Do Now
Identify 3 things every organism needs to
survive.
Write your answers in your notebook.
List one food chain in the following picture. Name the
producer, primary consumer, secondary consumer and
tertiary consumer.
Big Picture
LS2.A: Interdependent Relationships in Ecosystems
Similarly, predatory interactions may reduce the number of organisms or eliminate whole populations
of organisms. Mutually beneficial interactions, in contrast, may become so interdependent that each
organism requires the other for survival. Although the species involved in these competitive,
predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of
organisms with their environments, both living and nonliving, are shared. (MS-LS2-2)


LS2.B: Cycle of Matter and Energy Transfer in Ecosystems
Food webs are models that demonstrate how matter and energy is transferred between producers,
consumers, and decomposers as the three groups interact within an ecosystem. Transfers of matter
into and out of the physical environment occur at every level. Decomposers recycle nutrients from
dead plant or animal matter back to the soil in terrestrial environments or to the water in aquatic
environments. The atoms that make up the organisms in an ecosystem are cycled repeatedly between
the living and nonliving parts of the ecosystem. (MS-LS2-3)
Objectives:
•
--By observing models, students will investigate the types of
interactions organisms have with each other in their environments.
--Students will use vocabulary to describe the types of interactions.
Vocabulary

Learning Target

Today I will: Learn about the types of
interactions organisms have with each
other in their environment


So that I can: Apply those concepts to
how organisms in an ecosystem are
connected.
I will know I got it if: I can identify the
three main ways organisms affect each
other.

carrying capacity

prey

predator

Agenda

symbiosis

Today we will:

mutualism

Watch a quick video

commensalism

Teacher presentation

parasitism

Group and Individual work

coevolution

Exit ticket
What is a Limiting Factor?
 Limiting Factors are…
(two similar definitions)
conditions of the environment
that limit the growth of a
species.
biotic and abiotic factors that
prevent the continuous growth
of a population.
What is a Limiting Factor?
 Populations
would continue to
increase if they had all of the
resources they require in unlimited
amounts, but there are always
factors that limit their increase.
 Limiting
factors control
population growth.
Limiting Factors
 There
are many types of limiting factors.
Some examples are:
Food
and water
Space
Weather
What is Carrying Capacity?
Carrying
capacity is
the number of
individuals of a
species that an
ecosystem can
support.
What is Carrying Capacity?
 Because of these limiting factors,
each ecosystem has a finite capacity
for growth connected to its carrying
capacity.
Carrying Capacity & Limiting Factor
Review

In nature, populations of organisms rarely grow
uncontrolled. Each ecosystem has a carrying
capacity (or number or organisms it can
sustain/support).

Remember, limiting factors are biotic and abiotic
factors that prevent the continuous growth of a
population.

Because of limiting factors, the number of organisms
in a population is often well below carrying capacity.
Limiting Factors worksheet
Interactions Between Organisms
• Individuals and Populations Interact
Populations contain individuals of a single
species that interact with one another, such as
a group of rabbits feeding in the same area.
• Communities contain interacting populations,
such as a coral reef with many species of
corals trying to find living space.
Competition
• Individuals and Populations Interact
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.
• Competition can happen within a population,
or between populations.
Predator and Prey
 Predation describes an interaction
where a predator species kills and
eats other organisms, known as prey.
 Predator/prey
 Sometimes, predators themselves
become prey.
 Praying mantis captures grasshopper.
 Anole captures and eats praying
mantis.
Predators and Prey
• Predators are organisms that eat all or part
of another organism. Organisms that are killed
and eaten by other organisms are called prey.
• Predator Adaptations To survive, predators
must be able to catch their prey. Predators
have a wide variety of methods and abilities
for doing so.
Predators and Prey, continued
• Prey Adaptations Prey have their own
methods and abilities to keep from being
eaten. Prey are able to run away, stay in
groups, or camouflage themselves. Some prey
are poisonous.
• Camouflage One way animals avoid being
eaten is by being hard to see. Blending in with
the background is called camouflage.
Predators and Prey, continued
• Defensive Chemicals Some animals defend
themselves with chemicals. The skunk and the
bombardier beetle both spray predators with irritating
chemicals. Bees, ants, and wasps inject a powerful
acid into their attackers.
• Warning Coloration Animals that have a chemical
defense need a way to warn predators that they
should look elsewhere for a meal. Their chemical
weapons are often advertised by warning colors.
Symbiosis
 Symbiosis is a close ecological
relationship between the
individuals of two or more
species.
 Sometimes a symbiotic
relationship benefits both species
 Mutualism, commensalism,
parasitism, co-evolution
Mutualism
Mutualism
is an association
between organisms of two
different species in which
each member benefits.
Ants (Hymenoptera) protect
the aphids (Aphididae) and
the aphids provide
honeydew for the ants
Commensalism
Commensalism
is a symbiotic relationship
between two organisms of different species in
which one derives some benefit while the
other is unaffected.
 The
Remora fish has a dorsal fin modified as a sucker-like
attachment organ. It attaches to the sides of larger fish and turtles
using them as transport hosts and obtains food fragments dropped
from the host.
Parasitism
Parasitism
is a form of symbiosis in which
one species benefits at the expense of
another species; similar to predation, but
acts more slowly than predators and may
not always kill the host.
Head lice
Ticks
Fleas
Heart worm
Parasitism
The
organism that benefits
is called a parasite.
The organisms that it lives
on or in is called a host.
Coevolution
• What Is Coevolution? When a long-term change
takes place in two species because of their close
interactions with one another, the change is called
coevolution.
•Bees (Hymenoptera) and Plants
• Coevolution and Flowers Flowers have changed
over millions of years to attract pollinators. Pollinators
such as bees, bats, and hummingbirds can be
attracted to a flower because of its color, odor, or
nectar.
Exit Ticket
Identify 3 ways predators and
prey adapt to their ecosystem.
What are the three main ways
organisms affect each other an
ecosystem?