1. Human Evolution

2. Evolution of Homer

3. Background Info Primates Evolved ~65 million years ago
Current members include lemurs, lorises, pottos, tarsiers, monkeys, and apes (lesser and greater), etc.

4. Apes differ from other primates in that they lack prehensile tails
Lesser apes - gibbons
Greater apes (hominoids) – chimps, orangutans, gorillas, bonobos, and HUMANS

5. DRAW Fig 32-15, pg. 834

6. Trends in Primate Evolution
Hair and nails instead of fur and claws.
Five digits with an opposable thumb.
Well developed cerebrum.
Binocular vision (both eyes in front improved depth perception) and retina with both rods and cones for color vision.
Reduction in the sense of smell.
Longer period for parental care and learning.
Uprightness
Freed the hands to develop and use tools
Gave better vision (higher up and straight forward)

7. Primate Evolution Movie

8. Comparing Human and Gorilla Skeletons
Hominid Evolution
About 4 million years ago, ancestors of humans and apes diverged
Hominids include modern humans and extant human-like forms
Evolved with bipedal motion (walk upright) and larger brains
Comparing Human and Gorilla Skeletons
Modern Gorilla
Modern Human
Modern Gorilla
Skull atop S-shaped spine
Spinal cord exits at bottom of skull
Arms shorter than legs; hands do not touch ground during walking
Pelvis is bowl- shaped
Thigh bones angled inward, directly below body
Skull atop C-shaped spine
Spinal cord exits near back of skull
Arms longer than legs; hands touch ground during walking
Pelvis is long and narrow
Thigh bones angled away from pelvis

9. In 1978, members of a team led by Mary Leakey discovered the fossilized footprints of human ancestors in Laetoli, Africa. The footprints were formed 3.6 million years ago when at least two individuals walked over wet volcanic ash. The wet ash hardened like cement and was then covered by more ash.
The footprints show that the individuals had perfect, two-footed strides. They also reveal that one hominid was larger than the other. The imprints left behind at Laetoli clearly show the weight distribution of true upright walkers.

10. Laetoli Footprint Movie

11. Hominid Evolution Timeline
About 20 different species of hominid fossils categorized so far
Many are not direct ancestors of humans
Tree of life has many dead end branches
Hominid Evolution Timeline
Trends in hominid physical traits toward Homo sapiens
Jaws and teeth are smaller
Cranium (skull) is larger
Forehead is less sloped
Hips are wider
Dispelling misconceptions about Homo sapiens
Did not evolve from monkeys
Did not co-exist with dinosaurs
Humans evolved like every other species on Earth
Cranium is larger and rounder to accommodate increasing brain size especially frontal cortex, jaws and teeth are smaller because we learned to cook our food. Dinosaurs went extinct mya

12. Some Hominid Species Sahelanthropus tchadensis
Oldest known hominid fossil (7 million years old) named “Toumai” found in Chad, Africa
Primitive ape-like features (small brain size cc) mixed with later hominid features (small canine teeth and brow ridges)
Thought to be close to original ancestor of chimps and humans, as it is from time apes and hominids diverged
May not be a true hominid, as not enough fossil evidence exists and its spinal cord hole in the skull is far back like an ape’s

13. Toumai Movie

14. Australopithecus afarensis (3-4 mya)
~ 300 fossils found, “Lucy” is most famous
Lived in Eastern Africa in savanna woodland
Features:
Apelike, 1 meter tall, ~50 lbs
Lived in groups, ate fruit, nuts, seeds
Bipedal with locking knees
A direct relative
Lucy was found by Donald Johanson and Tom Gray on the 24th of November, 1974, at the site of Hadar in Ethiopia

15. Australopithecus Afarensis Movie

16. Homo habilis (1.5 - 2 mya) Lived in eastern Africa, savanna woodland
Features:
more humanlike
smaller jaw and teeth
diet: generalized diet, included meat
“handy man” – used simple stone tools for scavenging large animals (bone marrow) and preparing vegetables
a direct ancestor or close “cousin”
Used tools to crack open bones and eat marrow = more fat in their diet, allowed brain to evolve

17. Homo erectus (1.8 million – 300,000 years)
Originated in Africa were nomadic and migrated into Asia and Europe
Features:
More human like but still had many ape-like features
Much larger brain than previous hominids
Worked cooperatively and hunted large animals.
Extremely strong
Used advanced tools (hand axe and fire)
A cousin
Turkana boy. May have lived at same time as Neaderthals

18. Homo neanderthalensis (200,000 – 30,000 years ago)
Location: Siberia, Europe & Middle East, cold woodlands and tundra (Ice Age)
Lived at the same time as early Homo sapiens
Many Neandertal skeletons show signs of broken bones and other traumas. A study by Erik Trinkaus and Tomy Berger showed that the pattern of bone injuries was very similar to that of rodeo riders (Gore 1996). This suggests that Neandertal hunting involved quite a lot of close-quarters contact with large and savage animals. Neandertals apparently never invented thrown projectiles, and their spears seem to have been designed for thrusting while being held

19. Large brain, large brow bone, no chin
Features
Short, stocky bodies
Large brain, large brow bone, no chin
Reliance on meat, some vegetables
Purposeful burial of dead
Used simple “language” - FOXP2 gene allowing for complex speech and language
DNA studies do not show Neanderthals to be direct ancestors of modern humans, but our genes differ by only 0.5%
Chimps are 98.9% identical to humans
Extra Credit: Read National Geographic article about Neanderthals and complete 8 question online quiz

20. Skull Comparison of Hominids
Large brow
ridge
Large nose
Large canine
teeth
Face protrudes
forward
Australopithecus afarensis
Homo erectus
Round, high
skull
Weak brow
ridge
Large brain
case
Inflated
cheeks
Large nose
Even teeth
Strong chin
Neanderthal
Cro-Magnon
Modern Homo sapiens
HUMAN FAMILY TREE

21. Human Family Tree

22. Homo sapiens (195,000 y.a. – present)
Location: from Africa then migrated, reached Australia 60,000 years ago, North & South America 12, ,000
Features:
Lighter skeletal build
Large brain (1350 cc)
Small eyebrow ridge
Prominent chin
Larynx in the throat is lower allowing for complex language
FOXP2 gene (evolved ~100,000 y.a.)
Modern forms of Homo sapiens first appear about 195,000 years ago. Modern humans have an average brain size of about 1350 cc. The forehead rises sharply, eyebrow ridges are very small or more usually absent, the chin is prominent, and the skeleton is very gracile. About 40,000 years ago, with the appearance of the Cro-Magnon culture, tool kits started becoming markedly more sophisticated, using a wider variety of raw materials such as bone and antler, and containing new implements for making clothing, engraving and sculpting. Fine artwork, in the form of decorated tools, beads, ivory carvings of humans and animals, clay figurines, musical instruments, and spectacular cave paintings appeared over the next 20,000 years. (Leakey 1994)
Even within the last 100,000 years, the long-term trends towards smaller molars and decreased robustness can be discerned. The face, jaw and teeth of Mesolithic humans (about 10,000 years ago) are about 10% more robust than ours. Upper Paleolithic humans (about 30,000 years ago) are about 20 to 30% more robust than the modern condition in Europe and Asia. These are considered modern humans, although they are sometimes termed "primitive". Interestingly, some modern humans (aboriginal Australians) have tooth sizes more typical of archaic sapiens. The smallest tooth sizes are found in those areas where food-processing techniques have been used for the longest time. This is a probable example of natural selection which has occurred within the last 10,000 years (Brace 1983).

23. Cro-Magnon man (40,000 years ago)
“caveman”
gene microcephalin, which increases brain size, shows up at 37K y.a.
sophisticated culture
tools of bone and antlers, clothing
cave paintings, sculptures, musical instruments, jewelry
The gene Microcephalin (MCPH1) regulates brain size and has evolved under strong positive selection in the human evolutionary lineage. We show that one genetic variant of Microcephalin in modern humans, which arose ~37,000 years ago, increased in frequency too rapidly to be compatible with neutral drift. This indicates that it has spread under strong positive selection, although the exact nature of the selection is unknown. The finding that an important brain gene has continued to evolve adaptively in anatomically modern humans suggests the ongoing evolutionary plasticity of the human brain. It also makes Microcephalin an attractive candidate locus for studying the genetics of human variation in brain-related phenotypes
Mammoth ivory flute
Cro-magnon cave paintings

25. 5. DNA evidence
Mitochondrial DNA (mtDNA) is passed from mother to child
Y chromosome is passed from father to son
Areas of both the Y chromosome and mtDNA get occasional harmless mutations at a constant rates that are called “markers”
We can calculate when and where a genetic marker occurred
By comparing genetic markers to those of native peoples today, it tells us when in time the mutation occurred and the migration patterns of hominids

26. Human DNA Movie

27. Homo sapien Migration