1.) What are the five driving forces in evolution? Define and describe each one
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Question
1.) What are the five driving forces in evolution? Define and describe each one being sure to include specific examples of each. (8pts) B A population of lizards is separated into two populations due to rising water levels submerging a land bridge that has been there for thousands of years. The two populations adapt to their individual areas and we see signifanct differences in body size, coloration, and diet. Compare and contrast allopatric versus sympatric speciation and describe which one applies to the lizards. (5 pts) 2.)Explanation / Answer
Hi
The evolution is the continues process which has shaped millions of life forms on earth as we know it. There are 5 major driving factors of evolution:
1. Genetic drift.: it is the change in allele frequencies over time due to chance alone. Here the organisms live or die only due to chance event and is not attributed to genotype. Example: Imagine there is a small population living in an island. One unfortunate day Tsunami happen to hit the island coast and all those who were playing at the beach, were washed off. The remaining population survived just because they didn't go to the beach on that day. Due to this effect, the genes and alleles in the population get reshuffled and new combinations arise.
There are 2 subtypes of genetic drift: Bottleneck and founders effect.
2. Migration or gene flow: The movement of individuals from one population to another. This is very common occurrence especially in birds and herd animals. The migration brings about newer alleles and genes into the population. Example: The entry of US soldiers in Vietnam in 1960s. though the soldiers left te country after the war, they had added new genes and alleles to the native population.
3. Mutation: it is the genetic phenomenon, where one or more bases in DNA mutate or change in order to cause changes in phenotype. Some are beneficial and some not. One of classic example of mutation is evolution
4. Natural selection: It is a neutral force acting on the organisms which selects the one which suits the environment. The organisms have different phenotypes and genotypes. Under certain conditions only some of the variants are benefited and others are eliminated. One of the best example is white and dark moths . The moths are of two color white and black. The smoke and dust covering on the tree trunks provided a camouflage to the black ones and as a result the white ones were eaten by the birds. Over the time all the moths were black and no white was left out. This caused evolution.
5. Non-random mating: the mating between partners is biased and is preplanned. This preferential mating increases the homozygosity and reduces the heterozygosity. These effects are prominently seen in communities. Example, the peahens select for the peacocks with brighter and longer tails.
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