Transcript Types of Interactions

Limiting Factors
EQ: How do the biotic and abiotic factors of an ecosystem
interact?
https://www.youtube.com/watch?v=QI2ixJeIxEU&spfreload=10
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1. Fit as many organisms (m&m’s) into
your ecosystem (the box labeled
“Carrying Capacity”) as you can without
stacking them or overlapping over the
sides
Count your organisms
This is your ecosystem’s carrying capacity.
What is meant by carrying capacity?
T-P-S
What Limits Your Species?
Look at the seaweed
forest on the left.
 How many fish do
you count?
 How many seaweed
plants can you see?
 Why do you think
there are more
members of the
seaweed population
than members of the
fish population?
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Types of Interactions
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Most living things produce more offspring than will
survive.
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A female frog will lay hundreds of eggs in a small pond
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In a few months, the frog population will not increase
appreciably.
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T-P-S – Why?
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Organisms, such as frogs, interact with the biotic and
abiotic factors in its environment.
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The environment will control the size of its population
Interactions with the Environment
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Populations cannot
grow without
stopping, because
the environment
has a limited
amount of food,
water, living space
and other resources
Limiting Factors
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A resource that is
so scarce that it
limits the size of a
population is called
a limiting factor.
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Food
Water
Space
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Limiting Factors
Limiting factors are
very closely tied to
carrying capacity.
 Many species of plants
and animals can
increase in number
very quickly, and may
exceed the carrying
capacity of their
habitat.
 This results in stress,
starvation, predation,
parasites, and damage
to the habitat.
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Limiting Factors
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Conditions that may
limit the population
of an ecosystem
include, but are not
limited to are:
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Disease
Accidents
Natural Factors (fires,
floods, etc.)
Starvation
Hunting
Predation
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Limiting Factors
The largest population
that an environment
can support is known
as its carrying
capacity.
 When a population
grows larger than its
carrying capacity,
limiting factors in the
environment cause
individual organisms to
die off and leave.
 This causes a decrease
in population
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Carrying Capacity
For example,
multiplying otters can
quickly eat all of the
fish in a stream.
 With the fish gone, food
becomes a limiting
factor and the otters
will starve or move to
another area.
 The stream now has a
reduced carrying
capacity for river otters
until the fish population
grows back again
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Limiting Factors & Carrying
Capacity
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1. I will give you a question, then I
will announce "Heads Together!“
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A resource that is so scarce that it
limits the size of a population is
called: __________________
2.Students stand up and lean in
toward the others in your small
group - literally heads together!
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Conditions that may limit the population
of an ecosystem include, but are not
limited to are:
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3.In your group, you will discuss
answers to the question
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Which resources may become so scarce
that it limits the size of a population?
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4.After a minute or two, I will
announce "Heads Apart!“
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The largest population that an
environment can support is known as
its __________________
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5.Students end their discussion
and sit back down.
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Why is it essential that the
population of an ecosystem stay
balanced?
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What would happen if limiting factors
didn’t exist?
Heads Together!
Part 2: Interactions
EQ:How do the biotic and abiotic factors of an ecosystem
interact?
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Nature is amazing! For the most part, it keeps itself
balanced (homeostasis) without human interference.
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An ecosystem can only support a certain number of
organisms (its carrying capacity).
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To keep this number in check, each organism within an
ecosystem has a specific role, or niche to fill.
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As a result of the interactions between organisms as they
carry out their roles, ecosystems generally stay balanced.
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Limiting factors!
Interactions
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Ecologists have
described four main
ways that species
interact:
Competition
Predator/Prey
Symbiotic
Coevolution
Interactions Between Organisms
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Competition
When two or more
individuals or
populations try to
use the same
resource such as
food, water, shelter,
space or sunlight, it
is called competition
Ex: Buffalo
competing for
mates
One wins, the other
loses
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Because resources
are in limited supply
in the environment,
their use by one
individual or
population
decreases the
amount of
resources
available to other
organisms
Competition
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Many interactions
between species
consist of one
organism eating
another.
The organism that is
being eaten is the
prey.
The organism that
eats the prey is called
the predator.
Ex: Lion and zebra
Predator/Prey
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Predator/Prey
To survive,
predators must be
able to catch their
prey.
To survive, prey
must have methods
and abilities to
avoid capture.
These methods and
abilities are called
adaptations.
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Some species have
very close
interactions with
other species.
Symbiosis is a
close, long-term
association
between two or
more organisms
or species.
Symbiosis
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In addition to the competitive relationships
that help limit the population of an area,
there are also cooperative relationships in an
ecosystem that allow the habitat to function.
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They are:
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Mutualism
Commensalism
Parasitism
Symbiosis
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Mutualism
Mutualism is a
symbiotic relationship
in which both
organisms benefit.
Example: Insects
and plants
Insects get the
tasty nectar
Flower gets
pollinated
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A symbiotic
relationship where
one organism
benefits, and the
other is unaffected
is called
commensalism
Example: Clownfish
and sea anemone
Clownfish:
protection
Anemone: doesn’t
even notice
Commensalism
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Parasitism
A symbiotic
association in which
one organism
benefits and the
other is harmed is
called parasitism.
Example: Fleas and
dogs
Fleas: food as it
sucks blood from
the dog
Dog: harmed
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The Earth is not static, meaning that it stays
the same, but instead it is dynamic, or
constantly and continuously changing.
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Because the Earth itself is dynamic, the
organisms that inhabit the Earth must
change as well, or they will evolve out.
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Another relationship is called coevolution,
which is when two different species who are
interdependent evolve together in order to
perpetuate the species.
Coevolution
The term coevolution is used
to describe cases where two
(or more) species
reciprocally affect each
other’s evolution.
 So for example, an
evolutionary change in the
structure of of a plant, might
affect the structure of an
herbivore that eats the plant
 This in turn might affect the
evolution of the plant, which
might affect the evolution of
the herbivore...and so on.
 Example: Ant and acacia
tree
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Coevolution
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But the ants are not just taking
advantage of the plant—they also
defend their acacia plant against
herbivores.
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This system is probably the product
of coevolution:
The plants would not have evolved
hollow thorns or nectar pores unless
their evolution had been affected by
the ants,
And the ants would not have evolved
herbivore defense behaviors unless
their evolution had been affected by
the plants.
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Coevolution
Some Central American Acacia
species have hollow thorns and pores
at the bases of their leaves that
secrete nectar
These hollow thorns are the
exclusive nest-site of some species of
ant that drink the nectar.