Chapter 6 Review
Humans in the Biosphere
Sections 1,2,3 and 4
Bell Work
6-1 A Changing Landscape
All of the organisms- including humans- that live on Earth
share a limited resource base and depend on it for their longterm survival.
1. Increasing demands on what resources come with a
growing human population?
Land, Air, Water
2. What four human activities have transformed the
biosphere?
Hunting and Gathering, Agriculture,
Industry, & Urban Development
6-1
Hunting and Gathering
3. How did Hunters &
Gatherers change the
environment?
They caused a major
mass extinction of
animals
6-1
Agriculture
4. What is agriculture?
Farming
5. Why was agriculture an important event?
agriculture provides human societies with a
fundamental need: a dependable supply of food
6-1
6. What ecological changes came with the
cultivation of both plants and animals?
Pros: People became able to gather in settlements
rather than moving in search for food.
Cons: Overgrazing of Herbivores
Large demand of Water
6-1
7. What changes occurred in the 1800s as a result
of advancements in science and technology?
Farmers gradually acquired machinery, such as
plows and the seed drill to make work easier.
6-1
The Green Revolution
Modern agricultural techniques were
introduced, such as monoculture and the use of
chemical fertilizers.
8. How did the green revolution benefit society?
It increased food production
6-1
9. What occurred during the Industrial
Revolution of the 1800s?
Machines and Factories were added
6-1
To produce and power machines, we need energy.
10. From what resources do we obtain most of the
energy to produce and power machines?
Fossil Fuels : coal, oil, and natural gas
t
6-1
As urban centers became crowded, people began to
move from the cities to the suburbs: Suburban Sprawl.
11. How does the suburban sprawl place stress on the
plant and animal population?
it consumes farmland and animal habitats
6-2 Resources
The Tragedy of the Commons
Inhabitants of English villages could graze their cattle
on shared pasture land called the commons. Grazing
was free of charge and therefore, villages often put as
many cattle out as possible.
Even as the land became overused, people kept putting
more cattle on it. Overgrazing on the village commons
caused the pastures to deteriorate so badly that they
could no longer be used to support any cattle.
6-2
The Tragedy of the Commons
No one was responsible for preserving the land.
1. The idea that any resource, such as water in
the ground or fish in the sea, that is free and
accessible to everyone, may eventually be
destroyed.
6-2
Renewable Resource
• Regenerate if living or Replenished if nonliving
• Not necessarily unlimited
Tree: a new tree can grow in place of an old tree
Freshwater: replenished through
biogeochemical cycles
Freshwater can easily become limited by drought
or overuse
6-2
Nonrenewable Resource
• Cannot be replenished by natural processes
Fossil Fuels: when these fuels are gone, they are
gone forever.
What are three fossil fuels?
coal, oil, and natural gas
6-2
3. What is sustainable development?
Using natural resources without depleting them
4. How do human activities affect renewable
resources?
Affect the quality and supply of renewable
resources such as land, forest, fisheries, air, and
fresh water.
6-2 Land Resources
6. If managed properly, soil is a _____________
Renewable Resource
7. Soil Erosion is…
the wearing away of surface soil by water and wind.
6-2 Land Resources
8. How does plowing the land increase the rate
of soil erosion?
It removes the roots that hold the soil in place
6-2 Land Resources
9. The conversion of previously soil rich area into
a desert is called ________________.
Desertification
There are a variety of sustainable development
practices that can guard against this, such as
leaving the stems and roots of the plants from
the previous years crop in place.
6-2 Forest Resources
10. Why have forests been called the “lungs of
the Earth”?
They remove carbon dioxide and produce oxygen
Forests also store nutrients, provide habitats
and food for organisms, moderate climate, limit
soil erosion, and protect freshwater supplies.
6-2
11. What is deforestation and how does it affect
the biosphere?
The loss of forests can lead to soil erosion as
soil is exposed to heavy rains.
6-2 Fishery Resources
12. Fish and other animals that live in water are
a valuable source of ______________.
Food
13. The practice of harvesting fish faster than
they can reproduce is called ______________.
Overfishing
6-2 Fishery Resources
14. What is one approach to sustainable use of
fisheries?
Controlling how many fish and of what size,
could be caught in various parts of the oceans
6-2 Fishery Resources
15. What is aquaculture?
Raising of aquatic animals for human consumption
6-2 Air Resources
16. What is smog?
It is a mixture of chemicals that occurs as a
gray-brown haze in the atmosphere.
6-2 Air Resources
17. What is a pollutant?
a harmful material that can enter the
biosphere through the land, air, or water
Is smog a pollutant?
Yes
6-2
18. How does the burning of fossil fuels affects
air quality?
It can release pollutants that cause smog and
other problems in the atmosphere
6-2 Freshwater Resources
19. Why are protecting water supplies from
pollution and managing demand for water
major priorities?
Freshwater is a limited resource
Pollution threatens water
supplies in several ways.
6-2 Freshwater Resources
20. What is water sewage and how does it
threaten water supplies?
Water sewage is waste water from sinks and
toilets. It contains compounds that encourage
algae growth and bacteria in aquatic habitats.
6-2 Freshwater Resources
As water flows slowly through a swamp, densely
growing plants filter certain pollutants out of the
water.
Similarly, forests help to purify the water that
seeps into the ground or runs off into rivers and
lakes.
6-3 Biodiversity
1. What is biodiversity?
the sum total of the genetically based variety
of all organisms in the biosphere
6-3
Ecosystem Diversity
Variety of habitats, communities, and ecological
processes in the living world
Species Diversity
The number of different species in the biosphere
Genetic Diversity
Sum total of all the different forms of genetic
information carried by all organisms living on Earth
6-3
3. Why is biodiversity one of Earth’s greatest
natural resources?
species of many kinds have provided us with
foods, industrial productions, and medicinesincluding painkillers, antibiotics, heart drugs,
and anticancer drugs
6-3 Threats to Biodiversity
4. What are four ways that human activity can
reduce biodiversity?
• altering habitats
• hunting species to extinction
• introducing toxic compounds into food webs
• introducing foreign species to new
environments
6-3 Habitat Alteration
As habitats disappear, the species that live in
those habitats vanish. In addition, the
development often splits ecosystems into
pieces, a process called ___________( #7)___.
Habitat Fragmentation
6-3 Demand for Wildlife Products
5. A species whose population size is declining in
a way that places it in danger of extinction is
called an __________________.
Endangered Species
Some species are hunted for
meat, fur, hides, or are believed
to have medicinal purposes.
6-3
6. Why does a declining population make a
species more vulnerable to extinction?
the species loses genetic diversity
6-3 Pollution
8. What is DDT?
one of the first widely used
pesticides
At first, it seemed to be perfect. It is cheap,
remains active for a long time, and kills many
different kinds of insects.
6-3 Pollution
9. What two properties of DDT make it
hazardous over the long term?
• Non-Biodegradable (cannot be broken down)
• It can be picked up by
all organisms
6-3 Pollution
10. What is biological
magnification?
The process in which
concentrations of
harmful substances
increase in organisms at
higher trophic levels
in a food chain/ food web.
6-3 Introduced Species
Humans can easily transport seemingly harmless plants
and animals around the world either accidentally or
intentionally.
Plants and animals that have migrated to places where
they are not native are called ________.
Invasive species
Invasive Species reproduce rapidly due to lack to parasites
and predators from “back home”
They have ideal conditions for exponential growth
6-3 Conserving Biodiversity
In ecology, the term conservation is used to describe
the wise management of natural resources, including
the preservation of habitats and wildlife.
13. What is the purpose of conservation
biology?
Seeks to preserve Biodiversity
6-4
Charting a Course for the Future
Researchers are gathering data to monitor and
evaluate the effects of human activities on
important systems in the biosphere. Two of
these systems are the ozone layer and the global
climate system.
1. What is ozone?
Ozone gas has 3 oxygen molecules
It is found in the Earth’s atmosphere
Ozone Layer
6-4 Ozone Depletion
2. What is causing the problem of ozone
depletion?
gases called chlorofluorocarbons or CFCs
6-4 Global Climate Change
3. What is Global Warming?
The increase in average temperature of the biosphere
4. What is the most widely accepted hypothesis
about the cause of global warming?
human activity
6-4 Global Warming
5. If global warming continues at the current
rate, how might sea levels be affected?
Sea levels will rise due to melting polar ice caps
6-4 Value of a Healthy Biosphere
6. What goods and services do a healthy
biosphere provide to us?
The raw materials for food and medicine
7. What is the most important shift that a
society can make to solve todays ecological
problems?
Energy conservation
6-4
8. What is the first step in charting a course that
will improve living conditions without harming
the environment?
Understanding we are part of the ecosystem
Let’s see how much you remember 
Chapter 6: test your knowledge
1. What is always true of a renewable resource?
a.
b.
c.
d.
D
It creates no pollution
It is instantly replaced
It is unlimited
It is replaceable by natural means
Chapter 6: test your knowledge
2. Ozone depletion has been caused by
a. monoculture
b. suburban sprawl
c. aquaculture
d. CFCs
D
Chapter 6: test your knowledge
3. Concentrations of harmful substances
increase in organisms at higher trophic levels in
a food chain. This process is called:
a. aquaculture
b. monoculture
c. pesticide use
d. biological magnification
D
Chapter 6: test your knowledge
4. Which of the following human activities was
NOT important in transforming the biosphere?
a. agriculture
b. industry
c. aquaculture
d. urban development
C
Chapter 6: test your knowledge
5. Civilizations could not develop without
a. monoculture
b. hunter-gatherers
c. agriculture
d. crop exchange
C