EVOLUTION - EVOLUTION 1. Biological populations change...

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EVOLUTION 1. Biological populations change through time = the pattern of evolution 2. The causes of change: the mechanisms of evolution = the process of evolution The Pattern of Evolution -Biologists believe that: populations of organisms have changed through time. Darwin called this “descent through time.” -all organisms are genetically linked Aneagenesis lineage—does not break off into new species Cladogenesis—species change in lineage Evidence that change is happening NOW 1. we can produce change in biological selection (i.e. domesticated animals), artificial selection 2. changes in the wild (w/o human influence): beak shape in finches 3. formation of new species Evidence that change happened in the PAST 1. grand scale changes in history of life 2. fine-grained examples of change in fossil records Additional evidence that organisms are related to one another (genealogically connected): 1. Design flaws—indirect evidence that we evolved/are relatable 2. Vestigial organs—only make sense in light of history examples: whale pelvis, wisdom teeth etc. these are the imprints of the evolutionary history of these organisms a. Design flaws occur because evolution cannot construct new traits from scratch; new traits must be modifications of previously existing traits. This often prevents evolution from producing the “best design” for a structure b. Vestigial structures have no apparent current function and exist because they were used by an ancestor 3. If the diversity of life was produced by a branching pattern of evolution, then the features that species share in common should be largely determined by their ancestry. Similar structures that have a common ancestry are called homologies (homology) a. Homologies: structure that is shared by ancestor (i.e. hand structure of chimpanzees and humans) b. Vast majority of organisms’ features are homologies of one kind of another c. The vast majority of morphological, behavioral, and molecular characters have homologies in closely related organisms. i. Thus this fact that the features of organisms are arranged in this way strongly suggests a historical pattern of branching. Some features do not fit this pattern—these are analogies
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d. Analogies: are characters that have evolved by convergent evolution (e.g. wings in insects and birds are convergent analogs, but they do not share
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EVOLUTION - EVOLUTION 1. Biological populations change...

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