One anatomical difference between cercopithecoids and hominoids is
A. hominoids lack tails
B. cercopithecoids have relatively larger brains
C. cercopithecoids do not have post-orbital closure
D. hominoids rely on their sense of smell for communication
The Correct Answer and Explanation is :
The correct answer is A. hominoids lack tails.
Explanation:
Cercopithecoids (Old World monkeys) and hominoids (apes, including humans) are both part of the primate order but differ in several key anatomical and physiological features. One of the most significant differences is that hominoids lack tails, while cercopithecoids possess them. This distinction is often used to differentiate these two groups within the primate evolutionary tree.
Tails
Cercopithecoids, which include species like baboons, macaques, and colobus monkeys, have tails that vary in length and function. In many species, the tail is not prehensile (i.e., it cannot grasp objects), but it plays an important role in balance and locomotion. In contrast, hominoids, which include gibbons, orangutans, gorillas, chimpanzees, and humans, have evolved without tails. This is a key characteristic of the hominoid lineage and is likely related to their different modes of locomotion and life in the trees or on the ground.
Other Differences:
- Brain Size: Hominoids generally have relatively larger brains compared to cercopithecoids. While cercopithecoids are intelligent, hominoids show a higher level of cognitive abilities, which is reflected in their more complex social structures, use of tools, and communication.
- Post-Orbital Closure: Both cercopithecoids and hominoids have post-orbital closure, meaning their eye sockets are enclosed by bone. This trait helps protect the eyes and is common in higher primates.
- Sense of Smell: Neither group relies heavily on the sense of smell for communication. Primates, in general, have a reduced reliance on olfaction compared to other mammals, relying more on vision and social cues.
Thus, the absence of a tail in hominoids is a defining feature that sets them apart from cercopithecoids.