Evidence of Evolution

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by trevorhoughton
Last updated 4 years ago

Evolutionary Biology

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Evidence of Evolution

By: Trevor Houghton

Evidence of Evolution

Fossils of land animals, first appear in rocks that are about 370 million years old. In older rocks, only sea creatures are found. But in 1998, scientists found a fossilized fin, 370 million years old, with eight digits similar to the five fingers humans have on their hands. However, the fin was undoubtedly a fish's, which means this fossil is strong evidence of a transitional form.

Evolution is a process whereby populations are altered over time and may split into separate branches, hybridize together, or terminate by extinction. The evolutionary branching process may be depicted as a phylogenetic tree, and the place of each of the various organisms on the tree is based on a hypothesis about the sequence in which evolutionary branching events occurred.

Homologous: Variations of the same structure that has enabled the organism to adapt to different environments.Arm of human, wing of bat, flipper of whale, foreleg of horse. All anatomically similar; suggests a close evolutionary relationship.

Analogous: Structures having the same function, but suggest neither similarity in anatomy nor close relationship.wing of bird and wing of insect

Vestigial: Structure that currently has no function but may have been of use in the evolutionary past.appendix,tail bone, extra toe on dogs, maybe wisdom teeth.

Correlations of fossils can be enhanced by more precise age dates, but these also place a high expectation on the fit between fossil first occurrence and cladistic results.

Some types of evidence, such as fossils and similarities between related living organisms, were used by Darwin to develop his theory of natural selection, and are still used today. Others, such as DNA testing, were not available in Darwin's time, but are used by scientists today to learn more about evolution.


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