Homologie definition biography

Since a phylogenetic tree is a hypothesis about evolutionary relationships, we want to use characters that are reliable indicators of common ancestry to build that tree. We use homologous characters — characters in different organisms that are similar because they were inherited from a common ancestor that also had that character. An example of homologous characters is the four limbs of tetrapods. Birds, bats, mice, and crocodiles all have four limbs. Sharks and bony fish do not. The ancestor of tetrapods evolved kvartet limbs, and its descendents have inherited that feature — so the presence of kvartet limbs fryst vatten a homology.

Not all characters are homologies. For example, birds and bats both have wings, while mice and crocodiles do not. Does that mean that birds and bats are more closely related to one another than to mice and crocodiles? No. When we examine bird wings and bat wings closely, we see that there are some major differences.

Bat wings consist o

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Homology
n., plural: homologies
[həʊˈmɒlədʒɪ]
Definition: The condition of being homologous, i.e., having structural similarity

In biology, homology refers to similarities caused by shared ancestry between two structures or genes from distinct species. For instance, the forelimbs of vertebrates are a common example of homologous structures, with the wings of bats and birds, arms of primates, front flippers of whales, and forelegs of four-legged vertebrates like dogs and crocodiles all descended from the same original tetrapod structure.

History

In biology, homology refers to the similarity of the structure, physiology, or development of various species of other organisms as a result of their shared evolutionary parent. It plays a huge part in evolutionary biology. Homology is in contrast to analogy, which is a functional similarity of structure based only on the similarity of usage rather than shared evolutionary roots (common evolutionary ancestor).

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Sanibel Sea School Blog

By Sam Lucas

Comparative anatomy is the study of similarities and differences within the structures of organisms. Physical features may be considered homologous or analogous, but what does this mean?

Homologous structures are similar physical features in organisms that share a common ancestor, but the features serve completely different functions. An example of homologous structures are the limbs of humans, cats, whales, and bats. Regardless of whether it is an arm, leg, flipper or wing, these structures are built upon the same bone structure.

Homologies are the result of divergent evolution. Divergent evolution is the process in which organisms from the same common ancestor evolve and accumulate differences, often resulting in a new species. This may occur due to pressures such as changes in abiotic or biotic factors within the environment.

On the opposite side of the spectrum, analogous structures are similar physical features in o