anthro lecture exam 2

how to track microevolution in a population

use Binomial Bernoulli equation to look for gene pool and measure allele frequencies

• Hardy-Weinberg Equilibrium Model

gene pool

amt of alleles in a population

Hardy-Weinberg Equilibrium Model

foundational principle that allele and genotype frequencies in a population will remain constant throughout generations if no evolutionary forces are acting upon it

Assumptions of Hardy-Weinberg Equilibrium Model

1. population is indefinitely large

2. there are no mutations/ new alleles being introduced to population

3. no gene flow

4. no selection

5. there is random mating

binomial bernoulli equation

equation for finding allele frequencies in a population:

p + q = 1 —> pq x pq = p² + 2pq + q² (after doing pq pq punnet square)

• if answer to equation changes over time, there is an evolutionary force acting upon population

non-random mating

1. positive assortment mating

2. negative assortment mating

3. inbreeding

positive assortment mating

seeking mates who are SIMILAR to you —> increases homozygosity

negative assortment mating

seeking mates who are DIFFERENT to you —> increases heterozygosity

• HLA antigens and NHC complex: naturally attracted to ppl who are most genetically different from you (scents)

inbreeding mating

consanguinity —> increases homozygosity

• can be very detrimental if autosomal recessive conditions are passed down in family and eventually passed down to offspring

polymorphisms

when a genetic loci has more than 1 allele and occurs in a population at >1% frequency

• usually due to gene flow, genetic drift, or natural selection

lactose

sugar found in breast milk

• digested by all mammals in early development

lactase

enzyme that breaks down lactose

lactose intolerance

when lactase is turned OFF during development and cant break down lactose —> bundles in intestines —> why it upsets your stomach

• usually happens once mammals are adult

how lactose is integrated into different cultures

ppl with lactase still turned on = came from pastoralist ancestry (raised cattle)

• if food famine happens —> still able to get nutrition from milk bc lactase is turned on —> lactose integrated in daily food practice

chromosome 2 mutation

mutation that maintains lactase activity even in adulthood

primitive traits

older/ancestral traits you inherited from common ancestor

• ex: 5 digits on mammals

derived traits

newly evolved traits, not from common ancestor

• ex: bipedal locomotion

primate as primates characteristics

• Grasping hands and feet

• Opposable digits; 5

• Nails instead of claws

• Forward-facing eyes

• large brains + body

• Flexible shoulders and limbs

• longer maturation/ increased lifespan

• generalized diet

• post orbital bar

• decreased reliance on olfaction —> better vision

what makes primates mammals

• body hair

• long gestation (pregnancy) followed by live birth

• mammary glands

• heterodonts

• homeothermy (regulates own body temp)

• increased brain size

• behavioral modification

marsupials

pouched mammals

• ex: koalas, kangaroos

monotremes

egg laying mammals

• ex: platipus

placental mammals

mammals that have placentas (internalized egg)

• creates more developed brain

• ex: humans

streppsirrhines

lemurs (lemuroidea) , lorises and galagos (lorisoidea); 2-1-3-3

• wet nose

• rhinarium

• laterally placed eyes

• shorter gestation/ maturation

• dental comb

• grooming claw

• unfused mandibles

• nocturnal —> tapetum lucidum (can see in dark)

• post orbital bar

haplorrhines

tarsiformes (tarsiers) and anthropoids (monkeys, apes, humans)

• dry nose

• no rhinarium

• eyes facing forward

• bigger brains

• reduced olfaction

• fully enclosed eye orbit

• longer gestation/ maturation

• fused mandible

platyrrhines (haplorrhine —> anthropoid)

NWM; 2-1-3-3 (except callitrichids)

• broad/ flat noses w/ laterally facing nostrils

• cebids (callitrichids)

• atelids

cebids (haplorrhine —> anthropoid —> platyrrhine)

capuchin, squirrel monkeys, marmosets and tamarins (callitrichids)

• western hem monkey

• broad/ flat noses w/ laterally facing nostrils

• grasping tails (semi prehensile)

• 2-1-3-3 dental formula

callitrichids (happlorrhine —> anthropoid —> platyrrhine —> cepid)

marmosets and tamarins

• polyandrous: many males

• gives birth to twins

• reproductive suppression

• males take care of offspring

• 2-1-3-2 dental formula (bc smaller size)

atelids (haplorrhine —> anthropoid —> platyrrhine)

new world/ western hem monkeys (owl monkeys, spider monkeys, howlers, muriqui, titi monkeys)

• broad/ flat noses w/ laterally facing nostrils

• larger bodied monkeys

• prehensile tail

• monogamous

• 2-1-3-3 dental formula

catarrhines (haplorrhine —> anthropoid —> catarrhine)

OWM, greater/ lesser apes, humans

• downward facing nostrils

• greater (hominidae): orangutans, gorillas, chimpanzees, bonobos

• lesser (hylobatids): gibbons, siamangs

• 2-1-2-3 dental formula

greater apes (haplorrhine —> anthropoid —> catarrhine —> hominoid —> hominid)

orangutans, gorillas, chimpanzees, bonobos

• larger body

• larger brain

• absence of tails

• shortened trunk (reduced # of vertebrae)

• suspensory locomotion (shoulder adaptation)

• more complex behavior

• bigger lifespan + period of maturation

cladistics

grouping organisms into branching family trees based on derived traits/ characteristics shared by common ancestor

gradistic (traditional taxonomy)

putting animals into groups based on shared physical traits/ complexion

why tarsiers caused the reorganization of order primates

lacks post orbital bar (boney cup for eye), no rhinarium, no tapetum lucidum, DNA closer to anthropoids —> redo taxonomy

orangutan (Pongo pygmaeus)

• 2-1-2-3 dental formula

• asian apes

• very large bodies

• frugivores (fruit = scarce —> solitary)

• sexually dimorphic

• Noyau = female + dependent offspring (group of orangutans)

Gorilla gorilla

• 2-1-2-3 dental formula

• african apes

• sexually dimorphic

• harem: 1 reproductive male w/ multiple females

• folivores/ herbivores

Chimpanzees (Pan tryglodites)

• 2-1-2-3 dental formula

• closest living relative to humans

• multi male, multi female groups

• strict hierarchy, aggressive

• fission fusion (split into groups to hunt)

• generalized diet

• tool use

Bonobos (Pan paniscus)

• 2-1-2-3 dental formula

• multi male, multi female groups

• no strict hierarchy —> egalitarian

• pith diet —> very friendly

order primate categories

1. order = primates

2. suborder = strepsirrhines + haplorrhines

3. infraorder = tarsiers + anthropoids

4. parvorder = platyrrhines + catarrhines

5. superfamily = cercopithecoids + hominoids

6. family = atelids + cebids + hylobatids + hominids

7. subfamily

8. genus = pongo + gorilla + pan + homo

9. species = pygmaeus + gorilla + tryglodytes + paniscus + sapiens

New World Monkeys dental formula

2-1-3-3 (except callitrichids = 2-1-3-2)

Old world Monkeys dental formula

2-1-2-3 🐒

callitrichids dental formula

2-1-3-2

apes + humans dental formula

2-1-2-3 🦍

humans (Homo sapiens)

• 2-1-2-3 dental formula

• bipedal

• lives in bisexual groups (males bonded to females)

• larger brains relative to size

• highly advanced use of symbolic language

• culture = main adaptive response

• division of labor btw sexes

• relaxation of the estrus cycle (mating occurs throughout estrus cycle)

generalized trait

trait that is relatively unspecialized and can be useful in various circumstances

specialized trait

trait adapted for a particular function or environment

cercopithecoids (haplorrhine —> anthropoid —> catarrhine)

• OWM: baboons, macaques, guenons, colobos, langurs; 2-1-2-3

• downward facing nostrils

• ischial callosites (butt pads)

• mostly arboreal, some terrestrial

hylobatids (haplorrhine —> anthropoid —> catarrhine —> hominoid)

• lesser apes; 2-1-2-3

• gibbons and siamangs

• monogamous (males take care of offspring)

tarsiers (haplorrhine —> tarsiformes)

• no rhinarium

• lacks post orbital bar

• both eastern hem/ old world and western hem/ new world

derived traits of certain primates

• marmosets/ tamarins (callitrichids): birth to twins

• macaques/ baboons (OWM): cheek pouches

• OWM: ischial callosites, bilophodont molars

• NWM: prehensile tails

• strepsirrhines: tooth comb

• great apes + humans: Y-5 molars

• humans: bipedalism

geographical distribution of the primates

• strepsirrhines = madagascar

• OWM, gorillas, chimpanzees, bonobos = africa

• orangutans, gibbons, lorises, macaques, langurs = asia

• New World monkeys (capuchins, howler monkeys, spider monkeys, and marmosets) = Central and South America

brachiation

Moving by swinging from branch to branch using the arms; arm to arm

• Long arms + curved fingers

• Highly mobile shoulder joints

• lesser apes: gibbons + siamangs

knuckle walking

Walking on the ground using the knuckles

• Strong forelimbs

• short back, long arms

• great apes: chimpanzees and gorillas

bipedalism

walking on two legs

• S-shaped spine

• Arched feet, non-opposable big toe

• humans

arboreal quadrupeds

Legs longer than arms for jumping, long tails

• Capuchins, tamarins, marmosets, most OWM and NWM

terrestrial quadrupeds

arms and legs the same size, not as long tails

• OWM (baboons, macaques, guenons)

Vertical clinging and leaping

• long/ strong hindlimbs, short arms

• arboreal

• tarsiers, strepsirrhines

semi brachiation

brachiation w/ aid of prehensile tail

• spider monkeys, howler monkeys, muriquis (NWM)

Visual predation hypothesis

Primates evolved grasping hands, accurate depth perception, and improved visual abilities to catch insects and other small prey on branches

Arboreal hypothesis

Primates evolved traits like grasping hands and feet, nails, and forward facing eyes as adaptations for moving and feeding in trees

angiosperm radiation hypothesis

Primate traits evolved alongside the adaptive radiation of flowering plants (angiosperms)

adaptive radiation hypothesis

organism moves to unpopulated area and disperses to take advantage of different ecological niches

why chimpanzees can’t produce spoken language

lack the same combination of vocal-tract anatomy and fine neural control of speech production that humans possess

• Communicate vocally through calls

• Use gestures and facial expressions

• Learn certain symbols or signs in research settings

• Communicate information about their surroundings and social relationships

ecology

Study of an organism's relationship with everything in its environment

behavioral ecology

Study of the evolution of behaviors, recognizing the rules of the environment

monogamy

1 male + 1 female pair

• male stays w/ female even when not reproducing

• ex: humans, gibbons

polygyny

1 male, multiple females (harem)

• gorillas (both male and females leave offspring)

polygamy

multiple males, multiple females

• strong dominance hierarchy

• baboons, macaques, chimpanzees (male stays, females leave)

polyandry

1 female, multiple males

• marmosets and tamarins

  • cooperative breeding: many help raise offspring, including males and non family members

noyau/ solitary

female and dependent offspring in orangutans

• orangutans (adult males)

philopatry

stays in natal group

sexual dimorphism

physical difference between male and female of a species

• polygyny —> high amt of sexual dimorphism

• polygamy —> lots of sexual dimorphism

• monogamy —> low sexual dimorphism

male-male competition, canine size

why social living is common in primates

1. food/ resource competition hypothesis: increased feeding competition + defends resources easier

2. predation hypothesis: predator avoidance (strength in numbers)

core social group for primates

female and dependent offspring

male and female reproductive strategies

• male: access to females (in order to reproduce)

  • less energy in producing sperm

  • reproductive success can increase by mating with multiple females —> competes with other males for access to mates

  • provides extensive parental care if offspring cant survive w/o it + has enough food for both

• female: access to resources (in order to nourish offspring)

  • Invest heavily in eggs, pregnancy, nursing

  • Often benefit from choosing mates that provide good genes, resources, protection, helps with parenting

r selected lifestyle

population's potential rate of increase

• considered more r-selected if produces many offspring quickly with relatively little investment in each; unstable and unpredictable (has random explosions of carrying capacity)

  • # of offspring: lots

  • low intraspecific competition

  • parental care: short/ limited

  • development: shorter/ rapid

  • age at reproduction: younger

  • offspring mortality: higher

usually with smaller animals (mouse); marmosets and tamarins + strepsirrhines

K selected lifestyle

carrying capacity of an environment

• more K-selected if produces fewer offspring and invests more resources in each; stable and predictable (stays at carrying capacity)

  • # of offspring: few

  • high intraspecific competition

  • parental care: lots/ extensive

  • development: long time/ slower

  • age at reproduction: older

  • offspring mortality: lower

usually bigger in size (elephant); great apes and humans