Question

Identify the examples of homologous structures from the following.
A. Vertebrate hearts
B. Thorns in Bougainvillea and tendrils of Cucurbita
C. Food storage organs in sweet potato and potato

Answer 1

Hint: Structures which are functionally distinct but anatomically or structurally similar are referred to as homologous organs. Different lifestyles have made a difference, that is. modify organs so they can survive. Analogous structures are organs that are functionally similar but structurally different.

Complete answer:
Studying the homology of an organ means studying its morphological origin, development and position. Organs, no matter how different they appear, are homologous when they are morphologically identical. The analogy, on the other hand, has to do with the physiological appearance and behaviour of an organ. Organs are analogues if they are externally identical and fulfil the same function, however different their origins.
A. Vertebrate hearts: The hearts in various vertebrates (fishes, amphibians, reptiles, birds) show similarities in the basic plan but they have varied degrees of specialization according to the habitat in which they live, their energy requirements and period of evolution.
Hence this is an example of a homologous organ.
B. Thorns in Bougainvillea and tendrils of Cucurbita:, Thorns in Bougainvillea and tendrils of Cucurbita are examples of homologous structures. In both plants, thorns and tendrils both are situated in axillary position and are the modifications of axillary buds. But they perform different functions as thorns are for protection and tendrils help the plants in climbing.
C. Food storage organs in sweet potato and potato: Sweet potato is a modified underground root and potato is a modified underground stem, therefore, otherwise, organise both are entirely different. But they have similar functions and are meant for the storage of food, hence, are examples of analogous structures. So we arrive at a conclusion that Vertebrate hearts and Thorns in Bougainvillea and tendrils of Cucurbita both are examples of homologous organs.

Note:
Convergent evolution is the independent evolution of similar traits in species from different periods or epochs. Convergent evolution creates analogous structures that have a similar form or function but were absent from the last common ancestor of this group.
Divergent evolution is a phenomenon in which two species share a common ancestor but, due to changes in the environment, develop different characteristics that slowly adapt and therefore produce new species. Divergent evolution creates homologous organs.
Convergent evolution occurs in organisms that are not closely related, whereas divergent evolution occurs in organisms that are closely related