Grade 7 Science
Unit 4
Interactions Within
Ecosystems
What is Ecology?
 The study of the relationships between
living organisms and their environment.
 Scientists who study these relationships are called
ecologists.
Ecosystem: What is it?
What is an Ecosystem?
 The interactions between living and non-
living things in a particular environment.
 E.g. A rotting log is an example of an ecosystem. The
organisms living in and on the log and the soil,
temperature, and other non-living features around the
log are interacting.
Ecosystems...
Can be described by the types of
organisms and the conditions found
there.
include abiotic (non-living) and
biotic (living) things.
Can be large or small.
Let’s go Outside…
 School yard activity
Local Area:
Living
Things
Local
Conditions
The Abiotic Environment
The non-living parts of the
environment.
The upper and lower limits in
which an organism can survive is
called the organism’s range of
tolerance.
Abiotic Factors:
Examples include...
1. Intensity of sunlight
2. Temperature
3. Soil
4. Air and wind
5. Water
The Biotic Environment
The living parts of the
environment.
Includes MANY species of
organisms ( living things).
Species: a group of organisms that can
reproduce to produce similar, fertile
organisms.
What do living things need
for survival?
With a partner, generate a list of
the things that all living things
must have for survival.
The Needs of Living Things
 All living things from spiders, to sunflowers, to
humans need…
1)Food
2)Water
3)Habitat
4)Air (gas exchange)
 Living things are always interacting with
each other and with the non-living things
in their environment.
Adaptation
 Adaptation: is an inherited characteristic that
helps an organism survive and reproduce
in its environment.
 E.g. A duck has webbed feet so it can swim well
 E.g. Many birds have hollow bones so they can fly
easily.
Continued…
 There are however many characteristics that help animals
survive in their environment that are learned.
 E.g. Humans learn to look both ways before crossing the
street.
 These however, are not adaptations.
Can you remember what an
Ecosystem is?
 An ecosystem is the interactions
between living and non-living things in a
particular environment.
 What is a Biome?
 Complete the Biome Worksheet
Levels of Organization
ecosystem
community
population
individual
The Roles of Organisms in an
Ecosystem
 Niche: The role of an organism in its ecosystem.
 To determine an organism’s niche, you must look
at what it eats, where it lives, and how it
interacts with other organisms in its ecosystem.
Interactions Between Living Things
in an Ecosystem
 Symbiosis: Occurs when two species live closely together
in a relationship that lasts over time.
 Can you think of any examples??
3 Types of Symbiosis
 Mutualism: Each partner benefits from the relationship!
 e.g. The remora fish uses suckers on its head to attach
itself to a shark. It then eats the bacteria living on the
shark’s skin.
 Other examples??
Continued…
 Parasitism: One partner benefits from the relationship and
the other is harmed.
 Which is which?? Parasite or host??
Examples: tapeworm, mosquito, leech
Types of Ecosystems...
Ocean
Forest
Pond
Arctic
Use your textbook and the internet
to complete the following chart on
each type of ecosystem.
Ecosystem Flora Fauna Abiotic
plants animals Cond.
1. Oceans
2. Forest
3. Pond
4. Arctic
Field Trip to the Schoolyard
Habitat –vs- Niche
Habitat: the organism’s address;
where does it live?
Ex. A moose’s habitat is the boreal
forest.
Niche: the organism’s job; what
role does the organism play in its
environment. It includes:
where it lives
how it obtains food
how it affects its environment
Ex. A moose lives in the boreal
forest, it is a herbivore (plant
eater), it provides a home for
parasites and it provides food for
coyotes.
Interactions in the Environment
Biotic - abiotic
Abiotic - abiotic
Biotic - biotic