl Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any approach to its modern scope became possible only after 1827, when Robert Brown established the existence of truly naked ovules in the Cycadeae and Coniferae, and applied to them the name Gymnosperms.[citation needed] From that time onward, as long as these Gymnosperms were, as was usual, reckoned as dicotyledonous flowering plants, the term Angiosperm was used antithetically by botanical writers, with varying scope, as a group-name for other dicotyledonous plants.

What term did Paul Hermann come up with in 1690?

Angiosperm

What did Hermann use the term angiosperm a primary division of in the plant kingdom?

primary

Who restricted the application of the angiosperm term?

Carl Linnaeus

What did Robert Brown establish the existence of in Cycadeae and Coniferae?

naked ovules

What is the group-name angiosperm has been used for by botanical writers?

other dicotyledonous plants

Who coined the term dicotyledonous?

I'm not sure.

In what year was the term dicotyledonous created?

I'm not sure.

Why did Robert Brown use the term dicotyledonous?

I'm not sure.

How was the term angeion maintained by Robert Brown?

I'm not sure.

In 1690 what happened to the term angeion as used by Robert Brown?

I'm not sure.


In most taxonomies, the flowering plants are treated as a coherent group. The most popular descriptive name has been Angiospermae (Angiosperms), with Anthophyta ("flowering plants") a second choice. These names are not linked to any rank. The Wettstein system and the Engler system use the name Angiospermae, at the assigned rank of subdivision. The Reveal system treated flowering plants as subdivision Magnoliophytina (Frohne & U. Jensen ex Reveal, Phytologia 79: 70 1996), but later split it to Magnoliopsida, Liliopsida, and Rosopsida. The Takhtajan system and Cronquist system treat this group at the rank of division, leading to the name Magnoliophyta (from the family name Magnoliaceae). The Dahlgren system and Thorne system (1992) treat this group at the rank of class, leading to the name Magnoliopsida. The APG system of 1998, and the later 2003 and 2009 revisions, treat the flowering plants as a clade called angiosperms without a formal botanical name. However, a formal classification was published alongside the 2009 revision in which the flowering plants form the Subclass Magnoliidae.

In taxonomies, what type of group are flowering plants treated?

coherent

What does anthophyta mean?

flowering plants

What do the Wettstein and Engler systems use at the assigned rank of subdivision?

Angiospermae

How does the APG system of 1998, with its 2003 and 2009 revisions, treat flowering plants?

a clade called angiosperms

What formal subclass classification were flowering plants given in 2009?

Magnoliidae

What are coherent groups not linked to?

I'm not sure.

What do Anthophyta and Magnoliophytina use as the assigned rank of subdivision?

I'm not sure.

How does the APG system of 1996 treat flowering plants?

I'm not sure.

What taxonomy was published alongside the 2003 revision?

I'm not sure.

What does Magnoliophytina mean?

I'm not sure.


The internal classification of this group has undergone considerable revision. The Cronquist system, proposed by Arthur Cronquist in 1968 and published in its full form in 1981, is still widely used but is no longer believed to accurately reflect phylogeny. A consensus about how the flowering plants should be arranged has recently begun to emerge through the work of the Angiosperm Phylogeny Group (APG), which published an influential reclassification of the angiosperms in 1998. Updates incorporating more recent research were published as APG II in 2003 and as APG III in 2009.

What internal component has undergone considerable revision?

classification

What system did Arthur Cronquist put forth in 1968, but not publish in full form until 1981?

The Cronquist system

What consensus is the AGP trying to reach?

how the flowering plants should be arranged

Who published an influential reclassification of the angiosperms in 1998?

APG

What classification system was published by APG II in 1968?

I'm not sure.

When was the APG II system published fully?

I'm not sure.

What is no longer believed about the APG system?

I'm not sure.

What consensus has emerged through the work of Arthur Cronquist?

I'm not sure.

What did Arthur Cronquist publish about angiosperms in 1998?

I'm not sure.


Recent studies, as by the APG, show that the monocots form a monophyletic group (clade) but that the dicots do not (they are paraphyletic). Nevertheless, the majority of dicot species do form a monophyletic group, called the eudicots or tricolpates. Of the remaining dicot species, most belong to a third major clade known as the magnoliids, containing about 9,000 species. The rest include a paraphyletic grouping of primitive species known collectively as the basal angiosperms, plus the families Ceratophyllaceae and Chloranthaceae.

What type of groups do monocots form, based on a recent APG studies?

monophyletic

Eudicots or tricolpates are part of a monophyletic group formed by what species?

dicot

What third major clade can many dicot species be found in?

magnoliids

How many species dicot species are magnoliids?

about 9,000

Basal angiosperms are what type of grouping of primitive species?

paraphyletic

How many species of Chloranthaceae are eudicots?

I'm not sure.

What do studies by the monophyletic group show?

I'm not sure.

What do a majority of monocot Ceratophyllaceae species form?

I'm not sure.

What do the remaining monocot species belong to?

I'm not sure.

What is the group known as that remainig monocot species belong to?

I'm not sure.


The number of species of flowering plants is estimated to be in the range of 250,000 to 400,000. This compares to around 12,000 species of moss or 11,000 species of pteridophytes, showing that the flowering plants are much more diverse. The number of families in APG (1998) was 462. In APG II (2003) it is not settled; at maximum it is 457, but within this number there are 55 optional segregates, so that the minimum number of families in this system is 402. In APG III (2009) there are 415 families.

What is the estimated range for the number of flowering plants?

250,000 to 400,000

How many species of moss is there?

What does the large number of flowering plant species indicate is true of them in general?

diverse

What are the minimum number of families in the APG system?

How many families are in AGP III?

How is moss seen more than families in the system?

I'm not sure.

What is true about families more than moss or pteridophytes?

I'm not sure.

How many flowering plants are in APG in 1998?

I'm not sure.

What are the minimum number of species of moss in the APG system?

I'm not sure.

In APG III how many species of flowering plants are there?

I'm not sure.


In the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium. By the formation of a layer of cambium between the bundles (interfascicular cambium), a complete ring is formed, and a regular periodical increase in thickness results from the development of xylem on the inside and phloem on the outside. The soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings.

What shape are the bundles in the young stem of dicotyledons arranged in?

an open ring

What does the cambium separate?

xylem and phloem

What is a layer of meristem or formative tissue known as?

cambium

What results from the development of xylem on the inside and phloem on the outside?

increase in thickness

What's another name for the concentric rings in trees?

annual rings

What is formed  when a layer of dicotyledons is formed between the bundles?

I'm not sure.

What causes a regular increase in young stems?

I'm not sure.

What happens when the annual rings are crushed?

I'm not sure.

How is soft phloem marked for each growth season?

I'm not sure.

How are bundles in young stems arranged in branches?

I'm not sure.


The characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species. The function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf (where the petiole attaches to the stem). Occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. More typically, the flower-bearing portion of the plant is sharply distinguished from the foliage-bearing or vegetative portion, and forms a more or less elaborate branch-system called an inflorescence.

What is the defining feature of angiosperms?

flower

What characteristic flowers show variation in?

form and elaboration

What do flowers provide the best external feature for doing?

establishing relationships among angiosperm species

What is it the function of the flower to ensure fertilization of?

the ovule

What is the name of a branch system?

inflorescence

What is a main feature of vegatative portion of a plant?

I'm not sure.

What does the foliage-bearing part of the plant form to bear flowers?

I'm not sure.

What are some things that an elaborate branch system shows?

I'm not sure.

What does fruit with seeds provide to establish relationships among species?

I'm not sure.

What is the function of the petiole?

I'm not sure.


The flower may consist only of these parts, as in willow, where each flower comprises only a few stamens or two carpels. Usually, other structures are present and serve to protect the sporophylls and to form an envelope attractive to pollinators. The individual members of these surrounding structures are known as sepals and petals (or tepals in flowers such as Magnolia where sepals and petals are not distinguishable from each other). The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially the bud. The inner series (corolla of petals) is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators. Attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower. The characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans.

What is a willow's flower comprised of?

only a few stamens or two carpels

What have some structures evolved to protect?

the sporophylls

Individual members of enveloping structures are known by what terms?

sepals and petals

What appearance are calyx of sepals typically?

green and leaf-like

The features of flowers which attract pollinators also attract what other creature?

humans

What do sporophylls form that is attractive to pollinators?

I'm not sure.

In what flower are stamens and sporophylls not able to be distinguished from each other?

I'm not sure.

What do corolla of petals function to protect?

I'm not sure.

What color is the more delicate willow?

I'm not sure.

What characteristics of the flower attract sporophylls?

I'm not sure.


While the majority of flowers are perfect or hermaphrodite (having both pollen and ovule producing parts in the same flower structure), flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization. Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot easily transfer pollen to the pistil (receptive part of the carpel). Homomorphic flowers may employ a biochemical (physiological) mechanism called self-incompatibility to discriminate between self and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers.

What sexual feature do a majority of flowers demonstrate?

hermaphrodite

Why did flowering plants develop numerous morphological and physiological mechanisms?

reduce or prevent self-fertilization

Why are a heteromorphic flower's carpels and stamens different lengths?

so animal pollinators cannot easily transfer pollen to the pistil

What type of mechanism might homomorphic flowers use to tell the difference between foreign and self pollen grains?

biochemical

How are some male and female parts separated for some species?

different flowers

What feature do a majority of biochemical mechanisms have?

I'm not sure.

What do hermaphrodite flowers use to discriminate between self and non-self pollination?

I'm not sure.

What happens to male and female parts of carpels that are hermaphrodites?

I'm not sure.

Why did long stamens develop numerous morphological and physiological mechanisms?

I'm not sure.

What do homomorphic flowers have to make it harder to be pollinated by animals?

I'm not sure.


Double fertilization refers to a process in which two sperm cells fertilize cells in the ovary. This process begins when a pollen grain adheres to the stigma of the pistil (female reproductive structure), germinates, and grows a long pollen tube. While this pollen tube is growing, a haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid (n) sperm cells. As the pollen tube grows, it makes its way from the stigma, down the style and into the ovary. Here the pollen tube reaches the micropyle of the ovule and digests its way into one of the synergids, releasing its contents (which include the sperm cells). The synergid that the cells were released into degenerates and one sperm makes its way to fertilize the egg cell, producing a diploid (2n) zygote. The second sperm cell fuses with both central cell nuclei, producing a triploid (3n) cell. As the zygote develops into an embryo, the triploid cell develops into the endosperm, which serves as the embryo's food supply. The ovary now will develop into fruit and the ovule will develop into seed.

What process does double fertilization refer to?

two sperm cells fertilize cells in the ovary

What does a pollen grain adhere to, to start the process of double fertilization?

the stigma of the pistil

What type of cell travels down the pollen tube while it's growing?

haploid generative

Where does the pollen tube release its sperm cells?

one of the synergids

What serves as the embryo's food supply?

endosperm

When a pollen tube fertilizes cells in the ovary, what is it called?

I'm not sure.

What begins the process of synergid?

I'm not sure.

What does a sperm cell adhere to to start double fertilization?

I'm not sure.

What degenerates as a pollen grain adheres to the stigma?

I'm not sure.

What does the zygote fuse with to produce a triploid?

I'm not sure.


The character of the seed coat bears a definite relation to that of the fruit. They protect the embryo and aid in dissemination; they may also directly promote germination. Among plants with indehiscent fruits, in general, the fruit provides protection for the embryo and secures dissemination. In this case, the seed coat is only slightly developed. If the fruit is dehiscent and the seed is exposed, in general, the seed-coat is well developed, and must discharge the functions otherwise executed by the fruit.

The appearance of the seed coat bears a definite relation to that of what?

the fruit

What does the seed coat protect?

embryo

What does the fruit of the flower secure?

dissemination

How developed is the seed coat when it's used for dissemination?

slightly

What is the embryo character related to?

I'm not sure.

What do dehiscent fruits directly promote?

I'm not sure.

What does the exposed seed protect?

I'm not sure.

What does the embryo in an indehiscent fruit secure?

I'm not sure.

What must a indehiscent fruit do that is usually done by the fruit?

I'm not sure.


Agriculture is almost entirely dependent on angiosperms, which provide virtually all plant-based food, and also provide a significant amount of livestock feed. Of all the families of plants, the Poaceae, or grass family (grains), is by far the most important, providing the bulk of all feedstocks (rice, corn — maize, wheat, barley, rye, oats, pearl millet, sugar cane, sorghum). The Fabaceae, or legume family, comes in second place. Also of high importance are the Solanaceae, or nightshade family (potatoes, tomatoes, and peppers, among others), the Cucurbitaceae, or gourd family (also including pumpkins and melons), the Brassicaceae, or mustard plant family (including rapeseed and the innumerable varieties of the cabbage species Brassica oleracea), and the Apiaceae, or parsley family. Many of our fruits come from the Rutaceae, or rue family (including oranges, lemons, grapefruits, etc.), and the Rosaceae, or rose family (including apples, pears, cherries, apricots, plums, etc.).

On what is agriculture almost completely dependent?

angiosperms

What family of plants is most important for human sustenance?

Poaceae

What is the more common name of the Fabaceae?

legume

What family do potatoes, tomatoes and peppers belong to?

Solanaceae

What family would you find cherries in?

Rosaceae

What does the legume family provide as the most important of all the plant families?

I'm not sure.

What is the more common name of the Solanaceae family that is second place?

I'm not sure.

What does the rue family provide that is needed for livestock?

I'm not sure.

What are some examples of what the nightshade family provides as the most important group?

I'm not sure.

What does the rue family provide that makes it one group of high importance?

I'm not sure.


Traditionally, the flowering plants are divided into two groups, which in the Cronquist system are called Magnoliopsida (at the rank of class, formed from the family name Magnoliaceae) and Liliopsida (at the rank of class, formed from the family name Liliaceae). Other descriptive names allowed by Article 16 of the ICBN include Dicotyledones or Dicotyledoneae, and Monocotyledones or Monocotyledoneae, which have a long history of use. In English a member of either group may be called a dicotyledon (plural dicotyledons) and monocotyledon (plural monocotyledons), or abbreviated, as dicot (plural dicots) and monocot (plural monocots). These names derive from the observation that the dicots most often have two cotyledons, or embryonic leaves, within each seed. The monocots usually have only one, but the rule is not absolute either way. From a diagnostic point of view, the number of cotyledons is neither a particularly handy nor a reliable character.

What do monocots usually have two of within each seed?

I'm not sure.

According to the Cronquist system how is the number of cotyledons viewed?

I'm not sure.

What other descriptive names are allowed by the English system?

I'm not sure.

How many groups are flowering plants divided into in the English system?

I'm not sure.

What is one group that is used under the English system?

I'm not sure.


Hyderabad (i/ˈhaɪdərəˌbæd/ HY-dər-ə-bad; often /ˈhaɪdrəˌbæd/) is the capital of the southern Indian state of Telangana and de jure capital of Andhra Pradesh.[A] Occupying 650 square kilometres (250 sq mi) along the banks of the Musi River, it has a population of about 6.7 million and a metropolitan population of about 7.75 million, making it the fourth most populous city and sixth most populous urban agglomeration in India. At an average altitude of 542 metres (1,778 ft), much of Hyderabad is situated on hilly terrain around artificial lakes, including Hussain Sagar—predating the city's founding—north of the city centre.

Which city is the capital of Telangana?

Hyderabad (i/ˈhaɪdərəˌbæd/ HY-dər-ə-bad; often /ˈhaɪdrəˌbæd/) is the capital of the southern Indian state of Telangana

How many square miles does Hyderabad cover?

250 sq mi

What river is Hyderabad next to?

the Musi River

What is the population of Hyderabad?

about 6.7 million

At what altitude is Hyderabad, in meters?

an average altitude of 542 metres


Established in 1591 by Muhammad Quli Qutb Shah, Hyderabad remained under the rule of the Qutb Shahi dynasty for nearly a century before the Mughals captured the region. In 1724, Mughal viceroy Asif Jah I declared his sovereignty and created his own dynasty, known as the Nizams of Hyderabad. The Nizam's dominions became a princely state during the British Raj, and remained so for 150 years, with the city serving as its capital. The Nizami influence can still be seen in the culture of the Hyderabadi Muslims. The city continued as the capital of Hyderabad State after it was brought into the Indian Union in 1948, and became the capital of Andhra Pradesh after the States Reorganisation Act, 1956. Since 1956, Rashtrapati Nilayam in the city has been the winter office of the President of India. In 2014, the newly formed state of Telangana split from Andhra Pradesh and the city became joint capital of the two states, a transitional arrangement scheduled to end by 2025.

In what year was Hyderabad established?

Established in 1591

Who is the person that established Hyderabad?

Muhammad Quli Qutb Shah

What dynasty controlled Hyderabad until the early 18th century?

the Qutb Shahi dynasty

Which Mughal viceroy created a dynasty in early 18th century Hyderabad?

Mughal viceroy Asif Jah I declared his sovereignty and created his own dynasty

Which dynasty did Asif Jah I create?

Nizams of Hyderabad


Relics of Qutb Shahi and Nizam rule remain visible today, with the Charminar—commissioned by Muhammad Quli Qutb Shah—coming to symbolise Hyderabad. Golconda fort is another major landmark. The influence of Mughlai culture is also evident in the city's distinctive cuisine, which includes Hyderabadi biryani and Hyderabadi haleem. The Qutb Shahis and Nizams established Hyderabad as a cultural hub, attracting men of letters from different parts of the world. Hyderabad emerged as the foremost centre of culture in India with the decline of the Mughal Empire in the mid-19th century, with artists migrating to the city from the rest of the Indian subcontinent. While Hyderabad is losing its cultural pre-eminence, it is today, due to the Telugu film industry, the country's second-largest producer of motion pictures.

Which individual commissioned Chaminar?

Muhammad Quli Qutb

When did Hyderabad become important culturally in India?

the mid-19th century

Which two groups had an influence in making Hyderabad a cultural center?

The Qutb Shahis and Nizams

What culture is most represented in the food of Hyderabad?

Mughlai culture

Hyderabad has India's second biggest film production industry, what is it called?

Telugu film industry


Hyderabad was historically known as a pearl and diamond trading centre, and it continues to be known as the City of Pearls. Many of the city's traditional bazaars, including Laad Bazaar, Begum Bazaar and Sultan Bazaar, have remained open for centuries. However, industrialisation throughout the 20th century attracted major Indian manufacturing, research and financial institutions, including Bharat Heavy Electricals Limited, the National Geophysical Research Institute and the Centre for Cellular and Molecular Biology. Special economic zones dedicated to information technology have encouraged companies from across India and around the world to set up operations and the emergence of pharmaceutical and biotechnology industries in the 1990s led to the area's naming as India's "Genome Valley". With an output of US$74 billion, Hyderabad is the fifth-largest contributor to India's overall gross domestic product.

What items had been historically traded in Hyderabad?

pearl and diamond

What is a nickname for Hyderabad?

City of Pearls

What are three historic bazaars in Hyderabad?

Laad Bazaar, Begum Bazaar and Sultan Bazaar

What is the economic output of Hyderabad?

US$74 billion

What is the rank of Hyderabad among cities contributing to India's GDP?

fifth-largest


According to John Everett-Heath, the author of Oxford Concise Dictionary of World Place Names, Hyderabad means "Haydar's city" or "lion city", from haydar (lion) and ābād (city). It was named to honour the Caliph Ali Ibn Abi Talib, who was also known as Haydar because of his lion-like valour in battles. Andrew Petersen, a scholar of Islamic architecture, says the city was originally called Baghnagar (city of gardens). One popular theory suggests that Muhammad Quli Qutb Shah, the founder of the city, named it "Bhagyanagar" or "Bhāgnagar" after Bhagmati, a local nautch (dancing) girl with whom he had fallen in love. She converted to Islam and adopted the title Hyder Mahal. The city was renamed Hyderabad in her honour. According to another source, the city was named after Haidar, the son of Quli Qutb Shah.

What does the Oxford Concise Dictionary of World Place Names say Hyderabad means?

"Haydar's city" or "lion city"

Hyderabad was named in honor of someone, who was it?

Caliph Ali Ibn Abi Talib

What does Andrew Petersen say that Hyderabad was originally known as?

Baghnagar (city of gardens).

Who founded what came to be known Hyderabad?

Muhammad Quli Qutb Shah

What person is Hyderabad said to have been renamed for?

"Bhagyanagar" or "Bhāgnagar" after Bhagmati, a local nautch (dancing) girl