REVIEW SHEET FOR ECOLOGY
Autotroph- an organism that produces its own food (from inorganic compounds and sunlight)- also called a producer (Ex. Tree, shrubs, grass)beginning of food chain
Biodiversity- the number of different species in an ecosystem (variety of life)
Biological Magnification- buildup of a pollutant in organisms at higher trophic levels in a food chain- the increasing concentration of a
harmful, and usually toxic, substance as it moves up the food chain- the toxins tend to be stored in the fatty tissues of the animal (Ex. DDT was
400x more concentrated in top carnivores than in the producers. Other pollutants that tend to biomagnify include mercury, lead and PCB’s)
Biomass- the total dry weight of the organisms in a community- Biomass pyramids are used to represent the total dry weight of organisms in an
ecosystem
Carrying Capacity- the maximum number of individuals of a given species, than an environment can support for the long term, that the size of
population would not negatively impact the environment
Community- a collection of interacting populations that live in the same ecosystem (the living portion of an ecosystem)
Consumer- an organism in a community that is heterotrophic- 1st level consumer (Primary): herbivores (feed off of producers)- 2nd level
consumer (Secondary): carnivores- 3rd level consumers (Terery)-obtains 10% of the energy from each trophic level before it (3 rd level consumer
contains least amount of energy)- also called Heterotrophs
Decomposer- an organism that breaks down dead organic material (Ex. Bacteria, fungi)- break down nutrients in dead organisms so matter can
cycle and be recycled by producers- organisms that feed on wastes and dead organic matter from all trophic levels (Ex. Bacteria, fungi)
Detritus- particles of dead organic matter- it includes the wastes and remains or organisms that are no longer alive- it is an important
component of some food webs
Ecological Pyramids- A diagram that represents the relative amounts of energy or matter in each trophic level of a food web- 10% of energy
from each trophic level is transferred- rest of energy is released as heat into atmosphere (Ex. Number pyramid, energy pyramid, biomass
pyramid)
Ecology- the study of organisms and how they interact with their environment
Ecosystem- consists of the living communities and the nonliving (abiotic) factors in an environment
Eutrophication- the process where bodies of water are overloaded with nutrients- it is often the result of human activities (Ex. Fertilizer runoff,
detergents, leaking sewage)- it can lead to rapid growth of algae in aquatic ecosystems that ultimately depletes the oxygen levels in the water
and reduces water quality
Food Chain- the pathway that the transfer of energy takes in an ecosystem (shows feeding sequence- involves producers, consumers,
scavengers, and decomposers)- feeding sequence in which organisms obtain energy- interrelated food chains are called a food niche- model of
the energy flow from one organism to another trophic level
Food Web- consists of all the interconnecting food chains in an ecosystem- producers make up the 1st trophic level
Herbivore- a consumer that eats only plants- eats producers- (Ex. Rabbit, cows)
Heterotroph- an organism that cannot make its own food- consumers- obtain energy and nutrients by devouring other organisms
Niche-the specific role, function, or position of an organism is an ecosystem
Limiting Factor- a condition that restricts a population’s growth (Ex. Space, food availability, lack of particular nutrient, disease)
Carbon Cycle and processes- carbon held in fossil fuels, until human activities, such as burning fossil fuels, release it into the atmospherecarbon is with oxygen as carbon dioxide- Surface Ocean Route: got here by diffusing from atmosphere, decomposing marine life, or circulating
water from the deep ocean (chilly water absorbs carbon faster); Deep Ocean Route: gets CO2 from circulation with surface ocean and dead and
decaying marine life-holds over 65% carbon-stays in ocean for 100’s of years; Marine Life Route: photoplankton take carbon and use it for
photosynthesis-marine can’t survive without carbon-high levels of carbon are harmful to algae, mollusks, and corals; 30% increase in CO2 over
150 years )since Industrial Revolution); carbon is universal; carbon from the deep ocean moves from deep ocean to surface ocean and then to
atmosphere- Land Plants Route: plants use carbon for photosynthesis; they grow faster with more CO2; they release carbon back into
atmosphere after respiration; Soil Route: plants died so carbon is in soil as detritus (decomposing plants and animals); soil is made of inorganic
parts; stores 3% carbon; carbon sent to atmosphere after break down of detritus; Atmospheric Route: plants release carbon back into the
atmosphere
Nitrogen Cycle and processes- the pathway by which nitrogen moves through the environment (includes nitrogen fixation, denitrifying,
amnonification)-Nitrogen Fixation changes nitrogen into amnonia (asobactor and lasogna are bacteria that help this change)- nitrification
changes the amnonia into nitrates, and then into nitrates (lightning can change nitrogen to nitrates- a lot of energy to make nitrogen gas into
nitrates)- denitrification takes nitrates and makes them into nitrogen gas
Omnivore- a consumer that eats both producers (Ex. Plants) and consumers (Ex. Other animals) (Ex. Humans, bears, crows)
Primary Productivity- the rate at which organic matter (biomass) is created by producers in an ecosystem
Producer- an autotroph that provides food for a community- receives energy from sun- first level in a food web
Scavenger- a consumer that feed on the remains of dead organism (Ex. Hawk)
Succession- the gradual replacement of one plant community by another one- succession starts with pioneer species towards the climax
species- pioneer species is the first species to inherit an ecosystem; first plant species to colonize an area that is void of vegetaion- climax
species is the species that occurs at the end of succession- climax community: a community dominated by plant species that are relatively stable
and self-sustaining in a specific environment- primary succession begins with bare rock exposed by geologic activity (Ex. Rock, lichen, moss,
grass, shrub, trees, oak, hickory forest)- secondary succession beings on soil from which previous community has been removed (by fire,
agriculture); old field succession (Ex. Grass, shrub, trees, oak hickory forest); can proceed much faster because the soil has been prepared by
the previous community- General trends: early stages are productive but lose and need nutrients; biomass is uncommon but fluctuates; species
reproduce quickly but die young; energy to reproduction; climax stages create favorable environment; biomass doesn’t fluctuate; nutrients are
recycled; individual organisms live longer
Trophic levels- a step in the transfer of energy (and matter) in a food chain- each trophic level receives only 10% of the energy from below it