Section 14-1 and 14-2
“Habitats and
Communities”
Write everything
that is underlined
14.1 Habitat & Niche / 14.2 Community Interactions
Section 14.1 KEY CONCEPT:
Every organism has a habitat and a
niche.
14.1 Habitat & Niche / 14.2 Community Interactions
I. Habitat & Niche
1. A habitat is all aspects of the
area in which an organism lives.
Includes:
–biotic
factors
–abiotic
factors
14.1 Habitat & Niche / 14.2 Community Interactions
2. A niche is all of the factors that a
species needs to survive, stay
healthy, and reproduce.
Includes:
–food
–abiotic
conditions
–behavior
14.1 Habitat & Niche / 14.2 Community Interactions
3. Resource availability gives
structure to a community.
a. Species can share habitats and
resources.
b. Competition occurs when two
species use resources in the same
way.
c. Competitive exclusion keeps two
species from occupying the same
niche.
14.1 Habitat & Niche / 14.2 Community Interactions
4. Possible Outcomes of Competitive Exclusion:
a. One species is better suited to the
niche and the other will either be
pushed out or become extinct.
b. The niche will be divided.
c. The two species will further
diverge.
14.1 Habitat & Niche / 14.2 Community Interactions
5. Ecological equivalents are species
that occupy similar niches but live in
different geographical regions.
Madagascar
South America
14.1 Habitat & Niche / 14.2 Community Interactions
Section 14.2 KEY CONCEPT :
Organisms interact as individuals
and as populations.
14.1 Habitat & Niche / 14.2 Community Interactions
I. Competition
1. Competition occurs when two
organisms fight for the
same limited resource.
Competition can be:
• within the same
species
(Intraspecific)
• or between different
species
(Interspecific)
14.1 Habitat & Niche / 14.2 Community Interactions
In your notes…
Example of Interspecific and Intraspecific competition
• Two squirrels race up a tree to reach a hidden pile of
nuts. _____________
• A hyena chases off a vulture to feast on an antelope
carcass.___________
• Brown bears hunting for fish on a river’s edge fight
over space.________
14.1 Habitat & Niche / 14.2 Community Interactions
II. Interactions in a Community
• Predation occurs when one
organism captures and eats
another.
14.1 Habitat & Niche / 14.2 Community Interactions
2. There are three major types of symbiotic
relationships:
a. Mutualism: both organisms benefit
14.1 Habitat & Niche / 14.2 Community Interactions
b. Commensalism: one organism
benefits, the other is not harmed
+
Demodicids Eyelash
mites find all they
need to survive in
the tiny follicles
of eyelashes.
Magnified here 225
times, these
creatures measure
0.4 mm in length and
can be seen only
with a microscope.
Ø
Human Our
eyelashes are home
to tiny mites
that feast on oil
secretions and dead
skin. Without
harming us, up to 20
mites may be living
in one eyelash
follicle.
Ø
Organism is not affected
+
Organism benefits
14.1 Habitat & Niche / 14.2 Community Interactions
c. Parasitism: one organism benefits,
+
the other is harmed
_
Hornworm
caterpillar
The host
hornworm will
eventually die
as its organs are
consumed
by wasp larvae.
_
Organism is harmed
Braconid wasp
Braconid larvae
feed on their
host and
release
themselves
shortly before
reaching
the pupae stage
of development
+
Organism benefits
14.1 Habitat & Niche / 14.2 Community Interactions
– Parasites meet their needs as
ectoparasites (such as leeches) and
endoparasites (such as hookworms)
14.1 Habitat & Niche / 14.2 Community Interactions
Review Questions Section 14.1 and 14.2
Write the question and answer on a separate sheet of
paper.
• Every organism has a ___________ and a
_________.
• Define habitat and niche.
• How does competition occur?
• When does Predation occur?
• Name the three types of symbiotic relationships and
describe each.
14.1 Habitat & Niche / 14.2 Community Interactions
Answers for questions
1. Every organism has a HABITAT and a NICHE
2. Habitat is all aspects of the area in which an
organism lives.
Niche includes all of the factors that a species needs
to survive, stay healthy and reproduce
3. Competition occurs when tow species use
resources in the same way.
4. Predation occurs when one organism captures and
eats another.
5. Mutualism: Both organisms benefit
Commensalism: one organism benefits, the other is
not harmed
Parasitism: one organism benefits, the there is
harmed