Transcript Chapter 10

Extinct Species Activities
1. Research an Extinct Species and make an info
card for our class timeline that includes the
species name, date the species is believed to
have gone extinct, and the reasoning scientists
believe the species went extinct. No two
students may do the same species, so once you
have selected your species, put its name on the
board so other students can see your selection.
Once finished, put your species info card on the
class timeline.
2. Write a Eulogy about your species. The
eulogy should include the positive
characteristics of the species and why it will be
missed…get creative with your work and feel
free to add appropriate humor!
Chapter 10
Biodiversity
Chapter 10, Section 1
Biodiversity at Risk
•The extinction of many species in a relatively
short period of time.
•Probably caused by a global change in
climate.
•It takes millions of years for biodiversity to
rebound after a mass extinction.
•Example: Dinosaurs
Are we currently in a
mass extinction?
What is
Biodiversity?
Biodiversity
(biological diversity)
The number and variety
of species in a given area.
Unknown Diversity
Humans causing
extinction…
Human population is increasing at a rate of about
220,000 people each DAY!
Because the population is growing so rapidly and
changing the environment so dramatically, we are
causing other species to become extinct at an
accelerated rate.
Scientists estimate that species are disappearing at
least 1,00 0 times faster than at any other time in the
last 65 million years.
So, why is the increase in the human population so
devastating to other species?
So, why is the increase in the
human population so devastating
to other species?
1. Habitat Destruction
2. Unregulated hunting
3. Introduction of
nonnative species
Habitat
Destruction
As human populations grow, we use more land to build homes and harvest
resources and in turn destroy the habitats of other species.
It is estimated that habitat loss causes almost 75% of the extinctions now
occurring.
Most extinctions are occurring in tropical rain forests when the land is
cleared for farming or cattle grazing.
Biologists estimate that at least 50% of the world’s species live in tropical
rain forests, even though these forest cover only 7% of the Earth’s land
surface!
Rain forests contain MILLIONS of species that have never been described,
many of which may become extinct before we know much about them.
Hunting
Unregulated hunting can also lead to species extinction.
In the early 1900s for example, 2 billion American passenger pigeons were
legally hunted to extinction in the US.
In the 1800s, the American buffalo (AKA bison) was nearly hunted to extinction,
but thanks to today’s laws that protect the buffalo, their population is more than
200,000.
Legal hunting is no longer a major cause of extinction in developed countries
with wildlife laws. In the US, hunting organizations and government agencies
work together to ensure that only a certain number of game animals are
killed each year.
However, in developing countries, where animal meat or cash for game can
mean the difference between starvation and survival, hunting still threatens
many species. In those countries, poaching (illegal hunting) can threaten
animals with extinction.
Exotic Species
Exotic species: a species that is not native to a particular region.
Exotic species can threaten native species, which have not natural
defenses against them….think about the Burmese Pythons in the
Florida Everglades….
Extinction is a natural process…throughout
the history of life on Earth, species have
appeared, flourished for a time, and then
become extinct. Probably 99% of all the
species that have ever lived are now extinct.
Protecting species on the verge of extinction
is difficult and expensive….why should we
work so hard to slow the rate of extinction?
Because…..
1. Species are Connected to Ecosystems
2. Practical Uses of Species
3. Ethical and Aesthetic Reasons
Humans depend on healthy ecosystems to
ensure a healthy biosphere that has balanced
cycles of energy and nutrients.
Species are part of these cycles because
species have roles in their environment. Every
species is dependent on or depended upon by
at least one other species.
Species that are clearly critical to the
functioning of an ecosystem that they are
called keystone species.
2. Practical Uses of Species
People throughout history have used the variety of
organisms on Earth for food, clothing, shelter, and
medicine.
About 40%of the drugs prescribed in the United States
are derived from living things. Almost all antibiotics
are derived from chemicals found in fungi!
The scientific community continues to find new uses for
biological material and genetic diversity, from
combating diseases to understanding the origins of
life.
Page 259, Figure 10-7: Pick 3 to include in your notes!
3. Ethical & Aesthetic Reasons
Some people believe that we should preserve
biodiversity for ethical reasons. They believe that
species and ecosystems have a right to exist
whether or not they have any other value.
People also value biodiversity for aesthetic or
personal enjoyment-keeping pets, camping,
picking flowers, or watching wildlife.
Some regions earn the majority of their income
from ecotourism
Ecotourism: a form of tourism that supports the
conservation and sustainable development of
ecologically unique areas.
United States
Public Policy
Endangered Species
Act
Passed in 1973 by US Congress
Designed to protect plant and animal
species in danger of extinction.
The four main provisions are found on
page 261, Figure 10-10
Add these to your notes….
Which is Which?
Endangered
Species that is
likely to
become
extinct if
protective
measures are
not taken
immediately.
Threatened
Species that
has a declining
population and
that is likely to
become
endangered if
not protected.
Extinct: Gone forever!
Worldwide Efforts to
Prevent Extinctions
World Wildlife Fund
Works to protect biodiversity, especially in tropical forests, by encouraging the
sustainable use of resources
Nature Conservancy
Manages over 1,500 sanctuaries in the US and other countries
Friends of the Earth
Group that lobbies governments and disseminates information to the public
Greenpeace International
Stages dramatic protests to help stop the destruction of rain forests and the killing of
endangered animals
Worldwide Efforts to
Prevent Extinctions
International Union for the Conservation of Nature
and Natural Resources (IUCN)
In the forefront of efforts to protect species and habitats
This organization is a collaboration of almost 200 governments and government
agencies and over 700 private conservation groups!!
Publishes data books that list species in danger of extinction around the world
One offshoot of IUCN is and international treaty, the Convention on International Trade
in Endangered Species (CITES)
Biodiversity Treaty
One of the most ambitious efforts to tackle environmental issues was the Earth Summit
where more than 100 world leaders and 30,000 other participants met in Rio de Janeiro,
Brazil, in 1992
One of the agreements that came out of the Earth Summit was the Biodiversity Treaty,
which encourages wealthier countries to give money to poorer countries for the
protection of potentially valuable species.
Areas of Critical Biodiversity
Certain areas of the world contain a greater diversity of
species than other areas do.
An important feature of such
areas is that they have a large
portion of endemic species.
Endemic species: species that
are native to and found only
within a limited area.
Ecologists often use the # of
endemic species of plants as
an indicator of overall
biodiversity, because plants
form the basis of ecosystems
on land.
These areas
include:
Tropical Rain
Forests
Coral Reefs &
Coastal
Ecosystems
Islands
Saving Species One at a Time
When a species is clearly on the verge of
extinction, concerned people sometimes make
extraordinary efforts to save the last few
individuals such as:
Captive-breeding programs
Germ-Plasm Banks
The Ecosystem Approach
Captive Breeding Programs
Zoos and wild-animal parks can increase the
population of an endangered or threatened
species through these programs
This involves breeding animals under careful
managed circumstances.
Botanical gardens is another form of this
Are storehouses of genetic diversity
Worldwide, they house 90,000 species of plants….even so, the gardens don’t have
the space or funds to preserve most of the world’s rare and threatened plants
Germ-Plasm Banks
Store germ plasm for future use in case species
become critically endangered.
Germ plasm is the genetic material contained
within the reproductive (germ) cells of organisms.
Plants may be stored as seeds and animals may be
stored as frozen sperm and eggs
The germ plasm is stored in refrigerated and
humidity-controlled environments that allow the
genetic material to survive for many years.
The Ecosystem Approach
2 main reasons for focusing on entire
ecosystems:
1. Many more species are in danger of extinction
than can possibly be placed on official lists. By
concentrating on entire ecosystems, we may be
able to save most of the species in an
ecosystem rather than just ones that are on an
endangered species list
2. The health of the entire biosphere depends on
the preservation of individual ecosystems
Conservationists suggest that at least 10% of the Earth’s land be set
aside to protected preserves, especially “hot spots”
“Hot Spots”
Regions that contain unusually large
numbers of species.
18 of these are listed on page 269…pick 5
to add to your notes!
Human Needs
Sometimes the desire to protect biological resources can
come into conflict with people’s jobs or in the poorer
nations can even become a life and death matter….it is
difficult to blame a parent who shoots an endangered
animal so that their child won’t starve.
We must find ways to meet human needs and manage
living resources at the same time.
Preserving these resources will perhaps be the greatest
challenge of the 21st century!