Biology – Chapter 2 – Principles of Ecology – Section 1, 2 & 3

Ecology
Scientific study of all the interrelationships between organisms and their enviroment.

Biosphere
Relatively thin layer of Earth and it’s atmosphere that supports life.

Biotic factor
Any living factor in an organ’s enviroment.

Abiotic factor
Any non living factor in an organisms enviroment, such as soil,water temperature, and light availability.

Population
Group of organisms of the same species that occupy the same geographic place at the same time.

Biological community
All the interacting populations of different species that live in the same geographic location at the same time.

Ecosystem
Biological community and all the non living factors that affect it.

Biome
Large group of ecosystem that share the same climate and have similar types of communities.

Habitat
Physical area in which an organism lives.

Niche
Role, or position, of an organism in its enviroment.

Predation
Act on one organism feeding on another organism.

Symbiosis
Close mutualistic, parasitic, or commensal association between two or more species that live together.

Mutualism
Symbiotic relationship in which both organisms benefit.

Commensalism
Symbiotic relationship in which one organism benefits and the other organism is neither helped nor harmed.

Parasitism
Symbiotic relationship in which one organism benefits at the expense of another organism.

Autotroph
Organism that captures energy from sunlight or inorganic substances to produce its own food; provides the foundation of the food supply for other organisms; also called a producer.

Heterotroph
Organism that cannot make its own food and gets its own food and gets its nutrients and energy requirements by feeding on other organisms; also called a consumer.

Herbivore
Heterotroph that eats only plants.

Carnivore
Heterotroph that preys on other heterotrophs.

Omnivore
Heterotroph that consumes both animals and plants.

Detritivore
Heterotroph that decomposes organic material and returns the nutrients to soil, air, and water, making the nutrients available to other organisms.

Trophic level
Each step in a food chain or in a food web.

Food chain
Simplified model that shows a single path for energy flow through an ecosystem.

Food web
Model that shows many interconnected food chains and pathways in which energy and matter flow through an ecosystem.

Biomass
Total mass of living matter at each trophic level.

Matter
Anything that takes up space and has mass.

Nutrient
Chemical substance that living organisms obtain from the environment to carry out life processes and sustain life.

Biogeochemical cycle
Exchange of matter through the biosphere involving living organisms, chemical process,and geological processes.

Nitrogen fixation
Process in which nitrogen gas is captured and converted into a form plants can use.

Denitrification
Process in which fixed nitrogen compounds are converted back into nitrogen gas and returned to the atmosphere.