I.                    Ecosystems  Chapter 3

A.     A system is made of many parts that work together for a purpose.

B.     An ecosystem is all the living and nonliving things in an environment and the many ways they interact.

1.                  Kinds of ecosystems

a)                  Desert

b)                  Grassland

c)                  Tundra

d)                  Forest

e)                  Tropical rain forest

C.     Organisms and their environment

1.                  A population is all the members of one species that live within an ecosystem.

2.                  A community is different populations that interact with each other in the same area.

3.                  The area or place an organism lives is called its habitat.

4.                  The specific role or job an organism has in its habitat is its niche.

a)                  Type of food it eats

b)                  How it gets its food

c)                  Which species use it as food

d)                  Adaptations it has to its habitat determine its niche.

5.                  For example a roadrunner’s habitat is the desert, but its niche as a predator is chasing scorpions, lizards, and snakes for food.

II.                 How energy flows in ecosystems

A.     The main source of energy for life is sunlight.

B.     Plants make or produce their own food, so they are producers.

C.     Organisms that eat, or consume, other living things are consumers.

1.                  Consumers that get energy from plants are herbivores.

2.                  Consumers that eat only animals are carnivores.

3.                  Consumers that eat both plants and animals are omnivores.

a)                  Scavengers eat dead plants or animals.

D.     Organisms have adaptations that help them in their niche.

1.                  claws

2.                  sharp teeth

E.      A food chain is a process by which energy moves from one type of living thing to another.

1.                  The flow of nutrients and minerals travel in one direction.

2.                  It travels from producers to consumers.

3.                  Decomposers replace nutrients and minerals in the food chain.

a)                  Decomposers digest the waste and remains of dead plants and animals.

b)                  They break down dead plant and animal tissues into minerals and nutrients that are put back into the soil, air, and water.

c)                  Bacteria, fungi, and insects are decomposers.

F.      A food web is a system of overlapping food chains in which the flow of energy branches out in many directions.

1.                  Producers and consumers can be eaten by more than one kind of organism.

2.                  Some predators eat more than one prey.

3.                  Disease, storms, pollution, and hunting that effect the population of the organisms will cause a food web to change.

G.     Water Ecosystems

1.                  deep in the ocean

2.                  ponds

3.                  swamps

4.                  flow of matter

a)                  Algae are producers that make food from the sun.

b)                  Snails and zooplankton eat the algae.

c)                  Cranes, blue heron, and fish  feed on the snails.

d)                  Decomposers, such as fungi and bacteria, break down the dead organisms and return minerals to the ecosystem.

e)                  Then the energy and mineral cycle begins again with new algae.

H.     Rate of decay in an ecosystem

1.                  The time it takes an organism to decay depends on several things.

a)                  temperature

b)                  amount of moisture

c)                  oxygen

2.                  Dead organisms would pile up and interfere with the habitats of living things if they didn’t decay.