Download CHAPTER 31: CONSERVATION BIOLOGY

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CHAPTER 60: BIODIVERSITY AND CONSERVATION
BIOLOGY
WHERE DOES IT ALL FIT IN?
Chapter 60 builds on the foundations of biodiversity and provides detailed information about
environmental interactions of organisms. Students should be encouraged to recall the principles of
organismic classification and comparative anatomy. The information in chapter 60 does not stand
alone. It connects the information on organismic diversity to evolution and ecology coverage.
Students should know that animals and other organisms are interrelated and originated from a
common ancestor of all living creatures on Earth.
SYNOPSIS
Although species extinction is a normal evolutionary process, humankind has accelerated the rate
of species extinctions. Whether because of greed or ignorance, extinctions due to actions of
humans are surpassed only by the cataclysmic mass extinctions caused by large body impacts
(celestial events) into the Earth’s. As humans invade new territories, they reconstruct the habitat
to fit their needs (intentionally or innocently), rarely considering how those changes will affect
the native inhabitants. The species that are in the greatest danger of extinction are endemic
species that are usually found in isolated geographical areas. All species found on earth today
have a value. We humans may not know, understand, or accept that value, but it still exists.
Many organisms, like those used for food, clothing, and shelter, have an obvious, direct
economic value. Others may have an indirect value where their presence helps maintain a
healthy ecosystem. The bugaboo of time travel is that the repositioning of a single grain of sand
could alter the entire course of humanity. The loss of a single species may have the same effect
on an organism’s ecosystem.
Humankind must act as guardians for the diversity of all life since only we have the ability to so
readily destroy it. Certain species are more vulnerable to extinction than others because of their
endemic distribution, declining population size, lack of genetic variability, and/or hunting
pressures by humans. Five factors associated with human activities play key roles in species
extinctions. They include overexploitation of a species, introduction of other species into a
habitat, disruption of ecological relationships, loss of a species genetic variability and habitat
loss and/or fragmentation. As difficult as it can be to recognize which species are vulnerable to
extinction, preservation of these species is even more complicated. Recovery programs are
complex and expensive.
Habitat restoration is imperative as it makes no sense to reintroduce individuals from a captive
breeding program into a deficient habitat. Genetic variability must be maintained, but by the time
the problem is discovered, it is often too late. Keystone species need to be preserved, though
identifying them can be difficult. Whole ecosystems must be conserved, not merely pieces of
them or only their most noteworthy species. In some cases it is appropriate to say—“if it’s not
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broken don’t fix it.” In this case, we humans need to learn to take better care of our belongings to
ensure that we do not break them in the first place! Once extinction is complete, the species
along with its unique DNA sequences and niche are gone.
LEARNING OUTCOMES
60.1 What Is Biodiversity?
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Describe the three levels of biodiversity.
60.2 Why Conserve Biodiversity?
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Explain the economic, ecological, and ethical reasons for preserving biodiversity.
60.3 The Causes of Extinction and Loss of Biodiversity
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Describe the main causes of extinction.
Explain the means by which habitat fragmentation leads to decreased biodiversity.
60.4 Conservation Strategies
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Explain what an endemic species is.
Describe the importance of endemic species to conservation efforts to protect geographic
hot spots of biodiversity.
Explain why the equilibrium model of island biogeography can be applied to nature
reserves.
Explain the difference between restoration of species and restoration of ecosystem
functioning.
Provide examples of species that would qualify in each category of the single-species
approach to conservation.
List the strategies for habitat restoration.
Explain the rationale for captive breeding programs.
COMMON STUDENT MISCONCEPTIONS
There is ample evidence in the educational literature that student misconceptions of information
will inhibit the learning of concepts related to the misinformation. The following concepts
covered in Chapter 60 are commonly the subject of student misconceptions. This information on
“bioliteracy” was collected from faculty and the science education literature.
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Students believe that ecosystems always rebound back to normal after damage
Students view extinction as affecting only that particular organism
Students are unaware of the impacts of invasive species
Students believe that ecological research is driven by emotional values
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Students are unaware of the complexity of biomes
Students believe that biomes are fixed entities and therefore static
Students are unfamiliar with microhabitats
Students believe that biomes are solely determined by temperature
Students are unaware the deserts and grasslands are defined by rainfall
Students do not distinguish between habitat and niche
Students do not distinguish between ecosystem and biome
Students think the term biome is synonymous to biosphere
Students are unaware of many abiotic factors in the environment
Students do not make the connection between latitude and biome differences
Students do not make the connection between altitude and biome differences
Students are unaware of evolution at the population level
Student think that selection is directional and produces superior characteristics
INSTRUCTIONAL STRATEGY PRESENTATION ASSISTANCE
Introduced species include kudzu in the southern Unites States and cane toads, rats, and cats in
Australia. American dandelions are an introduced species (from England). European rabbits
were introduced into Australia and have managed to remain quite viable despite numerous
efforts to eliminate them over decades of time. Naturalists have a great fear of dogs and cats
destroying the populations of iguanas in Galapagos Islands. There are many cases where
humans have accidentally introduced harmful species, then introduced another species to control
introduced species; that species then becomes a problem when (if) the accidentally introduced
species is controlled. There are other examples where humans introduce species for their own
benefit—not being aware of (or more likely, not caring about) the overall effects to the natural
environment.
If internet connections are available in class, have students use a metasearch engine
(www.Dogpile.com or Google) with the following string of terms—“introductions + flora +
fauna + United + States” and discuss the results in class.
There is an interesting article in Discover (August 2000) magazine about the importance of
parasites in ecosystems. The author contends that even though parasites are considered harmful
to their hosts, the loss of a single one could grossly disrupt its ecosystem. He provides several
examples including a snail fluke and a killifish brain parasite. In the first, if the fluke is
eradicated, the snail population nearly doubles and thins out the algae carpet in the salt marsh. In
the second, the parasite alters the behavior of the fish, enabling it to be captured more readily by
local bird populations, thereby helping to sustain them.
Another case study examines the Riddly sea turtles. Eggs from eastern Mexican beaches are
caught as mothers lay them. They are placed in sand from certain beaches in Texas and hatched
in incubators. Hundreds have been released into Gulf off eastern Texas over the past 10 years.
Recently, scientists have found 12 nests on beaches already this year where none existed before.
The translocation is, so far, successful. The process continues to ensure a maximum rate of
hatching and survival. It was accidentally discovered that higher incubation temperatures result
in all turtles becoming female. The researchers now incubate at that temperature to increase the
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numbers of females in the wild, more effectively populating the Texas habitats.
This is a “current events” kind of chapter. It is extremely important to be aware of the recent
political and environmental issues worldwide, but especially those in your own area. Will a new
mall affect the drainage patterns of a creek and the possible local extinction of a snail, insect,
amphibian, or aquatic plant, or perhaps a nesting area for a particular bird species? The general
public often considers scientific studies of ecosystems to be a waste of money. It is important to
characterize them so that we have data to restore them after we have screwed them up!
Ecological characterization is quite cheap compared to molecular/medical research.
Although if offers little financial gains, it is ethically and aesthetically important.
Ask guest speakers (Earthwatch, Sierra Club, Audubon Society) to come to your class and make
brief comments on actual case studies where their efforts have made a difference either in a
species recovery or a habitat restoration.
HIGHER LEVEL ASSESSMENT
Higher level assessment measures a student’s ability to use terms and concepts learned from the
lecture and the textbook. A complete understanding of biology content provides students with the
tools to synthesize new hypotheses and knowledge using the facts they have learned. The
following table provides examples of assessing a student’s ability to apply, analyze, synthesize,
and evaluate information from Chapter 60.
Application
Analysis
Synthesis
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Have students explain how environmental disruption can cause the
extinction of a species of birds.
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Have students explain why the extinction of one species can cause the
overpopulation of another.
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Ask students how the introduction of invasive species can lead to the loss
of native species in a hotspot.
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Have students explain the difference between conservation and
preservation.
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Have student contrast the types of human activities that caused extinctions
in ancient times compared to today.
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Ask students how genomic analyses are assisting with the preservation of
endangered organisms.
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Ask students find a use for plant tissue culture in the conservation of
tropical rain forests.
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Have students design an experiment to investigate the effects of global
climate change on extinctions in arctic environments.
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Ask the students come with a strategy for reducing the impacts of
deforestation associated with suburban growth.
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Evaluation
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Ask students assess pros and cons of using genetic engineering to bring
back extinct species of animals for reintroduction into their native
habitats.
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Ask students to evaluate the pros and cons of killing off mosquitoes that
spread human diseases in tropical areas.
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Ask students present an argument for preserving a keystone species of
fish in your area.
VISUAL RESOURCE
A demonstration for those who use an overhead projector: Collect several objects or simple
shapes and show them to the class. Turn off the lamp and place the objects on the overhead,
covering half of it (objects and all) with cardboard. Turn the lamp back on and ask the students
to remember the placings of all of the objects. Then tell them that you will give an “A” to anyone
who can correctly place all of the objects. Of course they will begin to complain that they cannot
complete the task because they did not see where half of the items were located due to the
cardboard. Ah ha—precisely why it is so difficult to restore any habitat to a pristine condition!
This is where television can be a real asset to teaching. Contact your local PBS station and/or
cable communications (The Learning Channel, Discovery Channel, the Animal Planet are among
the best) to find out what programs of interest may be broadcast during the appropriate semester.
It is unlikely that you will have either the time or resources to show such films in class (make it
an outside class required assignment if you can). (If not somehow tested upon, very few students
will view the resources. And those that need to be enlightened the most will be least likely to get
it.)
Tons of “favorite” animal and plant web sites exist. Many are factually correct and well known;
others are drivel. Find or create a website as class assignment to inform students about
conservation biology as well as the value and operation of the internet.
There is an excellent article entitled “Conserving Biodiversity’s Coldspots,” pages 344-351,
American Scientist, Vol. 91, July-August 2003.
Have students collect and bring to class any news article (newspaper or popular magazine)
relating to conservation efforts around the Earth. Display a collection of these articles during
class to make an impact on student thinking related to conservation efforts.
IN-CLASS CONCEPTUAL DEMONSTRATIONS
A. A Bird’s Eye View of Local Conservation Needs
Introduction
This demonstration has the instructor lead students through the rationale that biologists
use to define biodiversity loss hotspots.
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Materials
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Computer with Media Player and Internet access
LCD hooked up to computer
Web browser with previously downloaded Google Earth at http://earth.google.com/
Google Earth on computer desktop
Procedure & Inquiry
1. Tell the class they will be viewing aerial images of their area using Google Earth
2. Click on the Google Earth icon
3. Add “Roads” , “Terrain”, “Borders”, and “Buildings” to the view as a reference point for
students to identify particular features of the area
4. Toggle the “Earth Image” to your region and slowly zoom in
5. The “Roads” can be removed when looking at close up view to prevent road labeling from
covering terrain features.
6. Other details can be added or subtracted using the “Layers” window.
7. Ask the students to assess the development of their area and identify areas conducive to
sustainable wildlife populations.
8. Ask the students to identify areas that may cause environmental decay.
9. Have students assess the particular features of building developments and roadways that
sector the area into isolated habitats or ecosystems.
LABORATORY IDEAS
A. Sustainability Laboratory
This activity has students develop a rationale and sustainable way of using natural
resources that are used in everyday life.
a. Explain that they will be placed into brainstorming groups.
b. Then tell them that each group will be charged with finding a sustainable way of using a
current resource or technology.
c. Have the students review the topic of sustainability with a web search.
d. Provide the students with the following:
a. Group 1: Metal food cans
b. Group 2: Hard plastic case used in retail merchandise
c. Group 3: Food item
d. Group 4: Pesticide bottle
e. Group 5: Construction brick
f. Group 6: Cardboard box
e. Ask the students to record and summarize their findings after the brainstorming session.
f. Tell them that each group will present their proposed sustainable idea to the class for
discussion.
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LEARNING THROUGH SERVICE
Service learning is a strategy of teaching, learning and reflective assessment that merges the
academic curriculum with meaningful community service. As a teaching methodology, it falls
under the category of experiential education. It is a way students can carry out volunteer projects
in the community for public agencies, nonprofit agencies, civic groups, charitable organizations,
and governmental organizations. It encourages critical thinking and reinforces many of the
concepts learned in a course.
1. Have students host a litter cleanup campaign for the area.
2. Have students volunteer at a community recycling center.
3. Have students do a public information presentation on natural resource conservation for a
local civic group.
4. Have students volunteer with a conservation group on local conservation projects.
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