ecology	the study of the interactions between organisms and their environment
biosphere	the part of Earth that supports life, including the top of Earth’s crust, all the waters, and the atmosphere
ecosystem	environment made up of the biotic and abiotic things that interact there (all the organisms living in an area and the nonliving features of their environment)
biotic	living organisms in an area
abiotic	the nonliving features of the environment
habitat	the place where an organism lives. It provides food, water and living space (shelter).
species	Related organisms capable of interbreeding (reproducing).
niche	a specific role in an ecosystem (how an organism survives in its environment)
population	all the organisms in an ecosystem that belong to the same species. Ex: all the deer, or all the wild roses.
community	all the populations in an ecosystem.
limiting factor	anything that restricts the number of individuals in a population.

Sun	energy source that drives an ecosystem
producers	organisms that use an outside energy source (such as sun) to make energy-rich molecules (food). Most are plants, some are bacteria and algae.
producers	These are the source of all the food in an ecosystem.
consumers	organisms that can’t make their own energy. They obtain energy by eating living organisms.
herbivores	organisms that eat plants (eat producers)
carnivores	organisms that eat other animals (eat consumers)
omnivores	organisms that eat plants and animals (eat producers and consumers)
scavengers	organisms that feed on bodies of dead organisms
decomposers	organisms that eat wastes and dead organisms. They break down once-living matter and release nutrients into soil – recyclers.
predators	organisms that capture and eat other consumers
prey	organisms that are being captured and eaten
food chain	a simple model of feeding relationships; a series of producers and consumers
food web	a complex model of the feeding relationships among the organisms in an ecosystem; it contains several food chains
10% Rule	only about 10% of energy is transferred to next energy level. About 90 % is used for life processes or lost as heat in the environment.