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Ecology
Interactions of Living Things
Fact or Fib
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Sea otters wrap themselves in a
blade of kelp to keep from drifting
while they sleep.
FACT
Blades of kelp can grow as tall as the
Statue of Liberty and they can be
useful to sea otters.
Fact or Fib
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Many animals prefer to live in areas
with acidic soil.
FIB
Acidic soil limits the number of plants
that will grow and therefore limits
the food source for many animals.
Fact or Fib
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The Australian mallee fowl relies on
bacteria and fungus to regulate the
temperature of its nest.
Fact
As they decompose leaves on the
nest, they give off heat. When it’s
just the right temperature, the birds
lay their eggs.
Fact or Fib
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Alligators make homes for fish and
other aquatic life.
FACT
They dig a hole for themselves
and when they leave that hole is
inhabited by other animals.
What is common in each of these?
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Australian mallee rely on bacteria
and fungus.
Sea otters rely on kelp.
Some aquatic animals rely on
alligators.
Many animals rely on fertile soil.
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All living things are connected.
What do we call the study of
relationships among organisms?
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Ecology
Lesson 1- Matter, Energy, & the
Environment
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Ecology is the study of the
interactions between organisms and
the environment
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An organism’s environment is
anything that affects the organism
including living & non-living factors
Living vs. Not Living Factors
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Biotic- living things
• Examples:
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Animals
Plants
Bacteria
Abiotic- non-living things
• Examples:
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The sun
Climate- average weather conditions in an area over time
Temperature
Water
Atmosphere- layer of gases that surround Earth
Soil
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If either a biotic or abiotic factor is
disturbed, other parts of the
ecosystem are affected.
biotic
from Greek biotikos, means “fit for
life”
Living Things Need Energy
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Organisms in an
ecosystem can be
divided into 3 groups
based on how they
obtain energy.
Producers
• Use sunlight to
make food using
photosynthesis
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Plants
Some Algae
Some Bacteria
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Consumers
• Eat producers or other organisms
• They cannot directly use sunlight
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Herbivores- plant eaters
Carnivores- meat eaters
Omnivores- eat both meat & plants
Scavengers- feed on bodies of dead
animals
Decomposers
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•
•
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Break down the remains of dead
organisms.
Natures recyclers because they
produce simpler material such as
water and carbon dioxide.
Examples: bacteria and fungi
How does energy move through
ecosystems?
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In most cases,
energy flow begins
with the Sun and
moves from one
organism to
another.
Food Chain
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A model that shows how energy
flows in an ecosystem through
feeding relationships.
In a food chain, arrows show the
transfer of energy.
•The amount of available energy decreases every time it is transferred from one organism
to another.
Food Web
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Food webs illustrate
all the complex
feeding relationships
in a real ecosystem.
Some organisms in a
food web might be
part of more than one
food chain in that
web.
Few organisms eat
just one kind of food
There are many
possible connections
Food chains & Food webs
video clip
Energy Pyramid
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shows the amount of energy
available in each step of a
food chain.
• The steps of an energy
pyramid are called trophic
levels.
• Producers, such as plants,
make up the trophic level at
the bottom of the pyramid
• Consumers that eat producers
make up the next trophic
level.
• Consumers that eat other
consumers make up the
highest trophic level.
• Less energy is available for
consumers at each higher
trophic level.
Energy Pyramid
video clip
What would happen to the food
web if a specific organism were
removed?
Gray wolves were almost wiped out when
the US wilderness was settled
This caused the elk population to
increase.
How do you think the fox population
was effected by this?
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Their population decreased…why?
Here’s why.
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Wolves eat elk
Elk graze
Overpopulation of elk causes
overgrazing
This means, there is not enough food
for hares which also means not
enough food for foxes.
How do wolves help the
community?
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Wolves kill old, injured, or diseased
elk and regulate the populations in
the community.
How would the introduction of
an exotic (invasive) species
affect the food web?
•Mute swans were brought to the Hudson River
Valley during the 19th century to ornament the
estates of the wealthy.
•They consume enormous quantities of submerged
aquatic vegatation (SAV) and edge other waterfowl
out of their habitats.
A thought to take with you.
• When one tugs at a single thing in
nature, he finds it attached to the rest
of the world."
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Muir, John Naturalist, Preservationist and
Founder of the Sierra Club (1838-1914)
Lesson 2- Populations &
Communities
5 Levels of the environment
Individual organism
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5 Levels of the environment
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A group of individuals of the
same species that live together
in the same area at the same
time make up a population.
5 Levels of the environment
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All populations of different species that
live in the same area make up the
community
5 Levels of the environment
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Community
plus abiotic
factors make
up the
ecosystem
5 Levels of the environment
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Anywhere that life exists is the
biosphere
• From the deepest parts of the ocean to
very high up in the atmosphere
Population Sizes
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Changes in environmental factors can
result in population size changes.
• Populations cannot grow indefinitely
• Environments only contains so much food,
water, living space, and other resources
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When one of these becomes scarce, it is
said to be limiting
A limiting factor is anything that restricts
the size of a population.
• Available sunlight is a limiting factor for most
organisms.
• Without sunlight, green plants cannot make
food, which effects animals that eat plants.
Population Sizes
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Temperature is a limiting factor for
some organisms.
• When the temperature drops below
freezing, many organisms die because it
is too cold to carry out their life
functions.
• Disease, predators, and natural
disasters such as fires or floods are also
limiting factors.
Population Sizes
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The largest number of individuals of
one species that an environment can
support is the carrying capacity
A population grows until it reaches
the carrying capacity of an
environment.
Carrying capacity is determined in
part by limiting factors
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The carrying capacity
of an environment is
not constant because
it increases and
decreases as the
amount of available
resources increases
and decreases.
When the size of a
population becomes
larger than the
carrying capacity of its
ecosystem,
overpopulation occurs.
Communities, Habitats & Niches
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A community is made up of all the
species that live in the same
ecosystem at the same time.
Habitat
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The place within an ecosystem where an
organism lives is its habitat
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A habitat provides all the resources an organism
needs, including food and shelter.
•Forests
•Grasslands
•Deserts
•Tundra
Niche
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An organism’s way of life within an
ecosystem
Different species have different
niches in the same environment
How an organism obtains energy is
an important part of its niche.
Relationships in Communities
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Competition- 2 or more
individuals or populations try to
use the same limited resource
such as food, water, shelter, or
sunlight
Can occur within or between
populations
Relationships in Communities
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Predators and Prey- interaction when
one organism eats another
Prey-organism that is eaten
• Adaptations to survive- run, stay in
groups, camouflage, poisonous
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Predators- organism that eats the
prey
• Adaptations to catch prey- fast,
camouflage
Relationships in Communities
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A close relationship between two or
more organisms of different species
that live in direct contact is called
symbiosis
Individuals can benefit from, be
unaffected by, or be harmed
Kinds of Symbiosis
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Mutualism-both organisms benefit
from the relationship
Ex. Algae produce food for coral, which provides
shelter for algae
Kinds of Symbiosis
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Commensalism- one organism
benefits and the other is unaffected
• Ex. Sharks and Remoras
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Remoras “hitch a ride” and feed on scraps of
food left by sharks; shark is unaffected
Kinds of Symbiosis
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Parasitism-one benefits and the
other is harmed
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Ex. Fleas & ticks on your pet
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Parasite benefits (ex: ticks, tapeworms)
Host is harmed
How do humans rely on other
organisms?
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"Treat the earth well: it was not given to
you by your parents, it was loaned to you
by your children. We do not inherit the
Earth from our Ancestors, we borrow it
from our children."
• Proverb-Ancient Native American
• -More quotes about [Ecology]
[Interdependence] [Stewardship] [NativeAmerican]
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-More quotes about [Common Good] [Core
Democratic Values] [Ecology] [Interdependence]
[Stewardship]