Energy enters the biosphere by photosynthesis. For some organisms, energy enters their part of the biosphere through the process of chemosynthesis.
Cellular respiration and photosynthesis (and chemosynthesis) are related processes. Photosynthetic producers capture the Sun’s energy and convert it to chemical energy (glucose). Chemosynthetic producers capture the chemical energy stored in chemical bonds and convert it to chemical energy (glucose).
A food chain shows the linear pathway through which food is transferred from producers to primary consumers and to progressively higher feeding levels.
A food web shows energy transfer among several food chains.
Decomposers obtain energy by eating dead organisms or waste matter from organisms Examples: earthworms, fu ngi, bacteria, b eetles, centipe des, other insects.
Pyramids are divided into TROPIC LEVELS Only 10% of the energy available at a particular trophic level is transferred to the next.
Each pyramid is based on the biomass of organisms in each trophic level (g/m3).
MONOCULTURES – habitat that contains primarily one species of plant (i.e.) – farmer’s field, lawn, apple orchard Monocultures lack biodiversity – very few species of consumers can be supported – therefore unhealthy food web
BIOMAGNIFICATION toxic chemicals (eg – DDT, PCBs, lead, mercury, etc) accumulate in the soft tissues of organisms and concentrate up the food chain Higher level consumers are the most severely affected Humans are often higher on the food chain as well