1. Earth History GEOL 2110 The Dawn of Humans and the Effects of Climate on Civilizations The Pleistocene Epoch The Dawn of Humans and the Effects of Climate on Civilizations

2. Major Concepts Climatic changes produced distinctive flora and fauna that was adapted to cold weather Among flora were the expansion of grasslands, tundra, boreal spruce forests, and hardwood forests Among the fauna, cold adapted mammals such as mastodons, mammoths, wooly rhinos, giant bison, ground sloths, and saber-toothed cats flourished. The first hominids appeared about 7 Ma; the genus homo, bipeds with big brains, appeared around 1.8 Ma just as glaciation took off. The first modern humans (homo sapiens) appeared about 90,000 ybp in East Africa and expanded to Asia and Europe by 40,000 ybp. Expansion to the Americas occurred round 12,000 as the Laurentide Ice sheet began to retreat

3. Effect of Glaciation on Flora

5. Buried Forest at Two Creeks, WI

6. Effect on Fauna 40,000 ybp La Brea Tar Pits, Los Angeles

7. Effect on Fauna Mammals at the La Brea Tar Pits Herbivores Columbian mammoth (Mammuthus columbi) American mastodon (Mammut americanum) Harlan's ground sloth (Paramylodon harlani) Jefferson's ground sloth (Megalonyx jeffersonii) Shasta ground sloth (Nothrotheriops shastensis) Giant bison (Bison latifrons) Ancient bison (Bison antiquus) American camel (Camelops hesterus) Stilt-legged llama (Hemiauchenia macrocephala) Western horse (Equus "occidentalis") Mexican horse (Equus conversidens) Peccary (Platygonus compressus) Pronghorn (Antilocapra americana) Dwarf pronghorn (Capromeryx minor) California tapir (Tapirus californicus) Elk (wapiti) (Cervus canadensis) Deer (Odocoileus sp.) Carnivores Short-faced bear (Arctodus simus) Brown bear (Ursus arctos) Black bear (Ursus americanus) Scimitar cat (Homotherium serum) Sabre-toothed cat (Smilodon fatalis) American lion (Panthera leo atrox) Jaguar (Panthera onca augusta) American cheetah (Miracinonyx inexpectatus) Cougar (Puma concolor) Bobcat (Lynx rufus) Dire wolf (Canis dirus) Gray wolf (Canis lupus) Coyote (Canis latrans) Weasel Omnivores Human (La Brea Woman) Raccoon Skunk Brown bear

8. Fig. 16.29 Evolution of Primates Tetonius, an early primate of the Early (warm) Eocene, Western North America Similar to present day lemurs of Madagascar Cooling through the Cenozoic limited their range to Africa Fossils are rare due to their upland existence

10. Aegyptopithecus Early ape, Oligocene ( Sivapithecus Miocene (8 Ma) ape ancestor to our species Mid-Cenozoic Apes develop Hominoid attributes

11. Molecular evidence Biological Similarities between Humans and Apes chromosome structure - mostly identical amino acid sequences for hemoglobin (all 287) are identical in chimpanzee and humans (we differ from gorilla in only two amino acids, and from orangutan in only four) comparison of all genetic material reveals that humans differ from chimpanzees in only 1.6% of their DNA (gorillas differ by 2.3% from chimpanzees) genetic data also suggests that the separation from the gorilla lineage occurred about 10 million years ago and the human lineage split from that leading to chimpanzees about 7 million years ago genetically humans are a lineage in the anthropoid class - we are closely related to great apes

12. Anatomical Differences with Apes two major differences make humans unique balanced bipedal posture – head is balanced on the spinal column – rib cage is more barrel shaped – backbone is re-curved and the pelvic structure is rotated – our legs are twice as massive compared to our bodies as gorillas and our arms only 2/3 as massive – our hind limbs (legs) are proportionately longer and altered to permit striding gait large brain to body weight ratio – unlike in apes and other mammals, the human brain continues to grow for a year after birth – our huge mental capacity allowed for the development of language and a unique culture

13. Evolution of Humans Homonids split from Ape relatives 6-7 Ma

15. Between 6 and 3 Ma the record is patchy, but: Ardipithecus from about 5.8 - 4.4 Ma Australopithecus (including Lucy): big molar teeth and jaw structure hips intermediate between chimps and humans Genus Australopithecus Appears 4.2 Ma

16. Australopithecus afarensis Lucy About 3.5 My old Lucy 20 yrs old 3.5’ tall

17. Laetoli footprints (3.5 million years old)

18. Paranthropus (large toothed) co-existed with genus Homo go extinct around 1.3 Ma with a number of other African mammals Australopithecus Genus Splits at 2.7 M into Homo and Papanthropus lineages

19. Homo erectus appears about 1.6 Ma, with strong resemblance to modern humans limbs designed for long-distance running Disperses out of Africa around 1.0 Ma to Dmanisi, Georgia Takes on the behavior of large carnivores Disperses as far as China and Indonesia Like apes, grew up early and died young Developed the hand axe First use of fire around 700,000 years ago Homo habilis (“The Handy Man”) fossils about 1.75Ma stone tool artifacts attributed to Homo appear around 2.6 Ma larger brain, about 700 to 1000 cc in capacity

20. Dmanisi ‘Ubeidiya, Israel 1.4 my 1.4 my Mojokerto 1.8 my ? Sangiran 1.66 my ? Nihewan, China 1.6 my Spain 1.2 my Italy 0.8 my

21. Tools since 2.6 Ma Perhaps marking the first appearance of Genus Homo

22. Homo Erectus ~1.7 Ma (onset of continental glaciation) migrate to Java and China Neanderthals disperse throughout Africa and Europe 500,000 to 30,000 years ago Homo Sapiens greatly expanded in numbers and migrated out of Africa around 75,000 years ago

24. Migration into the Americas

25. Climate effects on Humanity since the glaciers left Lush environment in the Nile and Tigris River Valleys Large Mammals go extinct due to overhunting and warming of climate Drought and famine hit the Mediterranean Greenland settled Famine & disease in Europe, Greenland abandoned Potato Famine

26. The Dawn of Humans Next Lecture The Pleistocene Epoch The Dawn of Humans Chapter 16 (p. 485-499)