Biology review of Units 1-2.

1. Biology Review
for Unit 1-2

2. ECOLOGY AND ECOSYSTEMS

3. FOOD CHAINS
Original source of energy for most chains is the sun
1st trophic level is producer
2nd trophic level is primary consumer
2rd trophic level is secondary consumer
Decomposer not shown on chain, but they recycle
nutrients
Energy is “lost” as
you mover “up” the
food chain

4. SYMBIOSIS

5. PREDATION
– Predator EATS Prey
– The populations cycle
– Predator has lower curve
– There can’t be more predators
than prey

6. POPULATION GROWTH
EXPONENTIAL GROWTH – LOGISTIC GROWTH
J-curve
Occurs when
unlimited resources
are available
S-curve
Occurs because
resources are
limited
Carrying capacity
reached

7. HUMAN POPULATION GROWTH
Overpopulation of
humans leads to
– Destruction of habitats
(pollution and/or
destroying)
– Loss of biodiversity
– Introduced species
–Outcompete native
species