Miller & Levine Biology - Ecology

Our entire planet, with all its organisms and physical environments
group of similar organisms that can breed and produce fertile offspring
group of individuals of the same species that live in the same area
assemblage of different populations that live together in a defined area
scientific study of interactions among organisms and between organisms and their environment
all the organisms that live in a place, together with their physical environment
group of ecosystems with similar climates and typical organisms
biotic factor
any living part of the environment with which an organism might interact
abiotic factor
physical, or nonliving part of the environment
organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds
Examples of autotrophs and primary producers
plants, algae,
cyanobacteria, chemosynthetic bacteria
primary producer
first producer of energy-rich compounds that are later used by other organisms
Examples of biotic factors
animals, plants, fungi, protists, bacteria archeabacteria
Examples of abiotic factors
sunlight, heat, precipitation, humidity, wind, water currents, soil type, water availability.
organism that obtains food by consuming other organisms
organism that relies on other organisms for its energy and nutrients
organism that obtains energy by killing and eating other animals
Examples of carnivores
lion, tiger, shark, wolf, hawk
organism that obtains energy by eating only plants
Examples of herbivores
cow, rabbit, grasshopper, deer
animal that consumes the carcasses of other animals
Examples of scavengers
hyenas, vultures
organism that obtains energy by eating both plants and animals
Examples of omnivores
bears, raccoons, humans
organism that breaks down and obtains energy from dead organic matter. They produce detritus.
Examples of decomposers
bacteria, fungi
organism that feeds on detritus. They may also digest decomposers that live on and in detritus particles.
Examples of detritivores
earthworm, mites, snails, shrimp, crabs
food chain
series of steps in an ecosystem in which organisms transfer energy by eating and being eaten
food web
network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem. It is a network of food chains.
trophic level
each step in a food chain or food web
Water cycle
Water molecules enter the atmosphere as water vapor through evaporation from the ocean or other bodies of water or through transpiration (evaporation from leaves of plants. If the air carrying the water vapor cools, it condenses into cloud-forming droplets that may precipitate to rain, snow, sleet or hail. Some precipitation flows along the the surface of the land and is called runoff. Runoff can enter a river or stream and be carried to an ocean or late. Precipitation can also be absorbed into the soil as groundwater. Groundwater can be taken up by plants or flow into streams, rivers, lakes, oceans, or underground reservoirs.
Carbon cycle
Carbon dioxide is continuously exchanged between the atmosphere and oceans through chemical and physical processes. Plants and other photosynthetic organisms take in carbon dioxide during photosynthesis and the the carbon to build carbohydrates. Carbohydrates then pass through food webs to consumers. Many animals, both on land and in the sea, combine carbon with with calcium and oxygen as the animals build skeletons of calcium carbonate. Organisms release carbon in the form of carbon dioxide gas by respiration. Also, when organisms die, decomposers break down the bodies, releasing carbon to the environment. Geologic forces can turn accumulated carbon into carbon-containing rocks or fossil fuels. Carbon dioxide is released into the atmosphere by volcanic activity or by human activities such as the burning of fossil fuels and the clearing and burning of forest.
Nitrogen cycle
Bacteria convert nitrogen gas into ammonia by nitrogen fixation. Other soil bacteria convert the fixed nitrogen into nitrates and nitrites. Once these forms of nitrogen are available, primary producers can use them to make proteins and nucleic acids. Consumers eat the producers and reuse nitrogen to make their own nitrogen-containing compounds. Decomposers release nitrogen from waste and dead organisms as ammonia, nitrates, and nitrites, that producers may take up again. Other soil bacteria obtain energy by converting nitrates into nitrogen gas, which is released into the atmosphere by denitrification. A relatively small amount of nitrogen gas is converted into usable forms by lightning by atmospheric nitrogen fixation. Humans add nitrogen to the biosphere through the manufacture and use of fertilizers.
limiting nutrient
single essential nutrient that limits productivity in an ecosystem
nitrogen fixation
process of converting nitrogen gas into nitrogen compounds that plants can absorb and use