Differences between homologous and analogous

In a biology class, students find it confusing to grasp concepts on the anatomy of organisms. A comprehensive study of analogous and homologous structures play a significant role in understanding how similar or different various organisms are. Anatomical similarities and differences help scientists know which animals are the best alternative to use instead of risking human life on experimentation when doing therapeutical research.

  1. Homologous organs have structural similarity and origin, but different functionalities 

In all plants, roots, and stem have structural similarity yet, performs different functions like food storage or support. Similarly, in bats, all upper limp of mammals and human arms have similar structures and arrangements of the bones, yet their functions depend on habitation. In contrast, analogous organs perform similar functions, although their structures and origin differs. It is very common to discover that in plants, stem tendrils originate from the stem, and leaf tendrils come from foliar, yet both organs work to support the plants through coiling. For animals, bat wings are from bony structures, while insect wings instigate from membranous extensions, yet in both cases, wings are for flying.

  1. Analogous structures exhibit  traits of convergent evolution

As an explanation of why some organisms have different anatomical structures, but very same structures perform the same functions, such as wings in birds and insects. The reason for this is that a group of dissimilar organisms was exposed to the same environment, and they developed similar structures as an adaptation to survive in the environment.  On the contrary, homologous structures exhibit  characteristics of divergent evolution. Divergent evolution is evidenced when natural selection and genetic drifts occur as a result of characteristic changing, and genetic fixation happens after subjecting similar groups to different environments allowing diffusions forming new species.

  1. Homologous organs develop organisms that are naturally related 

The evolution theory explains that homologous organs only grow in organisms that share a common ancestry modification. For instance, in mammals, male and female reproductive organs, that is, testicles and ovaries are said to be homologous. On the contrary, Analogous organs does not develop from related organisms. Analogous organs appear when a large group of organisms that are not related in any way, but when exposed to the same surrounding, they develop similar structures to help them survive in that environment. Some adaptations are either for protection from predators or for preying safely.

  1. Internal structures of homologous organisms are similar

By look, you may presume they are different due to their superficial appearance, but the internal structures of homologous organisms are similar despite having unrelated functionalities, while analogius organisms have disparate internal structures. Forget the superficial resemblance; analogous organs have internal structures that are quite unlike. So despite that in both the bats and birds wings having like functions, bats have thinly stretched skin covering their wings, while birds are covered by feathers. 

Key Takeaway

Based on these differences between analogous and homologous structures, you can know how various species of organism differ from each other. Modern science in the field of medicine has made huge steps in developing vaccines and drugs to counter diseases in plants, animals, and human beings organisms with related anatomical structures. 

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