Unit 2 Quiz 2 Flashcards
Determinants of species richness?
time: longer an ecosystem exists more opportunities for colonization, speciation, and extinction
climate: availability of light, sufficient temps, and availability of precip influence plant growth.
Abiotic factors: range of tolerance and fundamental niche
biotic: competition, realized niches
Theory of Island Biogeography:
size of a habitat and distance of a habitat from a source of colonizing species influence number and types of species present.
Habitat fragmentation:
how does it relate to theory of island biogeography
creates habitat islands and we can apply the theory of island biogeography to these
Population?
composed of interbreeding individuals that belong to the same species and live in a given area at a particular time
population ecology studies…
what are these?
distinctive characteristics of a population.
size
density: individuals/area
Distribution: 3 types. Clumped, uniform, and random
Sex ratio: M to F
Age structure
Density dependent vs. independent factors of population size
life history traits?
dependent: tends to be biotic. How significant it is depends on density as name implies. Examples are competition, predation, disease, parasitism, etc.
independent: tend to be abiotic. Just as impactful regardless of density. Examples are weather, disasters, human activity, etc.
LHTs: general features of an organism’s lifestyle (long term evolutionary outcomes)
Intrinsic growth rate (r)?
Exponential growth model?
Carrying capacity?
Logistic growth model?
r: describes max growth potential per individual over a period of time, under ideal conditions with unlimited resources.
EGM: Nt = N0*ert
J-shaped curve. Predicts a population’s biotic potential. Unlikely to occur though, because in real life conditions are not ideal.
carrying capacity (k): limit of how many individuals in a population can be sustained based on availability of resources.
LGM: Nt = N0ert[(K-N0)/K]
predicts a populations growth assuming constraint from carrying capacity. S shaped curve. As N0 approaches k, the new term approaches 0. This shows that when initial population is large most predicted growth won’t occur. Opposite applies when initial population is small.
Often, species exhibit near exponential growth until _____ and _____
Overshoot:
carrying capacity, encounter environmental resistance
Species pass carrying capacity leading to rapid resource depletion and die-off
r/K selection theory
Selection of combinations of traits in organisms that trade off between quality and quantity.
r-selection: selection for quantity with little to no provisioning to ensure offspring survival. Usually occurs in uncrowded environments with abundant resources.
k-selection: favors traits that make fewer offspring provided with more care that increases likelihood of successful offspring.
which reproductive strategy do you think is associated with invasive species? (r or K selection)
r selection. reflect on why
r & k selection is a ____. If conditions allow, selective pressures will _____
spectrum. shift.
Survivorship curve:
3 types
proportion of individuals surviving to each age for a given cohort of a population.
type 1: live toward end of lifespan
type 2: equally likely to die young or old
type 3: tend to live fast and die young
