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