Ecology Flashcards
what does food kind/proportion/seasonality explain?
primating ranging habits
group patterns
social patterns/commpoisions
types of consumption
nut crackin
teeth and hands
ripping plant foods
non-specialized primates?
homoinoids
specialized folivorous primates examples?
cercopithecines: cheek pourches
colobines: sacculated stomacths
what nutrients do we need and why
fat= for body temperature sugar= energy protein= growth and development
why are humans altricial despite being k-selected?
‘big head problem”; humans head is bigger than birth canal so humans born underdeveloped=
- first year of life is extra-uterine development
- thus humans are ‘SECONDARILY ALTRICIAL”
adolf poamana termed…
‘sekundärer nest hocker’; secondary altricial nature of humans
types of resource competition
within group+ between group
scramble + contest
scramble competition (definition)
when food is disperesed + no one can monopolize
‘more or less situation
contest competition (definition)
when food is clumped/high quality and winner gets greater share
(‘all or nothing’ situation)
competition for a resource in which the winner physically deters another organism from obtaining part or all of a fought-over resource
where is scramble competition common
in terrestial/herbacious environments with low quality but abundant food:
- grass
- leaves
- terrestial hebacious vegetation (THV)
primates examples of scramble competition
geladas (grass)
howler, colobus (leaves)
gorilla (THV)
types of contest competition food
fruit
gum
insects
mammalian prey
(high quality but rare)
examples of primates who engage in contest competition
vervets for fruit
tamarins for gyum
chimps for insects
baboons for mammal brey
Competition for food resources is generally inferred from
any of the following observations…
(1) female dominance hierarchies within groups;
(2) female aggression between groups;
(3) increasing home-range size with increasing group size;
(4) longer day-range length with increasing group size; and
(5) lower reproductive rates in larger groups.
within group contest…
per capita food intake depends on dominance= as group rize increases you eat less if you’re low ranking
contest between group competition
the TOTALLY more dominant group gets more
differences of competition between males and females
males; for ova (fight to death= contest)
females: scramble for food (more bickering)
intragroup scramble competition:
- how much aggression?
- how much kin support?
- how is the rank stability?
- how do groups change hierarchy?
rare aggression
rare kin support
low rank stailibity
groups change by migration, egalitarian, individualistic/nonlinear
intragroup contest competition:
- how much aggression?
- how much kin support?
- how is the rank stability?
- how do groups change hierarchy?
common aggression
common kin suport
high rank stability
groups change hierarchies by: splitting, linear, despostic and nepotism
differences of competition between males and females
males; for ova (fight to death= contest)
females: scramble for food (more bickering)
van shaik ‘synthethic model’ of competition
scramble and contest competition vary according to resource, predators and phylogeny variables
van shaik ‘synthethic model’ of competition
scramble and contest competition vary according to resource, predators and phylogeny variables
what is female group living decided by
- resource defense
2. predator defence
richard wrangham 1979 hypothesis of female group living
for resource defense:
–> higher access as a group to food patches resulting in range defense or cheek pouch competitions
van shaik 1983 hypothesis of female group living
for predator defense (all or nothing)= ecological pressure:
small groups have more food but less protection therefore big groups allow for better protection and reproductive potential
predation; affects LIFEtime reproductive output over DAILY reproductive output
types of primate predators
snakes
raptors
cats
other primates
robin dunbars testing of Wrangham Hypothesis
–> prediction; birth rates increase as group size increases
findings= intragroup competition fo rresources outweights intergroup competition in large groups;
so within group competition sets limit to the group size
robin dunbars hypothesis testing of Van Shaik
–> prediction; birth rates decline with increasing group competition ecause nothing counteracts within group competition
findings= all or nothing situation
Robin Dunbar Conclusion about why females live in groups
when high predataion risk= sets lower limit of group size
when high intra-group competition= sets upper limit
socioecological model
diveristy in social systems determined by environmental characteristics
role of the environment
‘where to survive’;
important for females who need resources/nutrients to increase their own reproductive potential
why do females need resources
- high costs of paternal care such as pregnancy or lacation
- limited resource influence birth rate and offspring survival
- safety (predator) influences birht rates/ofsfpring suvival
Robert Trivers 1972: Variances of Reprodutive Success
reproducitve succes varries more among males than females as females have greater paternal investment due to costs/energy of pregnancy, lactation and care
differences in reprodutive potential: (higher female investment needed to produce an offspring)
males have one sperm
females have one ovum, pregnancy and lcatiation
variance between female and male offspring production
on average; they produce the SAME mean offspring but the BARIANCE differs as males can sire more offspring but females will always have the same number of children.
ecological determinism
diversity recorded in social systems accounts is accounted for characteristics in the environment.
colobine adaptations
specialized guts to deal with folivory diets
what does a fruit rich diet teeth look like
thick enamel for processining sugar
what is retention time
amount of time it takes to digest and absorb nutrients from the same food
whats aspect of female social structure are related to food competition and how
there is strong within-group competition; whereby female social bonds + nepotlism heabily affect it.
the sythethic model..
supplemneatry variables of Van Shaiks and Wranghams Hypothesisi by Sterk, Watts and Van Shaik in 1997
critiques of socio-ecological model (theirry)
- creating a synthethic model is impossible as there are too many variations of primate social behaviour
- phylogeny also influence trait variations (not just environmental conditions) that imfluences across caldes
- the model needs to be improved (defintiions and measurement wise; i.e. patichess or qualtiy of food)
- other factors need to be factored in: diseases, population density, group size,etc. that impact social groups
when within-group contest is strong and between-group contest is weak we expect to see..
strong female dominance hierarchciaes
matrillineal alliances
female philopatry
male dispersal
when within group contest is weak and between group competition is strong we expect to see..
egalitarian dominance relationships among females
group level coalations
female philosoptru
how do female social relations influence fitness
- rank
2. maternal kin bonds (nepotisitc/matrilieneal dynasties)
karen strier showed what about female social relationships in…
muriquis; males form closer ties with females than females do:
- bonds are strong
- grooming is rare (males dont fight and share a lot with receptive females)
what did Anja Widdig demonstrate
monkeys can recognize PATERNAL kin (in female rhesus macaqueson cayo santiago)
they do this by:
1. age similiarities (good proxy for kinship when a male monopolizes mating activity)
- females prefer paternal kin over unreleated females when interacting (phenotypic cues)
