Chapter 10.1 – Biodiversity at Risk
The Earth has experienced several mass extinctions in its geologic
history, mostly due to climate change (due to atmospheric changes from
volcanic eruptions, meteor impacts, etc.), but scientists believe that we
are currently living during another mass extinction period, but this time
the cause is due to human activities. Scientists fear that by the year 2100,
25% of all species on the planet as of the year 1900 will have become
extinct.
Why?
The human population is increasing by a rate of about
220 000 people per day. This growth is causing dramatic impacts on our
natural environment as we continue to develop land in order to keep up
with our demands for space, food, resources and create waste.
Questions
#1.) Explain how habitat destruction can cause the extinction of species.
- Species can become extinct when the natural conditions of their
environment needed for survival change or disappear. Some species
cannot adapt quickly enough to new conditions in order to survive.
#2.) Explain how protecting one species can preserve and entire
ecosystem.
- Each species in an ecosystem has a specific role to play. Just as the
disappearance of one species can negatively impact a whole
ecosystem, the protection of just one species can protect a whole
ecosystem as well.
#3.) What are some practical disadvantages of losing a species?
- Loss of some species can mean the loss of medicinal plants, food
species, and other resources we value.
#4.) Do you think humans should try to protect all plant and animal
species from extinction? Why or why not.
- Yes. Scientists have documented 1.6 million different species on the
planet to date, but the actual number of different species on the
planet could be much higher; anywhere from 13 to 50 million in total.
If we do not protect all plant and animal species, we may be causing
the extinction of species with qualities that we may need in the
future, endangering our own survival.
- No. Since we cannot currently know for sure how many diverse the
species on the planet is, it is not possible to reasonably be able to
protect all species of plants and animals, especially as our
population continues to grow.
Chapter 10.2 – Biodiversity and Public Policy
As of 2007, the purpose of Canada’s Endangered Species Act specifies
the following:
1. To identify species at risk based on the best available scientific
information, including information obtained from community
knowledge and aboriginal traditional knowledge.
2. To protect species that are at risk and their habitats, and to
promote the recovery of species that are at risk.
3. To promote stewardship activities to assist in the protection and
recovery of species that are at risk.
In spite of this Act, there are currently 631 species that are endangered in
Canada today, including plants, birds and fish according to Nature
Canada.
Questions
#1.) What is the difference between an endangered species and a
threatened species?
- Endangered species are species whose numbers have declined to
the point that they may become extinct if not protected.
- Threatened species are species that are likely to become
endangered if they are not protected.
#2.) Why can’t some species survive on small plots of land?
- Most species require a large range of land to obtain adequate food
supplies, to find a suitable mate and to rear young. Also, if left to a
small plot of land, unusually harsh weather or a blight of some kind
can easily wipe out the entire species.
#3.) Do you think it is reasonable for an expensive dam project to be
stopped by the discovery of an endangered species that would be
threatened by the dam? Why or why not?
- Yes. People should find ways to be more efficient with water or to
use alternate sources of energy instead of destroying so much
habitat and endangering species because creating a dam might
seem like a simpler solution for human needs.
- No. Human needs are growing as does our population. Even with
water efficiency and alternate sources of energy, we may still need
to dam areas. Arguably, this is part of Darwin’s law of survival for
the fittest.
Chapter 10.3 – The Future of Biodiversity
In order to promote biodiversity into the future, human will need to slow
their development on the land and consider practices such as continuing to
save individual species under policies such as the Endangered Species Act,
but also through:
- Captive-Breeding Programs (breeding animals in captivity to promote
reproduction, then ideally release them back into the wild)
- Use of Botanical Gardens (these specialized gardens are concentrated
areas of species diversity to help preserve rare or endangered species
of plants)
- Use of Germ-Plasm Banks (these are special laboratories where
genetic material of plants that includes their reproductive cells can be
stored – such as seeds, sperm and eggs, in temperature and humidity
controlled environments that can allow them to survive for years).
- Using a Whole Ecosystem Approach (protecting entire ecosystems)
By concentrating on protecting entire ecosystems we can save the
greatest number of species, not only those on endangered lists, which
considering that we don’t know how many species there actually are
on the planet, can be of most benefit. The health of the entire
Biosphere depends on the preservation of combined ecosystems
How? Through establishing conservation areas and protected land
areas, especially in “hot zones” that contain a large number of
endangered species that are found nowhere else on the planet
(California, Ecuador, Chile, Brazil, Ivory Coast, South Africa, Tanzania,
Madagascar, Sri Lanka, Philippines, etc.)
Questions
#1.) Which of the ways to save individual species involves the preservation
of only part of the species?
- Germ-Plasm Banks
#2.) Why are some conservationists beginning to concentrate on protecting
entire ecosystems rather than individual species?
- Many species can be protected, known and unknown, not just those
that are listed as endangered, which contributes to the overall health of
the Earth’s Biosphere.
#3.) The Biodiversity “hot spots” share several characteristics other than
endangered species. What are they? Refer to map on p. 269.
- They are located in tropical regions close to the Equator, often on
islands and located mostly in developing countries. Sadly, these
countries can often least financially afford conservation policies.