quiz Flashcards
2 ways communities change
- temporal turnover
- spatial turnover
3 factors influencing community change
- ongoing colonization and extinction
- natural disturbances
- global change
trophic level vs food chain
- trophic level: how a species obtains its energy, who its eating
- food chain: transfer of energy, links between trophic levels including producers, to top consumers and decomposers
what is biomass
measures the total mass of living organism in a trophic level
community function vs ecological efficiency
- Community Function is the measure of the amount of energy or matter that moves in and out of a community per unit of time
- Ecological Efficiency: Refers to the overall transfer of energy from one trophic level to the next.
2 reasons for low ecological efficiency
- use for metabolism
- excrete as waste
what is an ecological niche?
the physical and biological environment a species inhabits and its ecological role
2 aspects of species diversity
- species richness
- relative abundance (eveness)
shannon diversity index
high H = high diversity
what happens to NPP as diversity increases
npp goes up to a certain point.. platues due to competition
trophic cascade
series of direct and indirect effects when the actions of the top consumer in a food web impacts other trophic levels
what are 2 patterns of diversity
- Global: Latitudinal Diversity Gradients
- Regional Species Diversity
list 3 claims of Latitudinal Diversity Gradients
- Climates are typically more stable at the tropics, therefore, tropical species have likely experienced fewer extinction and more speciation events.
- Tropics have abundant solar energy and high productivity, therefore, greater energy flow through communities to support food webs.
- Variation in habitat structure leads to greater niche specialization.
Species-Area Relationship
Diversity increases with increasing area of “patch” and distance to
other “patches” is also important
Theory of Island Biogeography
The number of species on an island represents an equilibrium
between the rate at which species migrate and the rate at which resident species go locally extinct.
(Equilibrium represents when these two concepts are equal.)
Life Tables
Keeps track of demographic events
cohort
A group of individuals (N) born at the same time (so where age = x)
Survivorship
the proportion of individuals that survive from birth to age x
First Breeding
the proportion of birds that reproduced for the first time that given year
Fecundity
The average number of daughters that each female produces at a given age.
Principle of Allocation
resources can’t be used for 2 functions
(maintenance, defense, growth, reproduction)
simultaneously
Carrying Capacity (k)
number of individuals of a species that can
be supported in an environment. NO exponential growth of
populations due to limited resources
R = density dependent
Increased population density = Decreased resource availability
