EcologyBiodiversity and Conservation

Textbook Chapter 5

Review Book Topic 6

What is Biodiversity?

• The variety of life in an given area

• Determined by the number of different species present

• High biodiversity increases the stability and health of an ecosystem

• Three types:– Genetic diversity– Species diversity– Ecosystem diversity

• Genetic diversity– Variety of genes or inheritable characteristics

(within DNA) that are present in a population

– Characteristic examples:• Color• Resistance to disease• Adaptability to the environment

– Within a population, genetic diversity ↑ the chances of survival during changing environmental conditions or threats of disease

• Species diversity

– Number of different species and the relative abundance of each within a community

– Not evenly distributed across the biosphere

• Increases from the polar caps to the equator

• Ecosystem diversity

– Variety of ecosystems within the biosphere

– Remember ~ Ecosystems consist of the interacting population and the abiotic factors that support them

– All of the ecosystems on earth support a diverse collection of organisms

Why is Biodiversity Important?

• Direct economic value

– Humans depend on plants and animals for food, clothing, energy, medicine, and shelter

– Preserving the organisms we use today is important to sustain our current way of life

– Humans must also preserve species which may be useful in the future

– Some organisms we use today are not very diverse or capable of meeting our needs

• Closely related counterparts might be a better source to meet our needs

• Genetic engineering–Ex. Corn versus teosinte

–Ex. Madagascar periwinkle, penecillian, and salicin

• Indirect economic value– Green plants produce oxygen which we

breathe and recycle carbon dioxide

– Natural processes provide us with drinking water

– Ecological cycles of carbon, phosphorous, nitrogen, oxygen, etc.

– Decomposers, climate

regulators, fertile soil,

protection against

floods/droughts,

– Nature can provide

services at less expense

than using technology to

provide the same service

in some instances

• Aesthetic (personal/emotional) and scientific value

Threats to Biodiversity

• Extinction occurs when an entire species permanently disappears from the biosphere

– Past causes of extinction

were natural gradual

extinctions where new

species evolved and

biodiversity recovered after millions of years

– The current high rate of extinction is due to a single species – humans - who are changing Earths conditions faster than species can evolve to meet these changes

• 25% – 33% or all plant and animal species will become extinct within the next 100 years

• Current extinction rates are 1000 more than normal extinction rates of the past

• Most extinctions will occur near the equator and on islands

← May 15, 1989

← 1651

1937 →

September 1914 →

Mammal List

• Loss of Natural Resources

– All materials and organisms found in the biosphere

– Includes minerals, fossil fuels, nuclear fuels, plants, animals, soil, clean water, clean air and solar energy

– Species trying to cope with extinction (including evolving to meet these new conditions) do not have the natural resources they need

• Habitat Loss (#1)

– Destruction of habitat• Has direct impact on biodiversity of the area• Ex. clearing of land with bulldozers, fire, cutting

down forests

– Disruption of habitat• Habitat not destroyed but specific populations are

affected• Disrupts food web and all species in that habitat• Ex. Over harvesting within “fishing grounds”

• Overexploitation (#2)

– Excessive use of species that have economic value

– Ex. American bison• 50 million at one point• Today, there are less than 1,000 left in the wild

– Ex. Ocelot, rhinoceros, tigers, elephants• Hunted for pelts and body parts

which are used to produce goodsand medicine

• Fragmentation of

Habitat

– Separation of a

habitat into smaller

pieces of land

– Forces populations to be confined to small habitats

• Many species will not cross man-made barriers

• Smaller habitat = smaller populations

• Increases inbreeding and genetic problems in populations

• Less able to survive in changing environments or through disease

• Pollution

– Changes the composition of the air, soil and water

– Some substances that are released into the environment (man-made or natural) are considered pollutants

• Pesticides• Industrial chemicals• Waste products

– Biological magnification

• Increasing concentration of toxic substances in organisms as trophic levels increase in food chains/webs

– Producers – low concentration

– Top consumers – high concentration

– Ex. Pesticide DDT was used on plants to prevent bugs from eating the leaves but it almost lead to the extinction of the bald eagle

– Acid precipitation

• Created from the burning of fossil fuels

• Releases sulfur dioxide and nitrogen oxide into the air

• When these gases react with water, sulfuric acid and nitric acid are produced

• Enters the water cycle in various forms of precipitation

– Affects soil, plants and animals

– Eutrophication

• Form of water pollution that destroys underwater habitats

• Occurs when fertilizers, animal wastes or sewage flow into waterways

• Causes extreme algae growth which depletes the oxygen in the water and poisons the water

• Natural process but human activities have increased the rate at which it occurs

• Invasive Species

– Nonnative species have been introduced to a habitat intentionally or by accident

– Population controls are not in place in these new habitats to regulate the effects of the introduced species

– Out compete, over populate and exploit the native species within the affect habitat

– Estimated that 40% of extinctions since 1750 have resulted because of invasive species

– Billions of dollars are spent yearly to try to clean up or control the damage caused by these species

– Ex. Fire ants, purple loosestrife, zebra mussels

Conserving Biodiversity

• Natural Resources

– An increase in human population increases the need and consumption of natural resources

• Not evenly distributed

– Developed countries have lower populations but higher consumption rates

– Renewable resources are replaced naturally at a fast enough rate for continuous consumption

• Ex. Solar energy, agricultural plants/animals, water, air

• These resources are NOT unlimited

• If demand is higher than supply, resources can be depleted

– Nonrenewable resources take extremely long periods of time to be renewed

• Ex. Coal, minerals, oil, extinct/endangered species

– Sustainable use is an approach where we use resources at a rate in which they can be replaced or recycled (preserving biodiversity and ecosystems)

• Protecting Biodiversity

– Setting up conservation areas worldwide

• Ex. United States national park system

• Ex. 7% of the world is set aside for conservation purposes

– Focus conservation on biodiversity hotspots

– Create corridors between habitat fragments for safe travel and chances of genetic diversity

• Restoring ecosystems

– Bioremediation is a technique where organisms are used to detoxify a polluted area

– Biological augmentation is a technique where natural predators are added to an ecosystem to control population sizes of other species

• Legal Protection

– Since the 1970’s, legal action to protect species, environments and the biosphere has increased

– Ex. United States (1973) ~ Endangered Species Act

– Ex. Worldwide (1975) ~ Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES)