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| Biodiversity | Variety of life at all levels of organization. Includes: Species diversity, genetic diversity, and population/community diversity |
| Species biodiversity | The number or variety of species in a particular region. Richness = the number of species. Evenness (relative abundance) = the similarity in numbers between species |
| Genetic diversity | Encompasses the differences in DNA among individuals. Populations with higher genetic diversity can survive and cope with environmental change |
| Inbreeding depression | Genetically similar parents mate and produce inferior offspring |
| Taxonomist | Scientists who classify species |
| Classification system | Domain, kingdom, phylum, class, order, family, genus, species |
| Species | A distinct type of organism, a set of individuals that uniquely share certain characteristics and can breed with one another to produce fertile offspring |
| Subspecies | Populations of species that occur in different areas and differ slightly from each other. Conservation value of subspecies: The subspecies concept can be beneficial to conserving diversity at a population level |
| Distribution of species | Insects outnumber all other species |
| Latitude and biodiversity | Species richness increases toward the equator. This is due to climate stability, high plant productivity, and no glaciation |
| Biodiversity hotspots | Prioritizes regions most important globally for biodiversity. Support a great number of endemic species = species found nowhere else in the world. The area must have at least 1,500 endemic plant species, and it must have lost 70% of its habitat due to humans |
| Extinction | Occurs when the last member of a species dies and the species ceases to exist |
| Extirpation | The disappearance of a population from a given area, but not the entire species globally (99% of all species that ever lived are now extinct) |
| Background extinction rates | These are natural extinctions. For mammal or marine species, each year, 1 species out of every 1–10 million goes extinct |
| Mass extinctions | Earth has had five mass extinctions in the past 440 million years. Each event eliminated at least 50% of all species. Humans are causing this sixth extinction event |
| Human caused extinctions | Extinctions followed human arrival to islands and continents. The current extinction rate is 100 to 1,000 times greater than the background rate, and will increase tenfold in future decades |
| The Red List | Species facing high risks of extinction. Mammal species (21%), bird species (12%) |
| Causes of biodiversity loss: Habitat fragmentation | The gradual degradation of a habitat – continuous habitats are broken into patches. Habitat loss is responsible for declines for 83% of mammals and 85% of birds. 99% of US prairies have been converted to agriculture |
| Causes of biodiversity loss: Pollution | Air pollution degrades forest ecosystems; water pollution impairs fish and amphibians; agricultural runoff harms terrestrial and aquatic species. Toxins, garbage, oil, and chemicals impact organisms |
| Causes of biodiversity loss: Over-harvesting | Targets vulnerable species (K-selected), causes huge biodiversity loss |
| Causes of biodiversity loss: Invasive species | Push native species towards extinction |
| Causes of biodiversity loss: Climate change | The frequency of extreme weather events increases. Increased stress forces organisms to shift their geographic ranges. Most animals and plants will not be able to adapt |
| Biodiversity and ecosystem services: Food security | Industrial agriculture has narrowed our diet, but wild and rare species can improve food security. Genetic diversity within crops is enormously valuable: Turkey’s wheat crops received $50 billion worth of disease resistance from wild wheat. Wild strains provide disease resistance and many grow back year after year without being replanted |
| Biodiversity and ecosystem services: Ecotourism | Biodiversity generates economic benefits via ecotourism, especially in developing countries. This provides jobs and income to once poverty-stricken areas, as well as incentive to preserve natural areas |
| Biodiversity and the ecosystem:Biophilia | Edward O. Wilson’s idea that human beings have an instinctive love for nature and feel an emotional bond with other living things. It is the deeper value of biodiveristy |
| Conservation biology | A scientific discipline devoted to understanding the factors, forces and processes that influence the loss, protection, and restoration of biological diversity |
| Conservation geneticist | Study genetic attributes of organisms to infer the status of their populations |
| Minimum viable population | How small a population can become before it runs into problems |
| Metapopulations | A network of subpopulations (small populations are most vulnerable to extinction and need special attention) |
| Endangered Species Act | The primary U.S. legislation for protecting biodiversity. It forbids the government and citizens from taking actions that destroy endangered species or their habitats or trading in products made from endangered species |
| Controversy over endangered species | Opponents feel that the ESA values endangered organisms more than the livelihood of people. They think that protection will restrict land use and cost jobs. “Shoot, shovel, and shut up”: Landowners conceal the presence of endangered species on their land |
