Transcript Environment Types of Interactions cp1

Types of Interactions
In natural communities, populations of
different species vary greatly. The
interactions of these populations
affect the size of the populations.
The seaweed
forest is home
to a large
number of
interacting
populations.
Limiting Factors
Amount of food
Amount of living space
Amount of water
When a population becomes too large for
the amount of a given resource, it will
become a limiting factor.
Carrying Capacity
The largest a population can get in a
given environment over a long period of
time.
When a population get larger than the
carrying capacity, a limiting factor
causes the population to decline.
Competition
When two or more individuals or
populations try and use the same
limited resource.
Food
Water
Shelter
sunlight
Competition
Can be with in a
population
Weird Science
Green herons make interesting
use of biotic and abiotic part of
their environment in Japan. They
will drop sticks and even break crumbs
into the water to attract fish. Sometimes
they catch a fish 2-3 seconds after they
drop the bait!
Pretty Cool!
Misconception Alert
While it’s true that all members of an ecosystem have
important roles, some members are more important
than others to the overall health of the ecosystem.
Such species are called keystone species. Like
removing the keystone that holds up the other stones in
an arch, removing the keystone species can cause the
whole system to collapse. This occurred when the
sea otter was hunted to near extinction in the kelp
forests of the Pacific Ocean. With the otters gone,
nothing was left to eat the sea urchins, which
multiplied and ate all the kelp. The kelp was home to
dozens of animals, all of which disappeared, along
with most of the sea urchins. When the sea otter
was reintroduced, all these organisms
returned!
Discussion
The lynx relies primarily upon the
snowshoe hare for food.
How would the abundance of plants
affect the hare population?
What will happen to the lynx?
What happens when the food
runs out for the hare?
Predator
Predators must adapt to catch the prey
Speed
Ambush
camouflage
Prey
Prey need adaptations to escape the
predator
Run/hide (burrow)
Live in groups
Camouflage
Poison/color warning
Symbiosis
Close long-term association between
two or more species.
Individuals within a symbiotic
relationship may:
benefit
be unaffected
be harmed
Mutualism
Both organisms benefit
Bacteria in our intestine.
They get food
We get vitamins
Coral and algae
Coral provides home to algae
Algae provides food for the coral.
Commensalisms
One organism benefits
Other organism is unaffected.
Parasitism
One organism benefits = parasite
Other organism is harmed = host
Can cause death of the host!
Coevolution
A long-term change that takes place in
two species because of their close
relationship with one another.
Mimicry
When one organism “mimics” another to
take advantage of their defense’s.
Viceroy Butterfly
Monarch Butterfly
The viceroy and monarch were once
thought to exhibit Batesian mimicry,
where a harmless species mimics a
toxic species. Studies conducted in
the early 1990's suggest that the
viceroy and the monarch are actually
examples of Mullerian mimicry where
two equally toxic species mimic each
other to the benefit of each. Just goes
to show you there's always something
new to discover in the natural world!
Both species benefit by this mimicry. A predator that
avoids one will avoid the other.
The killdeer is a ground-nesting bird that will distract a predator from
its nest or chick with a “broken-wing” display. It will limp and drag a
wing on the ground making itself appear to be an easy catch. But
because it is actually quite healthy, it always stays one step ahead of the
predator.
Misconception Alert
The phrase balance of nature does not imply
that the components of an environment
are static. Populations are in balance
when their sizes are stable. That
stability is the result of constant
interactions between individuals of a
population, between populations in a
community, and between populations
and environmental factors.
Brain Food
Studies have shown that ducks can
have one-half of their brain asleep while
the other half is awake. The side that is
awake can even have an eye opened
and respond to stimuli. The sides can
also switch so that the half that was
awake can rest and the rested half can
become alert. Why might this be helpful
to ducks?
Honeyguides live in Africa and
India and are so called because
they lead honey badgers and
humans to the nests of wild bees
using a series of calls. After the
nest has been raided for honey,
the bird gets the chance to feed
on bee grubs from the open nest.
The bird’s unique
digestive system
allows it to eat wax
as well. Which
animals in this story
are in a mutualistic
relationship?
Which animals are
prey? Which are
predators?
Weird Science
Pancake tortoises live on rocky hillsides
in Africa. They are very flat and can
wedge themselves into the cracks in the
rocks for protection from predators.
Their bottom shells are pliable and can
“inflate” so that a predator can’t pry the
tortoises out.