NIS - BIOLOGY

Lecture 18Biodiversity

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What is Biodiversity

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Look at the pictures below and state which species is the most abundant, which is less abundant.

What is Biodiversity

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Biodiversity is the variety of life in an area that is determined by the number of different species in that area.Entire species may permanently disappear from the biosphere in a process called extinction.Extinction reduces biodiversity.What do we mean by variety of life?Three types of biodiversity:

Genetic diversitySpecies diversityEcosystem diversity

Genetic Diversity

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The variety of genes or inheritable characteristics that are present in a population comprises its genetic diversity.The variety of colors demonstrates a form of genetic diversity.Some characteristics are not as apparent as color.The ability to to recover from a diseaseThe ability to to obtain nutrients from a new food source etc.

Species Diversity

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The number of different species and the relative abundance of each species in a biological community is called species diversity.As you move from the polar regions to the equator, species diversity increases.How many different species can you identify in the picture?

Ecosystem Diversity

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The variety of ecosystems that are present in the biosphere is called ecosystem diversity.Different locations around hte world have different abiotic factors that support different types of life.

The Importance of Biodiversity

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Why is conserving biodiversity important?What benefits do we get by conserving biodiversity?

Economic value:Conserving genetic biodiversity might be helpful in the future to improve domestic crop species. Example: Teosinte corn plantsBeing able to transfer genes makes it extemely important to maximize the variety of genes.Deriving medicines from plants and other organisms.

The Importance of Biodiversity

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Aesthetic and scientific value:Beauiful species and ecosystems.. Scientifically interesting to study.

NIS - BIOLOGY

Lecture 19Threats to Biodiversity

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Extinction RatesCheck these out!http://video.nationalgeographic.com/video/inde

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How long did the dinosaurs live on Earth?Were they biologically diverse?How did they become extinct? Did they become extinct by time or all of a sudden?How do we call it if there is a sudden extinction of a species?Dinosaurs became extinct by mass extinction.Mass extinction is an event in which a large percentage of all species become extinct in a relatively short period of time.Table 5.1

Extinction Rateshttp://video.nationalgeographic.com/video/inde

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How many tigers were living about 15 years ago? How many tigers live now?Why did they decrease in number?What term do we use for the species close to extinction?Assuming that in the next decade these tigers become extinct, is there any similarity between the extinction of the dinosaurs and the extinction of these tigers? What is the difference?The gradual process of species becoming extinct is known as background extinction.

Extinction Rates – Background ExtinctionStable ecosystems: Natural process of extinction by the activity of other organisms, climate changes or natural disasters.This natural process of extinction is not a big concern.Increase in the rate of extinction is a big concern!Some scientists predict that between 1/3 or 2/3 of all animal and plant species will become extinct by the end of this century.Check out Table 5.2 to see the number o fextinctions since 1600.Why are species on islands are more vulnerable to extinction? 12

Factors that Threaten BiodiversityWhat is the main reason for these high rates of extinction?

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Homo SapiensActivities of homo sapiens change the conditions on Earth faster than new traits can evolve to cope with the new conditions.After a mass extinction, new species can evolve over time and biodiversity recovers.But as humans change the conditions faster than evolving rate of species, biodiversity cannot recover.Humans also use up the natural resources for their own need, leaving not enough to some other species.Natural resources are all materials and organisms found in the biosphere, including minerals fossil fuels, nuclear fuels, plants, animals, soil clean water, clean air and solar energy.

Factors that Threaten Biodiversity - Overexploitation

OverexploitationOverexploitation is the excessive use of species that have economic value.Example: Bisons in North America have been hunted to the brink of extinction because of their meat and hides. They were also hunted for sports.

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Factors that Threaten Biodiversity - Overexploitation

Other examples subject to overexploitation:Passenger pigeonsOcelotWhite rhinoceros

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Factors that Threaten Biodiversity – Habitat Loss

Habitat LossThere are several ways that species can lose their habitatIf a habitat may be destroyed or disrupted, the native species might have to relocate or they will die.

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Destruction of habitat: The clearing of tropical rainforest has a direct impact on global biodiversity.Tropical rainforests are being cleared for agriculture, grazing animals etc.More than half of all species live in the tropical rainforests and the removal of the rainforests will cause many species on Earth to become extinct.

Factors that Threaten BiodiversityDisruption of habitat: Habitats might be disrupted.How does a decline in the number of sea lions and harbor seals affect other species in Figure 5.11?

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Fragmentation of Habitat:The separation of an ecosystem into smaller pieces of land is called habitat fragmentation.A habitat can be fragmented by constructing roads or human made barriers.If a parcel of land is smaller, it supports fewer species.

Factors that Threaten Biodiversity – Habitat Fragmentation

Fragmentation reduces the opportunity to reproduce with individuals from another area.Fragmentation also increases the number of parcels that have edges creating edge effects.Edge effects are different environmental conditions that occur along the boundaries of an ecosystem.For example: Edges of a forest near a road have different abiotic factors than the interior of a forest.

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Factors that Threaten Biodiversity –Pollution

Pollution and atmospheric changes threaten biodiversity and global stability.Many types of pollution: Air pollution, water pollution, soil pollution etc.Human made dangerous chemicals, pesticides such as DDT, are ingested by organisms when they drink water or eat other organisms that contain the chemical. These dangerous chemicals accumulate in the tissues of organisms.

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Factors that Threaten Biodiversity – DDTCarnivores at the higher trophic levels seem to be most affected by this accumulation because of a process called biological magnification.Biological magnification is the increasing concentration of toxic substances in organisms as trophic levels increase in a food chain or food web.Check out Figure 5.13How exactly does DDT threaten the survival of the fish eating birds?

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Factors that Threaten Biodiversity – DDT

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Factors that Threaten Biodiversity –Pollution

Acid precipitation: When fossil fuels are burned, sulfur dioxide is released into the atmosphere.Also, fuels burned in automobile engines release nitrogen oxides in to the atmosphere.These compounds react with water and other substances in the air to produce sulfuric and nitric acid.By precipitation these acids eventually fall back on the surface of Earth and damage plants and other species in the soil by removing potassium calcium and other nutrients.

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Factors that Threaten Biodiversity – Pollution

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Factors that Threaten Biodiversity –Pollution

Eutrophication: A form of water pollution, called eutrophication, destroys underwater habitats for fish and other species.Eutrophication occurs when fertilizers, animal waste, sewage or other substances rich in nitrogen and phosphorus flow into waterways.These substances in water result in rapid algae growth.These algae use up most of the oxygen available in the water.Other organisms in the water, as a result, suffocate.Eutrophication is a natural process but human activities (dumping sewage, fertilizers in waterways etc.) accelerate the rate at which it occurs. 24

Factors that Threaten Biodiversity – Pollution

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Factors that Threaten Biodiversity –Introduced Species

Introduced species: Nonnative species that are either intentionally or unintentionally transported to a new habitat are known as introduced species.Under normal conditions, predators, parasites and competition between species keep the native ecosystem in balance.When new species are introduced into a new area, these controlling factors are not in place.Introduced species reproduce in large numbers and because of a lack of predators and become invasive species in their new habitat.Check Figure 5.15 for imported fire ants in the US.

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Factors that Threaten Biodiversity –Introduced Species

http://video.nationalgeographic.com/video/index.html?widgets=unknown%7cSyndicatedVideoPlayer

What do cane toads eat?When and why were they brought to Australia?Why and how are they dangerous to the other species?What term do we use for the species like cane toads?Why is it bad to introduce new species to an ecosystem?

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Factors that Threaten BiodiversityAssignment due Friday:Choose one of the factors that threatens biodiversity below and write an informative essay on it.

Overexploitation (bisons)Habitat loss (tropical rainforests)Pollution (acid rain)Introduced Species (fire ants)

Your essay should be more than 400 words typed in MS Word (Times New Roman, 12, 1.5 paragraph)Include at least 2 pictures in your essay.Give as many relevant information as you can without sacrificing consistency.Make 5 copies of your essay and bring them with you on Friday to be distributed to each person in the class.

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NIS - BIOLOGY

Lecture 20Conserving Biodiversity

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Natural ResourcesMore than 6 billion humans on EarthIncrease in human population ----> Increase in the need for natural resources

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Look at the pictures and try to identify which resources are very limited in supply and which are not as limited as others.

Renewable ResourcesThe resources that are replaced by natural processes faster than they are consumed are called renewable resources.Example: Solar energy, clean air, clean water, agricultural plants and animals etc.The supply of these resources are NOT unlimited.If the demand exceeds the supply of any resource, the resource might become depleted.

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Nonrenewable ResourcesThe resources that are found on Earth in limited amounts or those that are replaced by natural processes over extremely long periods of time are called nonrenewable resources.Example: Fossil fuels, mineral deposits etc.Species are considered renewable resources until the last of a species die (it is lost forever)

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Use of Natural ResourcesThe consumption rate of natural resources is not evenly distributed. Check out Figure 5.16!Developed countries consume more natural resources than developing countries. Why?

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As the human population increases, a long-term plan for the use and conservation of natural resources is important.One approach is sustainable use.Sustainable use means using resources at a rate in which they can be replaced or recycled while preserving the long-term environmental health of the biosphere.Reducing the amount of resources consumed, recycling and preserving ecosystems.

Protecting BiodiversityWe know from Section 5.2 that human activities affect ecosystems.Many efforts are underway worldwide to slow the loss of biodiversity and to use natural resources sustainably.International Protected AreasBiodiversity Hot Spots: (Figure 5.19)

Endemic species are species that are only found in that specific geographic location.There must be at least 1500 species of vascular plants tha tare endemic.The region must have lost 70% of its original habitat.

Corridors Between Habitat Fragments 34

Protecting BiodiversityBiodiversity Hot Spots

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Restoring EcosystemsCheck out Figure 5.21 and try to interpret the graph.How long does it take to recover from some human caused disasters?What are the ways to speed up this recovery time?

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Bioremediation: The use of living organisms, such as prokaryotes, fungi or plants to detoxify a polluted area is called bioremediation.Example: Oil spillsBiological augmentation: Adding natural predators to a degraded ecosystem is called biological augmentation.Example: Ladybugs eating aphids, which transmit plant diseases that destroy crops.