2. Energy enters the biosphere by photosynthesis. For
some organisms, energy enters their part of the
biosphere through the process of chemosynthesis.
3. 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).
4. A food chain shows
the linear pathway
through which food
is transferred from
producers to
primary consumers
and to progressively
higher feeding
levels.
5. A food web shows energy transfer among several food
chains.
6. Decomposers
obtain energy
by eating dead
organisms or
waste matter
from
organisms
Examples:
earthworms, fu
ngi, bacteria, b
eetles, centipe
des, other
insects.
7. Pyramids are divided into TROPIC LEVELS
Only 10% of the energy available at a particular
trophic level is transferred to the next.
8. Each pyramid is based on the biomass of
organisms in each trophic level (g/m3).
9. 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
10. 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