Environmental Science Ch' 10: Biodiversity

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Environmental Science Ch. 10Biodiversity
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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.

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Ch. 10-1 Biodiversity At Risk

• Key Terms
• Biodiversity
• Exotic Species
• Poaching

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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.

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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

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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!

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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.

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Ch. 10-2 Public Policy

• Key Terms
• Endangered Species
• Threatened Species

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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.

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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.

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Key Sections Ch. 10-2

• Public Policy
• The Endangered Species Act
• Developers vs. Environmentalists?
• Worldwide Efforts to Prevent Extinctions
• Preventing Poaching
• The Biodiversity Treaty

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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Ch. 10-3 The Future of Biodiversity

• Key Terms
• None.

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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.

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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.

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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?

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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.

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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

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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.

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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.

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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.

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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).

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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.

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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.

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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.

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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.

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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.