Biological Diversity

Objectives:

1. Define biodiversity and distinguish between species richness, genetic diversity, and ecological diversity.

2. Describe several important ecosystem services provided by biodiversity.

Biological Diversity

Biodiversity

Species Richness - # of species

Genetic Diversity- variation within a population of species

Ecosystem Diversity- variety of interactions among organisms in communities

Biological DiversityGenetic Diversity in Corn

Biological Diversity

Why We Need Organisms

• Ecosystem Services and Species Richness

Maintains smaller fish populations by eating gar

Digs underwater holes used by other aquatic organisms

Gator trails clear out aquatic vegetation

Nests eventually become small islands of trees

Biological Diversity – GOOD STUFF!• Ecosystem Services

– Forests maintain freshwater supplies, reduce floods, and prevent erosion

– Plants depend on insects for pollination– Soil fertility– control pests and disease-carrying organisms– Decomposers recycle nutrients in ecosystems

• Genetic variablilty is important to the long-term health of a species

• Genetic diversity is utilized in genetic engineering applications

• Organisms are used for medicines, agriculture, and industrial products

• Aesthetic, Ethical value or organisms

Biodiversity and Human Health

• Organisms have a role in maintaining clean fresh water supplies

• Biodiversity keeps populations of disease carrying organisms from increasing

• Organisms are sources of medicines and foods.• Organisms serve as medical models that help

scientists understand physiology and disease.• Certain organisms sensitive to environmental

pressures can warn of potential threats to human health.

Endangered and Extinct Species

Extinction – elimination of a species from Earth (irreversible?)

Background extinction – a continuous low-level rate of extinction that has occurred throughout Earth’s history

Mass extinction – numerous species become extinct over a geologically short period of time.

Endangered and Extinct Species

Background Extinction vs. Mass Extinction

Continuous, slow rate of extinction over millions of years

Numerous species disappear over geologically short time frame.

Endangered and Extinct Species

Endangered and Threatened Species

Could become extinct soon.

Population declining very fast.

5 Mass Extinction Events

5 Mass Extinction Events

Ordovician – 440 million years ago•Massive glaciation – water locked up in the form of ice/drastic decline in sea level•Many marine organisms disappeared (85%)

Cause: Climate Change

5 Mass Extinction Events

Late Devonian –•359 million years ago•75 % of all species disappeared

Possible causes: asteroid, comet, or meteor impact climate change

5 Mass Extinction Events

Permian•250 million years ago•95 % of all species disappeared•Largest extinction event

Possible causes:•Impact event (asteroid)•Catastrophic methane release•Flood basalt eruptions•Drop in oxygen levels•Sea level fluctuation

5 Mass Extinction Events

Triassic-Jurassic•200 million years ago•50 % of species disappeared•Mainly effected animals rather than plants

Possible causes:•Climate change•Flood basalt eruptions•Impact event

5 Mass Extinction Events

Cretaceous-tertiary•65 million years ago•Famed for the extinction of dinosaurs•Many other species also disappeared.

Possible causes:•Flood basalt eruptions causing climate change, subsequent sea level decline, followed by an asteroid or comet impact

Are we in the middle of a 6th mass extinction event?

And will it include humans?

• Scientists estimate that the rate of extinction is currently 100 to 1000 times larger than the background extinction rate.

Endangered and Extinct Species

American Bald Eagle

•In 1963, there were only 417 nesting pairs in the lower 48 US states

•7500 nesting pairs in 2004

•Now listed as threatened species

Endangered and Extinct Species

Factors Leading to the Decline of Bald Eagles

1. Loss of habitat

2. Many were hunted for sport and to save commercial fishing

3. Slow rate of reproduction

4. DDT – contaminated food caused shells to be too thin for embryos to survive

Endangered and Extinct Species

Factors contributing to the recovery of Bald Eagles1. DDT was banned in the US in 19722. Bald Eagles were listed as an endangered

species when the Endangered Species Act was passed in 1973

3. Bald Eagles were bred in captivity4. Eggs were removed from nest in nature and

baby eagles were raised in wildlife refuges and returned to nature

5. Removal of eggs helped because eagles lay additional eggs to replace ones that were removed.

Which is more likely to become endangered?

The tiburon mariposa lily is only found on a single mountaintop in northern California

The common chicory is found on roadsides in Europe, North America, and Australia

Which is more likely to become endangered?

The california ground squirrel is a primary consumer that rarely travels more than 50 m from it’s burrow.

The california condor is a tertiary consumer that requires hundres of square kilometers to find an adequate supply of food.

Which is more likely to become endangered?

The American robin is found in all parts of North America

The Hawaii O’o is a bird found only in Hawaii.

Which Species is More Likely to Become Endangered?

The blue whale produces a single calf every other year..

The cane toad lays 8,000 to 25,000 eggs at a time.

Which species is more likely to become endangered?

The pacific salmon is a saltwater species that migrates to freshwater to spawn once and die.

The brown trout is a freshwater species that do not migrate to spawn and spawn numerous times throughout their lives.

Endangered and Extinct Species

Characteristics of Endangered Species

• Extremely small range

• Requiring large territories

• Living on islands

• Low reproductive success

• Specialized breeding areas

• Specialized feeding habits

Tiburon mariposa lily

California condor

Hawaii ‘O’ o

Blue whale

Green sea turtle

Giant panda