1. Hominoids to Hominins

2. Hominoids Include all nonmonkey anthropoids
The living and extinct gibbons, orangutans, chimpanzees, gorillas, and humans
Earliest hominoid fossils appear 25 mya
Retain some ancestral primate features – bodies adapted for brachiation
Had relatively large brains and shoulders and hips that move freely and some could stand on two legs
Chimpanzees and bonobos are the closest living relatives to humans
Share at least 96% of their DNA

6. Hominoid Characteristics
Largest of the primates
Have the largest brain size in relation to their body
Broad pelvis, long fingers, no tail, flexible arm and shoulder joints
Have semi-upright or upright posture
Except for hominins, their arms are longer than their legs
Teeth are less specialized than those of other animals
molars have a distinctive pattern scientists use to distinguish hominoid fossils from other primate fossils

7. Hominoid Biogeography
24-25 mya the world’s climate became warmer and drier
Tropical rainforests in Africa began to shrink
Many new animals, including new hominoids, evolved as they adapted to the changing environment
23-14 mya as many as 100 hominoid species existed
Early hominoids were more diverse than modern apes and migrated from Africa to Europe and Asia

8. Hominins
The lineage that split from other apes to form humans did so 8-5 mya
Include humans and all their extinct relatives
Have bigger brains than other hominoids, with more complexity in parts of the brain where high-level thought occurs
Face is thinner and flatter, teeth are smaller, thumbs are longer, and wrists are more flexible than that of other hominoids
Are bipedal
Shortened arms, restructured pelvic bones and foot bones, skull attaches inferiorly to the spine
Evolved before many other hominin traits is thus used to identify hominin fossils

9. Disadvantages of Bipedalism
Easier for predators to spot
Can’t run as fast
Greater strain on the hips and back
Uses more energy when standing

10. Advantages of Bipedalism
Adaptation to the new savanna environment
Uses less energy than walking on all fours over long distances
Easier to see and reach food sources
Able to use arms to carry things while walking

11. Ausralopithecines
Lived in the east-central and southern part of Africa between 4.2 and 1 mya
Small (males being 1.5 m tall)
Apelike brains and jaws but humanlike teeth and limb joints

12. Hominin Evolution
Within the last 30 years many more early hominin fossils have been discovered and new genus designations have developed
Kenyanthoropus and Paranthropus were other hominin genus that lived alongside human ancestors but were not directly related
By 1 mya the only hominin species left are of the genus Homo

13. The Genus Homo
3 to 2.5 mya the African environment became considerably cooler, forests became smaller in size, and the range of grasslands was extended
The genus Homo, which includes living and extinct humans, first appeared during these years.
Many scientists believe they evolved from an ancestor of australopithecines
Had bigger brains, lighter skeletons, flatter faces, and smaller teeth than australopithecines
First species to control fire and modify stones for tool use

14. Homo habilis
Earliest species that is generally accepted as a member of the genus Homo
Lived in Africa 2.4 to 1.4 mya
Used stone tools
Had a brain 20% larger that australopithecines
Was small, long armed, and seemed to retain the ability to climb trees

15. Homo ergaster Lived 1.8 to 1.3 mya
Had an even larger brain and was taller and lighter than H. habilis
also had longer legs and shorter arms
First human nose with nostrils facing downward
Had tool use including axes
Migrated in large numbers to Asia and possibly Europe
Evolves into Homo erectus and is thus probably the ancestor of modern humans

16. Homo erectus Lived 1.8 million to 400,000 years ago
More versatile than H. ergaster
Larger than H. habilis and had a bigger brain
Had teeth that were more humanlike
Is was as tall as H. sapiens but had a longer skull, lower forehead, thicker facial bones, and more prominent brow ridge than H. ergaster and H. sapiens
Made sophisticated tools, used fire, and sometimes lived in caves

17. Homo heidelbergensis Lived 700,000 to 300,000 years ago
Considered a transitional species between H. ergaster and H. sapiens
Had larger brains and thinner bones than H. ergaster
Still had browridges and receding chins

18. Homo neanderthalensis
Lived 300,000 to 30,000 years ago
Evolved exclusively in Europe and Asia
Shorter but had more muscle mass than most modern humans
Brains were larger than modern humans
Had thick skulls, bony browridges, and large noses
Lived near the end of the last ice age and had lives of hardship
Bone fractures and arthritis were common
Used fire and constructed complex shelters
Had language
Cared for their sick and buried their dead
May have interbred with H. sapiens

20. Homo sapiens Lived 195,000 years ago until present
Displaced H. neanderthalensis
more slender appearance than all other Homo species
Thinner skeletons, rounder skulls, and smaller faces with prominent chins
Made chipped hand axes and other sophisticated tools
Spears, bows, and arrows
Very versatile
Had complex language and culture
First evidence appears 40,000 years ago, right before Neanderthals go extinct
Express themselves symbolically
First to fish and tailor clothing and domesticate animals

21. H. sapiens evolution
Some scientist believe modern humans evolved multiple times around earth from other primate populations due to convergent evolution
Most scientists believe that humans evolved just once in Africa and migrated to the rest of the earth from there
Supported by mitochondrial evidence
Probably happened in waves several times to populate the earth with interbreeding with species that they displaced