biodiversity biological diversity or “biodiversity” = the sum of the genetically based variety...
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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
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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!
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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
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
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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
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