Question

homework - evidence of evolution
the image shows the analogous forelimbs of two animals that are adapted to live in water
shark (fish) dolphin (mammal)
fin flipper
what can be said about the two animals after studying the image?
the forelimbs are structurally alike as the animals have a common ancestor
the forelimbs have become structurally alike due to exposure to similar habitats
the forelimbs are structurally different as the animals belong to different vertebrate classes
the forelimbs have become structurally different as the animals occupy different environmental niches

Explanation:

Analogous structures are those that have similar functions but different evolutionary origins. Sharks (fish) and dolphins (mammals) are not closely related (different vertebrate classes - Chondrichthyes for sharks and Mammalia for dolphins), but they live in similar aquatic habitats. Natural selection has led to the development of similar - looking forelimbs (fin in shark, flipper in dolphin) for swimming (similar function) despite different underlying skeletal structures (different evolutionary origins). So, the forelimbs have become structurally alike due to exposure to similar habitats (convergent evolution).

Answer:

The forelimbs have become structurally alike due to exposure to similar habitats.