Chapter 3:
Ecosystems
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Chapter 3 Vocabulary
ecosystem
population
community
niche
herbivores
carnivores
omnivores
decomposers
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Lesson 1: What are the parts of ecosystems?
What a System Is
 A system is made of many parts that work together for a____________________.
 A system can have ____________________ and ____________________ parts.
 Most systems need ____________________, or things coming into the system from
outside the system.
1) How is a bicycle an example of a simple system?
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2) Give an example of a system from your everyday life. Write about the parts that work
together.
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Ecosystems
 An ecosystem is one kind of ____________________.
 ____________________ interact with each other and with the nonliving parts of the
system.
1) Explain how a “desert” and a “rotting cactus” can both be ecosystems.
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2) What are some nonliving parts of an ecosystem?
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Kinds of Ecosystems
 ____________________ can survive only in environments in which their needs are met.
 The kinds of plants and animals that live in an area depend on the
____________________ and the ____________________.
1) Why do plants and animals do well in a desert ecosystem?
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Kinds of Ecosystems
Desert
Grassland
Tundra
Forest
Tropical Rain Forest
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Organisms and Their Environment
 The size of each population may change depending on the amount of
____________________, ____________________, and ____________________ that is
available.
 The different populations that interact with each other in the same area form a
____________________.
 The area or place where an organism lives in an ecosystem is called a
____________________.
 You can think of a habitat as an organism’s ____________________.
 A habitat contains all of the living and nonliving things than an ____________________
needs.
Special Roles
 If an organism’s habitat is its address, its ____________________ is its job.
 ____________________ also help determine an organism’s niche.
1) How is the niche of a roadrunner and hummingbird different?
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2) Using the picture on page 83, explain the levels of a system.
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Lesson 2: How does energy flow in ecosystems?
Energy in Plants and Animals
 ____________________ is the main energy source for life on Earth.
 In the process of ____________________, green plants change sunlight energy into
chemical energy.
 Since plants make, or produce, their own food, they are called ____________________.
 Organisms that eat, or consume, other living things are called ____________________.
Types of Consumers
Definition
Examples
Herbivores
Carnivores
Omnivores
1) Explain how the adaptations of different teeth help both herbivores and carnivores.
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A Food Chain
 The energy stored by producers can be transferred along a ____________________
____________________.
 A food chain always begins with energy from ____________________.
 ____________________ are the next link in the food chain.
 ____________________ get the energy they need by hunting and killing prey.
Small Things That Make a Big Difference
 Some ____________________, ____________________, and ____________________
are decomposers.
 ____________________ break down dead plant and animal tissues into minerals and
nutrients that are put back into the soil, air, and water.
 Whatever affects the decomposers of an ecosystem affects the health of the
____________________ and all the ____________________ that eat them are affected
too.
1) Explain how the food energy stored by the grass is transferred to the hawk in the diagram.
grass → grasshopper → mouse → snake → hawk
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A Food Web
 An ecosystem has many ____________________ ____________________.
 A system of overlapping good chains is called a ____________________
____________________.
 In a food web, the flow of energy branches out in many ____________________.
1) Using the illustration on page 89, explain the connection of at least three organisms of the
food web.
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2) Do you think a roadrunner competes with other animals for a food source?
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3) Draw a diagram of a food web that includes humans and at least four other organisms.
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Lesson 3: How does matter flow in ecosystems?
Water Ecosystems
 Almost ____________________ of Earth’s surface is covered with water.
 Organisms that live in the ____________________ habitats of oceans are different from
organisms that live in ____________________ habitats.
 The ____________________ Swamp is a wetland that is home to many organisms.
 Since single-celled algae carry out photosynthesis, they are ____________________.
How Matter Flows Through a Food Web
 Many of the ____________________ and ____________________ of a swamp
ecosystem are part of more than one food chain.
 In this food web, the algae uses energy from ____________________ and matter from the
____________________ to live.
1) Using the Food Web on page 92, explain how the blue-spotted sunfish is part of three
different food chains.
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Decay in Ecosystems
 All living things eventually die and rot, or ____________________.
 Without decay, dead organisms and wastes would pile up and interfere with the
____________________ of living things.
 During the process of decay, ____________________ feed on the remains of the dead
organisms.
 ____________________, such as fungi and bacteria, break down the dead organisms.
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Rate of Decay
 Many factors affect how ____________________ or ____________________ dead
organisms decay.
 The amount of ____________________ can affect decay.
 We cover food in the refrigerator because many decomposers grow more quickly when
there is plenty of ____________________.
 Things that were once alive change more ____________________ than things that were
never alive.
1) How do warmer or cooler temperatures affect the rate of decay?
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2) How does moisture affect the rate of decay?
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3) Explain how carbon dioxide and oxygen are used in photosynthesis.
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Math in Science – Graphing Population (Page 98-99)
1. ______
2. ______
3. ______
4. ________________________________________________________________________
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