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89 Cards in this Set

  • Front
  • Back
can reproduce
all the individuals that reproduce together
how many populations exist in a species
can be many
everything a population uses, that affects the population, and everything the population affects
what are the outcomes of interactions in population ecology
changes in the distribution and abundance of the organism
How do we find out about distribution and abundance?
Determine how many individuals of a particular species are in a particular location.
What are population dynamics?
describes the processes taht change the number of individuals in a population
population size at time t
each individuals contribution to the population growth
r is the intrinsic rate of increase
assuming each individuals contribution to population growth in constant
Is population growth exponential?
Yes, except that it is usually limited.
carrying capacity of the population
each individuals contribution to population growth
Logistic population growth
r strategy population growth
rapid development; early single reproduction; short life span; good dispersal ability; disturbed habitats.

ephasizes rapid population growth
(ex. argentine ant)
k strategy population growth
slow development, late reproduction, long lifespan, poor dispersal, non disturbed habitats.

limited by population carrying capacity
(ex. red harvester ant, desert species)
In a population gowing logistically how do all individuals contribute to growth?
What is demograhpy?
the study of population growth
In a real population, how does an individuals contribution to growth vary?
varies depending on their life history
life history
the manner in which an organism progresses from birth, reproductive period, to death
Age determines
an orgnisms probability of survival, mortality, fertility, and probability of reproduction
life table
keeps track of the effects of age on population growth
how is the birth rate defined
Birth rate (t)= integral (# of births from prnt age x)dx
(# of indv. age x)(# of births/indv. age x)
(number of births x yrs ago)(fraction surviving to age x)
To track population growth
must know number of indv of each age, birth rate, survival rate
Birth rate (t)=integral (B(t-x) l(x) m(x)) dx
stupid equation
What does a frequency distribution show?
The numbers or proportion, or frequency in each category of some measure.
Are populations always stable?
What do changes in population growth lead to?
Changes in age distribution.
What effects variability of live births in golden tamarinds?
Only body mass

NOT - infants from previous season, age of mother, number of males in group, number of helpers, or the interbreeding coeff
includes habitat, biotic and abiotic factors, organisms are part of their own envrironments - modify their environments through behavior
a populations niche is a way of describing all of the resources it uses
How do changes environments affect population size?
They can increase or decrease size.

ex: rainfall affects food supply, affects types of species that are most fit
What interactions between populations affect population dynamics?
Competition, predation, mutualism, etc
must be a limited resource for this to occur
density dependence
when individuals within a population compete for a limited resource
When does competition between species occur?
when two niches overlap

causes a loss in growth for one population
What are the Lotka-Volterra derived from?
Come from the logistic equation

include the effect of the competing species on each other
What is the factor alpha_12
the intensity of competition, measure empirically

the effect of species 2 on species 1

competition is thus described as a pair of equations
What do ecological processes on the time scale of individuals drive?
evolutionary processes over generations
What are the 3 requirements for natural selection?
- variation in a trait
- heretitability of traits
- diff reproductive success due to traits
What does differential reproductive success depend on?
ecological processes
when one species benefits at the detriment of the other
What do the parameters mean in the HIV predation model?

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)
What are some benefits of the HIV model?
Shows virus active even when viral load not changing. Allowed interpretation of results of drug treatment. Help determine time course for treatments.
both populations benefit
What are some benefits of mutualism:
disperse seeds, pollinate flowers, defend against herbivores, parasite adn predators, gather nutrients in short supply, feed adn digest, photosynthesize adn respire
Some examples of mutualism:
- ants that clear all plants except host plant

- ants live inside acacias and ward off herbivores in exchange for awesoem housing
populations together form a community
What do food webs link?
populations in communities
Primary productivity
the rate at which biomass is produced per unit area by plants
mass of organisms per unit area of ground
Describe Eltons pyramid
Number of species at top has small number of individuals, large amount of biomass
trophic web
maps energy flow from producers to consumers (same as food web)
ecological interactions change communities overtime;

pioneer plants -> alders -> transition stage -> spruce forest
community plus abiotic environment, may contain many connected communities
Does primary productivity vary among ecosystems?
Yes, (ex. higher in in forest than desert)
What is secondary productivity?
herbivores, affected by primary productivity
Is energy lost in the transfer from one level to another in the food web?
What is a nutrient cycle?
The flow of nutrients through different ecosystems.
What is most living matter comprised of?
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)
Describe the phosphorus cycle:
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
What are the main biogeochemical cycles
P, N, S, C
How are nutrient levels and energy flow linked?
Nutrient availability limits productivity.
What are some limits to primary productivity.
solar radiation, carbon dioxide, water, soil nutruents, temperature, photosynthesis, nutrients
Where are N,S,P mostly
N - mostly in atmosphere
S - mostly in atmosphere, soil
P - mostly in sediment
How do nutrient levels in the soil reflect soil age?
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
What factors are generally limiting to growth in different types of soil?
N - limits growth in young soil
P - limits growth in old soil
both - limit productivity in intermediate sites
What nutrients are transported in the atmosphere?
P, Ca, K
Is any ecosystem on earth isolated?
What is regional change driven by?
human activity
Why are all ecosystems influed by global change in climate?
Because climate change affects the the flow of nutrients and energy.
Describe the greenhouse effect:
incomign light warms earth -> emits heat as infrared -> trapped by water vapor, CO2, methane, nitrous oxide and aerosal particles
What human activity increases the amounts of CO2, methane, nitrous oxide, and aerosal particles.
CO2 - burning of fossil fuels
methane - organic decay, drilling, mining
nitrous oxide - fertilizer
aerosal particles - burning fossil fuel
From what sources can data on temperature changes over time be derived?
Tree rings, extent of glaciation, changes in coral reefs, sunspot activity, volcanism
What is the current level of CO2 in the atmosphere?
370 ppm
How much will the earth warm in this century?
1.5 - 6 degrees
What are some consequences of global warming?
- 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
What are the currents trends for genera with global warming?
The fast growing genera are increasing, and the slow growing genera are decreasing.
How does CO2 increase affect plants.
Increases productivity, (esp C3 plants), rubisco prevented from acting as oxygenase, photosyn more efficient
How will this fast growth affect old growth, subcanopy species with denser wood?
This will dimish the slow growers, because fast growers can take over.
How will this affect CO2 levels.
Diminish forests ability to act as CO2 sinks, because less old growth.
How does global warming affect temperature besides direct warming?
changes wind patterns -> changes currents -> changes temperatures
How does changing ocean temperature impact global warming?
releases methane by thawing, a greenhouse gas
Name two ways humans cause extinction?
Get rid of habitats
Introduce invasive species
What is conservation biology?
science behind attempts to alleviate the harm done by habitat loss, invasive species, global climate change, and other human disturbance
What is a corridor?
A way provided for animals to move to both portions of a fragmented habitat. Reduces risk of extinction

- badger path under highway