Anth 1000 Exam 2

Taxonomy

assign and organize organisms to categories based on their relatedness or resemblance

Homology

similarities used to assign organisms to the same taxon

Analogy

common traits due to similar environmental pressures

Convergent Evolution

Two different species evolve similar traits but did not come from a common ancestor. EX: bats and birds

Primate Family Tree

Strepsirrhines/haplorrhines

New World/Old World Monkeys

Apes

Primate Tendencies

1. Grasping Ability

2. Reliance on Sight over Smell

3. Reliance on Hand over Nose

4. Brain Complexity

5. Parental Investment

6. Sociality

Strepsirrhines

Our most distantly related primate. Relatively small with a small brain. Nocturnal. Solitary

Haplorrhines

Diurnal. Gregarious and more social. A larger primate than prosimians.

New World Monkeys

Prehensile tail. Arboreal (tree-dwelling). Nasal Morphology. Mainly in South America

Old World Monkeys

Terrestrial. Greater degree of sexual dimorphism. Located in Africa and South Asia.

Ape Species

Gibbons, Orangutans, Gorillas, Chimpanzees, Bonobos

Sexual Dimorphism

noticeable difference between male and female

Orangutans

-Diet: varied diet of fruit, insects, bark, leaves

-Locomotion: more arboreal and climbs trees

-Social arrangements: Males forage alone, females and young stay together, also marked sexual dimorphism

Gorillas

-Diet: vegetation rich diet in bulk

-Locomotion: terrestrial (do not spend time in trees)

-Social arrangement: groups of around 20, lives in Africa, marked sexual dimorphism

Chimpanzees

-Diet: prefers fruit, omnivorous

-Locomotion: lighter weight so more arboreal

-Social arrangement: smaller degree of sexual dimorphism, communities of up to 50 chimps

Similarities (between humans and apes)

1. Learning

2. Tool Use

3. Hunting

4. Symbolic Commutation

Differences (between humans and apes)

1. Share Food

2. Plan, Carry out complex, multistage tasks

3. Spoken Language

4. Classify others as kin of various types and interact w them for life

Primate Tool Use

Termite fishing by Chimpanzees

Jane Goodall's Wild Chimpanzees

Discovered that Chimps make tools, eat and hunt for meat, and have similar social behavior to humans. Completely transformed our understanding of chimps

Bonobos

-Diet: omnivorous, like chimps

-Locomotion: arboreal

-Social arrangement: the community is centered around females

Hominid

Refers to the taxonomic family that includes humans and the African apes and their immediate ancestors

Hominin

refers to the human line after its split from ancestral chimps

Hogopan

hypothetical last common ancestor. the split 6-8 mya into different ecological niches and their diets became specialized

Earliest Potential Hominins

Ardi

Most complete hominid specimen

Close to 4 feet tall, 120 pounds

4.4 mya

Hominin Taxonomy

A. anamensis (4.2-3.9mya) Kenya

A. afarensis (3.8-3.0) East Africa

A. africanus (3.0-2.0) South Africa

A. garhi (2.5) Ethiopia

A. robustus (2.0-1.0) East/South Africa

A. boisei (2.6-1.2) East Africa

*Homo habilis lived alongside A. boisei for about a million years.

Hominin Evolutionary Trends

1. Body size

2. Locomotion (movement towards bipedalism)

3. Cranial capacity (bigger brains)

4. Tool use

5. Dentition (diets based on teeth)

6. Cranial morphology (brow ridge, sagittal crest)

7. Diet

Bipedalism

Ability to see over tall grass

Ability to carry items

Reduces body's exposure to solar radiation

Bipedalism and Physiological Traits

Position of spinal chord in back of skull

Pelvis forms a basket that balances the weight of trunk

The Rift Valley

Where early hominin evolution took place

Dentition and Diet

large molar size in correlation to diet; coarse gritty vegetation for heavy chewing on fibrous foods

Gracile and Robust Australopithecines

Robust - large post canine teeth, large molars, incisors canines reduced, flatter faces, large chewing muscles = heavy brow ridge, large zygomatic arches

Gracile - reduced zygomatic arch, less robust features in general

Oldowan Tools

• used for animal butchering

enabled some species to become omnivorous

• Cores and flakes - flakers were good for cutting and animal butchering

• Choppers for pounding, breaking, or bashing

Competition and Australopithecine Extinction

• Tool users displaced other hominins, pushing them into drier, less diverse zones, and some ultimately to extinction

• Ppl thought Homo habilis was first tool user but A. garhi also used tools

H. habilis

• coexisted w A. boisei for a million years (2.4 - 1.7 mya)

• relatively large brain

• long arges, small body (similar to a chimp)

• used Oldowan tools

H. erectus

• 200,000 yrs after habilis

• modern body and limbs

• even larger brain size

• rapid evolution

H. neandertalensis

• adapted to cold enviornments

• large torso with shorter limbs

• face pulled forward and broad long nose for added insulation for the brain

• more cranial capacity than modern humans

• used Mousterian tools

• wore fur hides

• diet was all meat

H. floresiensis

• 95,000 - 12,000 BP

• found on an island near Indonesia

• hobbit-like, human features

• very small brain

Hunting and Diet and Fire

allowed man to cook foods to make them softer and kill parasites. made man more reliant on hunting.

Anatomically Modern Humans

Homo erectus split into two groups: ancestral Neanderthals and Anatomically Modern Humans (AMH) early ones are known as Cro-Magnon

Behavioral Modernity

behavioral and cognitive traits that distinguishes current Homo sapiens from other anatomically modern humans, hominins, and primates.

Punctuated Equilibrium

periods of stasis followed by periods of rapid change