Chapter 3 The Biosphere Summary - Henriksen Science

Name______________________________ Class __________________ Date ______________

Chapter 3 The Biosphere

Summary

© Pearson Education, Inc. All rights reserved. 3–1 What Is Ecology? The process in which autotrophs use
light energy to make food is called photo-
Ecology is the scientific study of interactions synthesis. In photosynthesis, light provides
among organisms and between organisms the energy needed to turn carbon dioxide
and their environment. Earth’s organisms live and water into oxygen and carbohydrates.
in the biosphere. The biosphere consists of the The process in which autotrophs use chemi-
parts of the planet in which all life exists. It cal energy to produce carbohydrates is
includes land, water, and air, or atmosphere. called chemosynthesis. Chemosynthesis is
performed by only certain types of bacteria.
Ecology includes the study of all the dif-
ferent levels of life, ranging from the individ- Organisms that rely on other organisms
ual organism to the biosphere. Above the for their energy and food are called het-
level of the individual organism is the erotrophs. Heterotrophs are also referred to
species. A species is a group of organisms so as consumers. There are many different
similar to one another that they can breed types of heterotrophs. Herbivores, such as
together and produce fertile offspring. A cows, obtain energy by eating only plants.
group of individuals that belong to the same Carnivores, such as snakes, eat only animals.
species and live in the same area is called a Omnivores, such as humans, eat both plants
population. A collection of different popula- and animals. Detritivores, such as earth-
tions that live together in an area is referred worms, feed on plant and animal remains
to as a community. An ecosystem includes all and other dead matter. Decomposers, such
the organisms that live in a particular place, as fungi, break down organic matter.
together with their physical environment. A
group of ecosystems that have the same cli- Energy flows through an ecosystem in
mate and similar dominant communities is one direction. It flows from the sun, or from
called a biome. inorganic compounds, first to autotrophs
and then to heterotrophs. A food chain is a
Ecologists use three basic methods of series of steps in which organisms transfer
research: observing, experimenting, and energy by eating and being eaten. A food
modeling. Observing often leads to questions web links together all the food chains in an
and hypotheses. Experimenting can be used ecosystem. Each step in a food chain or food
to test hypotheses. Experimenting may be web is called a trophic level. Producers
done in a laboratory or in the natural world. make up the first trophic level. Consumers
Modeling helps ecologists understand com- make up higher trophic levels. Each con-
plex processes. sumer depends on the trophic level below it
for energy.
3–2 Energy Flow
An ecological pyramid is a diagram that
All organisms need to obtain energy from shows the relative amounts of energy or
their environment to power life processes. matter contained within each trophic level
Sunlight is the main energy source for life on in a food chain or food web. Types of eco-
Earth. Some organisms rely on the energy logical pyramids are energy pyramids,
stored in inorganic chemical compounds. biomass pyramids, and pyramids of num-
Organisms that can capture energy from sun- bers. Energy pyramids show how much
light or chemicals and use that energy to pro- energy is available within each trophic
duce food are called autotrophs. Autotrophs level. Only about 10 percent of the energy
are also known as producers. Only plants, available within one trophic level is
some algae, and certain bacteria are produc- transferred to organisms at the next trophic
ers. On land, plants are the main autotrophs. level.

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Biomass pyramids show the biomass, or The three most important nutrient
total amount of living tissue, within each cycles are the carbon, nitrogen, and phos-
trophic level. A pyramid of numbers shows phorus cycles. Carbon is a key ingredient of
the relative number of individual organisms living tissue. Processes involved in the car-
at each trophic level. bon cycle include photosynthesis and
human activities such as burning. Nitrogen
3–3 Cycles of Matter is needed by all organisms to build pro-
teins. Processes involved in the nitrogen
Matter, unlike energy, is recycled within cycle include nitrogen fixation and denitrifi-
and between ecosystems. Matter is passed cation. In nitrogen fixation, certain bacteria
from one organism to another and from one convert nitrogen gas into ammonia. In deni-
part of the biosphere to another through trification, other bacteria convert nitrogen
biogeochemical cycles. These cycles connect compounds called nitrates back into nitro-
biological, geological, and chemical proc- gen gas. Phosphorus is needed for
esses. Matter can cycle through the biosphere molecules such as DNA and RNA. Most of
because biological systems do not use up the phosphorus in the biosphere is stored in
matter, they only change it. rocks and ocean sediments. Stored phos-
phorus is gradually released into water and
All living things require water to sur- soil, where it is used by organisms.
vive. Water cycles between the ocean, atmo-
sphere, and land. Several different The primary productivity of an ecosys-
processes are involved in the water cycle, tem is the rate at which organic matter is
including evaporation and transpiration. created by producers. One factor that con-
Evaporation is the process in which water trols primary productivity is the amount of
changes from a liquid to a gas. Transpira- available nutrients. When an ecosystem is
tion is the process in which water evapo- limited by a single nutrient that is scarce or
rates from the leaves of plants. cycles very slowly, this substance is called a
limiting nutrient. If an aquatic ecosystem
All the chemical substances that an receives a large quantity of a limiting nutri-
organism needs to survive are called nutri- ent, there may be a sudden increase in the
ents. Like water, nutrients cycle within and amount of algae, called an algal bloom.
between ecosystems.

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Name____________________________ Class __________________ Date __________

Chapter 3 The Biosphere

Vocabulary Review

Hidden Word Answer the clues by writing the correct vocabulary
term from the words below in the blanks.

chemosynthesis ecosystem population
consumer evaporation species
decomposer photosynthesis

Clues
1. a process in which producers use chemical energy to make food

___ ___ ___ ___ ___ ___ ___ _ࠗ__ ___ ___ ___ ___ ___ ___

2. an organism that feeds on other organisms

___ ___ ___ ___ _ࠗ__ ___ ___ ___

3. all the organisms in one area and their physical environment

___ ___ ___ ___ ___ ___ _ࠗ__ ___ ___

4. a process by which water changes from a liquid to a gas

___ ___ ___ ___ ___ _ࠗ__ ___ ___ ___ ___ ___

5. a group of similar organisms whose offspring can breed

___ ___ ___ ___ _ࠗ__ ___ ___

6. an organism that breaks down organic matter

___ ___ ___ ___ ___ ___ ___ ___ _ࠗ__ ___

7. a process in which producers use light energy to make food

___ ___ ___ ___ ___ ___ ___ _ࠗ__ ___ ___ ___ ___ ___ ___

8. a group of organisms of the same species that live in an area

___ ___ ___ ___ ___ ___ _ࠗ__ ___ ___ ___

Use the circled letter in each term to find the hidden vocabulary word.

Hidden Word: ___ ___ ___ ___ ___ ___ ___ ___

Write a definition for the hidden word.

Definition:

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30

Name______________________________ Class __________________ Date ______________

Chapter 3 The Biosphere

Vocabulary Review

Matching In the space provided, write the letter of the definition that best matches each term.

__d___ 1. biosphere a. collection of different populations that live together in an
__a___ 2. community area
__g___ 3. autotroph
___i __ 4. chemosynthesis b. consumer that feeds on plant and animal remains and
other dead matter

c. process in which water evaporates from the leaves of plants

__b___ 5. detritivore d. combined parts of the planet in which all life exists
___f __ 6. biomass e. each step in a food chain or food web
__c___ 7. transpiration f. total amount of living tissue within a trophic level
___j __ 8. denitrification g. organism that can capture energy and use it to produce food
h. group of ecosystems that have the same climate and

__h___ 9. biome similar dominant communities

__e___ 10. trophic level i. process in which organisms use chemical energy to
produce carbohydrates

j. process in which bacteria convert nitrates into nitrogen gas

True or False Determine whether each statement is true or false. If it is true, write true in the space
provided. If the statement is false, change the underlined word or words to make the statement true.

ecosystem 11. A(An) species is a collection of all the organisms that live in a particular
place, together with their physical environment.

photosynthesis 12. The process in which autotrophs use light energy to make carbohydrates
is called nitrogen fixation.

omnivores 13. Heterotrophs that eat both plants and animals are referred to as
carnivores.

true 14. A(An) food web links together all the food chains in an
ecosystem.
primary
production 15. The rate at which organic matter is created by producers is called the
limiting nutrient of an ecosystem.
© Pearson Education, Inc. All rights reserved.
true 16. Ecology is the scientific study of interactions among organisms and
between organisms and their environment.

population 17. A(An) community is a group of individuals that belong to the same
species and live in the same area.

producers 18. Autotrophs are also called consumers.

decomposers 19. Organisms that break down organic matter are called herbivores.

true 20. The process in which water changes from a liquid to a gas is called
evaporation.

Name Class Date

Chapter 3 The Biosphere Chapter Vocabulary Review

Short Answer On the lines provided, define the following terms.
1. ecology

2. biosphere

3. species

4. community

5. biome

6. autotroph

Multiple Choice On the lines provided, write the letter of the phrase or term
that best answers each question.

7. What are the products of photosynthesis?

a. water and energy c. water and sugars

b. carbon dioxide and carbohydrates d. oxygen and carbohydrates

8. What process does the illustration below show?

a. photosynthesis c. chemosynthesis

b. evaporation d. transpiration

Bacterial Cell

Hysdurlfoidgeen+ Oxygen Sulfur + Energy © Pearson Education, Inc. All rights reserved.
compounds

9. Which of the following types of organisms obtain

energy by eating only plants?

a. producers c. omnivores

b. herbivores d. carnivores

10. Which of the following types of heterotrophs eat other

animals?

a. omnivores and carnivores c. carnivores only

b. herbivores and omnivores d. carnivores and herbivores

32 Teaching Resources /Chapter 3

Name Class Date

11. What are organisms that feed on plant and animal

remains and other dead matter called?

a. decomposers c. detritivores

b. omnivores d. herbivores

12. Which of the following types of heterotrophs would

bacteria and fungi be classified as?

a. detritivores c. carnivores

b. herbivores d. decomposers

13. What is the one-way flow of energy in an ecosystem called?

a. a food chain c. a food web

b. an energy pyramid d. a biomass pyramid

14. What links all the food chains in an ecosystem

together?

a. trophic levels c. a food web

b. an energy pyramid d. a biomass pyramid

15. What is each step in a food chain or food web called?

a. a trophic level c. an ecological pyramid

b. a biomass d. a limiting level

16. What pyramid represents the amount of energy or

matter that exists in each level of a food web?

a. a food pyramid c. an ecosystem pyramid

b. an ecological pyramid d. a food web pyramid

17. What is the total amount of living tissue within a

given trophic level called?

a. biomass c. biome

b. limiting nutrient d. nutrient

Completion On the lines provided, complete the following sentences.

18. Molecules are passed around again and again within the biosphere

in cycles.

© Pearson Education, Inc. All rights reserved. 19. The process by which water changes from liquid form to an

atmospheric gas is called .

20. During , water enters the atmosphere by

evaporating from the leaves of plants.

21. A chemical substance that an organism requires to live is called a(an)

.

22. The conversion of atmospheric nitrogen into ammonia is a process

called .

23. The conversion of nitrates into nitrogen gas is called

.

24. The rate at which organic matter is created by producers or

consumers is called .

25. A nutrient that is scarce or cycles slowly through an ecosystem is

called a(an) .

Teaching Resources /Chapter 3 33