Ecology Biodiversity 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 ← → 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 goods and 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)