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Environmental Science Ch' 10: Biodiversity

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Title: Environmental Science Ch' 10: Biodiversity


1
Environmental Science Ch. 10Biodiversity
2
California Content Standards for Science
Addressed
  • Life Science
  • 6(a) Students know biodiversity is the sum total
    of different kinds of organisms and is affected
    by alterations of habitats.
  • 6(b) Students know how to analyze changes in an
    ecosystem resulting from changes in climate,
    human activity, introduction of nonnative
    species, or changes in population size.

3
Ch. 10-1 Biodiversity At Risk
  • Key Terms
  • Biodiversity
  • Exotic Species
  • Poaching

4
Why Do I Need To Know This?
  • Because large amounts of our medicines and
    products come from plants and animals and will
    not be available to us if the plants and animals
    go extinct.
  • Because humans are causing extinction at a rate
    1,000 times faster than it has ever occurred in
    the past.
  • Because as our population grows, we continue to
    destroy habitat that is necessary for plants and
    animals to survive.

5
Key Sections Ch. 10-1
  • Biodiversity At Risk
  • A World Rich in Biodiversity
  • How Are Humans Causing Extinction?
  • Habitat Destruction
  • Hunting
  • Exotic Species
  • The Value of Biodiversity
  • Saving Species Preserves Ecosystems
  • Practical Uses of Species
  • Ethical and Aesthetic Reasons

6
Biodiversity At Risk
  • We are now living during an era of mass
    extinction.
  • In the past, there have been 5 periods of mass
    extinction that occurred naturally.
  • These typically resulted from mass catastrophes
    such as meteor impacts.
  • However, today, many scientists are concerned
    that up to 25 of all species will go extinct by
    the year 2100 due to human activities.

7
A World Rich in Biodiversity
  • The term biodiversity refers to the number and
    variety of species living on the Earth.
  • Presently, there are about 1.6 million known
    species on the Earth.
  • However, it is estimated that there may be
    between 13 million and 30 million different
    species presently living on the Earth.

8
How Are Humans Causing Extinction?
  • Humans are causing extinction in 3 ways
  • Habitat Loss
  • Hunting/Poaching
  • Introducing Exotic Species
  • Of the 3 ways, habitat loss is the most common
    and most damaging method of causing extinction.
  • This is because the human population is growing
    by 220,000 people everyday, habitat loss is
    happening on a massive and global scale.

9
Habitat Destruction
  • Whenever humans take over new land for use, they
    clear it and wipe out the species living on it.
  • It is estimated that up to 75 of all extinctions
    presently occurring are due to habitat loss.
  • Habitat loss is particularly hard on large
    animals, as they often require large amounts of
    area for their habitats.
  • Although habitat loss is a massive problem in
    developed nations, it is also a major problem in
    developing nations because their populations are
    growing more rapidly and most of the worlds
    species live in those nations.
  • The rain forests for example, contain about 50
    of all the worlds species, yet only cover 7 of
    the worlds land.

10
Hunting
  • Unregulated hunting (poaching) can also cause
    extinction.
  • For example, between 1900 and 1920, the American
    passenger pigeon became extinct even though there
    were over 2 billion passenger pigeons alive in
    1900!
  • Although a major problem in the past for the
    industrialized nations, unregulated hunting is
    not a major cause of extinction today because the
    government regulates the amount of animals to be
    killed.
  • Unregulated hunting, is, however a major cause of
    extinction in developing nations. For example,
    the number of wild chimpanzees in Africa has
    dropped from over 100,000 to around 6,000 in just
    the last 10 years!
  • Poaching is particularly devastating because the
    poached animal is often killed for just 1 thing
    and the rest of it is discarded.

11
Exotic Species
  • Exotic species are species that are not native to
    an area.
  • Introducing exotic species to an area is
    particularly harmful to an environment as they
    may not have any predators or animals in the area
    may not have any defenses against them.
  • Consequently, they can destroy an entire
    ecosystem very quickly.
  • This is a major cause of extinction in the
    developed nations, as we have imported thousands
    of species from around the world.
  • An example is the melaleuca tree, which was
    brought to Everglades in the early 1900s. It is
    now spreading at a rate of about 50 acres a day,
    wiping out species that depend on that wetland
    ecosystem.

12
The Value of Biodiversity
  • Although extinction is a natural process (over
    99 of all species that ever existed on the
    planet have gone extinct), there are 3 main
    reasons why we should preserve species. They
    are
  • Saving species can preserve an entire ecosystem
  • Humans depend upon species for many practical
    uses
  • Ethical and aesthetic reasons.

13
Saving Humans Preserves Ecosystems
  • Species, along with the abiotic factors, are what
    make up ecosystems.
  • Each species performs a vital role in maintaining
    a healthy ecosystem and plays a part in the
    cycling of materials and the transfer of energy.
  • Every time a species disappears it alters the
    ecosystem and makes the ecosystem less stable.
  • Some species are perform such an important role
    in an ecosystem that the entire ecosystem would
    collapse without it.

14
Practical Uses of Species
  • Many species have practical uses for humans
    today.
  • Over 40 of all prescription drugs in the United
    States were developed from plants and animals.
  • Diseases such as cancer, heart attack, and
    strokes, all of which are fatal, are all treated
    with drugs developed by endangered plants and
    animals.
  • You have about a 25 chance of getting cancer,
    50 chance of having a heart attack and about a
    33 chance of having a stroke!
  • Additionally, since we rely on plants an animals
    for food, the loss of biodiversity will affect
    the amount of overall food that is available for
    us to eat!
  • And, the lack of biodiversity will make the
    chance of our food supply becoming more at risk
    to disease and pestilence even greater!

15
Ethical and Aesthetic Reasons
  • Many people believe for religious and ethical
    reasons that humans are to maintain the world,
    not destroy it.
  • By causing extinction, we are removing objects of
    interest and curiosity on the only known planet
    to develop life.

16
Ch. 10-2 Public Policy
  • Key Terms
  • Endangered Species
  • Threatened Species

17
California Content Standards for Science
Addressed
  • Life Science
  • 6(a) Students know biodiversity is the sum total
    of different kinds of organisms and is affected
    by alterations of habitats.
  • 6(b) Students know how to analyze changes in an
    ecosystem resulting from changes in climate,
    human activity, introduction of nonnative
    species, or changes in population size.

18
Ch. 10 Section 2Why Do I Need To Know This?
  • Because you reside in the United States and will
    have the chance to vote for laws or politicians
    who will pass laws that will affect the
    environment.
  • Because you have the ability to help support
    national and international organizations that
    will help protect species.
  • Because your tax dollars are going to support
    national and international programs to help
    protect species.

19
Key Sections Ch. 10-2
  • Public Policy
  • The Endangered Species Act
  • Developers vs. Environmentalists?
  • Worldwide Efforts to Prevent Extinctions
  • Preventing Poaching
  • The Biodiversity Treaty

20
Public Policy
  • Many nations, especially the developed nations
    have passed many laws and regulations to protect
    the environment.
  • The laws in the United States are some of the
    toughest in the world.
  • The problem is that not all countries have the
    same laws, and so neighboring countries often
    treat the environment very differently.
  • Since ecosystems cross international borders,
    when neighboring countries treat the ecosystem
    differently, the overall ecosystem still
    sufferseven if one country is trying to save it.

21
The Endangered Species Act
  • In 1973, Congress passed the Endangered Species
    Act which requires that
  • The U.S. Fish and Wildlife Service must compile a
    list of all endangered and threatened species in
    the U.S.
  • Endangered species may not be caught or killed
    anywhere in the U.S. Endangered plants on
    government land may not be uprooted. No part of
    an endangered or threatened species may be sold
    or traded.
  • The federal government may not carry out any
    project that jeopardizes endangered species.
  • The U.S. Fish and Wildlife Service must prepare a
    species recovery plan for each endangered
    species.
  • The Endangered Species Act is one of the most
    controversial laws passed by Congress in the last
    50 years.

22
The Endangered Species Act
  • According to the Endangered Species Act, an
    endangered species is one where its numbers have
    fallen so low that it is likely to go extinct in
    the next few years.
  • A threatened species is one that is likely to
    become endangered in the next few years.
  • There are presently about 1,000 identified
    endangered species in the U.S. and about 300
    identified threatened species in the U.S.
  • Environmentalists criticize the Endangered
    Species Act because it takes too long to identify
    a species as endangered or threatened. So, many
    species have gone extinct while trying to become
    listed as endangered.
  • Environmentalists also criticize the Endangered
    Species Act because it mostly contains cute
    animals and often does not contain scarey or
    ugly animals on the list.

23
Developers vs. Environmentalists?
  • The Endangered Species Act is extremely
    controversial with developers (builders).
  • This is because the builders want to make money
    by clearing land and are often prevented from
    doing so by the Endangered Species Act.
  • Also, a lot of people who work in construction or
    who would have benefited from the jobs become
    upset about the loss of jobs/income.
  • In the end, most controversies end in a
    compromise, where the needs of the community and
    the needs of the environment are balanced.
  • Although there are many lawsuits over the
    Endangered Species Act, most get settled and
    never go to trial.

24
Worldwide Efforts to Prevent Extinctions
  • There are many international organizations that
    work to prevent extinction around the world.
  • Many of them try to prevent poaching and to
    educate people about the importance of saving
    them.
  • This has led to many international treaties to
    help prevent extinction of certain animals.
  • Some of them are buying up land around the world
    to setup international parks to protect entire
    ecosystems.
  • This has proven to be a much more effective than
    almost any other type of prevention.

25
Prevention of Poaching
  • The salvation of the African Elephant is an
    example of international groups working together
    to protect a species.
  • In 1989, they got a treaty passed (called CITES)
    that prevented the sale of ivory from African
    Elephants around the world.
  • Although many people thought at first that this
    idea would lead to more poaching of elephants, it
    in fact led to a deep drop in the price of ivory.
  • As a result, the poachers no longer hunted the
    elephants for their tusks because they could not
    sell the ivory, or if they did, they could not
    make much money at it.

26
The Biodiversity Treaty
  • In 1992, over 100 nations and 30,000 people met
    in Rio de Janeiro, Brazil to develop an
    international treaty to protect species around
    the world.
  • This treaty called the Biodiversity Treaty
    required the wealthier nations of the world would
    give money to the more poor nations in the world
    to help protect species.
  • Eventually, the United States signed the treaty
    in 1994.

27
Ch. 10-3 The Future of Biodiversity
  • Key Terms
  • None.

28
California Content Standards for Science
Addressed
  • Life Science
  • 6(a) Students know biodiversity is the sum total
    of different kinds of organisms and is affected
    by alterations of habitats.
  • 6(b) Students know how to analyze changes in an
    ecosystem resulting from changes in climate,
    human activity, introduction of nonnative
    species, or changes in population size.

29
Ch.10 Section 3Why Do I Need To Know This?
  • Because there are many ways that we can try and
    preserve biodiversity for the future.
  • Because our tax dollars will be used to buy land
    and set it aside to protect biodiversity.
  • Because we need to learn to balance human needs
    with the needs of nature.

30
Key Sections Ch. 10-3
  • The Future of Biodiversity
  • Saving Individual Species
  • Captive Breeding Programs
  • Botanical Gardens
  • Germ-Plasm Banks
  • The Ecosystem Approach
  • What About Human Needs?

31
The Future of Biodiversity
  • It is possible for us to slow down the rate of
    extinction around the world.
  • In order to do so, we must develop new approaches
    to conservation and new sensitivities to
    biodiversity/human needs around the world.
  • If we work and educate people now, we can make a
    huge impact on the future of biodiversity.

32
Saving Individual Species
  • People around the world are using many methods to
    preserve individual species.
  • They are
  • Captive-Breeding Programs
  • Botanical Gardens
  • Germ-Plasm Banks

33
Captive-Breeding Programs
  • Captive-Breeding is when scientists capture wild
    organisms and try and get them to breed in
    captivity in order to increase their overall
    number.
  • This is typically done at zoos and wild animal
    parks
  • An example of a successful captive breeding
    program is the California Condor.
  • In 1986, there were only 9 condors left (there
    once were millions of them ranging from
    California to Florida). By 1998, there were 93
    condors in zoos and 39 that had been released
    back into the wild!
  • Another example is the panda, where there are now
    more than 1,000 pandas saved as a result of
    captive-breeding.

34
Captive-Breeding Programs
  • Benefits and Risks
  • The benefits of captive-breeding programs are
    that it can work to save a single species.
  • This often works best when there are very few
    members of the species left and they reproduce
    very slowly or rarely.
  • The risks are that this is very expensive, and by
    placing all of the organisms together in 1 place,
    they could all be killed by a disease.
  • Additionally, if it does not work, most likely
    there will be no members of the species left at
    all.
  • And, if it does work, the animals may not learn
    the skills they need to survive in the wild while
    being raised by humans in a zoo.

35
Botanical Gardens
  • Around the world, more than 90,000 different
    plants are preserved in botanical gardens.
  • These can range from greenhouses to large open
    fields of plants.
  • As a result, they store protect a large amount of
    biodiversity and can be used for research.

36
Botanical Gardens
  • Benefits and Risks
  • The benefits of Botanical Gardens are that they
    protect a large number of plants around the
    world.
  • Additionally, botanical gardens are not too
    expensive as they are often sustained by the fees
    people pay to visit them.
  • The risks are that by placing all the plants
    together, pests and diseases could easily spread
    throughout the garden and kill off large numbers
    of plants very quickly.
  • Also, many plants require other animals in the
    ecosystem to help reproduce (such as bees and
    animals) which most likely arent present in the
    botanical garden. Without those other animals,
    the plants will not reproduce and may die.
  • Finally, there are far more plants that are at
    risk of going extinct than can ever be supported
    in botanical gardens (most likely there are more
    than 1 million different plant species on the
    planet).

37
Germ-Plasm Banks
  • Germ-plasm banks store DNA (either seeds or sperm
    and eggs) from organisms for future use.
  • The goal is to preserve the DNA of an organism
    until a time in the future when science is able
    to recover the species and reproduce it.

38
Germ-Plasm Banks
  • Benefits and Risks
  • The benefits are that the DNA that makes up the
    species will be saved for the future.
  • Hopefully science will develop a way to bring
    back the species that will not cost too much
    money.
  • The risks are that no one knows when or what
    science will develop or if it is possible.
  • Additionally, if the species is brought back, no
    one knows if it will learn what it needs to
    survive on its own.
  • And, since it the species will be based on the
    DNA on just a few organisms, any defects in that
    DNA will be present in all future members of that
    population.

39
The Ecosystem Approach
  • Recently, most environmentalists have begun to
    try and save an entire ecosystem rather than one
    single species at a time.
  • This is because there are far more species living
    than have been identified or labeled as
    endangered or threatened.
  • They do this by purchasing land to preserve it as
    a national park or refuge for organisms.
  • This works especially well in in the ecological
    hot-spots where as many as 50 of all the
    species living on the planet may be located.

40
The Ecosystem Approach
  • Benefits and Risks
  • There are many benefits to the ecosystem
    approach. They include
  • Large numbers of species can be saved at one time
    by preserving an entire ecosystem.
  • The natural setting is preserved so that only
    naturally occurring diseases and pests are likely
    to be present.
  • The species will be spread out in their own
    habitats, making them less susceptible to
    extinction.
  • There are very few risks associated with the
    ecosystem approach. As a result, this is
    becoming the most accepted approach for
    protecting biodiversity.
  • The biggest risk is setting aside too little
    land. Some conservationists believe that we
    should set aside 10 of all the Earths land in
    order to protect global biodiversity.

41
What About Human Needs?
  • In order to truly protect biodiversity, we must
    consider and balance the needs of humans as well
    as the needs for nature.
  • In the developed nations, the debates about
    biodiversity typically stem around jobs and
    economic factors.
  • In the developing nations, the debates about
    biodiversity typically stem around survival, as
    starving people will eat or use whatever they can
    to survive.
  • Finding ways to balance the competing needs for
    biodiversity will be a major challenge for the
    21st century.
  • However, if we can resolve those issues, we can
    preserve a much better world for ourselves and
    our future.
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