Study Guide

Evidence of Evolution Terms

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Evidence of Evolution Terms

Analagous Structure

A feature, such as a beak, wing, or eye that evolved independently in two or more organisms. Analogous structures, although they look and seem similar to each other, are not related to each other through common descent, like homologous structures, but may serve similar functions in the different organisms that possess them. For example, butterflies and birds both have wings that serve similar functions but are clearly not related through direct ancestry (in other words, butterflies and birds don't mate with each other).

Artificial Selection

A process by which humans select for certain desirable traits in organisms, allowing only individuals with those traits to reproduce.


The geographical distribution of organisms over the surface of the earth. Biogeographers are interested in where things live, and why they live there.


The idea that sudden, short-lived, catastrophic events are responsible for shaping the geological features of the earth.

Common Ancestry

The idea that all organisms share an ancestor at some point in their evolutionary past. The more recent the common ancestor between two or more organisms lived, the more closely related they are, and the more traits they will have in common.

Convergent Evolution

The independent evolution of similar structures in different kinds of organisms.


Extinction occurs when all individual members of a species die, such that the species no longer exists. Sniff.


Any preserved part of an ancient organism, or evidence that it was there. Fossils can be the mineralized remains of organisms (like bones, teeth, and shells), imprints of those objects (like impressions of shells or leaves), burrows, footprints, tracks, or coprolites (fossilized feces!). These are just a few examples…there are lots of other kinds of fossils.


The study of the earth, including its history and the materials and processes that shape its surface. James Hutton is considered the father of modern geology.

Homologous Structure

A feature in two or more organisms that is inherited from a common ancestor. You can tell structures are homologous to each other if they connect to the same bones, muscles, nerves, etc., and if they develop in the same way. Sometimes homologous structures serve similar functions, but especially in organisms living in different environments, homologous structures can evolve to serve different functions.

Inheritance of Acquired Characteristics (Lamarckism)

The hypothesis that characteristics acquired during an organism's lifetime can be inherited. The most famous example of this proposed mechanism of evolution is the giraffe stretching its neck: an ancestral short-necked giraffe stretches to reach higher leaves, and in the process permanently stretches its neck (ouch!). It then passes on this stretched neck to its offspring, who do the same stretching to reach increasingly higher leaves. Over many generations, giraffes wind up with really long necks.

Radiometric Dating

The use of naturally occurring radioactive isotopes and their decay rates to figure out how old sediments, fossils, and artifacts are. Radiocarbon dating and K-Ar dating are both forms of radiometric dating.


A feature that is only present during development, and which is the remnant of a feature that was present in an ancestor. For example, all of us have gill slits in our mother's womb, but these disappear as we develop—what a shame.


The study of layers of rock and sediment.


The idea that the same geological processes that are at work today—like erosion and sedimentation—were at work in the past. James Hutton came up with the principle of uniformitarianism, and it was later championed by Charles Lyell. Uniformitarianism replaced catastrophism as the predominant explanation for how the earth got to be the way it is.

Vestigial Structure

This is a part of an organism that does not seem to be useful at present, but which was likely important for its ancestors.

Roots of Common Terms in Evidence of Evolution

(L - Latin, G - Greek, F - French)


geo = earth (G) , logia = to study (G)


stratum = a covering (L), graphia = to write, record (G)


homologia = agreement (G)


fossilis = dug up (L)

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