Download Ecosystems, Food Chains and Webs

Ecosystems, Food Chains, and
Food Webs
How Can Humans Change Ecosystems?
• Human activities change ecosystems in
both good and bad ways. • Human affect ecosystems by destroying
habitats. Habitat loss is the main
reason why rates of extinction are
rising.
How Can Humans Change Ecosystems?
• Rain forest are one of the most
valuable resources on Earth. • Humans clear rainforest for land to
grow crops and raise livestock
Wetlands are sometimes
drained, and filled
to be used for farms,
business, and houses.
How Can Humans Change Ecosystems?
• Endangered Species – a species that is
close to extinction. • Threatened Species – a species that is
close to becoming endangered. • Bison or buffalo is a threaten species
because of human hunting them for
their hides, and other parts.
How Can Humans Change Ecosystems?
• Fossils fuels, such as oil, gas, and coal
can affect ecosystems. Burning these
causes pollution. Small particles from
the burning enter the air, and make it
unhealthy to breathe. • Pollution – the addition of harmful
things to the environment.
How Can Humans Change
Ecosystems?
CAUSE
EFFECT
!
•
Oil from a
tanker spills
into the ocean.
How Can Humans Change
• We can help! All around the world
people are working to reduce pollution,
and restore damaged ecosystems. How
can we make a difference?
Energy from Food
• In an ecosystem, energy flows from
producers to consumers to decomposers.
Producers
Consumers
Decomposers
•Make their own food -produce
own food.
•Plants are producers.
•They make their from air, water
and energy (from the Sun)
•Gets energy by eating food –
consume own food. •Humans and animals are
consumers.
•Get
energy
eatingrot,
food.
•Break
downby
(decay,
decompose) parts of dead produces
and consumers. •Bacteria and worms are
decomposers.
Energy from Food
• The plants are the producers. The
rabbit eats plants. The fox eats the
rabbit. When the fox dies the
mushrooms decomposes itsConsumer
body.
Consumer
Producer
Decomposer
s
• Food Chain – the description of how
energy
in anis
ecosystem
from one
What
a Foodflows
Chain?
organism to another. (one chain of
organisms)
• At the base of food chain are
producers, which are _____?_____.
• The next level has primary (first level)
consumers called herbivores, or plant
eaters. They eat producers.
• Secondary (2nd level) consumers are
called carnivores, or meat eaters.
They eat first level consumers.
What is a Food Chain?
• Tertiary (3rd level) consumers eat 2nd
level consumers and so on.
• There are some consumers called
omnivores, they eat both plant and
animals. • They maybe 1st, 2nd, or 3rd level
consumers
What is a Food Chain?
What is a Food Web?
• Food Web - description of all the food
chains in an ecosystem.
• Food webs show the relationship
between many different food chains in
a single ecosystem.
What is a Food Web?
What is a Food Web?
Energy Pyramid
• Energy Pyramid – shows how energy
moves to each level of an ecosystem.
!
• Look at the pyramid(on next slide),
each level gets smaller as the energy
moves up. Only about 10% of the
energy moves from one level to the
next.
Energy Pyramid
Energy Pyramid
• An energy pyramid helps explain the
populations of an ecosystems.
Producers almost always have largest
populations because they have the
most energy to use. The higher an
animal on the energy pyramid, the
more land it must cover for food.
Energy Pyramid
What could be at the top of this pyramid?