Cheatography
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Ecology & Biogeochemical Cycles
This is a draft cheat sheet. It is a work in progress and is not finished yet.
Population Ecology Definitions
microclimate |
climate patterns on a very fine scale (ex. under a log) |
abiotic factors |
nonliving properties of the environment |
biotic factors |
living factors in an environment |
population ecology |
study of populations in relation to their environment |
population |
group of the same species that live in the same area |
community |
all the populations of organisms in an area |
cohort |
group of the same age bracket |
territoriality |
animals defend a bounded physical space |
3 Life History Characteristics |
1. when they reproduce (age of maturity) |
2. how often they reproduce |
3. how many offspring are produced |
k-selection |
selection of life history traits that are sensitive to population density |
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↳ density-dependent selection (high density) |
r-selection |
selection for life history traits that maximize reproductive success |
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↳ density-independent selection (low density) |
density dependent |
characteristic that varies with population density/ % affected is high (biotic) |
density independent |
characteristic that is NOT affected by population density (abiotic) |
3 Dispersal Patterns |
1. clumped |
2. uniform |
3. random |
Survivorship Curve
survivorship curve |
members of a cohort that are still alive at each age |
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Death Rate Of Young |
Death Rate of Old |
# of Offspring |
Example |
Type 1 |
low |
high |
few |
people |
Type 2 |
constant |
constant |
several |
rodents |
Type 3 |
high |
low |
many |
fish |
Equations
EXPONENTIAL GROWTH |
equation: |
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symbols: |
dN~ change in population size |
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dt~ change in time |
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r max
~ rate of increase (max) |
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N~ population size |
shape: |
J |
LOGISTIC GROWTH |
equation: |
|
symbols: |
K~ carrying capacity |
shape: |
S |
Ecosystem Terms
primary producers |
(autotrophs) support all other levels/photosynthetic |
primary consumers |
(herbivore) eats plants & other autotrophs |
secondary consumers |
a carnivore that eats herbivores |
tertiary consumers |
a carnivore that eats other carnivores |
detritivores (decomposers) |
consumer that gets its nutrients from nonliving organic material |
primary productivity |
amount of light energy converted to chemcial energy |
gross primary productivity (GPP) |
total primary production/ chemical energy |
net primary productivity (NPP) |
GPP- R A
(autotrophic respiration) |
secondary productivity |
energy converted to a consumers biomass (GSP & NSP) |
production efficiency |
% of energy stored (used for growth in consumers) |
trophic efficiency |
% of production transferred between each trophic level (10%) |
net ecosystem production (NEP) |
GPP - R T
(total respiration) |
limiting nutrient |
element that must be present for production to increase in an area |
- factors that affect primary production: |
temp./moisture/light/nutrients/etc. |
Water Cycle
evaporation: liquid to gas
condensation: gas to a liquid
sublimation: solid to a gas
Nitrogen Cycle
nitrogen fixation: N2 to NH3
ammonification: break down organic molecules into NH4+
nitrification: NH4+ to NO2- to NO3-
denitrification: changes fixed N forms back into N2
|
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Interspecific Interactions
interspecific interactions |
relationship between individuals of 2+ species in a community |
1. COMPETITION |
interspecific competition |
competition for resources between individuals of 2+ species |
comptetive exclusion |
species compete for a resource but one will be more efficient & have a reproductive advantage that leads to the elimination of the other |
niche |
species use of biotic & abiotic resources in its environment |
resource partitioning |
division of environmental resources by species such that the niche of each species differs |
2. PREDATION |
cryptic coloration |
camouflage that makes species difficult to spot against its background |
aposematic coloration |
bright warning coloration of animals with physical or chemical defenses |
Batesian mimicry |
harmless species looks like a species that is poisonous or harmful |
Mullerian mimicry |
reciprocal mimicry by 2 species that are unpleasant to eat |
3. HERBIVORY |
↳ organism eats parts of a plant or algae |
- plants protect themselves by... |
chemical toxins & spines/thorns |
4. SYMBIOSIS |
parasitism |
one organism benefits at the expense of the other |
mutualism |
both participants benefit |
commensalism |
one organism benefits while the other is neither hurt nor helped |
5. FACILITATION |
↳ 1 species has a positive effect on the survival and reproduction of another species without intimate association |
Diversity
invasive species |
species that takes hold outside of its native range |
keystone species |
species that isn't abundant yet exerts a strong control on the community |
species diversity |
variety of different kinds of organism that make up the community |
↳ two components~ |
species richness & relative abundance |
↳ 2 benefits of high species diversity~ |
increased productivity & stability |
- latitude & diversity~ |
equator = high diversity / poles = low diversity |
- geographic area & diversity~ |
large area = high diversity / small area = low diversity |
Ecological Succession
primary succession: occurs in areas where no organisms are present and no soil has formed
secondary succession: occurs where an existing community has been cleared but leaves soil intact
pioneer species: species that are the first to colonize (ex. lichen)
Plant Adaptations
phototropism |
gorwth of a plant towards (positive) or away (negative) from light |
coevolution |
joint evolution of 2 interacting species, each in response to selection imposed by the other |
Pollination |
wind~ |
pollen grains |
insects~ |
fragrant & bright colors |
bats~ |
open at night |
birds~ |
bent floral tube |
Germination |
desert~ |
after substantial rainfall (soil wet) |
fire areas~ |
after intense heat (vegetation cleared) |
harsh winter~ |
after extended exposure to the cold (long growth season) |
small seeds~ |
after light (poke through the soil) |
digested~ |
after passed through digestive tract (travel distances) |
Dispersal |
water~ |
buoyant |
wind~ |
winged seeds |
animals~ |
edible fruits & burs |
Advantages of Reproduction |
Asexual |
Sexual |
1. no pollinator |
1. dispersal of offspring |
2. pass all genetics (suitable environment) |
2. variation (unstable environment) |
3. stronger offspring |
3. growth suspended |
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