1. True or false?
1. An ecosystem is all the animals that live together in a given area.
2. A layer of decayed leaves that covers the soil in a forest is an example of a living factor.
3. A habitat is the place where an animal lives.
Chapter Introduction

2. True or false?
4. Symbiosis is a close relationship between two species.
5. Energy from sunlight is the basis for almost every food chain on Earth.
6. A plant creates matter when it grows.
Chapter Introduction

3. What is an ecosystem?
An ecosystem is all the living things and nonliving things in a given area.
Ecosystems on Earth include forests, deserts, grasslands, rivers, beaches, and coral reefs.
Ecosystems that have similar climates and contain similar types of plants are grouped together into biomes.
Lesson 1-1

4. What is an ecosystem? (cont.)
The nonliving parts of an ecosystem are called abiotic factors.
Living or once-living things in an ecosystem are called biotic factors.
Lesson 1-1

5. What is an ecosystem? (cont.)
Biotic or Abiotic?
Sunlight
Worms
Decaying plants
Air
Rocks
The ocean
Lesson 1-1

6. Habitats
A habitat is the place within an ecosystem that provides food, water, shelter, and other biotic and abiotic factors an organism needs to survive and reproduce.
Organisms have a variety of habitats.
When biotic or abiotic factors in an ecosystem change, habitats can change or disappear.
Lesson 1-2

7. Populations Every ecosystem includes many individuals of many species.
A population is all the organisms of the same species that live in the same area at the same time.
All the populations living in the same area at the same time form a community.
Lesson 1-3

8. The community living in this vacant lot includes populations of dandelions, grasses, ants, spiders, and pigeons.
Lesson 1-3

9. Populations (cont.)
Population density is the size of a population compared to the amount of space available.
When population density is high, organisms live closer together and might not be able to obtain all the resources needed for life.
Diseases spread more easily when organisms live closer together.
Lesson 1-3

10. Populations (cont.)
Production of offspring increases the size of a population. The death of individuals reduces population size.
If births outnumber deaths, the population grows.
Changes in the abiotic or biotic factors in an ecosystem can cause organisms to move away or die out.
Lesson 1-4

11. Which type of abiotic factor provides energy for photosynthesis and warmth?
A. air
B. soil
C. sunlight
D. water
Lesson 1 – LR1

12. Which term refers to all the populations living in the same area at the same time?
A. biotic factors
B. community
C. ecosystem
D. habitat
Lesson 1 – LR3

13. 1. An ecosystem is all the animals that live together in a given area.
True or False?
1. An ecosystem is all the animals that live together in a given area.
2. A layer of decayed leaves that covers the soil in a forest is an example of a living factor.
Lesson 1 - Now

14. Competition
Competition describes the demand for resources, such as food, water, and shelter, in short supply in a community.
Competition can take place among the members of a population or between two populations of different species.
Competition limits population size.
Lesson 2-2

15. Overpopulation occurs when a population becomes so large that it causes damage to the environment.
Overpopulation is temporary because when resources eventually run out, some animals will move elsewhere, starve, or die from disease.
Lesson 2-2

16. Predation
Predation is the act of one organism, a predator, feeding on another organism, its prey.
Predators help control the size of prey populations.
When prey populations decrease, the number of predators usually decreases because less food is available.
Lesson 2-4

17. Symbiosis is a close, long-term relationship between two species that usually involves an exchange of food or energy.
Lesson 2-4

18. A symbiotic relationship in which both organisms benefit is mutualism.
For example, fish benefit by having tiny organisms removed from their bodies by cleaner shrimp, and cleaner shrimp benefit by getting food.
Lesson 2-4

19. A symbiotic relationship in which one organism benefits but the other neither benefits nor is harmed is commensalism.
Moss growing on the bark of a tree benefits by having somewhere to grow, and the tree is neither benefited nor harmed.
Lesson 2-4

20. A symbiotic relationship in which one organism benefits while the other is harmed is parasitism.
A parasitic wasp lays its eggs in a caterpillar’s body. The larvae develop and eventually chew their way out of the caterpillar and kill it.
Lesson 2-4

21. Which happens when a population becomes so large that it causes damage to the environment?
A. competition
B. overpopulation
C. predation
D. symbiosis
Lesson 2 – LR1

22. Which is a symbiotic relationship in which one organism benefits but the other neither benefits nor is harmed?
A. commensalism
B. mutualism
C. parasitism
D. predation
Lesson 2 – LR2

23. Which describes the demand for resources, such as food, water, and shelter, in short supply in a community?
A. competition
B. overpopulation
C. parasitism
D. predation
Lesson 2 – LR3

24. 3. A habitat is the place where an animal lives.
True or False?
3. A habitat is the place where an animal lives.
4. Symbiosis is a close relationship between two species.
Lesson 2 - Now

25. Matter and Energy
Almost all of the matter on Earth today has been here since it formed.
Matter can change form, but it cannot be created or destroyed.
Lesson 3-1

26. Matter and Energy (cont.)
Unlike matter, energy cannot be recycled, but it can be converted.
For example, the chemical energy in a log converts to thermal energy and light energy when it burns.
Lesson 3-1

27. Obtaining Energy
Most of the energy used by all organisms on Earth comes from the Sun.
Producers are organisms that use an outside energy source, such as the Sun, and produce their own food.
Lesson 3-2

28. Photosynthesis and cellular respiration occur throughout ecosystems.
Lesson 3-2

29. Obtaining Energy (cont.)
Consumers are organisms that cannot make their own food.
Consumers obtain food by eating producers or other consumers.
Lesson 3-2

30. Obtaining Energy (cont.)
Ecosystems include several different kinds of consumers.
Herbivores, such as snails, rabbits, deer, and bees, eat plants and other producers.
Carnivores, such as cats, snakes, hawks, frogs and spiders, eat herbivores and other consumers.
Lesson 3-2

31. Obtaining Energy (cont.)
Omnivores, including bears, robins, pigs, rats, and humans, eat producers and consumers.
Decomposers, including fungi, bacteria, wood lice, termites, and earthworms, break down the bodies of dead organisms into compounds that can be used by living organisms.
Lesson 3-2

32. Transferring Energy
The transfer of energy takes place in an ecosystem when one organism eats another.
A model that shows how energy flows in an ecosystem through feeding relationships is called a food chain.
Lesson 3-3

33. Transferring Energy (cont.)
A food chain always begins with a producer because producers are the source of energy for the rest of the organisms in a community.
Lesson 3-3

34. Transferring Energy (cont.)
Most ecosystems contain many food chains.
A food web is a more complex model of energy transfer that can show how the food chains in a community are interconnected.
Lesson 3-3

35. Identify the producers, consumers, hervibores, omnivores, and carnivores.
Lesson 3-4

36. Where does most of the energy used by all organisms on Earth come from?
A. water
B. the Sun
C. producers
D. consumers
Lesson 3 – LR1

37. Which model shows how energy flows in an ecosystem through feeding relationships?
A. community
B. ecosystem
C. food chain
D. food web
Lesson 3 – LR2

38. Which is a consumer that eats plants and other producers?
A. carnivores
B. decomposers
C. herbivores
D. omnivores
Lesson 3 – LR3

39. 6. A plant creates matter when it grows.
True or False?
5. Energy from sunlight is the basis for almost every food chain on Earth.
6. A plant creates matter when it grows.
Lesson 3 - Now

40. Which describes the nonliving parts of an ecosystem?
A. abiotic factors
B. biotic factors
C. habitat
D. humus
Chapter Review – MC1

41. Which refers to all the organisms of the same species that live in the same area at the same time?
A. community
B. ecosystem
C. habitat
D. population
Chapter Review – MC2

42. Which term describes the act of one organism, a predator, feeding on another organism, its prey?
A. commensalism
B. parasitism
C. predation
D. symbiosis
Chapter Review – MC4

43. Which describes organisms that cannot make their own food?
A. consumers
B. decomposers
C. omnivores
D. producers
Chapter Review – MC5

44. What are the living or once-living things in an ecosystem called?
A. abiotic factors
B. biotic factors
C. habitat
D. population
Chapter Review – STP1

45. Which term refers to the place within an ecosystem that provides biotic and abiotic factors an organism needs to survive and reproduce?
A. community
B. habitat
C. humus
D. population
Chapter Review – STP2

46. Which is a symbiotic relationship in which both organisms benefit?
A. commensalism
B. mutualism
C. parasitism
D. predation
Chapter Review – STP3

47. Which is a close, long-term relationship between two species that usually involves an exchange of food or energy?
A. mutualism
B. parasitism
C. predation
D. symbiosis
Chapter Review – STP4

48. Which are organisms that use an outside energy source, such as the Sun, and produce their own food?
A. carnivores
B. consumers
C. decomposers
D. producers
Chapter Review – STP5