1. Biodiversity
CHAPTER 5 LESSON 1 – P116-121

2. Biodiversity
• The variety of life in an area that is determined by the number of
different species there
• The greater the biodiversity the more stable an ecosystem is
• As species become extinct, biodiversity decreases and so does the
health of the ecosystem
• There are 3 types of biodiversity:
• Genetic Diversity
• Species Diversity
• Ecosystem Diversity

3. Genetic Diversity
• The variety of genes or inheritable traits in a
population
• Visible Traits
• Color
• Shape
• Size
• Invisible Advantageous Traits
• Resistance to diseases
• Ability to recover from diseases
• Ability to get energy from new food sources if old ones
disappear

4. Genetic Diversity
• Increases a populations chance of survival during environmental
changes or disease
• Genetic differences may give some individuals advantages

5. Species Diversity
• The number of different species and the relative amounts of each
species in a biological community
• A habit with many species present at healthy numbers has high
species diversity
• Species diversity changes across ecosystems and biomes
• Polar regions have low species diversity
• Areas near the equator have high species diversity

6. Ecosystem Diversity
• The variety of ecosystems that are present in the biosphere
• Ecosystems include interacting populations and abiotic factors
• Different abiotic factors support different types of life
• Tropical rainforest have abiotic factors necessary to support tropical bird species
• The loss of ecosystem diversity would likely result in a decrease in species
diversity

7. The Importance of Biodiversity

8. Direct Economic Value
• There are several reasons to preserve biodiversity
• Direct Resource Value
• Organisms we use for food, clothing, medicine, energy, and shelter
• Direct Genetic Value
• Organisms we do not use readily (wild species)
• Provide sources of desirable traits
• Possible transfer of desirable genes by genetic engineering
• Resistance to insects
• Increased nutritional value
• Resistance to spoilage

9. Direct Economic Value
• Medicine
• Many medicines today are derived from plants
• Many species may have medicinal value that have not be
discovered yet
• Agriculture
• The world’s food crops come from just a few species
• Little genetic diversity
• Transferring of genes by genetic engineering has helped
many crops
http://www.businessinsider.com/10-crops-that-feed-the-
world-2011-9?op=1

10. Direct Economic Value
• Example: Teosinte and Corn
• Teosinte is a distant relative of the corn we eat
• Teosinte is a wild plant with no direct resource value
• Later scientists found that teosinte is disease-resistant against a viral
disease that was damaging corn crops
• Using teosinte, scientists made disease-resistant corn varieties
• http://www.hhmi.org/biointeractive/breeding-corn-teosinte

11. Indirect Economic Value
• A healthy biosphere provides many services to humans
• Green plants make oxygen
• Removal of carbon dioxide
• Natural processes clean drinking water
• Protect against floods and droughts
• Generate and preserve fertile soils
• Detoxify and decompose wasters
• Regulate climate
• These advantages are difficult to attach economic value

12. NYC Watershed
• In the 1990s NYC wanted to improve the
quality of its drinking water
• NYC’s drinking water was supplied by the
Catskill and Delaware Watersheds that were
highly polluted
• The city had two options:
• 1. Build a new filtration system for 6 billion dollars
• 2. Clean up and preserve the watersheds for 1.5 billion
dollars
• The answer was clear.
• Often, preservation of a healthy ecosystem can
provide the same services as technology but at
less expensive costs and long lasting results.

13. Aesthetic and Scientific Values
• It is difficult to determine the economic value of having a beautiful and
healthy ecosystem
• It’s also difficult to find the economic value of studying healthy ecosystem
and how to protect them.

14. Threats to Biodiversity

15. Extinction Rates
• Many species become extinct because of natural processes like climate
change, other organisms, or natural disasters.
• These occurred even before humans existed
• This natural gradual process of extinction is known as background
extinction.
• These types of extinctions are normal and not what scientists are concerned about.

16. Extinction Rates
• Many scientists are worried about the recent increase in the rate of
extinction.
• Some estimate the current rate of extinction is 1000 times the normal
background extinction rate.
• Most of these extinctions are occurring near the equator.

17. Extinction Rates
• Some scientists believe we are witnessing a period of
mass extinction.
• A large percentage of living species become extinct in a short amount
of time
• Scientists predict 1/3 to 2/3s of all plants and animals will become
extinct in the second half of the century.
• The last mass extinction happened 65 million years ago when the last
remaining dinosaurs died out.

18. Extinction Rates
• Island species are most vulnerable to extinction.
• Many evolved with no natural predators
• New nonnative species can bring diseases
• Relatively small population sizes
• Species rarely travel between islands

19. Factors That Threaten Biodiversity
• Today’s current rate of extinction is different from past mass extinctions.
• Why is it special?
• After a mass extinction in the past, new species evolved and biodiversity
recovered over time (several millions of years)
• Today, humans are changing the conditions on Earth faster than new traits
can evolve to adapt
• Evolving species might not have the natural resources they need
• Minerals, fossil fuels, nuclear energy, plants, animals, soil, clean water and air, solar energy

20. Factors That Threaten Biodiversity
• 8 factors that threaten biodiversity:
• 1. habitat loss
• 2. destruction of habitat
• 3. disruption of habitat
• 4. overexploitation
• 5. fragmentation of habitat
• 6. Pollution
• 7. Acid Rain
• 8. Eutrophication

21. Overexploitation
• The excessive use of species
that have economic value
• Overhunting
• Bison
• Passenger pigeons
• Ocelot
• White rhinoceros
• Historically, overexploitation
was the primary cause of
species extinction.

22. Habitat loss
• Destruction of Habitat
• Clearing of rain forests
• Over half of all species live in the tropical rain forest

23. Habitat loss
• Disruption of Habitat
• Factors that cause a decline of an important species
• When one species plays a large role in an ecosystem, that species is
called a keystone species
• California Sea Otter
• Pisaster Starfish

24. Habitat loss
• Fragmentation of habitat
• The separation of an ecosystem into small pieces of land
• Unable or unwilling to cross human barriers

25. Habitat loss
• Fragmentation of habitat
• Consequences:
• Smaller land = fewer species it can support
• Decreased genetic diversity
• Less able to resist disease and respond to environmental
changes
• Edge effect
• Carving a large ecosystem into smaller pieces increases the
number of edges
• Conditions change along the boundaries of an ecosystem
• Temperature, wind, humidity

26. Pollution
• Pollution changes the composition of air, soil, and water
• Threaten biodiversity and global stability
• Types:
• Substances
• Acid precipitation
• Eutrophication
• Introduced species

27. Pollution: Substance
• Man-made chemicals
• Pesticides (DDT) and industrial chemicals like (PCBs)
• Polluted drinking water
• Eating other organisms that contain toxic substances
• Some substances can be digested or excreted
• Some substances accumulate in the tissues
• Harmful to organisms
• DDT -> thin weak eggshells

28. Pollution: Substance
• Biological Magnification
• The increase of toxic substances in
organisms as you go up the tropic
levels

29. Pollution: Acid Precipitation
• When fossil fuels are burned sulfur dioxide and nitrogen dioxide are
released into the air
• These compound react with water to form sulfuric acid and nitric acid
• These acids fall to Earth as rain, sleet, or snow
• Removes calcium, potassium, and other nutrients from the soil
• Damages plant tissues and slows growth
• High acid concentrations in lakes and rivers cause organisms to die

30. Pollution: Eutrophication
• Fertilizers, animal waste, sewage, or other substances rich in nitrogen and
phosphorus flow into waterways causing extensive algae growth
• Algae use up the oxygen supply
• Growth
• Decomposition
• Other organisms suffocate
• Eutrophication can occur naturally
• Humans accelerate normal rates

32. Pollution: Introduced Species
• Nonnative species are any species that has been transported to a
new habitat
• In their new habitats they lack natural predators, parasites, and
composition for resources
• Often leads to increased reproduction
• When a nonnative species threatens the biodiversity of an area
they are called invasive species