Download Food chain - Hall High School

2.2 nutrition and energy flow in ecosystems
2.2 vocab, finish 2.1 vocab
Objectives:
 Describe the flow of energy through an
ecosystem
 Identify the ultimate energy source for
photosynthetic producers
 Describe food chains, food webs, and pyramid
models
All energy for life on earth comes from the sun*
A.
How organisms obtain energy
1. Producers=autotrophs (self
nourishment)
a) autotrophs use sun to produce nutrients
(convert solar energy to chemical energy)
b) Ex: grass, any green plant, algae
The ocean and marine algae account for 5090% of the oxygen we breathe.
2. Consumers=Heterotrophs (other
nourishment)
a) cannot make their own food
b) consume other organisms
c) Herbivores: plant eaters (cows, sheep,
many insects)
d) Carnivores: meat eaters (cats, alligators)
e) Omnivores: eat plants and animals
(humans)
f) Scavengers: consume dead plants or
animals. (flies, hyenas, vultures)
g) Detrivores and consume small pieces of
dead things. (detritus) (worms, insects,
bottom feeders)
h) Decomposers: chemical breakdown
dead things, (fungus, microbes, compost
pile turned into dirt)
B.
Matter and energy flow in ecosystems.
1. Food chain
a)
model that shows how matter and
energy move from plants to animals
(arrows show direction of energy
movement)(pg. 43)
b) Trophic levels> nourishment levels on a
chain.
c) 3-5 links in a food chain (generally not
more than five)
d)
lots of energy (90%)is lost with each
step.
2.
Food web
a) Shows all feeding relations in a
community.
b) Network of interconnected chains.
3. Ecological pyramids: shows how
resources decrease as they flow up.
person<<300trout
<<90,000 frogs
<<27,000,000grasshoppers
<<20,000,000 lbs grass
a.
Pyramid of energy-90% energy
lost with each trophic level--
b. Pyramid of biomass—available
biomass (living weight)decreases as
trophic levels increase
c.Pyramid of numbers—numbers of
organisms decrease as trophic levels
increase
Chemo-autotrophs can manufacture energy from
chemicals—bacteria near deep ocean vents