Biodiversity Diversity of –Genes –Species –Populations –Ecosystems in a region

Extinction The death of a species Natural and common event in history A major consequence of human domination Results in a loss of biodiversity

Causes of Extinction Small population Low population density Living in small restricted areas Specialized organisms Low rate of reproduction

Extinction NOT!

Human Activity Whenever humans become the dominant organism … extinctions occur. This has resulted in reduced biodiversity. Advances in technology have led to more and faster extinctions caused by man and his tools.

Genetic Diversity Genetic Diversity is the term used to describe the number of different kinds of genes in a population or a species.

What Causes Genetic Diversity Mutations Mutations change genetic information Caused by natural events Also caused by manmade machines, weapons, chemicals

Mutations in Humans

What Causes Genetic Diversity Migration Migration of individuals from one population to another alter the gene pool and genetic diversity of a population.

What Causes Genetic Diversity Sexual Reproduction Sexual reproduction creates new genetic combinations through meiosis and recombination

What Causes Genetic Diversity Population Size The larger the population the larger the genetic diversity

What Causes Genetic Diversity Selective breeding Selective breeding can modify the characteristics of a species by artificially choosing desired traits.

Species Diversity The measure of the number of different species present in an area

Ecosystem Diversity The measure of all of the different kinds of ecosystems present in an area (biomes). Can vary due to latitude and altitude.

Value of Biodiversity Why do we need biodiversity? –Ecological Reasons –Economic Reasons –Ethical Reasons

Diversity’s Ecological Value Beauty of Nature Support of the environment –Atmosphere –Soil –Water Outdoor recreation Ecotourism

Diversities Economic Value Benefits include: –Biomass Fuel –Fruits/vegetables –Oil/gas/coal –Game/food –Raw materials –Medications

Diversity Ethical Value Intrinsic value of other organisms Right to survive Aesthetic value Entertainment value

Threats to Biodiversity Habitat Loss –Conversion to Agriculture –Forestry Practices Deforestation –Clear-cutting –Patchwork clear-cutting –Selective harvesting –Reforestation –Rangeland and Grazing Practices –Conversion to Urban and Industrial Uses

Agricultural Practices Stripping the land of natural vegetation to grow crops for human consumption. –Grains –Fruits –Vegetables –Lumber products

Foresting Techniques

Reforestation The replanting of a clear cut forest to assist in its recovery. –Especially important for coniferous forests

Plantation Forestry –The farming of trees for profit –Single species –Harvestable in 20 years

Rangeland and Grazing Rangelands are altered to be used for grazing domesticated animals –Poisonous plants removed –Predators removed –Loss of Biodiversity

Aquatic Ecosystem Loss Dragging the bottom of the ocean results in destruction of underwater species Dams cause the blocking of rivers for migrating fish.

Conversion to Urban Use Buildings and roads cover the natural landscape removing land and reducing biodiversity. –Buildings –Factories –Roads

Overexploitation of Resources Taking more from the Earth than can be replaced. –Overfishing –Overhunting

Unsustainable harvest –Overcollecting of exotic plants and animals –Usually to feed the hungry

Introduction of Exotic Species Bringing organisms into a new ecosystem in which they may have no natural predators –Rabbits in Australia –Horses in North America

Control of Pest Organisms Systematic killing of large predators –they preyed on domesticated animals Persecution of Pests –Rats –Mosquitoes –Fleas

Preserving Biodiversity What is being done? –Convention on Biological Diversity US Senate did not ratify –Endangered Species Act of 1973 Weakened by later legislation –Establishment of designated Wilderness National Parks

Wildlife Management Establishment of food water and cover for the indigenous species Habitat Management –Modifications made to ensure the survival of the local species

Migratory Animals Very difficult to assess their numbers –Move annually due to environmental factors –Populations in motion are hard to count –Waterfowl most common

Reduction of Biodiversity Loss of genetic diversity Loss of species diversity Loss of key species Primarily caused by –Loss of habitat –Introduction of exotic species –Killing of pest organisms