BIO 181 Test 2-Ecology

Ecosystem

A biological community of interacting organisms and their physical environment.

Organismal Ecology

study of an organism's relationship with its environment

Population Ecology

study of interaction between members of the same species

Biotic Factors

living organisms in an ecosystem

Abiotic Factors

non-living physical and chemical elements of an ecosystem

Population

groups of individuals of the same species in the same place

3 Characteristics of Populations

-same range/area
-pattern of spacing of individuals is the same
-change in size throughout time

Density-dependent factors

predation, inter and intra specific competition, accumulation of waste, diseases, etc.

Density-independent factors

weather, disasters, pollution, & other chemical/physical conditions

Cohort

group of individuals of same age

fecundity

number of offspring produced in a standard time

mortality

death rate in a standard time

life table

probability of survival and reproduction through a cohort's life

net reproduction rate

>1=increasing

survivorship

percent of original population surviving to given age

survivorship curve

graph of number of individuals surviving at each age interval

population growth

populations often remain same size regardless of number of offspring born

exponential growth

when the biotic potential of any population is exponential and left unchecked, the population will explode. (J curve)

carrying capacity(K)

maximum number of individuals that an environment can support

logistic growth

applies to populations as they reach K. (S curve)

Demography

quantitative study of populations

generation times

average interval between birth of an individual and birth of its offspring

K-selected species

-mature late
-greater longevity
-increased parental care
-increased competition
-fewer offspring
-larger offspring

r-selected species

-mature early
-lower longevity
-decreased parental care
-decreased competition
-more offspring
-smaller offspring

community ecology

the study of interacting populations of species living within a particular area or habitat

intraspecific competition

competition within a species

interspecific competition

competition between species

interference competition

direct, physical interactions over resources

exploitative competition

interact indirectly by consuming the same resources

mechanisms to avoid competition

-intimidation (coloration and features)
-camouflage
-isolation mechanisms
-specializing on particular resources
-temporal adaptations
-moving locations
-social behaviors for collaboration
-territoriality
-symbiotic relationships

competitive exclusion principle

two species cannot occupy the same niches in a habitat

niche

total range of conditions under which an individual (or population) lives and replaces itself

realized niche

actual set of conditions under which an organisms exists

fundamental niche

entire set of optimal conditions under which an organismic unit can live and replace itself

resource partitioning

the differentiation of niches that enables similar species to coexist in a community

character displacement

difference in morphology between sympatric species

predation

consumption of prey by its predator

coevolution

features that decrease predation are strongly favored

niche restrictions

-other species
-predators
-pollinators
-herbivores

aposematic coloration

specific coloration that signals a warning for predators

batesian mimicry

harmless species imitate warning signals of harmful species

Mullerian mimicry

related or unrelated poisonous species that share a predator come to resemble one another's warning signals

plant chemical defenses

-tough fibers
-high cellulose content
-oils, toxins, poisonous milky sap

types of symbiosis

-commensalism
-parasitism
-mutualism

commensalism

an interaction between two organisms in which one benefits and the other derives neither benefit nor harm

parasitism

an interaction between two organisms in which one benefits and the other (host) is harmed

endoparasites

live within the body of host

ectoparasites

live on surface of host

parasitoidism

parasite deposits eggs in/on host

endosymbiont

live inside another, but usually mutualistic

mutualism

an interaction between two organisms in which both organisms benefit

species richness

number of species present

abundance

number of individuals per species

relative abundance

how common or rare relative to others

diversity

species richness and evenness of species' abundances

evatranspiration

the release of water into the atmosphere as water vapor, by evaporation, transpiration, and respiration

dominant species

most abundant

keystone species

most influential with respect to trophic levels

foundation species

allows other species to inhabit an area by altering the environment

main abiotic cycles

-water
-carbon
-nitrogen
-phosphorus

flow of energy

the movement of energy through an ecosystem

how energy exists

-heat
-light
-chemical-bond energy
-motion

1st law of thermodynamics

energy is neither created nor destroyed; changes forms

2nd law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

major source of energy

the sun

trophic levels

group of organisms which occupy the same level in a food chain

autotrophs (primary producers)

"self-feeders" assemble inorganic precursors into the array of organic compounds of which they are made

photoautotrophs

gain energy from light

chemoautotrophs

energy from inorganic materials

heterotrophs (consumers)

obtain organic compounds by consuming other organisms

ten percent rule/law

during transfer of energy down trophic levels, only ~10% of energy is stored as biomass and is all that's available to the next trophic level

number of trophic levels

limited by energy availability

primary producers

autotrophs

consumers

-herbivores
-primary carnivores
-secondary carnivores
-detritivores

limiting nutrients

nutrients in shortest supply and put a limit on growth

gross primary productivity

rate at which primary producers incorporate energy from the sun

net primary productivity

energy that remains in primary producers after respiration and heat loss