Ch 10 Biodiversity

8/2/2019 Ch 10 Biodiversity

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Ch. 10 Biodiversity

Section 1


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What is biodiversity? Biodiversitynumber of different species in a given

area

Extinctionwhen last members of a species die

1.7 million known species (mostly insects) Another 8 million estimated unknown species


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Levels of diversity Species diversity - # of different species (most

studied)

Ecosystem diversityvariety of habitats,communities, and ecological processes within

an ecosystem

Genetic diversityall the different genes withina population


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Benefits of Biodiversity Healthy ecosystems depend on all of the species

within them

Maintains balanced cycles of energy and nutrients

When too many species are taken from a food web itwill collapse

Keystone speciescritical to maintaining balancewithin an ecosystem

Ie. Sea ottereats sea urchins which eat kelp

Sea otter is hunted almost to extinction, sea urchinsoverpopulate, kelp beds are eaten away


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More benefits Ethics, recreation

All species have a right to exist

ecotourism

Species and population survival Genetic diversity within a species increases the chance that

some individuals will survive environmental changes When populations shrink, genetic diversity shrinks

Medical, industrial, agricultural use of prescribed drugs come from plants

Antibiotics come from fungi

Unknown uses for biological material

Food


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Section 10.2 Risks to

Biodiversity

SEV5. Students will recognize that human

beings are part of the global ecosystem and will

evaluate the effects of human activities and

technology on ecosystems.

EQ: How do humans cause a decrease the

earths biodiversity?


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Species prone to extinction Species at risk

small populations in small areas

migrating species species that need large or special habitats

those exploited by humans

Endangered specieslikely to become extinct ifprotective measures are not used

Threatened speciesdeclining population thatwill likely become endangered without protectivemeasures


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How do humans cause extinctions? Destruction of habitatscauses 75% of current

extinction Habitat destroyed to build homes and to harvest

resources

Ie: Florida pantherdown to less than 100 Introduction of nonnative speciesexotic species

threaten native species because they have nonatural defenses

Pollutionpesticides, cleaning agents, drugs aremaking their way into food webs

Overharvesting speciesthrough hunting,harvesting, and poaching Poachingillegal hunting, fishing, harvesting and

trading of wildlife


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Areas of critical biodiversity Areas with large portion of endemic species

(native to and found in limited area)

Tropical Rainforestscover 7% of the earth andcontain over half of worlds species

Coral Reefs and Coastal Ecosytemssmall partof marine environment but contain the majority

of species, 60% are threatened, migration routes

Islandsvery distinct species that have evolvedover time, not found anywhere else


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Biodiversity Hotspots Most threatened areas of high species

diversity

25 areas around the world

Most have lost 75% of original vegetation

Mostly tropical rainforests, coastal areas,and islands

Ie: Madagascar


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Biodiversity in the US Wide variety of ecosystems

High numbers of species of freshwater fish,mussels, snails, crayfish

High diversity among land plants


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10.3 The Future of Biodiversity What are ways in which biodiversity is

protected?


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Ways to save species Captive Breeding Programsbreeding in

captivity and then reintroducing thepopulation back into its natural habitat I.e.California Condor

Preserving Genetic Materialstoring germ

plasm (reproductive cells of plants andanimals)

Zoos, Aquariums, Parks and Gardensoften house the last remaining individualsof a species

museums of the worlds biodiversity Problems with these methods:

sometimes captive species dont reproduce

small populations are vulnerable to geneticdisorders from inbreeding

these methods should be a last resort


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Preserving habitats and ecosystems Most effective way is to

preserve habitats which oftenmeans preserving large areasof land

Conservation strategies Protect entire ecosystems rather

than individual species

Focus on worlds hotspots

More study needed How large does a protectedpreserve have to be?

How much fragmentation canan ecosystem tolerate?


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Legal Protections US Laws

1973 Endangered Species Act

Established list of threatened and endangeredspecies

Protects any endangered species from human harm

guilty parties are fined Prevents the govt. from carrying out any project

that threatens an endangered species

Establish recovery plans

Recovery and Habitat Conservation Plans

Usually compromises between human interestsand species interests

Habitat conservation planattempts to protectone or more species across large areas of landthrough trade-offs


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International Cooperation IUCNInternational Union for the Conservation of

Nature and Natural Resources

International Trade and Poaching CITES Treatyplaced ban on trade of ivory stopping the

slaughter of African elephants

The Biodiversity Treaty Created in Earth Summit

Preserve biodiversity and ensure the sustainable and fair use ofgenetic resources in all countries

Objected to by some political groups

Private Conservation Efforts World Wildlife Fund Nature Conservancy

Conservation International

Greenpeace


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Balancing Human Needs Sometimes endangered species represent a

food source or source of income

Species not valued or understood

Development of land for human use /

economic use vs. Preservation of habitats

Ch 10 Biodiversity

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