Download Notes: 14.1-2 PPT - Learn District 196

14.1 KEY CONCEPT
Every organism has a habitat and a niche.
Habitat vs Niche
•
A habitat is all aspects of the area in which an organism lives.
• biotic factors
• abiotic factors
• An ecological niche is
how a species obtains the
resources it needs for its
survival.
– food
– abiotic conditions
– behavior
• Habitat = where a species
lives
• Niche = how it lives within
its habitat
Resource availability gives structure to a
community.
• Species can share habitats and resources.
• Competition occurs when two species use resources in the same way.
• Competitive exclusion keeps two species from occupying the same niche.
• Competitive exclusion has different outcomes.
– Two outcomes:
1. Niche Partitioning
2. Evolutionary Response
– Divergence
– Indicates
Coevolution
Ecological Equivalents
• Ecological equivalents are species that occupy similar
niches but live in different geographical regions.
• Convergent Evolution
Madagascar Mantella
South
America Dart
14.2 KEY CONCEPT
Organisms interact as individuals and as populations.
Competition and Predation
• Competition occurs
when two organisms
fight for the
same limited
resource.
• Intraspecific
competition
• Same Species
• Interspecific
competition
• Different Species
• Predation occurs when one organism captures and eats
another.
Symbiosis: a close ecological relationship between two or
more organisms of different species that live in direct
contact with one another.
• Three Types:
1. Mutualism –
both organisms
benefit
Ex: Bat and Cactus
Nitrogen Fixing Bacteria (+)
Legumes (+)
Fungi (+)
Plants (+)
2. Commensalism: one organism benefits, the
other is unharmed
0
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.
0
Commensalism
Organism is not affected
+
+
Organism benefits
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.
Whales (0)
Barnacles (+)
• 3. Parasitism: one organism benefits, the
other is harmed
+
Parasitism
+
_
Hornworm
caterpillar
The host hornworm
will eventually die as
its organs are
consumed
by wasp larvae.
_
Organism is harmed
+
Braconid
wasp
Braconid wasp
lays its eggs
inside a
caterpillar.
When the
larvae hatch,
they eat the
caterpillar from
the inside out,
consuming
nutrients they
need to
become an
adult.
Organism benefits
• Types of Parasites:
• 1. Ectoparasites (such as leeches)
• 2. Endoparasites (such as tapeworms)