Download Ecology Notes Chapter 15

Ecology Notes (part 2)
Chapters 4-2, 4-3, 5-2, 6-2, 6-3
I. What shapes an Ecosystem?
A. Biotic factors – living things (ex: Plants, decomposers, animals)
B. Abiotic factors – nonliving things (ex: water, soil, air)
C. Niche – an organism’s role in its ecosystem; how the organism lives
Ex: A niche includes:
climate it prefers
time of day it feeds
time of year it reproduces
what it likes to eat
where it finds food
D. Habitat – where an organism lives
II. Community Interactions
A. *Symbiosis – a close, long-term relationship between two or more
species. There are 3 types:
1. Parasitism – parasites feed on a host organism; parasites are
different from predators because they usually do not kill their host
ex: Tapeworms and humans
ex: fleas and dogs
2. Mutualism – both species benefit from each other
ex: Flowering plants and insects
ex: E. coli bacteria in human large intestine: E. coli live in
our large intestine and produce vitamin K for us; we provide
nutrients
ex: nitrogen fixing bacteria and plants: bacteria produce
nitrogen for plant and plant provides place to live for bacteria
3. Commensalism – one species benefits, the other is not affected
ex: whales and barnacles
ex: clown fish and sea anemones
III. Ecological Succession
A. Succession – species replacing each other in a developing ecosystem
B. Primary Succession- when succession takes place where there were no
species before (ex: plants on land that a volcanic eruption formed)
C. Secondary succession – succession in an area where there has been
previous life (ex: plants starting to grow in a field that was destroyed by fire)
IV. Limits to growth of a population:
A. Competition
B. Predation
C. Parasitism
D. Disease
E. Natural Disasters
F. Human Activities
V. Biodiversity – all organisms in biosphere
A. Value of biodiversity: food, medicine, other products
VI. Threats to biodiversity
A. Habitat alteration – land development
B. Over fishing/hunting
C. Pollution
1. Biological magnification – amount of pollutant increases as it
moves to higher trophic levels
D. Introduced Species – accidental or intentional introduction of a plant
or animal to a new area
1. Invasive species – reproduce rapidly due to no natural predator
ex: Nutria in Louisiana; Fire ants (1918)