Bi 6a 16 June 2010Biodiversity.ppt1. Biodiversity: is a term we use to describe the variety of life on Earth. It refers to the wide variety of ecosystems

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


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


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


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


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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


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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.


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

Documents

Bi 6a 16 June 2010Biodiversity.ppt1. Biodiversity: is a term we use to describe the variety of life on Earth. It refers to the wide variety of ecosystems