Question 2 of 20 Map det Sapling earning Place the homologou

Question 2 of 20 Map det Sapling earning Place the homologous characteristic that arose in each branch of the phylogenetic tree. Not every characteristic will be placed. Bat Platypus Bird Lizard Amphibian Shark amniotic sac placenta bilateral wing fur symmetry lungs camera eye endothermic jaw metabolism Which characteristic is analogous between birds and bats? AG Previous 2 Check Answer Next d Exit Hint

Solution

Homologous structures are parts of the body that are similar in morphology anatomy, genetics and embryology but dissimilar in their functions. These structures are inherited from common ancestors, they have similar developmental pattern in the embryos, and they have the same type of bones, blood vessels, nerves and muscles etc. but they do dissimilar function in different animals.

Examples of Homologous Structures;

Whales were earlier classified as a fish since they live in the water and have flippers. When it was discovered that the flippers in whales actually contained homologous structures to human legs and arms, they were moved to a part of the phylogenetic tree more closely related to humans.

Since bats fly, they were originally classified as closely related to birds and insects. Everything with wings was put into the same branch of the phylogenetic tree. After the discovery of homologous structures, it was apparent that not all wings are the same. Even though wings have same functions to make the organism fly they are structurally very different. It was found that the bat wing resembles the human arm structure wise.

Analogous structures: Animals belonging to different group live in same habitat. Hence they lead a similar type of life. This leads to the development of superficially similar structures to lead a similar type of life. It is actually more likely the analogous structures came from two separate branches of the phylogenetic tree (from different ancestors) and may not be closely related at all.

Examples of Analogous Structures;

The eye of a human is very similar in structure to the eye of the octopus. Actually, the octopus eye is superior to the human eye in that it does not have a \"blind spot\". However, the octopus and the human are not closely related and reside far away from each other on the phylogenetic tree of life.

Wings are a popular adaptation for many animals. Bats, birds, insects all have wings. A bat is more closely related to a human than a bird or insect based on homologous structures. Even though all these species have wings and can fly, they are very different in other ways.

i) Though bird and bat wings are analogous as wings, as forelimbs they are homologous structures.

ii) Fur of birds and scales in reptiles (lizard) are homologous structures.

iii) Amniotic sac that surrounds the developing embryo in birds, mammals and reptiles is considered as homologous structure.

iv) Lungs are homologous structures common to amphibians, reptiles, mammals, and birds.