Chapter 1
INTERACTIONS OF LIVING THINGS
BELLRINGER

Make a list of all the things that are found in a
pond ecosystem

Which of the things are living and which are
nonliving?
SECTION 1: EVERYTHING IS CONNECTED

All living things are connected in a web of life.

Ecology is the study of the interactions of
organisms with one another and with their
environment.
TWO PARTS TO AN ENVIRONMENT:
1.
Biotic – all of the organisms that live together
and interact with one another in an
environment
2.
Abiotic – the part of the environment that
consists of nonliving factors
THE 5 LEVELS OF ORGANIZATION OF THE
ENVIRONMENT
1.
The organism – one
single individual living
in an environment
2.
A Population – A group
of similar organisms in
the same species that
live together
3.
A Community – all of
the populations of
species that live and
interact in an area
4.
An Ecosystem – made
up of a community of
organisms and the
abiotic environment of
the community
5.
The Biosphere – the
part of the Earth where
life exists
FIND EXAMPLES OF EACH LEVEL OF ORGANIZATION IN THIS SALT
MARSH ENVIRONMENT
Section 2
LIVING THINGS NEED ENERGY
BELLRINGER

This is a flowering plant
called Indian Pipe. It
has no chlorophyll or
chloroplasts.

Can this plant still be a
producer?

If not, where does it get
the energy to survive?

All living things need energy to survive.

Organisms can be divided into three groups
based on how they get their energy:
1.
Producers –
organisms that use
sunlight directly to
make food using a
process called
photosynthesis

Most are plants but also
includes algae and some
bacteria

Examples: Grasses,
algae, trees
2.
Consumers – Organisms that eat other
organisms

There are several kinds of consumers:
1) Herbivore – only eats plants
Examples: grasshoppers, prairie dogs, bison
2) Carnivore – only eats animals
Examples: coyotes, hawks, badgers, owls
3) Omnivores – eat both plants and
animals

Examples: grasshopper mouse,
humans

Scavengers are omnivores that eat
dead plants and animals.
 Examples: turkey vulture
3.
Decomposers – organisms
that get energy by breaking
down dead organisms

Examples: bacteria and fungi

Remove stored energy from
dead organisms

They produce simple materials
such as water and carbon
dioxide which can be used by
other living things

Decomposers are important
because they are nature’s
recyclers!
FOOD CHAINS AND FOOD WEBS

A food chain is a diagram that shows how
energy in food flows from one organism to
another

A food web is a diagram that shows the feeding
relationships between organisms in an
ecosystem
`

An arrow goes from one animal to the next,
showing where energy is going. The arrows
point toward who is receiving the energy, or
who is doing the eating.
 Example
above: Energy is moving from the grass, to the
mouse, to the owl. Or the grass is eaten by the mouse,
and the mouse is eaten by the owl.

An Energy Pyramid is a triangular diagram that
shows an ecosystem’s loss of energy, which
results as energy passes through the
ecosystem’s food chain.
 An
energy pyramid has a large base and a small top
 Less
energy is available at higher levels because
only energy stored in the tissues of an organism
can be transferred to the next level.
WOLVES AND THE ENERGY PYRAMID

One species can be very important to the flow of energy in an
environment

Example is Gray Wolves

Wolves are at the “top of the food chain” which means they are consumers that
control a lot of other populations because they prey on large animals

When the gray wolf population declined, other species, such as elk, were no
longer controlled

This led to overgrazing

This led to lack of food for the elk and all other species dependent on the grass
for food.

Soon almost all of the populations in the area were affected by the loss of the
gray wolves

In 1995 Gray Wolves were reintroduced in an attempt to restore the natural
energy flow, bringing populations back into balance.

Balance in Ecosystems
 As
the wolf population returns, they will reduce the
number of elk, which will allow more plants to grow, so
the numbers in populations of animals that eat the
plants will increase.
Section 3
TYPES OF INTERACTIONS
BELLRINGER

Make a list of predators that are also prey
INTERACTIONS WITH THE ENVIRONMENT

Most living things produce more offspring than
will survive.
 Example:
Frogs lay hundreds of eggs. Why don’t
ponds and such become overrun with frogs?
 An
organism, such as the frog, will interact with
abiotic and biotic factors that can control
population size.
1.
Limiting Factors
 Populations
cannot grow without stopping because
the environment contains a limited about of food,
water, living space, and other resources
 Limiting
factors – resource that is so scarce that it
limits population size
2.
Carrying Capacity
 Carrying
capacity – the largest population that an
environment can support
 If
a population becomes larger than its carrying
capacity, limiting factors cause individuals to leave
or die
INTERACTIONS BETWEEN ORGANISMS
Four Main Ways that Species and Individuals
affect each other are:
1.
Competition – when two
or more individuals or
populations try to use
the same resource such
as food, water, shelter,
space or sunlight.

Occurs between individuals
within a population


Example: elks competing for
food in the winter
Also happens between
populations

Example: different types of
trees competing for sunlight
2.
Predators and Prey

The organism that is
eaten is the prey

The organisms that eats
the prey is called the
predator

Example: When a bird eats
a worm, the bird is the
predator and the worm is
the prey

Predator Adaptations – any characteristic that makes
a predator better at catching prey

Prey Adaptations – any characteristic that keeps prey
from being eaten

Camouflage – blending in with the
background

Defensive Chemicals:

skunk or beetle smells,

the acid of bees, ants,
wasps, and

deadly toxins on the skin
of some animals like a
poison arrow frog

Warning coloration – A
physical advertisement
that predators should
look for another meal;


predators will avoid any
animal that has the colors
and patterns they associate
with pain, illness, or
unpleasant experiences.
Locust Borer
(beetle)
The most common warning
colors are bright shades of
red, yellow, orange, black,
and white
Yellow Jacket
3.
Symbiosis – a close, long-term association
between two or more species
 Individuals
in a symbiotic relationship can benefit
from, be unaffected by, or be harmed by the
relationship
THERE ARE 3 GROUPS OF SYMBIOTIC RELATIONSHIPS:

Mutualism – symbiotic
relationship in which
both organisms benefit

Example: Bacteria living
in your intestines
Clown Fish and Sea Anemone

Commensalism – A
symbiotic relationship in
which one organism
benefits and the other
is unaffected

Example: sharks and
remoras

Parasitism – A symbiotic
association in which one
organism benefits while
the other is harmed





The organism that benefits
is the parasite
The organism that is
harmed is the host
The parasite gets
nourishment while the host
is weakened
Sometimes a host dies
Example: Mosquito and
human
4.
Coevolution – When a
long-term change takes
place in two species
because of their close
interactions with one
another

Example: the ant and the
acacia tree

Takes place between any
organisms that live close
together, but changes
happen over a very long
period of time

Coevolution and Flowers

A pollinator is an organism
that carries pollen from one
flower to another

Flowers have changed over
millions of years to attract
pollinators

Because flowers and their
pollinators have interacted so
closely over millions of years,
there are many examples of
coevolution between them.