Biodiversity
Chapter 10
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Section 1 What is
Biodiversity
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 Biodiversity – the number of different species in a given area
 Tropical rain forests have highest biodiversity on earth
 Known species – species that are collected and described scientifically
 1.7 million species (most of which are insects)
 Unknown species – Species not identified as of yet, located in remote locations
 More than 2 million possible (to be identified)
 Levels of diversity
 Species diversity : Number of species in a given area (most commonly know as
biodiversity)
 Ecosystem diversity: All the different habitats and ecological processes in an
ecosystem
Genetic diversity: All the different genes in all the members of a population
 A gene is a part of DNA that determines one particular trait (blue eyes, widow
peak)
A World Rich in Biodiversity
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• Species are connected to ecosystems.
• Every species is either dependent on or depended upon by at least one other
species.
• Think food webs, niches
• Keystone species – critical to the entire ecosystem
• Sea Otters: loss of the otter - led to the loss of kelp beds
Benefits of Biodiversity
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Species and Population Survival
• Genetic diversity is critical to species survival.
• Environmental changes affect less diverse populations more
• Ice Age – species not adapted to cold die - but species with genes to survive
cold live on
• If no one in species had cold gene, all die
• But what happens to genes in all the species that died?
• All other genes lost
Bottleneck effect – When a
population is reduced to a few
members. Only certain genes get
through the event.
Benefits of Biodiversity
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• Medicines and cures are constantly being found as we locate new
species
• Industry finds new chemicals in all types of species
• Better resistant crops being made because of genetic crossing
• Ethics, Aesthetics, and Ecotourism
• Should we preserve species because they deserve to be here?
• Should we preserve species because they are nice to look at and make
our lives beautiful
• Ecotourism – a form of tourism that supports the conservation
and sustainable development of ecologically unique areas.
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• Time for a reading quiz
That’s all for 10.1
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Section 2 Biodiversity at
Risk
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• Mass extinction – extinction of many species in a short period of
time
• Five previous mass extinction events
• Due to global climate change
• Dinosaurs:
ice ages and meteorites
• Possible cause of the next (current??)mass extinction:
• Due to human activities
• From 1800 to 2100 up to 25% of all species may become extinct
• Endangered species – species that will go extinct if not
protected immediately
• Usually a small population in a limited habitat
• Threatened species – species will become endangered if not
protected
Current Extinctions
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• Habitat Destruction and Fragmentation
• We use land for homes and food
production
• In the process – we destroy and fragment
the habitats of other species.
• Habitat loss is causing 75% of all current
extinctions
• Florida Panther: one of the most
endangered species in North America (due
to habitat loss)
How Do Humans Cause
Extinctions
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Invasive species
• New species introduced to an environment
• Native species have no defenses, and new species have no predators
• Kudzu, Cane Toads, Fire Ants
• Harvesting, Hunting, Poaching
• Passenger pigeon hunted out of existence, bison close
• People want rare species as a pet, food, medicine
• Monkey brains, shark fins,
• Poaching – capturing protected species against the law
• Ex: elephants for ivory (tusk) ; tigers for healing properties
Pollution
• Chemicals being dumped have harmful effects on other species
Ex: DDT in the food chain caused bald eagle egg shells to weaken
• Bald eagle nearly extinct until DDT banned.
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How Do Humans Cause Extinctions
• Endemic Species – species that live in a small specific habitat
• Tropical Rain Forest
• Home to half of world’s species
• Most not yet observed, but losing them as we clear the rain forest for
farming and housing
• Coral Reefs – Most of biodiversity in ocean
• A major source of food and ecotourism
• In danger due to overfishing, and pollution
• Hot Spots – the most threatened areas of high diversity on Earth
• Madagascar, Philippines, Florida Everglades, California Coast,
Hawaii
• United States Biodiversity
• We have several of the hotspots (Florida Everglades / coastal regions)
• Are we taking care of them?
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Areas of Critical Biodiversity
• Time for a reading quiz
That’s all for 10.2
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Section 3 The
Future of
Biodiversity14
• When a species is nearing extinction what can be done to help?
• Captive breeding
• Species are bred in captivity (zoos or shelters) and will be released
into wild when enough are bred
• California Condor
• Preserving Genetic Material
• Germ plasm – genetic material from reproductive cells
• Stored (usually frozen) for future use.
• Same as heirloom tomato seeds!
• Zoos and Aquariums
• Not just for entertainment
• Home for endangered species
• Successful breeding programs - Pandas!
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Saving Species One at a Time
• Conservation Strategies
• Focus on whole ecosystem not individual species
• Restore native habitats and expand them
• Legal Protections - US
• Endangered Species Act – passed in 1973
• Fish and Wildlife Service must keep list of all endangered or threatened
species
• Endangered and threatened species cannot be caught or killed.
Endangered/threatened plants may not be uprooted
No part of an endangered/threatened species may be sold or traded
• US Government cannot do any projects that might impact listed species
• The U.S. Fish and Wildlife Service must prepare a species recovery plan
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Preserving Habitats and Ecosystems
Legal Protection – International
• IUCN – International Union for the Conservation of Nature and
Natural Resources
Advise governments on endangered species
Publishes a “Red Lists” of endangered species around the world
• CITES – Convention on International Trade in Endangered Species
• Elephant Ivory Tusks – Poachers after them
• CITES made a worldwide ban on selling ivory
• Elephant poaching dropped
• Biodiversity Treaty
• Agreement generated during the Earth Summit (1992 – Rio de Janeiro)
• Goal is to preserve biodiversity and ensure sustainable/fair use of
genetic resources in ALL countries
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• Time for a reading quiz
That’s all for 10.3
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