Download CP Environmental Science Name: Unit 2B Homework

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Unit 2B Homework- Biodiversity
Paper Edition
1. Why is genetic diversity important for the survival of a species?
-Genetic diversity refers to all the different genes contained within all members of a
population. Genetic diversity plays an important role in the survival and adaptation of a
species. When a population’s habitat changes, the population may have to adopt to
survive; the ability of the population to adapt to the changing environment will
determine their ability to cope with an environmental challenges.
2. Describe three levels of biodiversity. Which is most commonly meant by biodiversity?
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Species Diversity – refers to the number of different species in an area (received the
most attention- most commonly meant by biodiversity)
Ecosystem Diversity – refers to the variety of habitats, communities, and ecological
processes within and between ecosystems.
Genetic Diversity - refers to all the different genes contained within all members of a
population.
3. Explain how biodiversity is important to ecosystems, and give examples of how it is
important to humans.
Biodiversity is important to each ecosystem because every species plays an important role in
an ecosystem. Every species is dependent on or depended upon by at least one other
species in order to survive.
Biodiversity is important to humans because people use variety of organisms on Earth for
food, clothing, shelter, and medicine. People also use different plant species to produce
medicine. People also value biodiversity for aesthetic or personal enjoinment- camping,
keeping pets, watching wildlife, national parks and many more aesthetical benefits.
4. Why do scientists warn that a mass extinction is occurring now?
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Scientists are warning of mass extinction because the rate of extinction is estimated to
have increased by a multiple of 50 since 1800. They state that by the end of 2100, up
to 25% of all species on Earth may have become extinct.
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5. Describe four ways that species are being threatened with extinction globally.
1. Habitat Destruction and Fragmentation – In the process of building homes
and harvest resources, humans destroy and fragment the habitats of other
species. 75% of all extinction is caused by habitat destruction.
2. Invasive Exotic Species – Humans brought many exotic species that do not
belong to a certain ecosystem. Since the exotic species are introduced to a
predator-free new environment, they can become an invasive species and
can threaten the native species.
3. Harvesting, Hunting, and Poaching – Excessive harvesting and poaching
can also lead to extinction. Many countries around the world have laws to
regulate hunting, fishing, harvesting and trade of wildlife. However, in poor
countries, an illegal activity such as poaching occurs where local species
are used as source of food, medicine, or income.
4. Pollution - Pesticides, cleaning agents, drugs, and other chemicals used by
humans are making their way into food webs around the globe.
6. Define and give examples of endangered species and threatened species.
Endangered- An endangered species is a species that is likely to become
extinct if protective measures are not taken immediately. (ex: Amur Tiger –
endangered due to hunting, now protected by law)
Threatened- Threatened species is a species that has a declining population
and that is likely to become endangered if it is not protected. (ex: Polar Beardue to ongoing and potential loss of their sea ice habitat resulting from climate
change, Polar Bears were listed as threatened species in 2008).
7. List areas of the Earth that have high levels of biodiversity and many threats to
species.
- Tropical Rain Forests – ( today, it covers around 7% of the Earth’s land surface)
- Coral Reefs and Coastal Ecosystems – It occupies a small fraction of the marine
ecosystem yet contains the majority of the biodiversity. The coral reefs provide the
people with food and tourist revenue. But nearly 60% of the coral reefs on our planet
are threatened by human activities such as overfishing and pollution.
- Islands – When an island is formed, it is colonized by a limited number of species.
Some of the species may evolve into several new species. However, due to human
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activities and transportation of exotic species, the island species are endangered by
competition from exotic species.
8. Describe one way in which the IUCN helps to protect species and habitats.
The International Union for the Conservation of Nature and Natural Resources (IUCN) had
published a “Red Lists” of species in danger of extinction around the world. The IUCN also
advises governments on ways to manage their natural resources and also they support
conservation projects.
9. Describe four types of efforts to save individual species.
1. Captive-Breeding Programs – Restoring a population of a species through
breeding species in captivity, with hope to reintroducing populations to their
natural habitats (ex: the California Condor).
2. Preserving Genetic Material – Saving genetic material (germ-plasm banks)
of plants and animals for future use in research or species-recovery efforts.
3. Zoos, Aquariums, Parks, and Gardens – Today, zoos house the few
remaining members
4. Habitat conservation plan – a plan that attempts to protect one or more
species across large areas of land through trade-offs or cooperative
agreements.
10. Explain the advantages of protecting entire ecosystems rather than individual species.
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The advantage of protecting entire ecosystems is the most effective way to save
species because species confined to a small area could be wiped out by a single
natural disaster. Some species require a large range to find adequate food or mate.
Therefore, protecting the habitats of endangered and threatened species often means
preserving or managing large areas (entire ecosystem).
11. Describe the main provisions of the Endangered Species Act (ESA).
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The U.S. Fish and Wildlife Services (USFWS), must compile a list of all endangered
and threatened species.
Endangered and threatened animal species may not be caught or killed. Endangered
or threatened plants on federal land may not be uprooted, sold or traded.
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The federal government may not carry out any project that jeopardizes endangered
species.
The USFWS must prepare a species recovery plan for each endangered and
threatened species.
12. Some species are so important to the functioning of an ecosystem that they are called
a. Threatened species.
b. Keystone species.
c. Endangered species.
d. Extinct species.
13. Which of the following statements about the Endangered Species Act is not true?
a. Parts of an endangered animal, such as feathers or fur, may be traded or sold
but only if the animal is not killed.
b. A species is considered endangered if it is expected to become extinct in the
near future.
c. The federal government cannot carry out a project that may jeopardize an
endangered plant.
d. A recovery plan is prepared for all animals that are listed as endangered.
14. What are invasive species, and how do they endanger other species?
An invasive species is a species that is not native to a particular region or ecosystem. When
a species is introduced to a new environment, it can become invasive due to the fact that it
does not have a natural predator to control their population. When the species becomes
invasive, it overtakes the new territory and it threatens native species by tacking their food
resources or by killing them.
15. Math Practice: There are 297,326 identified plant species on Earth today. Scientists
estimate that this number makes up 84% of the total plant species on the Earth.
Estimate how many plant species are actually in existence today, both identified and
unknown. Show your work.
0.84(x) = 297,326 species
solve for x
x = 297,326 / 0.84 = 353,960 species total, known and unknown