All energy of most ecosystems start as radiation from sun.

Trophic level – each step in the transfer of energy and matter in a community.

Autotrophs make food by converting inorganic compounds to organic.

Herbivores – organisms that eat only plants.

Carnivores – animals that eat only animals.

Omnivores – animals that eat both producers and consumers.

Decomposers – organisms that feed on and break down organic matter.

Food web – all interconnected food chains in an ecosystem.

Biomass – total mass of organic matter at each trophic level.

Ecological pyramid – shows relationship between consumers and producers at different trophic levels in ecosystem.

10% law – loss of available energy up the pyramid.

By 2010, 4/5 of nations landfills will be closed according to EPA.

Water cycle – repeated movement of water between Earth’s surface and the atmosphere.

Products of photosynthesis are glucose and oxygen.

Fossil fuels – energy-rich compounds formed from organic matter by geological processes.

Photosynthesis and cellular respiration are part of biological processes of carbon and oxygen cycles.

Nitrogen fixation – nitrogen gas in air is converted to usable nitrogen compounds in a process.

Animal wastes – urine and feces- contain nitrogen compounds that are converted to ammonia by decomposers.