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89 Cards in this Set
- Front
- Back
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individual
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can reproduce
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population
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all the individuals that reproduce together
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how many populations exist in a species
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can be many
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environment
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everything a population uses, that affects the population, and everything the population affects
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what are the outcomes of interactions in population ecology
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changes in the distribution and abundance of the organism
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How do we find out about distribution and abundance?
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Determine how many individuals of a particular species are in a particular location.
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What are population dynamics?
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describes the processes taht change the number of individuals in a population
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N(t)
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population size at time t
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dN(t)/dt
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each individuals contribution to the population growth
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dN(t)/dt=rN(t)
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r is the intrinsic rate of increase
assuming each individuals contribution to population growth in constant |
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Is population growth exponential?
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Yes, except that it is usually limited.
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K
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carrying capacity of the population
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(r-r/K)N
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each individuals contribution to population growth
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dN(t)/dt=r(1-N/K)(N(t))
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Logistic population growth
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r strategy population growth
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rapid development; early single reproduction; short life span; good dispersal ability; disturbed habitats.
ephasizes rapid population growth (ex. argentine ant) |
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k strategy population growth
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slow development, late reproduction, long lifespan, poor dispersal, non disturbed habitats.
limited by population carrying capacity (ex. red harvester ant, desert species) |
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In a population gowing logistically how do all individuals contribute to growth?
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equally
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What is demograhpy?
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the study of population growth
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In a real population, how does an individuals contribution to growth vary?
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varies depending on their life history
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life history
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the manner in which an organism progresses from birth, reproductive period, to death
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Age determines
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an orgnisms probability of survival, mortality, fertility, and probability of reproduction
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life table
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keeps track of the effects of age on population growth
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how is the birth rate defined
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Birth rate (t)= integral (# of births from prnt age x)dx
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m(x)
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(# of indv. age x)(# of births/indv. age x)
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l(x)
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(number of births x yrs ago)(fraction surviving to age x)
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To track population growth
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must know number of indv of each age, birth rate, survival rate
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Birth rate (t)=integral (B(t-x) l(x) m(x)) dx
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stupid equation
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What does a frequency distribution show?
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The numbers or proportion, or frequency in each category of some measure.
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Are populations always stable?
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No
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What do changes in population growth lead to?
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Changes in age distribution.
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What effects variability of live births in golden tamarinds?
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Only body mass
NOT - infants from previous season, age of mother, number of males in group, number of helpers, or the interbreeding coeff |
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environment
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includes habitat, biotic and abiotic factors, organisms are part of their own envrironments - modify their environments through behavior
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niche
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a populations niche is a way of describing all of the resources it uses
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How do changes environments affect population size?
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They can increase or decrease size.
ex: rainfall affects food supply, affects types of species that are most fit |
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What interactions between populations affect population dynamics?
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Competition, predation, mutualism, etc
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Competition
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must be a limited resource for this to occur
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density dependence
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when individuals within a population compete for a limited resource
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When does competition between species occur?
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when two niches overlap
causes a loss in growth for one population |
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What are the Lotka-Volterra derived from?
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Come from the logistic equation
include the effect of the competing species on each other |
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What is the factor alpha_12
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the intensity of competition, measure empirically
the effect of species 2 on species 1 competition is thus described as a pair of equations |
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What do ecological processes on the time scale of individuals drive?
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evolutionary processes over generations
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What are the 3 requirements for natural selection?
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- variation in a trait
- heretitability of traits - diff reproductive success due to traits |
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What does differential reproductive success depend on?
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ecological processes
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Predation
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when one species benefits at the detriment of the other
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What do the parameters mean in the HIV predation model?
T,s,p,k,V,T*,delta,c |
T - # uninfected T-cells
s - rate of prod of new uninf. T cells p - rate of prod of T cells from exist ones k - rate of inf of T cells by virus V - # of virions T* - # inf T cells delta - rate inf cells die c - rate immune system clears virus (unknown) |
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What are some benefits of the HIV model?
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Shows virus active even when viral load not changing. Allowed interpretation of results of drug treatment. Help determine time course for treatments.
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Mutualism
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both populations benefit
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What are some benefits of mutualism:
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disperse seeds, pollinate flowers, defend against herbivores, parasite adn predators, gather nutrients in short supply, feed adn digest, photosynthesize adn respire
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Some examples of mutualism:
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- ants that clear all plants except host plant
- ants live inside acacias and ward off herbivores in exchange for awesoem housing |
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community
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populations together form a community
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What do food webs link?
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populations in communities
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Primary productivity
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the rate at which biomass is produced per unit area by plants
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biomass
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mass of organisms per unit area of ground
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Describe Eltons pyramid
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Number of species at top has small number of individuals, large amount of biomass
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trophic web
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maps energy flow from producers to consumers (same as food web)
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succession
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ecological interactions change communities overtime;
pioneer plants -> alders -> transition stage -> spruce forest |
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ecosystem
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community plus abiotic environment, may contain many connected communities
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Does primary productivity vary among ecosystems?
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Yes, (ex. higher in in forest than desert)
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What is secondary productivity?
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herbivores, affected by primary productivity
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Is energy lost in the transfer from one level to another in the food web?
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yes
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What is a nutrient cycle?
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The flow of nutrients through different ecosystems.
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What is most living matter comprised of?
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Water
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How does seasonal change and climate affect nutrient cycling?
(name on major factor) |
climate affects how much and how fast water moves, which is important to nutrient cycles
(ice doesnt help nutrients flow) |
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Describe the phosphorus cycle:
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input of particulaate and dissolved P in rivers -> P particles in down-welling water -> mineralization -> P dissolved in up-welling water
particles can be lost to sediment |
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What are the main biogeochemical cycles
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P, N, S, C
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How are nutrient levels and energy flow linked?
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Nutrient availability limits productivity.
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What are some limits to primary productivity.
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solar radiation, carbon dioxide, water, soil nutruents, temperature, photosynthesis, nutrients
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Where are N,S,P mostly
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N - mostly in atmosphere
S - mostly in atmosphere, soil P - mostly in sediment |
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How do nutrient levels in the soil reflect soil age?
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new soil - (300-1200 yrs) - P levels identical to that in lava
intermediate - (20 - 150,000) - can absorb P, most chemically active older soil - (1.4 - 4.1) - most of P leached out, most biologically active mineral shave been lost due to weathering and leaching |
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What factors are generally limiting to growth in different types of soil?
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N - limits growth in young soil
P - limits growth in old soil both - limit productivity in intermediate sites |
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What nutrients are transported in the atmosphere?
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P, Ca, K
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Is any ecosystem on earth isolated?
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No
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What is regional change driven by?
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human activity
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Why are all ecosystems influed by global change in climate?
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Because climate change affects the the flow of nutrients and energy.
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Describe the greenhouse effect:
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incomign light warms earth -> emits heat as infrared -> trapped by water vapor, CO2, methane, nitrous oxide and aerosal particles
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What human activity increases the amounts of CO2, methane, nitrous oxide, and aerosal particles.
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CO2 - burning of fossil fuels
methane - organic decay, drilling, mining nitrous oxide - fertilizer aerosal particles - burning fossil fuel |
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From what sources can data on temperature changes over time be derived?
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Tree rings, extent of glaciation, changes in coral reefs, sunspot activity, volcanism
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What is the current level of CO2 in the atmosphere?
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370 ppm
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How much will the earth warm in this century?
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1.5 - 6 degrees
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What are some consequences of global warming?
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- heat stress (elderly and urban poor)
- heat on tourist industry - crops, livestock - increased electrical demand to control indoor temperature - more intense precipitation -> floods, landslides, avalanches, erosion - changes in ecological communities and diversity |
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What are the currents trends for genera with global warming?
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The fast growing genera are increasing, and the slow growing genera are decreasing.
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How does CO2 increase affect plants.
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Increases productivity, (esp C3 plants), rubisco prevented from acting as oxygenase, photosyn more efficient
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How will this fast growth affect old growth, subcanopy species with denser wood?
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This will dimish the slow growers, because fast growers can take over.
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How will this affect CO2 levels.
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Diminish forests ability to act as CO2 sinks, because less old growth.
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How does global warming affect temperature besides direct warming?
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changes wind patterns -> changes currents -> changes temperatures
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How does changing ocean temperature impact global warming?
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releases methane by thawing, a greenhouse gas
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Name two ways humans cause extinction?
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Get rid of habitats
Introduce invasive species |
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What is conservation biology?
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science behind attempts to alleviate the harm done by habitat loss, invasive species, global climate change, and other human disturbance
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What is a corridor?
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A way provided for animals to move to both portions of a fragmented habitat. Reduces risk of extinction
- badger path under highway |
