CHAPTER 3 - ECOSYSTEMS

Lesson 1 – Parts of Ecosystems

An ecosystem is made of living and nonliving parts that all work together. Every organism in an ecosystem has a part to play.

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

An ecosystem can be as large as a desert or as small as a rotting cactus.

Living & Nonliving Parts of Ecosystems Living Parts – animals, plants, fungi,

protists, and bacteria Nonliving Parts – air, water, soil, sunlight,

climate, and landforms

Ecosystems

There are many different kinds of ecosystems.

Some examples – Desert Grassland Tundra Forest Tropical Rain Forest Coral Reef Ponds

Desert

Arizona – A Desert Ecosystem Video

Grassland

Tundra

Tundra Video

Forest

Tropical Rain Forest

Rainforest Video

Coral Reef

Coral Reef Video

Population

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

Desert Example – Prairie dog

population Plant population

Community

The different populations that interact with each other in the same area form a community.

What might be a reason for a population decrease in a community? The amount of food decreases. This

means that the animal will have to leave that area in search of food.

Habitat

The area or place where an organism lives in an ecosystem is called a habitat. A habitat contains all the living and nonliving things an organism needs.

Niche

The specific role of an organism in its habitat is called its niche. A niche includes the type of food the organism eats, how it gets its food, and which other species use the organism as food. Adaptations also help determine an organism’s niche.

Review

1. What is the name for all of the members of one species that live within an area of an ecosystem?

2. What is the name for all of the living and nonliving things in an environment and how they interact?

3. What is the name for the specific role of an organism in its environment?

4. What is the name for the different populations that interact with each other in the same area?

5. Why is a desert considered an ecosystem?

Lesson 2 – Energy Flow in Ecosystems

Every living thing needs energy. Energy in an ecosystem is passed from one organism to another.

Producers

Producers are organisms that can make their own food.

Consumers

Consumers are organisms that cannot make their own food.

More about Consumers

There are three different types of consumers. Herbivores –

get energy by eating only plants

Carnivores – get energy by eating only animals (meat)

Omnivores – get energy by eating plants & animals

Herbivores

Carnivores

Omnivores

A Food Chain

The sun is the main source of energy for life on earth. A food chain begins with energy from sunlight.

Producers are the next link in the chain.

Predators get energy they need by hunting and killing prey.

An animal with no natural enemies is called a top predator.

http://magma.nationalgeographic.com/ngexplorer/0309/quickflicks/

Small Things That Make a Big Difference Decomposers digest the waste and

remains of dead plants and animals. Why are decomposers important to the

food chain? They add minerals and nutrients to soil, water & air.

A Food Web

Ecosystems have many food chains. The same food source can be part of more than one food chain. As a result, one food chain often overlaps other food chains.

What might happen if a population dies out? The food web will change.

Review

1. When a food chain overlaps with other food chains it is called a –

2. A food chain starts with an - 3. What is the main energy source for life on Earth? 4. What is the job of a decomposer and why is it

important to the food chain? 5. What is a producer? Give an example. 6. What is a consumer? Give an example. 7. What is a herbivore? 8. What is an omnivore? 9. What is a carnivore? 10. What might happen if a population dies out?

Lesson 3 – The Flow of Matter in an Ecosystem All organisms need more than energy to

survive. They also need matter in the form of minerals, oxygen, and carbon dioxide. This matter is then returned to the ecosystem when organisms die and decay.

Matter and energy flow through an ecosystem. Plants use minerals from the soil and gases in the air. Herbivores get the matter and energy they need to form the plants they eat. Carnivores get the matter and energy they need from the animals they eat.

Decay in Ecosystems

All living things eventually die and rot, or decay. Decay is a very important process. Without decay, dead organisms and wastes would pile up and interfere with the habitats of living things.

Decaying plants and animals are helpful because they put minerals back into the soil.