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Text reference: Chapter 2
The study of how organisms interact with
each other and with their environment.
ABIOTIC FACTORS:
non-living parts of the environment
Examples: temperature, precipitation, wind, soil, sunlight, etc.
BIOTIC FACTORS:
living components
Abiotic and Biotic factors
affect each other!
Example: Strip mining affects . . .
Levels of
Organization
1. Organism: a single
living thing
2. Population: a group of
organisms of the same species
living in the same area.
Species:

Organisms that look alike, can mate
and produce fertile offspring
(a horse and a donkey look alike and
can mate, but are separate species
since they cannot produce fertile
offspring (mule)
3. Community: all of the
populations in a particular
area.
Ex.: zebra, elephants, giraffes are part of this community
4. Ecosystem: a community
interacting with the abiotic
environment.
Ex. Ocean ecosystem
Ex. Desert ecosystem
Ex. Ocean vent ecosystem
Ex. Freshwater ecosystem
Biome:

"the world's major communities”
(classified by the predominant
vegetation and characterized by
adaptations of organisms to that
particular environment)
5. Biosphere: The portion of
the earth that supports life
(high in atmosphere to bottoms of
oceans!)
Habitat vs. Niche
Habitat :
 where an
organism
lives.
 Ex. Sharks
usually live in
a marine
habitat
Niche :
 what an
organism does
 Ex. Sharks
are carnivores,
they swim
quickly and
have sharp
teeth.
Example:
Habitat: ocean
Part of its niche:
eats seals
What happens when 2
species share the same
niche?
Competition!!!!
How Do Organisms
Obtain Energy?
1. Producers = Autotrophs

Most do Photosynthesis (use light energy
to make food)*
(a few do Chemosynthesis– remember ocean vents)


All other organisms in the biosphere
are dependent on them
they are at the bottom of every food
chain!
2. Consumers = Heterotrophs
 cannot make their own food.
 feed on autotrophs or other heterotroph;
What kind of heterotrophs are there?
1. Herbivore
2.Carnivore
3.Omnivore
4.Scavenger (feed on dead organisms)
5.Decomposer (take over where scavengers leave
off)
Symbiosis:
A close relationship between 2
species for a prolonged period
of time.
3 kinds of symbiosis:
1. Mutualism: (+,+) both species benefit.
Ex: The stinging anemone protects the clownfish from
predators; the clownfish protects the anemone from
angelfish that would eat it and also keeps the anemone
free of dirt and debris.
2. Commensalism (+, 0): one species
benefits and
the other is not affected.
Ex: The barnacle larvae swim around, attach to the whale, and
form the adult. As whale swims, barnacles get new food from
water. The whale does not appear to be harmed.
3. Parasitism (+, -): one species benefits
and the other species is harmed.
Example #1. Tomato horn worm and wasp
Example #2. Cowbirds are “brood parasites”
What kind of relationship are
each of the following?
#1: Bacteria/Plant root
Bacteria in the nodules of many plants can take nitrogen gas from the
atmosphere and turn it into a form that can be used by the plant; the
plant protects the bacteria from harmful oxygen and the bacteria get
food from the plant.
#2: Heartworm/Dog
The worm larvae are transferred from dog to dog through the bite of
an infected mosquito. The mosquito sucks larval heartworms with blood
from an infected dog. The mosquito then bites another dog and
transfers these microscopic larva as it bites. During the next few
months, these larva migrate through the dogs body arriving at the
heart several months later where they become adults.
#3: Oxpecker/Mammal
The oxpecker eats parasites on the mammal.
#4: Cattle/Egret
The cattle stir up grasshoppers and other insects that
the egret likes to eat.
#5: Misletoe/Tree
Mistletoe lives off the branches and stems of other trees. It can
photosynthesize a little but not enough to meet its needs. The tree
can be harmed.