Studied by 112 people
population
group of individuals of one species living @ same place & same time
community
group of popul. living @ same place & same time
ecosystem
all of living & nonliving factors that affect an organism in specific area
biosphere
portion of earth that supports life
niche
organism’s role in ecosystem
population ecology
study of growth, abundance, & distribution of popul.
size (N)
total # of individuals
density
amount of organisms in specific area
dispersion
how popul. are grouped
clumped dispersion
indiv. spaced close together (ex: school of fish)
uniform dispersion
indiv. evenly spaced (ex: apple orchard)
random dispersion
no pattern for dispersion
pyramid shape (age structure)
suggests rapid growth
tiers (age structure)
suggests slow growth; smaller @ top, larger @ bottom
equal sizes/width (age structure)
suggests zero growth (equal @ top & bottom)
type I survivorship curve
most likely to die when old (ex: humans)
type II survivorship curve
equal chance of death @ any age (ex: squirrels)
type III survivorship curve
most likely to die when young (ex: oysters)
broadcast spawning
oyster can’t move → can’t reproduce asexually → produce & directly release gametes into water → eaten by other organisms
biotic potential
max growth rate of popul. under ideal conditions
carrying capacity
max # of indiv. that can be sustained by a particular habitat
density dependent limiting factors
agents whose limiting effects become more intense as popul. becomes larger
affects larger rather than smaller popul.
ex: disease, competition for food
density independent limiting factors
occur regardless of popul. size but still effects popul.
ex: fire, volcanic eruptions, hurricanes
reproductive rate equation
r = (births - deaths)/N
N = popul. size
intrinsic rate
reproductive rate = max; affects indiv.
ex: bacteria
zero popul. growth
births - deaths = 0
exponential growth
as popul. grows, grows faster but eventually crashes due to density dependent factors (boom & bust cycles)
logistic growth
starts as exponential → stops @ carrying capacity due to density dependent factors
R-selected species
exhibits rapid growth
J-shaped curve (exponential)
opportunist & pioneer species
short-lived, lots of offspring, little parental care
ex: mosquitos, mice
K-selected species
relatively constant @ carrying capacity
S-shaped curve (logistic)
long-lived, few offspring, lots of parental care
ex: elephants, humans
competitive exclusion principle
states no two species can sustain coexistence if they occupy same niche in ecosystem
leads to either extinction or resource partitioning
resource partitioning
two species do a more narrow niche to avoid competition in ecosystem
fundamental niche
niche an organism occupies in absence of competing species (extinct)
realized niches
niche competition organisms occupy; prevents competition; occurs after resource partitioning
do niches overlap?
no overlap
symbiosis
relationship btwn two or more species
mutualism
type of symbiosis where both species benefit
commensalism
type of symbiosis where only one species benefits & other isn’t benefitted or harmed
parasitition
type of symbiosis where one species benefits & other is harmed
true predator (heterotroph)
kills & eats animals (ex: parasite)
parasite
organism that lives on another & feeds on its tissues
parasitoids
insects that lay eggs inside of host → larvae devour host until fully developed (ex: wasp & catapillar)
herbivore (plant predator)
feed on plant matter
granivore - grains
frugivore - fruits
grazer - grass
browser - leaves
ecological succession
series of changes in community structure → ultimately results in stable community
primary succession
occurs in an area that hasn’t been lived in yet (brand new habitat)
involves pioneer species (good at colonizing)
area has all rock, no soil
climax community
end result of succession; stable; same types of popul.
pioneer species
first species in new habitat
can live in marginal habitat (barely supports life)
bad at competition
ex: lichen = composite species (more than one species)
made up of algae, yeast, & fungi → mutualistic relationship
lives on bare rock & breaks it down into soil
secondary succession
there has been life where it occurs
when climax community was disturbed by natural disaster or human activity
faster than primary b/c has soil already
succession is…
less predictable than once thought
energy pyramid
shows amount of energy @ each trophic level
trophic level
feeding level in food chain
primary consumer
aka first order heterotroph
secondary consumer
aka second order heterotroph
tertiary consumer
aka third order heterotroph
primary producer
aka autotroph
does photosynthesis, makes its own energy
bar
all species of trophic level in ecosystem
arrows
shows flow of energy in food chain
as you move up in trophic level…
10% of energy moves up
biomass
amount of matter in living thing
biomass pyramid
shows amount of biomass @ each trophic level
why does biomass pyramid mirror energy pyramid
b/c energy makes up biomass
biome
group of similar organisms
abiotic factors that determine where each biome is
temp & precipitation
tropical rainforest
year round high temp & high precipitation
desert
winter: low temp, low precip
summer: high temp, low precip
taiga
winter: low temp, moderate precip
summer: moderate temp, moderate precip
mostly conifers
deciduous forest
winter: low temp, moderate precip
summer: high temp, moderate precip
chaparral
winter: low temp, moderate precip
summer: high temp, moderate precip
Note 
Flashcard (20)