1. Human Evolution

2. Primate Classification Characteristics: – Eyes in front of the face – Opposable thumb – Well developed brain – Omnivorous D: Eukarya K: Animalia P: Chordata C: Mammalia O: Primate

4. The Geological Time Scale Fossil Patterns were used to create 5 Major Categories of Time (Eras): 1.Archaean 2.Proterozoic 3.Paleozoic 4.Mezozoic 5.Cenozoic Humans Chimpanzees

5. Types of Evolution New species from heritable changes through time (linear) New species from speciation events (branching) Anagenesis Cladogenesis

7. Which pattern did human evolution follow? Anagenesis? Cladogenesis?

8. Aside: Hypothesis Driven Science How do you test hypotheses on the past? – Experimentation is not possible Need to come up with hypotheses that can be tested by observations

9. Evolution Fossils Biogeography Comparative Morphology Comparative Development Comparative Biochemistry

10. FOSSILS 1.The preserved remains or traces of organisms from the past 2.Found in sedimentary rock layers created by water deposition 3.Dated and used to determine Earth’s biological past Over time, fossils found in stratified soil layers show consistent patterns in the diversity of living organisms

11. Outstanding and mysterious question: what has happened to our species since the divergence from the lineage leading to chimpanzees? On November 30, 1974 Donald Johanson and Tom Gray discovered a remarkably complete hominid fossil in Hadar, Ethiopia. This fossil became known as ‘ Lucy ’ and was later determined (by radiometric dating) to be 3.2 million years old. This is one of the most compelling missing link fossils ever found. Lucy was not human—clearly a different species, which was named Australopithecus afarensis—but she was clearly hominid and very different from chimps.

12. What Makes A Hominid? - Bipedalism Primary feature distinguishing hominids from other hominoids is walking erect on two legs – erect bipedalism

13. Why did bipedalism become the primary adaptation of hominids? 1. Carrying behavior 2. Heat stress - facilitates heat loss through convection by exposing body to air currents, only humans have sweat glands that produce moisture to cool body 3. Most energy efficient way to travel long distances 4. Allows for better vision in open environments & defensive action against predators by freeing hands to throw objects

14. Was Lucy bipedal? Footprints in volcanic ash at Laetoli (3.7 million years old) The impressions in the ash suggest that weight was shifted during walking like a modern bipedal human rather than like a modern chimpanzee. Chimp Human

15. Other evidence for bipedalism. Chimp pelvis Lucy pelvis Angle that the femur makes with knee also is important, and different in bipeds than in chimps. This arrangement more efficient for bipedalism.

17. Variation within and between species Homo sapiensAustralopithecus afarensis How much “normal” variation can there be within a species?

18. Normal % Variation Standard Curve (Bell-shaped) N%V=((4*sd)/mean)*100 Mean 1 sd=66% 2 sd=95%

19. Lab Hints “R” program for statistics is on CU Learn website After completing one set of skull measurements, I will give you a handout with the rest Measure facial projection with zygomatic arches parallel to the floor (skull tilt affects the measurement) Lab report due next week There will also be a quiz next week.