History and Evolution: Natural Selection, Gene Flow, and Adaptation

This essay delves into the concepts of natural selection, adaptation, gene flow, mutation, and directional selection within the context of history and evolution. It highlights how natural selection influences organisms in diverse environments, citing examples such as urban-adapted Daphnia and burrowing owl genes. The discussion extends to gene flow, illustrated by the DNA of extinct cave bears found in living bears and the interbreeding of related species. Mutation is addressed as a source of genetic variation, while directional selection is explored through the adaptation of house sparrows to agricultural environments, demonstrating how extreme phenotypes can be favored over time. The essay provides a comprehensive overview of these evolutionary mechanisms and their impact on species development and adaptation.

Running head: HISTORY AND EVOLUTION
HISTORY AND EVOLUTION
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1HISTORY AND EVOLUTION
Activity 1: Evolutionary Concept- Natural Selection, adaptation
Natural selection occurs in the organism who have different features living in different
environment. As seen in the article, urban environments are influenced by natural selection.
Daphnia from urban well adapted in warmer environment which means they got naturally
selected as per their living environment. The gene of burrowing owl gets naturally selected in
their different population and show similar genetic response. It is seen in evolution of invasive
species, where there has been transfer of genetic variation from one population to other. In
natural selection, with the flow of gene, new population arose and tends to adapt in new
environment as seen in the spread of an invasive grass species by human.
Activity 2: Evolutionary Concept: Gene Flow, mutation
Gene flow refers to transfer of gene from population to other through reproduction or
migration. In the study of extinct cave bear who’s DNA has been found in living bears is an
example of gene flow. There must have been high gene migration from generation to generation
which persisted in the living bear. In the example of interbreeding, flow of gene is high in related
species which shows random variation in certain gene. Genome of bear shows polar bear and
brown bear are more related than cave bear which showed that gene variation is more in cave
bear which occur due to gene flow. There was random variation of gene of bear which might
have been due to mutation which has caused changes in genetic material.
Activity 3: Evolutionary Concept: Natural Selection, directional selection
In natural selection, genes get mutated and selected naturally depending on the
environment and allows survival of the fittest. The evolved species compete with the native
species for food for survival. It is seen in the article, housing sparrow have been evolved some

2HISTORY AND EVOLUTION
11000 years ago and its relationship with human is evident with invention of agriculture where
the sparrow adapted gene for long beak and to digest grains. These gene got naturally selected in
the population of urban housing sparrow. As the characteristic which got selected naturally is
extreme phenotype which has been favoured and led to directional selection causing allelic
frequency to shift with time in the same direction of the phenotype.