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Lesson Overview

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Lesson Overview 6.3 Biodiversity – PowerPoint PPT presentation

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Title: Lesson Overview


1
Lesson Overview
  • 6.3 Biodiversity

2
The Value of Biodiversity
  • Biological diversity, or biodiversity ? is the
    total of all the genetically based variation in
    all organisms in the biosphere.
  • Types of Biodiversity
  • ecosystem diversity,
  • species diversity,
  • genetic diversity.

3
Types of Biodiversity
  • Ecosystem diversity ?the variety of habitats,
    communities, and ecological processes in the
    biosphere.

4
Types of Biodiversity
  • Species diversity? The number of different
    species in the biosphere, or in a particular
    area.
  • Biologists have identified and named more than
    1.8 million species,
  • Biologists estimate that at least 30 million more
    are yet be discovered.

5
Types of Biodiversity
  • Genetic diversity? sum total of all different
    forms of genetic information carried by a
    particular species, or by all organisms on Earth.
  • Ex. Within each species, genetic diversity refers
    to the total of all different forms of genes
    present in that species.

6
Valuing Biodiversity
  • It is one of Earths greatest natural resources.
  • When lost, significant value to the biosphere and
    to humanity may be lost along with it.
  • Benefits to society include contributions to
  • medicine and agriculture,
  • the provision of ecosystem goods and services.

7
Biodiversity and Medicine
  • Wild species are the original source of many
    medicines.
  • ex. a foxglove plant contains compounds called
    digitalis that are used to treat heart disease.
  • The genetic information carried by diverse
    species is like a natural library from which we
    have a great deal to learn.

8
Biodiversity and Agriculture
  • Wild plants may carry genes we can usethrough
    plant breeding or genetic engineeringto transfer
    disease or pest resistance, or other useful
    traits, to crop plants.
  • Ex. wild potatoes in South America come in many
    colorful varieties.

9
Biodiversity and Ecosystem Services
  • Ex. When the otter population falls, the
    population of its favorite prey, sea urchins,
    goes up.
  • The number and variety of species in an ecosystem
    can influence that ecosystems stability,
    productivity, and value to humans.
  • The presence or absence of a single keystone
    species, like the sea otter, can completely
    change the nature of life in an ecosystem.?Ex?
  • Also, healthy and diverse ecosystems play a vital
    role in maintaining soil, water, and air quality
  • Population increases in sea urchins cause a
    dramatic decrease in the population of sea kelp,
    the sea urchins favorite food.

sea kelp
10
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11
Threats to Biodiversity
  • Species diversity is related to genetic
    diversity.
  • The more genetically diverse a species is, the
    greater its chances of surviving disturbances.
  • So as human activity reduces genetic diversity,
    species are put at a greater risk for extinction.
  • Species diversity is also linked to ecosystem
    diversity.
  • As ecosystems are damaged, the organisms that
    inhabit them become more vulnerable to
    extinction.
  • As species disappear, the potential contribution
    to human knowledge that is carried in their genes
    is lost.

12
How do humans reduce biodiversity?
  • Humans reduce biodiversity by
  • altering habitats,
  • hunting,
  • introducing invasive species,
  • releasing pollution into food webs,
  • contributing to climate change.

13
Altered Habitats
  • Eliminating natural habitat for agriculture or
    for urban development.
  • The development often splits ecosystems into
    pieces, a process called habitat fragmentation
  • Habitat fragmentation creates biological
    islands.
  • A biological island can be any patch of habitat
    surrounded by a different habitat.

14
Hunting
  • Some animals are hunted for
  • Meat, valuable hides or skins, or hunted to be
    sold as pets.
  • Hunted species are affected even more than other
    species by habitat fragmentation because
    fragmentation increases access for hunters and
    limits available hiding spaces for prey.
  • The Convention on International Trade in
    Endangered Species (CITES) bans international
    trade in products from a list of endangered
    species.

15
Introduced Species-invasive species
  • They can become invasive and threaten
    biodiversity.
  • Ex. One European weed, leafy spurge, infests
    millions of hectares across the Northern Great
    Plains.
  • Leafy spurge displaces grasses and other food
    plants, and it can sicken or kill cattle and
    horses.

16
Pollution-Many pollutants threaten biodiversity.
  • Ex. DDT ?prevents birds from laying healthy eggs.
  • Ex. Acid rain places stress on land and water
    organisms.

17
Climate Change
  • Prevents organisms from adapting to their
    environments
  • have specific tolerance ranges to temperature and
    other abiotic conditions.
  • If conditions change beyond an organisms
    tolerance, the organism must move to a more
    suitable location or face extinction.

18
Protecting Individual Species
  • The Association of Zoos and Aquariums (AZA)
    oversees species survival plans (SSPs) designed
    to protect threatened and endangered species.

19
Preserving Habitats and Ecosystems
  • Global conservation? the goal is to preserve the
    natural interactions of many species.
  • Governments and conservation groups work to set
    aside land as parks reserves.
  • The United States has
  • national parks,
  • forests, and other protected areas.
  • Marine sanctuaries are being created to protect
    coral reefs and marine mammals.

20
Preserving Habitats and Ecosystems
  • An ecological hot spot is a place where
    significant numbers of species and habitats are
    in immediate danger of extinction.
  • By identifying these areas, ecologists hope that
    scientists and governments can better target
    their efforts to save as many species as possible.
  • This is the Tonle Sap
  • a combined lake and river system in Cambodia.
  • the largest freshwater lake in Southeast Asia
  • an ecological hot spot that was designated as a
    UNESCO biosphere in 1997.
  • The floodplain provides a perfect breeding ground
    for fish.

21
Preserving Habitats and Ecosystems Ecological
Hot spots (shown in Red)
22
Considering Local Interests
  • The following are ways that people help protect
    biodiversity
  • The United States government, has offered tax
    credits to people whove installed solar panels
    or bought hybrid cars.
  • Many communities in Africa, Central America, and
    Southeast Asia have set aside land for national
    parks and nature reserves, like Thailands
    Elephant Nature Park, to attract tourist dollars.
  • In some Australian communities, farmers were paid
    to plant trees along rivers and streams as part
    of wildlife corridors connecting forest
    fragments.

23
Considering Local Interests
  • The use of carbon credits is one strategy aimed
    at encouraging industries to cut fossil fuels
    use.
  • Companies are allowed to release a certain amount
    of carbon into the environment. Any unused carbon
    may be sold back at a set market value or traded
    to other companies.
  • This strategy encourages industries to pay for
    lower-emission machinery and to adopt
    carbon-saving practices.

24
Carbon Credits
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