Adaptive radiation occurs most often in new environment with a variety of different unfilled niches so that plants and animals that are not adapted to those areas can exploit the resources in the respective niches. Once individuals begin exploiting the new niches, mutations that will benefit the species will spread throughout the population via natural selection giving the owners an overwhelming advantage over others without the mutation and throughout evolutionary time a new species is established. If sexual selection is linked to these mutations a new species can be established even faster. For example if a few individuals of a seed eating bird were to start eating fruit due to a surplus of fruit in the environment a few mutations would appear to make them better fruit eaters, which also happen to coincide with a change in the birds aesthetics or song, then the fruit eating birds may decide to mate amongst each other rather than seed eaters. Furthermore even if seed and fruit eaters were to interbreed, the result could be a bird that is neither a dominant seed nor fruit eater and lose out to purebred seed and bird eaters. The hybrids would be eliminated by natural selection due to decreased output capacity. Natural selection will then result in more district plumage or songs of fruit eaters allowing them to be identified with other fruit eaters avoiding mating with seed eaters.
Other individuals of the same seed eating ancestral species may find nectar as a viable source of food and evolve over time via natural selection into a new species.
Adaptive radiation is when a single species evolves into a number of distinct yet closely related species. Each new species is adapted to live in a different ecological niche. This process usually occurs when a variety of new resources are made available and are not used by any other species.
An example would be Dwarven’s finches. There are 13 different species that live in the Galapagos Islands all evolved from a common ancestor. Assuming that all the finches all had medium sized beaks that fed on medium sized seeds; individual with smaller beaks would have an easier time eating smaller seeds however there could be other birds that have already adapted for consumption of smaller seeds. This is the same for the birds with larger beaks. Other birds from a different species may already be programmed to consume seeds and thus competition is introduced.
Adaptive radiation is when a species is introduced into a new environment when competitors or predators are eliminated by a catastrophe and thus the species becomes isolated from competition. This can happen via mass extinction, continental drift or induction. Some examples of species that developed from are lemurs from primitive primates on the island of Madagascar, and a diverse range of primitive mammals that evolved into terrestrial, avian and aquatic forms during the tertiary period,
Bailey, Jill. "adaptive radiation." Science Online. Facts On File, Inc. Web. 18 Dec. 2012. . Record URL:
From: Encyclopedia of Biodiversity.
Adaptive radiation has nothing to do with unstable isotopes. It’s a form of evolution in which many different species have a single common ancestor.
Throughout the history of the world, species have become extinct by natural selection or simple misfortune while others produced many new species as a result of adaptive radiation. Adaptive radiation can occur when a species is relocated to a new location which the founding population undergoes adaptive radiation or the surviving remnants of a population of a once widespread species undergoes adaptive radiation. The result is increase in biodiversity over evolutionary time as the ancestral population separate into distinct populations that do not interbreed thus allowing different...
An example of adaptiveradiation occurring after a mass extinction is the extinction that killed off the dinosaurs. What caused this mass extinction was when a massive comet hit earth, off the Yucatan Peninsula. However, the mammals that survived this catastrophic event for the most part, survived because they could burrow in holes for shelter. Regardless, about 90% of all life on earth was destroyed. This led to an opportunity for the surviving plants and animals to disperse to new environments. When these animals dispersed to new environments, they evolved within these new ecosystems. These animals were pressured to adapt quickly if they were going to survive. As these animals became more adapted to their new environments, they changed so much that they became very different species. This is what adaptiveradiation is.
Charles Darwin observed this first hand on the Galapagos Islands. When Darwin first arrived on the Galapagos Islands, he discovered finches that looked astonishingly similar to the finches that found in South America's islands. However, these finches were different in size, diet, and habitat preferences. After years of studying, Darwin figured that these finches on these islands all had a common ancestor that came from the continent of South America and got stranded on these islands. After the ancestor finches were stranded, they quickly ate the...
...Evolution of Polar Bears
The observed fossil transitions that inform our knowledge of Polar Bear speciation are very well documented. Bear fossils change through time: generally, when examining the fossil record, successively deeper levels of sediments or sedimentary rocks yield successively older fossils. For some transitions from one species to another, one can find a well-characterized series of transitional specimens leading the observer across the species "boundaries" (Kurten, 1976).
Sometime during the mid-Pleistocene period (roughly 100,000 to 250,000 years ago), a number of brown(same as grizzly) bears (Ursos arctos) probably became isolated by glaciers. Many probably perished on the ice; however, they apparently did not all disappear. Some survived due to the fact that "organisms vary" (Gould, 1977); that is, every litter of grizzlies has a variation in coat thickness, coat color, etc., which imparted a slight evolutionary advantage to some individuals of each litter. Successive, successful individuals repeated this simple process, yielding a rapid series of evolutionary changes (driven, presumably, by the combination of small population, and extreme selection pressure) in order to survive. Note that these new variants were not necessarily "better" in any absolute sense, or on any absolute "bear" scale of perfection: they were simply more in keeping with their new environment than their immediate ancestors or their more unfortunate siblings....
AdaptiveRadiation, Convergence and the Marsupials
Metatheria (Marsupalia) originated upon Laurasia in the Cretaceous with the oldest fossilised remains having been dated to 125 Ma. The first period of metatherian diversification occurred in the late Cretaceous. The K-T mass extinction created an ecological void in which mammalian radiation occurred in the Palaeocene. With South America isolated from North America throughout the Tertiary, there was the second great period of metatherian diversification and there were numerous examples of placental and marsupial convergence. In the Eocene, one line of metatheria radiated across the Antarctic to Australasia and from that lineage the modern Australasian marsupials are descended. There are numerous examples of convergence within this marsupial population, which are now becoming evident with advances in DNA analysis. In the Pliocene the Great American Interchange occurred when the Isthmus of Panama was created and many South American marsupial fauna became extinct.
To examine the relationship between marsupials and placentals throughout the tertiary one must first understand the concepts of adaptiveradiation and convergent evolution.
In 1953, G.G. Simpson defined adaptiveradiation as the ‘more or less simultaneous divergence of numerous lines from much the same adaptive...
...Biological Effects of Cell Tower Radiation on Human Body
Neha Kumar (Director, WILCOM Technologies Pvt. Ltd.) Prof. Girish Kumar (I.I.T Bombay) ISMOT- 2009
Radiation measurements near the cell towers EMF exposure Safety norms Review Biological effects (far below current standards) Radiation Shield (reduce Radiation levels)
Electromagnetic RadiationsRadiation emitted from Cell Phones, Cell phone towers, Wi-Fi, TV and FM towers, microwave ovens, etc are called Electromagnetic radiations and are known to cause significant biological effects on the human body and health of animals.
Cell Tower Statistics in India
4.25 lakhs 3.75 lakhs
Antennas on Cell tower transmit in the frequency range of: • 869 - 890 MHz (CDMA) • 935 - 960 MHz (GSM900) • 1805 – 1880 MHz (GSM1800) • 2110 – 2170 MHz (3G)*
Microwave radiation effects are classified as: •Thermal •Non-thermal The current exposure safety standards are mainly based on the thermal effects, which are inadequate.
EXPERIMENT: Radiation level measurements near
several Cell Tower sites
A broadband monopole antenna of gain = 2 dB was used to measure radiated power by various cell phone towers (CDMA, GSM900 and GSM1800)
Measured Power -20 to -30 dBm (in dBm) For each frequency bands
-30 to -50 dBm
We can classify radiation into ionizing and non-ionizing radiation, according to the effects it produces on matter.
Ionizing radiation includes cosmic rays, X rays and the radiation from radioactive materials.
Non-ionizing radiation includes ultraviolet light, radiant heat, radio waves and microwaves.In medical practice ultrasound and magnetic resonance imaging (MRI) involve non-ionizingradiation.
+light n heat radiation produced by the sun
*ionizing radiation is produced by some minerals in the earth
*our bodies contain radioactive material
*dose rate increases with altitude and latitude
*natural rays- cosmic rays,gamma raysfrom the Earth, radon decay products in the air, and various radionuclides found naturally in food and drink.
*X rays, fallout from the testing of nuclear weapons in the atmosphere, discharges of radioactive waste from the nuclear industry, industrial gamma rays, and miscellaneous items such as consumer products
*COMMON USES OF RADIATION IN INDUSTRY — Radiography of welds and joints. Security inspection of bags and parcels. Level gauging of container contents.
*environmental radiation- nuclear weapon tests, radioactive discharges,depleted uranium,
Wireless Routers(Wi-Fi), Cell Phones,
The likelihood of such...
Radiation has a profound effect on matter. Particularly in forms where it has high energy. There are basically two kinds of radiation, and they are electromagnetic energy and particulate radiation. Low energy electromagnetic radiation isn't generally hazardous, as long as the field strengths are low. You wouldn't want to stand in front of a radar antenna when it's radiating, but we are swept by low power electromagnet energy all the time. Those so-called radio waves are everywhere. Light is this kind of energy, too, and it's not too bad. But at higher energies, electromagnetic radiation is a hazard. Particulate radiation is straight up a problem. We often refer to particulate and high energy electromagnetic radiation as ionizing radiation, and both kinds have the ability to do some damage. Jump in the ride, fasten your seatbelt and we'll take a cruise into the quantum mechanical hood to check it out. Pay attention to the scenery along the way so you'll be up to speed when we get there.
Matter is composed of atoms. Atomic nuclei are tightly bound protons and neutrons (1H excepted) with electrons hanging out in the electron clouds around them. Also, there are chemical bonds between atoms in a lot of different kinds of matter. These bonds involve the borrowing and loaning of electrons (the so-called ionic bonds) or the sharing of electrons (the so-called...
...species of finch led him toward formulating the principle of natural selection.
In his memoir, The Voyage of the Beagle, Darwin noted, almost as if in awe, "One might really fancy that, from an original paucity of birds in this archipelago, one species had been taken and modified for different ends."
Indeed, the Galapagos have been called a living laboratory where speciation can be seen at work. A few million years ago, one species of finch migrated to the rocky Galapagos from the mainland of Central or South America. From this one migrant species would come many -- at least 13 species of finch evolving from the single ancestor.
This process in which one species gives rise to multiple species that exploit different niches is called adaptiveradiation. The ecological niches exert the selection pressures that push the populations in various directions. On various islands, finch species have become adapted for different diets: seeds, insects, flowers, the blood of seabirds, and leaves.
The ancestral finch was a ground-dwelling, seed-eating finch. After the burst of speciation in the Galapagos, a total of 14 species would exist: three species of ground-dwelling seed-eaters; three others living on cactuses and eating seeds; one living in trees and eating seeds; and 7 species of tree-dwelling insect-eaters.
Scientists long after Darwin spent years trying to understand the process that had created so many types of finches that differed mainly in...
...The Theory of Evolution
One of the greatest questions of all time is: "Where did we all come from?" One of the most popular answers to this question is creationism, the idea that everything was created by a higher being. Another popular idea is evolution, the idea that all living organisms descended from a less complex organism. Evolution possesses a new way of thinking that is being greatly accepted by the scientific community, but not by pious groups of people. Creation and evolution are diametrically opposed. This debate between religion and science has its origin from the time when Charles Darwin first published the theory of evolution in his controversial 1859 book On the Origin of Species.
Evolution is based on two underlying principles as suggested by renowned Charles Darwin: heredity and natural selection. Heredity is the principle that organisms pass on different combinations of their traits to their offspring. If an organism has strong traits that help it to survive, then its offsprings are likely to possess some of those same strong traits and be more likely to survive. The second principle is natural selection, better known as "survival of the fittest." According to natural selection, the organisms with strong, "fit" traits are more likely to survive long enough to reproduce than are the organisms with weak, "unfit" traits; thus over time, the strong organisms will...