Question

1. Define the terms analogy and homology. Give an example of each and describe the significance of these terms in developing a classification system.

Answer 1

The terms homology and analogy generally indicates the evolution of a structure or an organ. Homology is a term used to indicate shared ancestry of organisms.

When an organ or a body part has evolved as similar in structure and different in function in two different organisms, then they are said to be homologous or share same origin.

Example: wing of a bat and hand of a human. Both have nearly same structural arrangement of bones but differ in function. Bats use their wings to fly and humans use their hands to perform different tasks.

Analogy in contrast means that if two organs or a body part has evolved to perform similar function but a different structure. It indicates different ancestory.

Example: wing of bat and a wing of a bird.

Both have the same function of flying but their structure is highly different. Thus, we can say that they have different evolutionary origin or no recent common ancestor.

Significance of these terms in developing a classification system:

Homology and analogy are two very important terms used in evolution to study the ancestry of the organisms over a period of time. Some of the great biologist like Charles Darwin has even given several examples citing the structural anatomical features to support the theory of natural selection and evolution. Today these two terms form the basis of a complete subject of comparitive anatomy wherein we can study the similarities and differences of body structures in different species.

The structures may be homologous or analogous and will help us to determine the shared common ancestory of a family of organisms which have also in turn evolved from a common ancestor. It forms the very base of phylogenetic studies and classifications giving us a broader understanding of how different orgainsms belonging to different phylums have evolved on earth over billions of years. Homology and analogy helps us to understand the relationship which each organism on this earth has with another forming a tree of life.