Midterm 1 Class Notes Flashcards
4 fields of anthropology
- Socio-cultural anthropology
- Linguistics
- Archaeology
- Physical anthropology (biological anthropology)
Socio-cultural anthropology
- ethnography, cross- cultural comparisons, humans, intraspecific
Linguistics
Language across space and time
Archaeology
Human and cultural remains
Physical anthropology (biological anthropology)
- anatomy, physiology
- primatology–> interspecific, across humans and Non-human primates
Why study primates in anthropology?
- primates are our closet living relative (learn about humans through primates)
- like other primates, humans are highly social
Two assumptions that must be true to study primates in anthropology
- That there is a close evolutionary relationship between humans and NHP
- Some morphological and behavioural characteristics we conceive as “human” are actually inherited from our NHP ancestors
Derived
- traits that appeared in a species after the last common ancestor, specialized trait
- example bipedalism
Primitive traits
- ancestral/ generalized
- traits that were probably shared with the last common ancestor
- example pentadactyly
Homology
A trait found in two or more species that is shared due to their common ancestry
Homoplasy
A trait found in two or more species that has evolved independently in each (do not have a shared common ancestor)
Shared traits
A) language and cognition
B) capacity to transform ones environment (ex: took use)
C) transmission of knowledge and the emergence of cultural traditions (ex potato washing)
Examples language and cognition
- Self awareness: mirrors and apes
- use of language
Examples of capacity to transform ones environment
Tool use:
- chimps use tools for fishing termites/ ants
- orangutans testing water depth
- capuchins use hammer and anvil stones to crack nuts
Examples of transmission of knowledge and the emergence of cultural traditions
- hand clasping during grooming
- Stone play
- potato washing by macaques
- indicates social learning
7 things we learn about humans and the human phenomenon by studying NHP:
1) to understand variation in social systems
2) to analyze derived traits
3) to understand early human behaviour
4) more sophisticated modelling: strategic models
5) to understand human behaviour and variation today
6) primates are flagships/ indicator species that can be used as a gauge of ecological disturbance
7) biological similarities mean primates can contribute to biomedical advances
Ways Social systems vary between species:
- number of individuals in a group
- male: female ratio
- degree of sexual dimorphism
- degree of paternal investment in offspring
- quality and intensity if relationships between individuals
Sexual dimorphism
- Morphological differences between males and females (often seen in canines and body size)
- associations between large male canine size and aggressive competition over access to mates
- suggest that if a species of early hominids has markedly sexually dimorphism males, it is likely males were involved in intense conflicts
Referential model
The use of a particular species for drawing analogies with others, when you use one species to understand a different species
Colour blindness
- many capuchin monkeys are colour blind
- colour blind sees camouflaged items better (ex invertebrates)
Primate Order
Mammals
Mammals are:
1: are endothermic (“warm-blooded- generate own body heat)
2. Have hair on bodies
3. Breastfeeding through mammary glands
4. Most are born alive (except monotremes)
Primate order includes:
- genus homo, apes, monkeys, tarsiers, strepsirhines
Genus homo examples
Us, Neanderthals, denisovans
Apes examples
Chimpanzees, gibbons, gorillas, orangutans
Monkeys examples
Baboons, macaques, capuchins, etc.
Strepsirhines examples
Lemurs, lorises, galagos
New world
Mexico, South America
Old world
Africa, Asia
Primate pattern
- no one trait identifies all primates
- general tendencies expressed by all primates= overall primate pattern
- fallen into 4 main complexes
- primates possess combination of ancestral and derived traits
Ancestral (primitive) trait
More closely resembling the common ancestor to the group
- does not mean less successful or less evolved
Derived traits
Specialized traits that are not shared with the last common ancestor
- example guenon facial patterning
4 complexes that make a primate a primate
- Grasping hands and feet
- Visual system
- Large complex brains, and associated behaviour
- Skeletal and dental features
Pentadactyly
- five fingers on hand, ancestral
features of grasping hands and feet:
- pentadactyly (ancestral)
- nail, not claws (derived)
- power and precision grip (derived)
- opposable thumb (derived)
- sensitive tactile pads (derived)
- vast majority have opposable big toe (humans are the exception, human trait is derived)
What is special about callitrichids with the the grasping hands and feet?
- have re-developed claws, within primates this is a derived trait
Traits of the visual system:
- vision is enhanced
- forward facing eyes
- stereoscopic vision (w/ depth perception)
- increased acuity
- trichromatic colour vision
- ancestral
Stereoscopic vision
- accurate depth perception
- an overlap in the visual field from each eye creates a 3-D image
Primate traits associated with the visual system:
- reduced reliance on olfaction
- reduction of the snout
- reduction of the olfactory centres of the brain, increase in visual centres
- flattening of he face (less prognathic)
- Large complex brains
- large brains relative to body size compared to other mammals
- big neocortex
- altricial newborns
- speciality
Big neocortex
link between large brain size, socialist, and learning: responsible for cognitive abilities such as reasoning and conscientiousness
Altricial newborns
- long period of development, born in a helpless state
- birth of single, relatively helpless young
- little reliance on instinct
- social learning is important
- infants are dependent on mothers
- grasping hands that are used to cling so that infants can go with mothers and are not left in nests
Implications of large brain size
- primates as a group have long periods of post natal care
- great ability to learn from experience
- great reliance on learning
Skeletal and dental features
- retention of an unspecialized skeleton, particularly in limb structure:
1. Retention of clavicle or collar bone- allows for greater range of motion that specialized quadrupeds
2. Retention of bones in forearm (radius, ulna) and lower leg (tibia, fibula)- flexibility
3. Reduction # of teeth
4. Trunks uprightness
Dental formula:
#s for half of jaw Incisors. canines. Premolars. Molars.
Humans dental formula:
2.1.2.3 (derived) - 32 teeth in total
Ancestral mammal dental formula
3.1.4.3
Primitive primates dental formula (strepsirhines & NWM)
2.1.3.3
Later primates dental formula (OWM, Apes, Humans)
2.1.2.3
Trunkal uprightness
- derived
- especially enhanced in apes and humans
- only for short periods of time once and a while (when compared to humans)
Why did primates evolve their particular set of traits: 4 theories
- the arboreal theory
- the visual predation theory
- the angiosperm radiation/ co-evolution theory
- fine- branch niche theory
- snake predation theory
Arboreal Theory
- primate pattern represents an adaptation to an arboreal habitat or to life in the trees
- most early mammals were arboreal, but primates stayed in the trees
- grasping hands, stereoscopic vision are assests
- complex 3-D environment with high risks
- proposed by Elliot- smith &a woods-jones (1920) further supported by Les Gros Clark
Arboreal theory objections
- other orders have arboreal species that do not share primate pattern (ie opposums, treeshrews, squirrels, Racoons)
- is claws are a better adaptation for climbing up and down vertical supports as opposed to nails
Visual predation theory
- primate pattern represents an adaptation to foraging for insects in the terminal branches of trees
- Cartmill
- based in comparative method, found similarities to other visual predators
- later adapted to include low light as a component of the hypothesis
Visual predation theory objections
- Fails to explain development of larger primates
- Forward facing eyes and stereoscopic vision are present in non-primate species
- There are visual predators with lateral eye sockets