Chapter 19, Problem S14.2BYB

Section 14.2 What is the difference between a homologous and an analogous structure?

Summary Introduction

To explain:

The difference between the analogous and the homologous structures.

Introduction:

Homologous structures are developed from same developmental patterns and have the same structural design but have very different functions. Analogous structures arise from the different developmental pattern and have a different structural design but are similar in function.

Explanation of Solution

Homologous structures are those which are similar to their structural design (anatomy) and have a similar developmental pattern (embryology), but these structures perform different functions. These structures are inherited from a common ancestor. Examples of homologous structures are the forelimbs of a human, a horse, or a bat. These structures or organs having the same type of bones, blood vessels, nerves, and muscles, but they perform different functions such as the forearms of humans are used for manipulation, a horse uses for running, a bat uses it for flying.

Analogous structures are those which superficially look similar in physical appearance but have a different structural design. These structures or organs perform similar functions. Examples of analogous structures are, wings of insects, birds, and bats that perform the same function for flying but the wings are of different origin.

Conclusion

Homologous structures have similar ancestries but dissimilar in their functions. This structure shows divergent evolution. Analogous structures have different ancestries, but they have the same function. This structure shows convergent evolution.