Biology Now, 2e

308 ■ CHAPTER 17 Animals and Human Evolution

BIODIVERSITY

65 mya

45 mya

35 mya

12–16 mya

7–8 mya

5–7 mya

Old World Orangutans

monkeys

New World

monkeys

Lemurs, lorises,

and others

Gorillas Chimpanzees Humans

Figure 17.7

The primates include lemurs, monkeys, and apes

Genetic analyses and a series of spectacular fossil discoveries have led scientists to propose that

the human lineage diverged from that of chimpanzees about 5–7 million years ago (mya). Similar

evidence suggests that the evolutionary lineage leading to humans diverged from the lineage

leading to gorillas about 7–8 mya, and from the lineage leading to orangutans about 12–16 mya.

Q1: According to this evolutionary tree, which primate group is most closely related to humans?

Q2: According to this evolutionary tree, which primate group is most distantly related to humans?

Q3: What characteristics are common to all the primates, including humans?

our extinct relatives, such as Neanderthals. The

members of the hominin lineage have one or

more humanlike features—for example, thick

tooth enamel or upright posture—that set them

apart from the other apes, like gorillas and

chimpanzees.

Rise of the Apes

A major step in hominin evolution, and the

main feature that distinguishes hominins from

other hominids, was the shift from moving on

four legs to being bipedal, walking upright on