Download Species interactions and symbiotic relationships

Population – group of individuals of the same species
living in the same area, potentially interacting
Community – group of populations of different species
living in the same area, potentially interacting
What are some ecological interactions?
Why are ecological interactions important?
Interactions can affect where an organism lives
(distribution) and
how many there are (abundance).
Interactions can influence evolution or adaptation.
Think about how the following interactions can affect
distribution, abundance, and evolution.
Types of ecological interactions
competition
predation
parasitism
mutualism
commensalism
symbiosis
Competition – two species share a requirement for a
limited resource  reduces fitness of one or both species
Trees competing for sun
Mice
competing
for food
Competition – two species share a requirement for a
limited resource  reduces fitness of one or both species
American Bison Competing
for a female.
predation – 1 species hunts, kills and eats another species
1 species benefits and other species life is lost.
Herbivory predation
Mutualism – two species provide resources or services
to each other  enhances fitness of both species
bacteria and plant roots:
the bacteria changes
nitrogen gas into usable
nitrogen and the plants
roots provide nutrients for t
bacteria to survive.
Fungus (base) and
algae(nutrients) produce
lichens.
Ants aerate and soil which
helps with drainage and
turning the soil. (cultivating)
Clown fish and sea
anenome
Parasitism – one species feeds on another  enhances
fitness of parasite but reduces fitness of host
Hookworm
in animal
feces
Tick
Corn
Blight
caused by
a fungus.
mistletoe
Head lice
Commensalism – one species receives a benefit from
another species  enhances fitness of one species; no
effect on fitness of the other species
Tree limb provides a base for
growth.
Ray provides
transport
Symbiosis – two species live together  can include
parasitism, mutualism, and commensalism
Organizing ecological interactions
effect on species 1
+
effect on
species 2
+
mutualism
0
commensalism
-
predation
herbivory
parasitism
0
-
commensalism
predation
herbivory
parasitism
competition
competition
competition