Chapter 16.2, Problem 3MI

Summary Introduction

To define:

The given vocabulary terms using a book or a dictionary.

Introduction:

The lineage that led to humans split off from the other African apes occurred sometime between 8 and 5 mya. Hominins include humans and all their extinct relatives. The evolutionary changes in hominoids led to bipedalism in hominins. The earliest fossils of species that show some degree of bipedalism are 6- 7 million years old.

Answer to Problem 3MI

Hominoid- It includes all non- monkey anthropoids such as the living and extinct gibbons, orangutans, chimpanzees, gorillas and humans.

Bipedal- It is the ability to walk upright on two legs.

Australopithecine- Theseare the hominins that lived in in east- central and southern part of Africa between 4.2 and 1 mya.

Explanation of Solution

The fossil transition from early anthropoid to ape is not distinct as very few fossils from the late Oligocene exist. The oldest hominoid fossil appears in about 25 mya at the beginning of Miocene. These hominoids retained some ancestral primate features.

Hominoids are the largest of the primates and they have the largest brain size in relation to their body size. They have semi- upright or upright posture and except for hominins they have arms longer than their legs. The oldest known hominoid fossil is from the genus Proconsul . It is considered to be the human ancestor. The hominins include humans and all their extinct relatives. Homo sapiens have evolved from hominoids.

Bipedalism is an important feature of hominins. It helped them to adapt to the new savanna environment.The first hominins that were truly bipedal were the australopithecines. They were small and had apelike brains and jaws. Their teeth and limb joints resembled those of humans.