Which body part is a vestigial structure?
a
horse hoof
b
whale hind limb
c
human arm
d
bat wing
The vestigial structure among the options you provided is the whale hind limb. It is believed that whales evolved from four-legged land animals, and over time, their hind limbs became unnecessary for survival in an aquatic environment. As a result, they have become reduced and rudimentary, serving no functional purpose.
B. Whale hind limb
The vestigial structure among the options provided is the whale hind limb.
To determine this, we need to understand what vestigial structures are. Vestigial structures are anatomical features that have lost their original function through the process of evolution. Over time, as species adapt to their environments, certain body parts may become unnecessary or less useful. These structures can serve as evidence of an organism's evolutionary history.
In the case of the options provided, a horse hoof (a) is not a vestigial structure, as it serves a crucial function in the locomotion and support of the horse. Similarly, human arms (c) and bat wings (d) are not vestigial structures, as they are still actively used by humans and bats respectively.
However, whales are descendants of land-dwelling ancestors, and as they evolved to live exclusively in water, their hind limbs lost their original function, which was likely for supporting movement on land. These whale hind limbs (b) have greatly reduced in size and are no longer used for locomotion. Therefore, the whale hind limb can be considered a vestigial structure.