Evolution of Humans

1. Evolution of Humans Marie Černá

2. Time scheme of EvolutionPrecambrian era 4.0 billion years ago 2.5 billion years ago 4.6 billion years ago 3.5 billion years ago 1.5 billion years ago multicellular eukaryotes (prokaryotes) unicellular eukaryotes

3. Time scheme of Evolution • Paleozoic era (supercontinent Pangea) • 500 million y. a. – plants, fungi, animals colonize land (Cambrian period) • Mesozoic era = “Dinosaurs period” • 250 million y. a. – first mammals • Cenozoic era (after extinction of dinosaurs) • 50 million y. a. – majority of mammals • 5 million y. a. – diversion of humans and apes

4. Time scheme of Human Evolution Homo ergaster

5. Time scheme of Human Evolution • 35 million years ago – dawn ape: anthropoid Aegyptopithecus • 5-7 million years ago - diversion of humans and apes • from the common ancestor • 4 million years ago – ape-man: Australopithecus • 2.4 million years ago – handy man: Homo habilis • 1.9 million years ago – working man: Homo ergaster • 1.8 million years ago – upright man: Homo erectus • 0.5 million years ago – archaicHomo sapiens 0.2-0.03 million years ago – Homo neanderthalensis • 0.2 million years ago – Homo sapiens

7. Important Characters of Human Evolution • Size of brain Australopithecus 400cm3 = Homo sapiens1 300cm3 • Shape of jawbone - shorter and reduced jawbone = flat face, chin protrusion, change of dentition • Upright bearing, bipedal locomotion → skeleton • Reduced sexual dimorphism higher weight of male than female: gorilla 2x = human 1,2x • Changes in social life monogamy with long-term pair-bonding – longer care of the young allows better learning and complex behaviour formula

8. Three Models for the Origin of Humans • Multiregional model – Modern humans evolved in many parts of the world from regional descendants of Homo erectus, who dispersed from Africa between 1 and 2 million years ago. • Monogenesis model (“out of Africa” model) – Only the African descendants of Homo erectus, who dispersed from Africa just 0.1 million years ago,gave rise to all the diverse populations of modern humans. All other regional descendants of Homo erectus, including Neanderthals, became extinct without contributing to the gene pool of modern humanity. • Intermediate model - Modern humans may be the result of a migration out of Africa as well as some genetic contribution from non-African archaic groups.

9. Multiregional Model for the Origin of Humans 1-2 million years ago

10. Monogenesis Modelfor the Origin of Humans 100 000 years ago

11. Proof for Monogenesis Model: • mitochondrial DNA divergence • greater genetic diversity within African populations • studies of DNA from the Y chromosome

12. Three Major Stages of Cultural Evolution • The first stagebegan with nomads who hunted and gathered food on the African grasslands 2 million years ago. They made tools, organized communal activities, and divided labor. • The second stage came with the development of agriculture in Africa, Eurasia, and the Americas about 10 000 - 15 000 years ago. Along with agriculture came permanent settlements and the first cities. • The third stage was the Industrial Revolution, which began in the 18th century. • Through all this cultural evolution we have not changed biologically in any significant way. • Our know-how is stored not in our genes but in the cumulative product of hundreds of generations of human experience, passed along by parents, teachers, books, and, most recently, by electronic means.

13. Literature Biology, eighth edition, Campbell, Reece Unit five: The Evolutionary History of Biological Diversity Chapter 34: Vertebrates Concept 34.8: Humans are mammals that have a large brain and bipedal locomotion Pages 728 – 733