17.4+Patterns+of+Evolution_6th

//** The Wikid Wiki For Patterns of Evolution **//   Refers to large scale evolutionary patterns and processes that occur over long periods of time. This includes evolution, coevolution, adaptive radiation, convergent evolution, and punctuated equilibrium. I. Evolution/Extinction-K.T.  1. More than 99% of all species that roamed the earth are now extinct. 2. Mass extinctions can cause biospheres, ecosystems, and food webs to collapse. This also leaves room for new, less developed organisms and mammals. Mass extinction is not caused by natural selection. a) The hypothesis/answer for the end of the Cretaceous period was a huge asteroid, that threw up a lot of dust and water molecules. This probably caused the dinosaurs to become extinct. b) Mass extinction was caused by multiple reasons. 3. Large volcanoes, moving continents, and changing sea levels were some reasons. 4.  Each extinction led way to new life, which caused fast evolution, like birds without dinosaurs.

II. Adaptive Radiation-R.M. -Studies of fossils or of living organisms show that a single species or a small group of species has evolved into diverse forms in different ways. This is by mutation and natural selection.

1 . Adaptive radiation can occur in large portions. Dinosaurs were the product of adaptive radiation for reptiles. The first dinosaurs and animals evolved at the same time. Dinosaurs ruled for 150 million years, then the small mammals became dominant with much diversity from Cenozoic Period. 2.  Organisms die off because of competition for resources, and environmental changes. Adaptive Radiation occurs because organisms need to fill the many ecological niches.

Three Basic Types of Adaptive Radiation 1. General adaptation- A particular species that develops a new ability which enables it to survive in a different part or niche of its environment (ex. A bird developing the ability to fly) 2. Environmental Change - A species that can survive in a new environment. The species might develop into different species that can take the new niches after an environmental change. (ex. Small mammals and birds developing after teh extinction of the dinosaurs. 3. Archipelagos- (   an archipelago is a large group of islands, such as the Galapagos Islands) A new species may colonize an island or mountain area and undergo rapid evolution. (ex. Darwin's finches upon arrival in the Galapagos Islands) III. Convergent Evolution-E.B.  1. Adaptive radiation can cause different organisms to look similar. However, unrelated animals can go under different changes. 2. Natural selection can cause bodily structures to change but stay similar. Flippers that changed from wings are an example. This is also very common in plants. a)   Organisms have similarities such as the ability to move through air, water, or to eat similar foods. b) For adaptations, birds (like penguins), fish, and dolphins are similar but have adaptations such as modified wings or flippers. These sort of changes are also very common in plants. 1. If organisms start out with completely different bodily structures, over time they might change due to climate or other factors. This convergent evolution can change over time. 2. Structures such as dolphins' flukes look similar to fins, but fish share no common ancestor with the dolphin. These fins are called analogous structures.

 IV. Coevolution-E.B. 1. Some organisms in similar environments can adapt in similar ways. This process of species changing in corresponding manners to each other can also be evolutionary. Some organisms adapt to each other so much that is is hard for them to be apart or to live without each other. 2. Some flowers need a certain environment that they have adapted to, in order to reproduce. These necessities can change over time, just like evolution. 3. Coevolution is the mutual evolutionary influence between two species (the evolution of two species totally dependent on each other). 4. Coevolution is an extreme example of mutualism. It is a process that is especially common with flowers and insects. Each of the species involved exerts selective pressure on the other, so they evolve together. a) Yucca moths and yucca plants b) Acacia ants and acacia trees c) Lichens d) This is similar to symbiosis in the relationship way. 5. Darwin noticed the insect to flower interaction, and his predictions were very close to what we know today. 6. Insects and plants are from the Mesozoic time period. Some plants have grown poisonous over time, to protect them from the insects. In reaction to this poison, the insects have learned to become immune, therefore keeping the cycle of evolution going. 7. The interaction that organisms have in response to each other can take millions of years to alter.
 * Convergent ** [|evolution] ** represents a phenomenon when two distinct ** [|species] ** with differing ancestries evolve to display similar
 * physical features.
 * __ [|Environmental] __ circumstances that require similar developmental or structural alterations for the purposes of ** [|adaptation] ** can
 * lead to convergent __ [|evolution] __ even though the species differ in descent.
 * All these characteristics are irrespective of the ** [|animal] ** involved or the physical location.
 * For example, in various species of plants that share the same pollinators, many structures and methods of attracting the pollinating
 * species to the ** [|plant] ** are similar.
 * One of the best examples of convergent evolution involves how ** [|birds and] ** ** [|bats] ** learned to fly.
 * Importantly, each species developed wings independently. These species did not evolve in order to prepare for the future.
 * Flight was induced by selective pressure imposed by similar environmental conditions, even though they were at different points
 * in ** [|time] **.
 * Some information from first bullet point under helpful hints.

• Insects and plants influence each other's evolution, by the evolution of insecticides in plants and of detoxification and avoidance mechanisms in insects. It has been argued that the evolutionary relations between insects and plants less often take the form of coevolution than of sequential evolution, in which plant evolution influences insect evolution but not vice versa. • The level of parasites can evolutionarily decrease or increase. It can be understood in terms of the parasite-host relationship: two factors that influence it are the selection and the mode of transmission of the parasite between hosts. • Coevolutionary “arms races” between predators and prey produce escalatory long-term evolutionary trends; they can be seen in the evolution of brain sizes in mammals.  • Coevolution within groups of competing species have  rates of change, and relative competitive abilities. Symbiosis can be similar to coevolution in some ways. Some information from second bullet point under helpful hints.
 * Coevolution occurs when two or more lineages influence each other's evolution. Coadaptation between species, such as in any example of mutualism, is probably, but not necessarily the result of coevolution.

V. Punctuated Equilibrium/Developmental Genes and Body Plans-R.M./K.T. __Gradualism__ is when biological organisms gradually change over time. Fossils prove this. a) Changes during embryological development may lead to changes in size and shape of the mature form. b) Until very recently, there was no way to prove this theory. Now, scientists can chose which genes are "turned on/off" and then analyze the results. c) Hox genes, or master control genes, tell the which parts of an embryo become the features like arms, legs, or even wings. These processes are relatively the same in vastly different animals like a fly and a human. Changes in the time of cell differentiation and gene expression can make differences in the size and shape of features like toes, fingers, and legs.



__Punctuated Equilibrium__- patterns of evolution in which long stable periods are interrupted by brief periods of more rapid change. A) This is a somewhat new idea that is presented by some biologists but is very controversial. 1)Some species haven't really changed over time after reaching a state of equilibrium. a) Horseshoe crabs 2) Rapid evolutions can happen for many reasons a) A portion of the population gets seperated b) A group migrates to another location (i.e Galapagos finches) c) A species moves in to fill an open niche. d) Mass extinctions may wipe out many species in that particular species enviorment. B) It is agreed that evolution happens at different rates for different species. 1) Bacteria vs. Human population  Helpful Links/Citation for information:
 * http://science.jrank.org/pages/2608/Evolution-Convergent.html
 * http://www.blackwellpublishing.com/ridley/tutorials/Coevolution_Summary.asp
 * http://evolution.berkeley.edu/evosite/evo101/images/bull_thorn_acacia.jpg|bull_thorn_acacia.jpg
 * []
 * //http://www.kk.org/thetechnium/coevolution.gif|coevolution.gifhttp://media-2.web.britannica.com/eb-media/52/6552-004-C5D667E1.jpg
 * <span style="font-size: 13.2pt; font-family: 'Times New Roman', Times, serif;">[|6552-004-C5D667E1.jpghttp://science.jrank.org/pages/2608/Evolution-Convergent.htmlhttp://images.google.com/imgres?imgurl=http://cas.bellarmine.edu/tietjen/Evolution/Charley/Converge36.gif&imgrefurl=http://cas.bellarmine.edu/tietjen/Evolution/convergent_evolution_examples.htm&usg=__f7u6CmtiyOpv8jvuClVCEAdcHtE=&h=497&w=493&sz=59&hl=en&start=3&um=1&tbnid=Cd9a1LNDwuEjqM:&tbnh=130&tbnw=129&prev=/images%3Fq%3DConvergent%2BEvolution%26hl%3Den%26client%3Dsafari%26rls%3Den-us%26sa%3DN%26um%3D1[[http://cas.bellarmine.edu/tietjen/Evolution/Charley/Converge36.gif|Converge36.gif     Change 1 of 2[[http://hausmannbio.wikispaces.com/page/diff/17.4+Patterns+of+Evolution_6th/62397430?mode=code#|<< First]
 * <span style="font-size: 13.2pt; font-family: 'Times New Roman', Times, serif;">http://biology.clc.uc.edu/courses/bio303/coevolution.htm
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