Biodiversity The degree of variation of life forms within a given ecosystem Biome Biosphere.

Biodiversity

The degree of variation of life forms within a given ecosystem Biome Biosphere

Largest forms of life

Smallest forms of life

Species Diversity

The number of species in a given area

Extinction

The end of a species of an organism No longer found on earth 800 plant and animal species in the past 500 yrs

Extinct animalsLabrador Duck (skunk duck)

1878: New York City Over harvesting by humans (hunting)

Extinct Species

Javan Tiger Indonesian Islands 1976 Human expansion Food source exhausted

(Rusa deer)

Bali Tiger 1937 Habitat loss Over harvesting

Extinct species

Tarpan (wild horse) Poland and Russia 1909

Extinct Species

North African ElephantEgypt and Mediterranean Used as war elephants

Extinct Species

Passenger Pigeon1914North America

Extinct Species

Dodo BirdLate 17th centuryIsland of Mauritius

Endangered Species

Endangered listA species whose numbers are so small that it

is at risk of extinctionArctic FoxArctic tundra (Alaska, Canada, Russia)

Pop. 100’s of thousands Climate change Fur harvesting Diseases from wild dogs

Endangered Species

Peregrine Falcon1650 breeding pairsU.S. and Canada: wide range

DDT and DDE (pesticides banned in the 1970’s) causes thinning of egg shells

Endangered Species

Killer WhaleLess than 50,000

Pollution and chemical contamination Makes them more susceptible to disease

Endangered Species

Monarch ButterflyNorth and Central America- migrate to

Mexico Harvesting lumber in the area Climate – changes migration area Loss of milkweed plants

Endangered Species

American AlligatorSoutheastern U.S.- 5 million

Climate change Loss of habitat Hunted for their skin

Endangered Species

American Bison (North America)500,000

Disease - Crossbreeding with cattle Hunting

Endangered Species

African and Asian Elephants450,000-700,000 African35,000-40,000 Asian

Habitat loss Tusk harvesting

Endangered Species

California Condor279 : 130 have been reintroduced into the

wildWestern U.S., Mexico, Canada

Lead poisoning Electrocution on power lines Poaching

Endangered Species

Mountain Gorilla700Virunga mountain region (East Africa)

Habitat loss due to human population growth Disease Poaching

Endangered Species

Woodland CaribouAlaska, Canada, British Columbia,

Washington2000

Habitat loss Climate change

Endangered Species

Black Rhino: 2,400White Rhino: 7,500Sumatran Rhino: 400Javan Rhino: fewer than 100Indian Rhino: more than 2,000 Poaching for horns

Endangered Species

OcelotNorth and South America800,000 – 1.25 million

Habitat destruction Fur harvesting

Endangered Species

Chimpanzee100,000 – 200,000African continent

Habitat destruction Commercial exploitation

Endangered Species

Giant PandaChina2000

Climate change affecting bamboo growth Habitat loss due to farming

Endangered Species

Koala BearAustraliaFewer than 100,000

Habitat destruction Hunted for furs Traffic accidents Attacked by domestic dogs

Reasons

PoachingPollutionPredationOver huntingLoss of habitatDiseaseIntroduction of a new speciesClimate changeNatural disasters

Hurricanes, volcanic eruptions etc.

Endemic Species

A species that is geographically isolated Native to the area

Endemic Species

Invasive Species

A species that does not naturally occur in a specific area Introduction causes harm to the rest of the ecosystem

Zebra MusselsDyer’s Woad

Cheatgrass

Keystone Species

A species that is vital to an ecosystemIf it becomes extinct the entire ecosystem will

be affected Prevents other species from dominating an ecosystem Maintain balance Maintain biodiversity Shape the land

Keystone Species

Mass Extinctions

99% of all species that have ever live are now extinct

Mass Extinction: when several groups of species die out due to a major ecosystem changing event Can affect land or sea life

1. Ordovician: 438 million years ago Cause: Ice Age 100 families extinct More than half of the bryozoan and brachiopod

species extinct

Mass Extinctions

2. Devonian: about 370 mya Cause: Global climate change: Ice Age or Warming

Period 19% of animal families extinct (mostly Aquatic)

3. Permian: about 245 myaLargest mass extinction

Causes? Climate change due to mass volcanic eruptions or plate tectonic movement

90% of all species

Mass Extinctions

4. Triassic: 210 mya Cause: Global Cooling: Ice Age or volcanic activity 28% of all animal families die out Most early dinosaur families went extinct

Mass Extinctions

5. Cretaceous-Tertiary (K-T): 65 mya Cause: meteor impact and/or volcanic eruptions About half of all life forms died out including

Dinosaurs Ammonites Many families of fishes Clams Snails Sponges Sea urchins

The 6th Extinction

1993: The Theory of the 6th Extinction Earth is losing an estimated 30,000 species per year

Human causesOnly extinction caused by biotic factors not

abiotic factors Pollution Habitat destruction Over harvesting Exploitation of resources (poaching) Introduction of invasive species