Title: Environmental Science Ch' 10: Biodiversity
1Environmental Science Ch. 10Biodiversity
2California 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.
3Ch. 10-1 Biodiversity At Risk
- Key Terms
- Biodiversity
- Exotic Species
- Poaching
4Why 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.
5Key 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
6Biodiversity 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.
7A 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.
8How 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.
9Habitat 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.
10Hunting
- 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.
11Exotic 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.
12The 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.
13Saving 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.
14Practical 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!
15Ethical 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.
16Ch. 10-2 Public Policy
- Key Terms
- Endangered Species
- Threatened Species
17California 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.
18Ch. 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.
19Key Sections Ch. 10-2
- Public Policy
- The Endangered Species Act
- Developers vs. Environmentalists?
- Worldwide Efforts to Prevent Extinctions
- Preventing Poaching
- The Biodiversity Treaty
20Public 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.
21The 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.
22The 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.
23Developers 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.
24Worldwide 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.
25Prevention 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.
26The 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.
27Ch. 10-3 The Future of Biodiversity
28California 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.
29Ch.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.
30Key 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?
31The 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.
32Saving Individual Species
- People around the world are using many methods to
preserve individual species. - They are
- Captive-Breeding Programs
- Botanical Gardens
- Germ-Plasm Banks
33Captive-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.
34Captive-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.
35Botanical 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.
36Botanical 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).
37Germ-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.
38Germ-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.
39The 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.
40The 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.
41What 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.