Final answer:
The Hominini subtribe, including humans and our direct ancestors, is characterized by bipedalism, larger brains, and opposable thumbs, while apes generally exhibit larger body sizes, lack tails, and have knuckle-walking locomotion. Great apes are more closely related to humans but maintain distinct differences, particularly in locomotion and brain size. Both groups adapted to their environments, with environmental pressures influencing their evolution.
Step-by-step explanation:
Hominini and apes are both part of the biological family Hominidae but have distinct characteristics. Members of Hominini, which includes modern humans (Homo sapiens) and their direct ancestors, are defined by key adaptations such as bipedalism (upright posture), larger brain sizes relative to body size, and a fully opposable thumb. For example, the early hominin Australopithecus shares a common ancestor with great apes and had both ape-like characteristics, like sexual dimorphism, and humanoid traits like bipedalism.
In contrast, apes, which evolved from catarrhines around 25 million years ago, are typically larger than monkeys and lack a tail. While apes are intelligent and capable of moving through trees, they generally spend more time on the ground and walk quadrupedally using their knuckles in contrast to the palm-walking monkeys. Great apes include Pan (chimpanzees and bonobos), Gorilla (gorillas), Pongo (orangutans), and Homo (humans), with humans being the only habitually bipedal species.
Notably, early hominins adapted to changing environments, which might have contributed to their evolution into bipedal creatures capable of crafting tools and developing complex social structures. Homo habilis, which evolved from an ancestor shared with Australopithecus, exemplifies the transition with attributes of large brains and smaller teeth reflective of humans but still maintained many ape-like features.