Difference Between Homologous Structures and Vestigial Structures

The key difference between homologous structures and vestigial structures is that homologous structures are the anatomically similar structures found in different organisms that share a common ancestor while vestigial structures are the anatomical structures which have lost their usefulness to an organism.

Homologous structures are vestigial structures are two types of anatomical structures which are evolutionary important. Homologous structures are similar structures present in different organisms that are coming from a common ancestor. In contrast, vestigial structures are structures that are no longer useful for organisms and have a reduced size.

CONTENTS

1. Overview and Key Difference
2. What are  Homologous Structures
3. What are Vestigial Structures
4. Similarities Between Homologous Structures and Vestigial Structures
5. Side by Side Comparison – Homologous Structures vs Vestigial Structures in Tabular Form
6. Summary

What are Homologous Structures?

Homologous structures are similar anatomical structures present in different organisms. Analyzing the evolution of these homologous structures reveals that those organisms share a common ancestor. Therefore, they are evolutionarily related organisms. For example, limbs of birds, crocodile, bat, whale and human are homologous structures. Furthermore, the hands of humans, bat, cat and whale are also homologous structures.

Homologous structures may employ different functions though they are anatomically similar. Moreover, they show the divergent evolution of organisms.

What are Vestigial Structures?

Vestigial structures are the anatomical structures that are no longer in use though they are present in organisms. In simple words, they are the inherited structures that have lost their usefulness to an organism. Generally, these structures have reduced their sizes with time when compared to their normal sizes. Human tailbone, appendix and whale pelvis are some examples of vestigial structures. Moreover, gill slits in human and birds and wisdom teeth of human are also vestigial structures.

However, vestigial structures are evolutionary important since they give major hints regarding the evolution of organisms or evolutionary history.

What are the Similarities Between Homologous Structures and Vestigial Structures?

• Homologous structures and vestigial structures are evolutionary evidence.
• They are anatomical structures present in organisms.

What is the Difference Between Homologous Structures and Vestigial Structures?

Homologous structures are structurally similar structures present in different organisms. On the other hand, vestigial structures are anatomical structures that are not useful to an organism. Thus, this is the key difference between homologous structures and vestigial structures. Furthermore, homologous structures provide evidence for divergent evolution while vestigial structures provide hints for the evolutionary history of an organism. This is another difference between homologous structures and vestigial structures.

Summary – Homologous Structures vs Vestigial Structures

Homologous structures and vestigial structures are two types of anatomical structures that are evolutionary important. Homologous structures are anatomically similar structures present in different organisms that are evolutionarily related. In contrast, vestigial structures are inherited structures that are no longer useful to an organism. Moreover, their sizes have become reduced with time since they have no function. Thus, this is the summary of the difference between homologous structures and vestigial structures.

Reference:

1. “Homologous Structures – Definition and Examples.” Biology Dictionary, 28 Apr. 2017, Available here.
2. Scoville, Heather. “Your Appendix: Evidence of Evolution.” ThoughtCo, ThoughtCo, 26 Jan. 2019, Available here.

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