20.1 Identifying Primates Opposable thumbs Wide range of limb motion Leg and foot structure Binocular vision: both eyes view same object at the same time, but from slightly different angles Color vision Large and advanced brains Methods of Communication Omnivorous One offspring born at a time- extra care Relations between primates

Chimpanzees and humans have similar brain sizes Hippocampus Bipedal Walking: upright walking Speech enabled by structure of vocal cords, mouths, tongues, ears Shared traits between primates and humans -Humans are more closely related to gorillas and chimpanzees than any other type of primate

Primates and Humans

20.2 Comparing Skeletal Evidence Hominids: human like animals, are bipedal Anthropologists compare skeletons of hominids to present-day humans Important features: skull, backbone, pelvis, femur Shape of features suggest lifestyles/whether animals could be related

Hominid Skulls

20.3 Comparing Molecular Evidence Some features too complex to examine genetically -Facial features, body size Homo sapiens are the only surviving species of humans. Humans and chimps are most closely related. (We did the molecular data thing.) Differences in codon frequency can determine similarity (e.g. AGA or CGC) - E. coli uses CGC 39 times more than AGA, while almost equal use in humans DNA can only very rarely be extracted from fossils.

Molecular data, fossils, radiometric age dating Determine when and where ancestors lived Ways to determine age of fossil Stratigraphy Rough picture of Earth’s geological historyRough picture of Earth’s geological history Can arrange fossils according to where they were foundCan arrange fossils according to where they were found Study groupings of fossil species Organisms that lived at same time, died at same timeOrganisms that lived at same time, died at same time Already dated fossils help date newly found fossilsAlready dated fossils help date newly found fossils Radiometric age dating Isotopes of several elements decay at known and constant rates – measured in rocks and fossilsIsotopes of several elements decay at known and constant rates – measured in rocks and fossils Scientists select an isotope to compare in the fossilScientists select an isotope to compare in the fossil Active area of research Dating Human Fossils

~Movie Time!~ Stratification Radiometric Age Dating Fossils

20.5 Early Hominids Fossils tell of evolutionary traits Hominids Ancestors to common humans Homo Genus of Homo sapiens (human) Walked upright Australopithecines Similar to hominids First hominids found in Africa (Lucy) Examining Skulls Difficult to determine species due to sex differences Changes in facial features show evolution

The first humans Scientists are constantly finding new fossil evidence as to the earliest ancestor to modern humans Possibly the closest physical resemblance of an ancestor has been found to be a adolescent boy who lived about 1.6 million years ago. A fossil of a creature very similar to a human has been found that was alive 1.9 million years ago yet its brain is only half that of a modern human’s

Distribution of humans Homo erectus or H. erectus is thought to have originate in Africa. By 1 million years ago H. erectus had migrated to southeastern and eastern Asia. H. Erectus stayed physically stable until as late as 300,000 years ago. Human fossils have been found in Europe from up to 780,000 years ago and are most likely ancestors of Neanderthals.

Neanderthals Scientists are still trying to determine whether Neanderthals were a different species from homo-sapiens. Neanderthals were much physically stronger and possibly had a more advanced culture than Homo-sapiens-sapiens. Much about Neanderthals has not been explained but they survived until 28,000 years ago when at that time they were rapidly replaced by Homo-sapiens (modern humans)

Human advances Despite the lack of physical changes H. sapien- sapiens made many advances in culture After Homo-sapiens appeared in history they made many advances in culture, such as improved craftsmanship, language, hunting and settling. Also H. Sapiens were taller than their ancestors showing maybe a departure from cave dwelling to living more in the open.

Allele frequencies in relation to interbreeding 1. In Europe allele frequency of type B blood 2. Spain had almost no people with type B blood 3. Now through interbreeding they have 10 –15 percent 20.7 Gene Pools

Genetic Disorders Sickle-cell anemia found in costal Africa, India, and countries bordering the Mediterranean Interbreeding caused this to spread and become more prevalently heterozygous The heterozygous form of this disease prevents malaria so it is somewhat beneficial