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BiodiversityBi 6a
16 June 2010 Biodiversity.ppt 1
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What is biodiversity?
Biodiversity:
is a term we use to describe the variety of life on Earth. It refers to the wide variety of ecosystems and living organisms: animals, plants, their habitats and their genes.
16 June 2010 Biodiversity.ppt
Biodiversity
1.7—2.0 million species identified Estimate :5-30 million
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Global Biodiversity Patterns
Species Rich
Tropical RainforestCoral ReefLarge Tropical LakesTropical Dry Habitat
Species Poor
Polar regionsDesertsOpen Oceans
16 June 2010 Biodiversity.ppt
Biodiversity
▪ High levels of biodiversity in tropical regions
Panama: > 500 species of breeding birds
▪ Arctic: 50-100 species▪ Dense concentrations
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WHY ARE THERE SO MANY SPECIES IN THE TROPICS?
1. Energy 2. Area 3. Long-term stability 4. Temp & Precipitation 5. Competition and specialization
16 June 2010 Biodiversity.ppt
Three levels of biodiversity
• Ecological diversity– different habitats, niches,
species interactions• Species diversity
– different kinds of organisms, relationships among species
• Genetic diversity– different genes &
combinations of genes within populations
16 June 2010 Biodiversity.ppt 7
Benefits of Biodiversity
Food and energy security
Increased diversity of genes within species e.g. as represented by livestock breeds or strains of plants, reduces risk from diseases and increases potential to adapt to changing climates.
Shelter Medicine 70,000 plant species
used in traditional and modern medicine
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Benefits of Biodiversity
Ecosystem services: a service people obtain from the environment. Ecosystem services are the transformation of natural assets (soil, plants and animals, air and water) into things that we value.
The value of global ecosystem services is estimated at $16-$64 trillion
Ex. Declining honeybees-> pollination loss
16 June 2010 Biodiversity.ppt
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Benefits of biodiversity
Genetic diversity is important in terms of evolution.
The loss of individuals,populations, and species decreases the variety of genes—the material needed for species and populations to adapt to changing conditions or for new species to
16 June 2010 Biodiversity.ppt
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Biodiversity in crisis
the diversity of nature cannot support the current pressure that humanity is placing on the planet.
70% of coral reefs are threatened or destroyed. 18,788 species out of 52,017 so far assessed are
threatened with extinction. 1,895 of the planet’s 6,285 amphibians are in
danger of extinction, making them the most threatened group of species known to date.
16 June 2010 Biodiversity.ppt
Threats to Biodiversity
Extinction and population reductions Hunting and overharvesting
▪ Tiger▪ Dodo▪ Whales▪ Sharks
Habitat loss -> human activity, population growth
population decreases
can’t predict what will happen
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Alteration in ecosystem composition
Loss or decline of species-> loss of biodiversity
Eliminating coyotes in Southern California->decrease in bird population
Bird eggs->raccoon-> coyote
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Non-native species
Disrupt entire ecosystems and decrease population of native species
Predators Infect ->
pathogens Competition
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Pathways
aircraft and air cargo Ship hulls, ballast water and ship
cargo hand-carrry/luggage Mail pet trade botanical gardens agriculture
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Brown Tree Snake
Brown Tree Snakes introduced to Guam in the 1950s. In less than 20 years they decimated bird, bat and lizard populations.
•On Guam--Caused one power outage every four days
•Estimated cost to Hawaii: $123 million
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Cost of Invasive species
Economic (direct & indirect) •Agricultural revenues = $300
million/year •Miconia in 2001 = Over $3 million •Salvinia = Over $1 million •Termite damage in 1995 = $150
million/year •Cost of safeguarding tourism =
Priceless($18.9 billion at risk from biting sand flies, malaria and more)16 June 2010 Biodiversity.ppt
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Human impact
Pollution-> affects all levels of biodiversity
Global climate change-> changes environmental conditions.
Species and population may be lost if they are unable to adapt to new conditions or relocate
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Much of the world's tropical rain forests are disappearing, resulting in a loss of habitat. What is one possible effect of this habitat reduction?
A. a decrease in biodiversity in the area
B. an increase in oxygen in the atmosphere
C. a decrease in land available for human use
D. an increase in the number of species in the area 16 June 2010 Biodiversity.ppt
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Nearly all of the fifty largest cities in the United States are located on the coastlines, major lakes, and rivers. The population growth of these cities has changed many wetlands that were a part of this environment. Which of these conditions is the DIRECT result of this alteration of wetland habitats?
A. increased stability B. increased speciation C. decreased emigration D. decreased biodiversity
une 2010 Biodiversity.ppt
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Which of the following tends to reduce biodiversity?
A. deforestation B. urbanization C. agriculture D. all of the above
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Which of the following best completes this statement? The more biodiversity in an ecosystem, the
A. less its stability and resiliency to continue.
B. greater its stability and resiliency to continue.
C. greater likelihood of depleted resources.
D. greater likelihood of mass destruction. 16 June 2010 Biodiversity.ppt
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