Chapter 5.1

BIODIVERSITY

Biodiversity

• Refers to the variety of life in an area• The most common measure of biodiversity

is the number of different species in an area• Maintaining biodiversity is important

because if a species is lost from an ecosystem, the loss will have consequences for other species in the same area

Which Has Greater Biodiversity?

Now which has greater Biodiversity?

Where is the most biodiversity?

• Biodiversity increases as you move towards the equator

• Climate (warm longer & more rain) means more variety of plants

• More producers mean more food for consumers

• Tropical regions contain 2/3s of all land species on earth

Tropical Regions

Importance of Biodiversity

• We can appreciate its beauty

• Species are interdependent on each other

• A loss may have consequences for other living things when relationships are broken

Biodiversity brings Stability

• A pest could destroy all the cotton in a farmer’s field, but it would be harder for a single type of insect or disease to destroy all species in a rain forest

boll weevil

More Stability

• Instead of being clumped together, plants exist scattered in many parts of the rain forest

• This makes it more difficult for a disease to spread

• Ecosystems are stable if their biodiversity is maintained

Importance• Humans depend on other organisms for

needs

• Oxygen is supplied, Carbon Dioxide is removed

• Meats: beef, chicken, tuna, shrimp, pork, fish & other seafood

• Plants: from almonds to zucchini!

• Raw materials for clothes, furniture, bldgs

Importance - Health

• Many medicines come from unusual species of plants & animals

• The antibiotic penicillin comes from a mold

• The drug, cyclosporine, which prevents transplanted organ rejection, was discovered in a soil fungus

Medical Drugs from Plants

• The Rosy Periwinkle is the source of drugs for Hodgin’s disease & leukemia

• Found in Madagascar

Medical Drugs from Plants

• Taxol, a strong anti-cancer drug, was first discovered in the Pacific yew tree

Preserving Biodiversity

• Preserving biodiversity ensures there will be a supply of living things, some of which may provide future drugs or new food sources as our resources are used up

• Will a cure for HIV or cancer be found in the leaves of an obscure rain forest plant?

Loss of Biodiversity

Extinction• The disappearance of a

species when the last of its members dies

Extinct Species

Dodo bird

Passenger pigeon

Steller’s Sea Cow

Tazmanian Tiger T-Rex

Saber toothed Tiger

Endangered

• A species is considered an endangered species when its numbers become so low that extinction is possible

Endangered Species

California Condor Sea turtle American Alligator

Bald EagleSilverback Mtn Gorilla

Endangered

Ferret & Prairie Dog

• The black footed ferret eats mostly prairie dogs

• Farmers killed prairie dogs because they were pests

• The ferret almost became extinct from lack of food

Threatened

• A species is considered threatened when the population has decreased in number and it may become endangered

Threats to Biodiversity

• Changes to habitats

Naturally or caused by humans

Habitat Loss

• This is one of the biggest reasons

• Rain forests cleared to farm

• Land cleared for housing

• Trees cut down for timber

Habitat Fragmentation

• Is the separation of wilderness areas from other wilderness areas

• Fragmented areas are similar to islands• Less biodiversity• Genetic isolation• Food & mate scarcity• Succession difficult-species can’t move

back in (separated)

Fragmentation

Pandas

• Habitat Loss and Fragmentation: The habitat is limited to the bamboo forests, they are being increasingly depleted. Those remaining have been isolated from each other, and this hinders the migration of panda bears.

• They are also losing their habitat due to China's increasing population that is using up their resources very rapidly.

Habitat Degradation

• Damage to a habitat by air, water or land pollution

• Air pollutants – breathing• Acid rain – pH changes in

water, effects plant growth, trees dying

Effects of Acid Rain

Degradation

Water & Land Pollutants

• Excess fertilizers, detergents, industrial chemicals get into lakes, streams, rivers

• Landfill waste gets into groundwater

• Pesticides enter food chain

Exotic Species

• A non-native species in an area• May take over niches of native

species in an area and eventually replace them

• Introduced intentionally or unintentionally

Sea Lamprey

• Erie Canal gave it a path from sea to Great Lakes

• Clamps onto fish’s body & sucks its fluid out

• Has totally eliminated certain fish species from Great Lakes

Other Invasive Exotic Species

Snakehead Fish