exam 2 bio anthro

Adaptation

long-term genetic changes in response to the environment.

Interspecific variation

differences between species

Intraspecific variation

differences within species

Parapatric speciation

reproductive isolation due to extreme changes in habitat rather than physical barrier

Allopatric speciation

reproductive isolation due to a physical or geographic barrier

Australopithecus afarensis:

- found in east africa

- ape-like skull & teeth

- expanded neocortext

Australopithecus africanus:

- found in south africa

- 1st species to have parabolic dental arcade

- 1st to have precision-grip hand anatomy

Homo erectus

- found in africa, asia, europe

- 1st species to migrate out of africa

- 1st cook food and incorporate lots of meat into diet

- modern limb porportions

Homo heidelbergensis

- found in africa, asia, europe

- 1st to hunt large game

- expanded frontal & parietal lobes

Homo sapiens

- migration to australia & the americas

- 1st species to make & use projectile weapons.

- canine fossa; chin, vertical forehead

Neanderthals

- found in europe, asia

- mid-facial prognathism, occipital bun

- 1st to intentionally burry their dead

somatic editing

- targets & affects specific cells only

- changes aren't passed down to future generations

germline editing

- applied to sperm, egg, or embros

- affects all fetal cells

- changes can be passed to future generations

Anatomical characteristics shared by all primates

- flexible limbs

- opposable thumbs/five digits

- generalized dentition

- primarily omnivorous

- k-selected

- binocular & stereoscopic vision

Behavioral characteristics shared by all primates

- tend to live in social groups

- more reliant on flexible, learned behaviors

k-selected

- longer pregnancy

- spend more energy on parental care

- reach sexual maturity "late"

- longer lifespan

primate suborder

- strepsirhini: "wet nose"

- haplorhini: "dry nose"

primate infraorder

- tarsiiformes (tarsiers)

- platyrrhini (monkeys)

- catarrhini (apes, humans)

primate superfamilies

- cercopithecoidea

- hominoidea

primate suborder: strepsirhini "wet nose"

- lemurs, lorises

- long snout

- dental comb

primate suborder: haplorhini "dry nose"

- tarsiers, monkeys, apes, humans

primate infraorder: tarsiiformes (tarsiers)

- huge eyes

- only carnivorous primate

primate infraorder: platyrrhini (monkeys)

- new world monkey

- prehensile tail

primate infraorder: catarrhini (apes, humans)

- old world monkeys, apes, humans

primate superfamilies: cercopithecoidea

- old world mokeys

- bilophodont molars

primate superfamilies: hominoidea

- apes, humans

- y5 molar

Skeletal adaptations for bipedalism

- Anterior placement of the foramen magnum

- "S-shaped" spine

- "Bowl-shaped" pelvis

- Linea aspera: raised ridge along the back side of the femur

- Bicondylar angle: "inward" slant from hip to knee

- Large, non-divergent hallux

- Longitudinal arch in foot

Provisioning hypothesis

- Explanation: bipedalism evolved to free male hands for carrying food to mates/offspring

- Suppporting evidence: reduced sexual dimorphism in canine

- Limitations: only explains bipedalism in males

Postural Feeding hypothesis

- Explanation: bipedalism evolved in trees as a food collection strategy

- Suppporting evidence: living primates adopt bipedal posture to get food in trees

- Limitations: doesn't explain why only hominins became bipedal

Thermoregulation hypothesis:

- Explanation: bipedalism evolved to help body stay cool

- Suppporting evidence:supported by experiments

- Limitations: experiments were unrealistic

Unique dietary adaptations found in the "robust" Australopiths (Paranthropus)

- sagittal crest

- flared zygomatics

- huge molar teeth

The Pre-Australopith species

- salhelanthropus tchadensis

- orrorin tugenenis

- ardipithecus ramidus

why salhelanthropus tchadensis status as hominin is debated

- skull has intermediate foramen magnum

- femur had no bipedal adaptation

why orrorin tugenenis status as hominin is debated

- femur with long neck & obturador extursus groove

(obturador extursus groove found in bipeds, but also in quadrupeds)

why Ardipithecus ramidus status as hominin is debated

- foot lacks bipedal adaptations

- foot had a divergent hallux and no longitudinal arch

Australopithecines behaviors

- diet mostly plant based; no evidence of large game hunting

- combined arboreal & terrestrial lifestyle

- long arms, curved fingers, bipedal adaptations

- may have had less competitive social organization

Early Homo behaviors

- greater emphasis on meat consumption

- scavenging, possible persistence hunting

- 1st evidence of fire control & cooking

- greater population density

homo neanderthalensis: distinct, separate species

- natural examples of hybridization

- morphological differences behaviors are more plastic than biology

homo sapiens neanderthalensis : one of us humans

- genetic evidence of frequent long-term breeding/genome integration

- biological species concept = mate recognition

- similarities in material culture