Biodiversity

Biodiversity• Biological diversity or “Biodiversity” = the sum of the

genetically based variety of all organisms in the biosphere• Our existence relies on a great variety of other organisms.• Some branches within biodiversity:

– Ecosystem diversity = variety of habitats, communities, and ecological processes in the ecosystem

– Species diversity = number of different species in the system

– Genetic diversity = total of all the different forms of genetic information carried by all organisms present

Insects

BacteriaFungi

Plants

Protists Other Animals

54.4%

4.2%

18%

3.4% 0.3%

19.7%

Section 6-3Species Diversity

Go to Section:

Value of Biodiversity

• Biodiversity is one of Earth’s greatest natural resources providing us with food, industrial products, and medicines (painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs)

• When biodiversity is lost, potential sources of material with significant value to the biosphere and to humankind may be lost.

• Think of biodiversity as a library- lost species are essentially lost books that can’t be replaced.

Solar energy

Production of oxygen

Storage and recycling of nutrients

Regulation of climate

Purification of water and air

Storage and distribution offresh water

Food production

Nursery habits for wildlife

Detoxification of human andindustrial wasteNatural pest and disease controlManagement of soil erosionand runoff

Section 6-4

Ecosystem services are provided, but it’s your responsibility to help save the Earth!

Go to Section:

Threats to BiodiversityHuman activities can reduce biodiversity by:

Habitat alterationHunting species to extinction

Extinction = occurs when a species disappears from all or part of its range

Endangered species = species in danger of extinction with declining population sizes

As the population declines, the species loses genetic diversity, making it more vulnerable to extinction

Introducing toxic compounds (pollutants) into food webs

Introducing foreign species to new environments

Habitat Alteration & Fragmentation• When land is developed, natural habitats may

be destroyed and the species that live in those habitats may vanish

• Habitat fragmentation = development of land that splits ecosystems into pieces resulting in biological “islands” with fewer species and smaller populations more vulnerable to further disturbances or climate changes– Reduces habitat space– Restricts movement– Reduces diversity

Fragmentation

Hunting/Wildlife Products• In the past, hunting for meat, fur, hides or other body

parts caused the extinction of some species• Today, endangered species are protected from hunting by

laws in most of the world• Endangered Species- species in danger of going extinct.

Protected by international and local laws– Poaching- illegal harvest of wildife is still a major problem

• Bear gall bladders, ivory, shark fins, tiger bones, etc.

Pollution• Pollution can threaten biodiversity, because toxic

compounds accumulate in tissue of organisms– Toxic wastes, sedimentation, thermal pollution

• Biological magnification = increasing concentrations of harmful substances in organisms at higher trophic levels in a food chain/web– Entire food web is affected, but top-level carnivores are at

highest risk

Fish-Eating BirdsMagnification ofDDT Concentration

10,000,000

100,000

10,000

1,000,000

1

1000

LargeFish

Small Fish

Zooplankton

Producers

Water

Section 6-3

Biological Magnification of DDT

Go to Section:

Thermal Pollution• Thermal pollution: is the degradation of water quality by

any process that changes ambient water temperature– Power plants and industry using local water supplies to cool

during manufacturing.– The temperature of the discharge water is significantly warmer

than normal– Warmer water holds less Oxygen, supports less life

Introducing Foreign Species

Biodiversity is also threatened by apparently harmless plants and animals that humans transport around the world either accidentally or intentionally

Invasive species = organisms introduced into new habitats and reproduce rapidly (think exponential) lacking the parasites and predators that control population size in their native country They can displace native species driving them close to

extinctionEx. Zebra Mussels

Invasive species Non-native species

reduce diversity in ecosystem examples

African honeybee (killer bees) gypsy moth zebra mussel purple loosestrife Phragmites

kudzu

gypsy mothgypsy mothphragmites

Purple loosestrife

19681968 19781978

reduces diversity loss of food & nesting sites for

animals

reduces diversity loss of food & nesting sites for

animals

Zebra mussel

ecological & economic damage

~2 months

reduces diversity loss of food & nesting sites for

animals economic damage

reduces diversity loss of food & nesting sites for

animals economic damage

Brown Tree Snakes, Guam• This introduced snake has caused the extinction

on Guam of 12 of 14 forest bird species, two of three bat species, and at least six lizard species.– Grow up to 8-10 feet long. – Hatch at 15 inches can grow to 3 feet in one year

Guam Bird Populations

Conserving Biodiversity

• Conservation = wise management of natural resources

– Preservation of habitats and wildlife to protect Earth’s biodiversity for future generations, however protected areas may not be enough

• Current conservation efforts focus on protecting individual species as well as entire ecosystems (to ensure natural habitats and interactions among different species are preserved).

• Biodiversity “Hot spots” = places around the world where everything possible is being done to conserve the ecosystem and species

World Wide Hotspots