Download 3.1 What Is Ecology?

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3.1 What Is Ecology?
Lesson Objectives
Describe the study of ecology.
Explain how biotic and abiotic factors influence an ecosystem.
Describe the methods used to study ecology.
Lesson Summary
Studying Our Living Planet Ecology is the scientific study of interactions among
organisms and between organisms and their environment.
Earth’s organisms live in the biosphere. The biosphere consists of the parts of the planet
in which all life exists.
Ecologists may study different levels of ecological organization:
• Individual organism
• An assemblage of individuals that belong to the same species and live in the same area
is called a population.
• An assemblage of different populations that live together in an area is referred to as a
community.
• An ecosystem includes all the organisms that live in a particular place, together with
their physical environment.
• A group of ecosystems that have similar climates and organisms is called a biome.
Biotic and Abiotic Factors Ecosystems include biotic and abiotic factors.
A biotic factor is any living part of an environment.
An abiotic factor is any nonliving part of an environment.
Ecological Methods Ecologists use three basic methods of research: observation,
experimentation, and modeling:
Observation often leads to questions and hypotheses.
Experiments can be used to test hypotheses.
Modeling helps ecologists understand complex processes.
Studying Our Living Planet
1. What is ecology?
2. What does the biosphere contain?
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3. How are human economics and ecology linked?
Use the diagram to answer Questions 4–5
4. Label each level of organization on the diagram.
5. Explain the relationship between ecosystems and biomes.
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Biotic and Abiotic Factors
6. Use the terms in the box to fill in the Venn diagram. List parts of the environment that
consist of biotic factors, abiotic factors, and some components that are a mixture of both.
air
animals
bacteria
heat
mushrooms
plants
precipitation
soil
sunlight
Both
Biotic
Factors
Abiotic
Factors
Ecological Methods
7. Why might an ecologist set up an artificial environment in a laboratory?
8. Why are many ecological phenomena difficult to study?
9. Why do ecologists make models?
3.2 Energy, Producers, and Consumers
Lesson Objectives
Define primary producers.
Describe how consumers obtain energy and nutrients.
Lesson Summary
Primary Producers Sunlight is the main energy source for life on Earth. Organisms that
can capture energy from sunlight or chemicals and use that energy to produce food are called
autotrophs, or primary producers.
The process in which autotrophs capture light energy and use it to convert carbon dioxide
and water into oxygen and sugars is called photosynthesis.
The process in which autotrophs use chemical energy to produce carbohydrates is called
chemosynthesis.
Consumers Organisms that rely on other organisms for their energy and food are called
heterotrophs. Heterotrophs are also referred to as consumers. There are many different types
of heterotrophs:
Herbivores, such as cows, obtain energy by eating only plants.
Carnivores, such as snakes, eat only animals.
Omnivores, such as humans, eat both plants and animals.
Detritivores, such as earthworms, feed on dead matter.
Decomposers, such as fungi, break down organic matter.
Scavengers, such as vultures, consume the carcasses of other animals.
Primary Producers
1. What do autotrophs do during photosynthesis?
2. Can some organisms survive without energy from the sun? Explain your answer.
3. Can organisms create their own energy? Explain your answer.
Consumers
4. Complete the table about types of heterotrophs.
Types of Heterotrophs
Type
Definition
Herbivore
Examples
cows, rabbits
Heterotroph that eats animals
humans, bears, pigs
Omnivore
Detritivore
Decomposer
Heterotroph that consumes the carcasses of
dead animals but does not typically kill them
itself
5. What is a consumer?
6. How would you categorize a consumer that usually catches and eats prey, but also eats
dead animal carcasses?
Apply the Big idea
7. What role do producers play in establishing Earth as a living planet?
3.3 Energy Flow in Ecosystems
Lesson Objectives
Trace the flow of energy through living systems.
Identify the three types of ecological pyramids.
Lesson Summary
Food Chains and Food Webs Energy flows through an ecosystem in one direction
from primary producers to various consumers.
A food chain is a series of steps in which organisms transfer energy by eating and being
eaten. Producers, such as floating algae called phytoplankton, are at the base of every
food chain.
A food web is a network of all the food chains in an ecosystem. Food webs are very
complex. Small disturbances to one population can affect all populations in a food web.
Changes in populations of zooplankton, small marine animals that feed on algae, can
affect all of the animals in the marine food web.
Trophic Levels and Ecological Pyramids Each step in a food chain or food
web is called a trophic level. Producers make up the first trophic level. Consumers make up
higher trophic levels. Each consumer depends on the trophic level below it for energy.
An ecological pyramid is a diagram that shows the relative amounts of energy or matter
contained within each trophic level in a food chain or food web. Types of ecological pyramids
are pyramids of energy, pyramids of biomass, and pyramids of numbers:
Pyramids of energy show relative amounts of energy available at different trophic levels.
Pyramids of biomass show the total amount of living tissue at each trophic level.
A pyramid of numbers shows the relative numbers of organisms at different trophic
levels.
Food Chains and Food Webs
1. Complete the table about feeding relationships.
Feeding Relationships
Relationship
Description
Food Chain
Food Web
Use the food chain to answer Questions 2–4.
2. Draw arrows between the organisms to show how energy moves through this food chain.
Write producer, herbivore, or carnivore under each organism.
3. Explain how energy flows through this food chain.
4. What would happen to this food chain if a disturbance caused a serious decline in the
shark population?
5. VISUAL ANALOGY What role does energy play in the diagram, and how is it
represented?
Trophic Levels and Ecological Pyramids
Write True or False on the line provided.
6. Primary consumers always make up the first trophic level in a food web.
7. Ecological pyramids show the relative amount of energy or matter contained
within each trophic level in a given food web.
8. On average, about 50 percent of the energy available within one trophic level
is transferred to the next trophic level.
9. The more levels that exist between a producer and a given consumer, the
larger the percentage of the original energy from producers is available to that
consumer.
Use the diagram to answer Questions 10–17.
Match the organism with its trophic level. A trophic level may be used more than once.
Organism
Trophic Level
10. algae
A. primary producer
11. grasshopper
B. first-level consumer
12. marsh grass
C. second-level consumer
13. marsh hawk
D. third-level consumer
14. plankton-eating fish
15. ribbed mussel
16. shrew
17. zooplankton
18. Complete the energy pyramid by writing the source of the energy for the food web and
how much energy is available to first-, second-, and third-level consumers.
For Questions 19–21, complete each statement by writing the correct word or words.
19. A pyramid of _______________ illustrates the relative amount of living organic matter
available at each trophic level in an ecosystem.
20. A pyramid of _______________ shows the relative numbers of individual organisms at
the trophic levels in an ecosystem.
21. A pyramid of _______________ shows the relative amounts of energy available at the
trophic levels of a food chain or food web
3.4 Cycles of Matter
Lesson Objectives
Describe how matter cycles among the living and nonliving parts of an ecosystem.
Describe how water cycles through the biosphere.
Explain why nutrients are important in living systems.
Describe how the availability of nutrients affects the productivity of ecosystems.
Lesson Summary
Recycling in the Biosphere Matter, unlike energy, is recycled within and between
ecosystems. Elements pass from one organism to another and from one part of the biosphere
to another through biogeochemical cycles, which are closed loops powered by the flow of
energy.
The Water Cycle Water moves between the ocean, the atmosphere, and land.
Evaporation is the process in which water changes from a liquid to a gas.
Transpiration is the process in which water evaporates from the leaves of plants.
Nutrient Cycles The chemical substances that an organism needs to survive are called
nutrients. Like water, nutrients pass through organisms and the environment.
Carbon Cycle: Carbon is a key ingredient of all organic compounds. Processes involved
in the carbon cycle include photosynthesis and human activities such as burning.
Nitrogen Cycle: Nitrogen is needed by all organisms to build proteins. Processes
involved in the nitrogen cycle include nitrogen fixation and denitrification.
• In nitrogen fixation, certain bacteria convert nitrogen gas into ammonia.
• In denitrification, other soil bacteria convert nitrogen compounds called nitrates back
into nitrogen gas.
Phosphorus Cycle: Phosphorus is needed for molecules such as DNA and RNA. Most of
the phosphorus in the biosphere is stored in rocks and ocean sediments. Stored
phosphorus is gradually released into water and soil, where it is used by organisms.
Nutrient Limitation A nutrient that, in short supply, can limit the productivity of an
ecosystem is called a limiting nutrient.
Recycling in the Biosphere
For Questions 1–3, write True if the statement is true. If the statement is false,
change the underlined word or words to make the statement true.
1. The four elements that make up over 95 percent of the body in most
organisms are oxygen, sulfur, nitrogen, and hydrogen.
2. Matter moves through an ecosystem in cycles.
3. Chemical and physical processes include the formation of clouds and
precipitation, “burning” food, and the flow of running water.
4. VISUAL ANALOGY The illustration draws an
analogy between the way energy drives matter to
cycle in an ecosystem and the way water causes a
waterwheel to turn. Give an example of another
analogy that could be used to show the
relationship between energy and the cycles of
matter.
5. Explain why Earth is considered a closed system.
6. How might building a new highway affect the cycles of matter?
The Water Cycle
7. What role do plants play in the water cycle?
Nutrient Cycles
9. Complete the chart about the carbon cycle.
Processes That Cause Carbon to Move
into the Atmosphere
Processes That Cause Carbon to Move
out of the Atmosphere
Process
Process
Description
Description
Photosynthesis
Respiration
the release of CO2 and
other gases into the
atmosphere through vents
in Earth's crust
For Questions 10–12, write the letter of the correct answer on the line at the left.
10. The carbon in coal, oil, and natural gas came from
A. the combustion of fossil fuels.
B. the remains of dead organisms.
C. carbon-fixing bacteria in swamp
soil.
D. carbon dioxide dissolved in ocean water.
11. How does most of the carbon in an organism’s body return to the
environment after the organism dies?
A. Decomposers break the body down into simpler compounds.
B. Heat from the sun causes the carbon in the body to evaporate.
C. Geological processes cause the body to turn into a fossil fuel.
D. Rainwater dissolves the carbon in the body and carries it to the ocean.
12. Human processes mainly contribute to the
A. release of carbon dioxide into the atmosphere.
B. decrease of the total amount of carbon found on Earth.
C. depletion of carbon dioxide reserves in the atmosphere.
D. increase in the amount of carbon contained in rock materials.
Write True if the statement is true. If the statement is false, change the underlined word
or words to make the statement true.
13. Nitrogen, in the form of ammonia, nitrate, and nitrite, is found in the
soil.
14. Nitrogen fixation is the process in which certain bacteria convert
nitrogen gas into nitrates.
15. Denitrification is the process by which some soil bacteria convert
nitrates into nitrogen gas.
16. All organisms require nitrogen to make amino acids, which in turn are
used to build carbohydrates.
17. Phosphate is released as rocks and sediments wear down.
18. Plants absorb phosphate from the soil or from water.
19. Phosphorus is the most abundant gas in the atmosphere.
20. Organic phosphate is taken up by producers during photosynthesis and
released by cellular respiration.
as
21. Phosphorus forms part of the important life-sustaining molecules such
DNA and RNA.
22. Plants absorb phosphorus from the atmosphere or water.
23. List and describe the biological steps in the nitrogen cycle.
24. What is atmospheric nitrogen fixation, and how does it affect organisms?
25. How do humans add nitrogen to the biosphere?
26. Which parts of the phosphorus cycle are geological processes?
Nutrient Limitation
Use the diagram of the interlocking nutrients to answer
Question 27.
27. VISUAL ANALOGY The visual analogy compares
interlocking gears to the major nutrients— potassium,
phosphorus, and nitrogen. What other “gears” would be
affected if these gears stopped working together?
28. If a nutrient were in short supply in an ecosystem, how might it affect an organism?
29. When is a substance a limiting nutrient?
4.1 Climate
Lesson Objectives
Differentiate between weather and climate.
Identify the factors that influence climate.
Lesson Summary
Weather and Climate Weather is the condition of Earth’s atmosphere at a particular
time and place. Climate is the average condition of temperature and precipitation in a region
over long periods.
Climate can vary over short distances.
These variations produce microclimates.
Factors That Affect Climate Climate is affected by solar energy trapped in the
biosphere, by latitude, and by the transport of heat by winds and ocean currents.
Temperature on Earth stays within a range suitable for life due to the greenhouse effect.
The greenhouse effect is the trapping of heat by gases in the atmosphere.
Earth’s curvature causes different latitudes to receive less or more intense solar energy.
The unequal distribution of the sun’s heat on Earth’s surface results in three main climate
zones: polar, temperate, and tropical.
Unequal heating of Earth’s surface also causes winds and ocean currents. Winds and
currents move heat and moisture through the biosphere.
Weather and Climate
1. How is weather different from climate?
2. What causes microclimates to form?
3. In the Northern Hemisphere, why are the south-facing sides of buildings often warmer
and drier than the north-facing sides?
Factors That Affect Climate
VISUAL ANALOGY
For Questions 4–5, refer to the Visual Analogy comparing the
Earth’s atmosphere to a greenhouse.
4. What is the source of radiation for both the Earth’s atmosphere and the greenhouse?
5. What happens to sunlight that hits Earth’s surface?
For Questions 6–9, write the letter of the correct answer on the line at the left.
6. What effect do carbon dioxide and methane have on Earth’s temperature?
A. They trap heat in the atmosphere.
B. They release heat from the atmosphere.
C. They block heat from entering the ocean.
D. They block heat from reaching Earth’s surface.
7. How would the temperature on Earth change without the greenhouse effect?
A. The temperature at the equator would be warmer.
B. The temperature would stay the same.
C. It would be 30°C warmer.
D. It would be 30°C cooler.
8. What causes solar radiation to strike different parts of Earth’s surface at an angle
that varies throughout the year?
A. Earth’s tilted axis
B. Earth’s erratic orbit
C. the moon’s orbit around Earth
D. solar flares on the sun’s surface
9. In which location is the sun almost directly overhead at noon all year?
A. the equator
B. the South Pole
C. the North Pole
D. North America
10. Complete the table about Earth’s three main climate zones.
Main Climate Zones
Climate Zone
Location
Areas around North and
South poles
Between the polar zones and
the tropics
Near the equator
Climate Characteristics
For Questions 11–14, write True if the statement is true. If the statement is false, change
the underlined word or words to make the statement true.
11. Patterns of heating and cooling result in ocean currents.
12. Warm air is less dense than cool air.
13. Surface water moved by winds results in ocean currents.
14. Deep ocean currents are caused by the sinking of warm water near the poles.
Apply the Big idea
15. Describe how a change in the temperature of an ocean current might affect the climate of
a nearby coastal area.
4.2 Niches and Community Interactions
Lesson Objectives
Define niche.
Describe the role competition plays in shaping communities.
Describe the role predation and herbivory play in shaping communities.
Identify the three types of symbiotic relationships in nature.
Lesson Summary
The Niche Every species has its own tolerance, or a range of conditions under which it
can grow and reproduce. A species’ tolerance determines its habitat, the place where it lives.
A niche consists of all the physical and biological conditions in which a species lives and
the way the species obtains what it needs to survive and reproduce.
An organism’s niche must contain all of the resources an organism needs to survive. A
resource is any necessity of life, such as water, nutrients, light, food, or space.
Competition Competition occurs when organisms try to use the same limited resources.
Direct competition between species often results in one species dying out. This is the
basis of the competitive exclusion principle. This principle states that no two species can
occupy exactly the same niche in exactly the same habitat at the same time.
Competition helps to determine the number and type of species in a community.
Predation, Herbivory, and Keystone Species Predator-prey and herbivore-plant
interactions help shape communities.
Predation occurs when one organism (the predator) captures and eats another (the prey).
Herbivory is an interaction that occurs when an animal (the herbivore) feeds on
producers (such as plants).
Sometimes changes in the population of a single species, often called a keystone species,
can cause dramatic changes in the structure of a community.
Symbioses Symbiosis occurs when two species live closely together in one of three ways:
mutualism, commensalism, or parasitism.
In mutualism, both species benefit from the relation ship.
In parasitism, one species benefits by living in or on the other and the other is harmed.
In commensalism, one species benefits and the other is neither helped nor harmed.
The Niche
1. What is a niche?
2. Give an example of resources a squirrel might need.
3. Three different warbler species live in the same tree. One species feeds at the top of the
tree, the second species feeds in the middle part of the tree, and the third species feeds at
the bottom of the tree. Do all three species occupy the same niche? Explain.
Competition
For Questions 4–8, write True if the statement is true. If the statement is false, change
the underlined word or words to make the statement true.
4. Competition occurs when organisms attempt to use the same resources.
5. Competition between members of the same species is known as
interspecific competition.
6. The competitive exclusion principle states that no two organisms can
occupy exactly the same niche in exactly the same habitat at exactly
the same time.
7. If two species of bacteria are grown in the same culture, one species
will always outcompete the other.
8. Members of the same species tend to divide resources instead of
competing over them.
Predation, Herbivory, and Keystone Species
Write the letter of the correct answer on the line at the left.
9. A lion eating a zebra is an example of
A. herbivory.
C. predation.
B. habitat destruction.
D. a keystone species.
10. A cow eating grass is an example of
A. herbivory.
C. habitat destruction.
B. predation.
D. a keystone species.
11. A keystone species is one that
A. eats a mixture of plants and animals.
B. is introduced into a community after a major disturbance.
C. causes the amount of diversity in a community to decrease.
D. helps to stabilize the populations of other species in the community.
Symbioses
12. Complete the table about main classes of symbiotic relationships.
Main Classes of Symbiotic Relationships
Class
Description of Relationships
Mutualism
Commensalism
Parasitism
Match the example with the type of relationship. A relationship type may be used more
than once.
Example
13. a tick living on the body of a deer
14. a bee eating a flower’s nectar and picking up the
flower’s pollen
15. a barnacle living on a whale’s skin
16. a tapeworm living in a person’s intestines
17. an aphid providing food to an ant in exchange for
protection
Type of Relationship
A. mutualism
B. commensalism
C. parasitism
Apply the Big idea
19. How do keystone species illustrate the interdependence of organisms living in a
community? Give an example.
4.4 Biomes
Lesson Objectives
Describe and compare the characteristics of the major land biomes.
Identify the areas that are not classified into a major biome.
Lesson Summary
The Major Biomes A biome is a group of terrestrial regional climate communities that
covers a large area and is characterized by soil type, climate, and plant and animal life.
In tropical rain forests, the tops of tall trees form a covering called the canopy. Shorter
trees and vines form another layer called the understory. It is hot and wet all year.
Tropical dry forests are found in areas with alternating wet and dry seasons. The trees in
these forests may be deciduous, meaning they shed their leaves during a particular
season.
In a tropical grassland, grassy areas are spotted with isolated trees.
Deserts have less than 25 centimeters of precipitation annually.
Temperate grasslands have warm summers, cold winters, and deep soil.
Temperate woodlands and shrublands are large areas of grasses and wildflowers such as
poppies interspersed with trees or shrubs.
Temperate forests are made up of deciduous and evergreen coniferous trees. Coniferous
trees produce seed-bearing cones and most have waxy needles. Temperate forests have
soils rich in humus, which forms from decaying leaves and makes soil fertile.
Northwestern coniferous forests have mild temperatures with cool, dry summers and
abundant precipitation in fall, winter, and spring.
Boreal forests, or taiga, are dense forests of coniferous evergreens.
Tundra is characterized by permafrost, a layer of permanently frozen subsoil.
Other Land Areas Some areas, such as mountains and polar ice caps, do not fall neatly
into the major biomes.
The Major Biomes
For Questions 1–4, complete each statement by writing the correct word or words.
1. The side of a mountain range that faces the wind often receives more
than the downwind side of the same range.
is a group of terrestrial communities that covers a large area and
2. A(n)
is characterized by certain soil and
conditions and particular types of
plants and animals.
3. Organisms within each biome can be characterized by
to live and reproduce successfully in the environment.
that enable them
4. In a tropical rain forest, the layer formed by the leafy tops of tall trees is called the
and the layer of shorter trees and vines is called the
.
THINK VISUALLY
Use the graph to answer Questions 6–9.
6. Complete the climate diagram by adding labels to the bottom and both sides of the graph
to show what the variables are.
7. Describe what a climate diagram summarizes.
8. Explain what the line plot on a climate diagram shows.
9. Explain what the vertical bars on a climate diagram show.
10. Complete the table about some of Earth’s major biomes.
Some Major Biomes
Biome
Climate and Soil
Plants and Animals
warm year-round with wet and
dry seasons; rich soil
plants: tall, deciduous trees; succulents
animals: undergo estivation or migration
Tropical rain
forest
cold, dark winters and short,
soggy summers; permafrost
plants: ground-hugging plants
animals: birds and mammals that can
tolerate the harsh conditions
Temperate
grassland
low precipitation with variable
temperatures
plants: short growth cycles, cacti
animals: adaptations to quickly lose body
heat and regulate body temperature
Boreal forest
Other Land Areas
11. What is the main cause for variation of abiotic and biotic conditions on a mountain?
12. Describe the conditions you would most likely find on a mountain in the Rocky
Mountains as you moved from the base to the mountain’s summit.
13. Which producers can be found in the polar ice regions?
14. Which animals can be found in the northern polar region?
5.2 Limits to Growth
Lesson Objectives
Identify factors that determine carrying capacity.
Identify the limiting factors that depend on population density.
Identify the limiting factors that do not depend on population density.
Lesson Summary
Limiting Factors A limiting factor is a factor that controls the growth of a population.
Some factors depend on the density of the population. Others do not.
Acting separately or together, limiting factors determine an environment’s carrying
capacity.
Limiting factors produce the pressures of natural selection.
Density-Dependent Limiting Factors
Density-dependent limiting factors operate strongly when the number of individuals per
unit area reaches a certain point.
Examples include:
• competition
• predation and herbivory
• parasitism and disease
• stress from overcrowding
Density-Independent Limiting Factors Some limiting factors do not necessarily
depend on population size.
Density-independent limiting factors depend on population density, or the number of
organisms per unit area.
Examples include severe weather, natural disasters, and human activities.
Some of these factors may have more severe effects when population density is high.
Limiting Factors
For Questions 1–6, write True if the statement is true. If the statement is false, change
the underlined word to make the statement true
1. Limiting factors determine the immigration capacity of a population.
2. A limiting factor controls the growth of a population.
3. Limiting factors operate when growth is exponential.
4. Populations grow too large in the absence of limiting factors.
5. Competition is an example of a limiting factor.
6. Population size can be limited by factors such as predation.
Density-Dependent Limiting Factors
7. What is a density-dependent limiting factor?
8. When do density-dependent factors operate most strongly?
9. What are four density-dependent limiting factors?
Use the graph to answer Questions 10–13.
10. What happened to the number of wolves on Isle Royale between 1975 and 1985?
11. What happened to the moose population when the number of wolves was low?
12. What is the relationship between the moose and the wolves on Isle Royale?
13. Is the number of moose on the island a density-dependent or density-independent limiting
factor for the wolf? Explain your answer.
Density-Independent Limiting Factors
14. What term describes a limiting factor that affects all populations in similar ways,
regardless of population size?
15. What is the usual response in the population size of many species to a densityindependent limiting factor?
16. Complete the graphic organizer with examples of density-independent limiting factors.
Population
Size
can be limited by
density-independent
factors such as
Apply the Big idea
17. A population continues at a stable size for many years. Suddenly, in a single season, the
population size drops by half. Is the cause more likely to be density-dependent, densityindependent, or both? Explain your answer.
6.3 Biodiversity
Lesson Objectives
Define biodiversity and explain its value.
Identify current threats to biodiversity.
Describe how biodiversity can be preserved.
Lesson Summary
The Value of Biodiversity The sum of all the genetic diversity among all the
organisms in the biosphere is called biodiversity. There are three general types of
biodiversity:
Ecosystem diversity is the variety of habitats, communities, and ecological processes in
the biosphere.
Species diversity is the number of different species in an area or in the biosphere.
Genetic diversity is the total of all genetic information carried in living things.
Biodiversity benefits humans through its contributions to medicine and agriculture and
through the provision of ecological goods and services.
Threats to Biodiversity Human activities threaten biodiversity.
Development splits ecosystems into pieces, resulting in habitat fragmentation. The
smaller the pieces of a habitat, the less likely that species in the habitat can survive.
Other threats to biodiversity include hunting, introduced species, pollution, and climate
change.
Conserving Biodiversity Conservation efforts are focused on three things:
Protecting single species is the focus of groups such as the Association of Zoos and
Aquariums (AZA), which oversees species survival plans (SSPs).
Protecting habitats and ecosystems is the main thrust of global efforts. Biologists are
particularly concerned about ecological hot spots, which are places where significant
numbers of habitats and species are in immediate danger of extinction.
Considering local interests is part of developing plans to replace harmful activities with
ones that conserve environments and biodiversity.
The Value of Biodiversity
1. What is biodiversity?
2. Why is biodiversity one of Earth’s greatest natural resources?
3. Complete the table to define the types of biodiversity.
Diversity in the Biosphere
Type of Diversity
Definition
Ecosystem diversity
Species diversity
Genetic diversity
Threats to Biodiversity
For Questions 4–8, write True if the statement is true. If the statement is false,
change the underlined word or words to make the statement true.
4. The current rate of species loss is 10 times the typical rate of
extinction.
5. The smaller a habitat “island,” the larger the number of species that
can live there.
6. Habitat fragmentation increases the impact of hunting on endangered
species.
7. Endangered species can become invasive and threaten biodiversity.
8. The increased concentration of carbon dioxide in air is making
oceans more acidic and putting stress on coral reefs.
9. What are five ways that human activity reduces biodiversity?
10. Identify three reasons why endangered species are hunted.
11. How can introduced species lead to economic losses?
12. How does climate change threaten biodiversity?
Conserving Biodiversity
13. What is the main purpose of biodiversity conservation today?
14. Why have ecologists identified ecological hot spots?
15. What are some of the challenges that conservationists face?
16. What are some strategies that encourage conservation? Provide an example of one of
these strategies.
Apply the Big idea
17. Why is preserving entire ecosystems a better idea than protecting single species from
extinction?