* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Biodiversity
Survey
Document related concepts
Unified neutral theory of biodiversity wikipedia , lookup
Occupancy–abundance relationship wikipedia , lookup
Introduced species wikipedia , lookup
Ecological fitting wikipedia , lookup
Theoretical ecology wikipedia , lookup
Island restoration wikipedia , lookup
Biodiversity wikipedia , lookup
Molecular ecology wikipedia , lookup
Latitudinal gradients in species diversity wikipedia , lookup
Habitat conservation wikipedia , lookup
Transcript
Biodiversity Biodiversity is the genetic, species and ecological variation of the organisms in a given area. Charles Darwin Diversity can be explained by the Theory of Evolution Genetic diversity produces phenotypic diversity Niche specialization can lead to Species Diversity leopard frog: found in lakes, rivers, ponds, streams, wetlands tailed frog: only in cold, clear mountain streams sensitive to siltation, warming Giant kelp bed Close to the surface On the bottom Tropical Rainforest Deciduous Forest Artificial Selection has a Goal Natural Selection does not What is the relationship between diversity and ecological stability. Method of Study Two test plots one with alot of diversity the other with little diversity. Monitor stability (interspecific competition) over time in stress without stress Must ask question Is the type of species important High Biodiversity implies many different species High Biomass has a lot of organisms irregardless of type. If total weight taken it could be quite high. Biodiversity is due to or affects the following – – – Genetic Diversity: A measure of the variety of different versions of the same genes within individual species Species Diversity: Describes the number of different kinds of organisms within individual communities or ecosystems Ecological Diversity: Assesses the richness and complexity of a biological community A species is all the organisms of the same kind able to breed in nature and produce live, fertile offspring How Many Species Are There? There are about 2.1 million species presently known, which is a small fraction of the total that probably exists 10-15% of the world’s species live in North America and Europe The centers of greatest biodiversity tend to be in the tropics Drugs and Medicines Certain anticancer alkaloids are derived from the Madagascar periwinkle 13.5 Aesthetic and Cultural Benefits Nature appreciation is economically important Existence Value: The knowledge that a species exists – This may be reason enough to protect and preserve it What Threatens Biodiversity? Extinction: The elimination of a species – This is a natural process 99% of all species that ever existed are now extinct Habitat Destruction Habitat fragmentation divides populations into isolated groups that are vulnerable to catastrophic events 13.8 Hunting and Fishing Over harvesting is responsible for depletion or extinction of many species Steam ships and explosive harpoons have made it possible to catch and kill even the fastest whales 13.11 Commercial Products and Live Specimens A variety of commercial products are obtained from nature Smuggling of furs, hides, horns, live specimens, and folk medicines amounts to millions of dollars each year Predator and Pest Control Some animals have been greatly reduced because they are regarded as dangerous to humans or livestock or because they compete with our use of resources Exotic Species Introductions Exotic species are considered to be among the most damaging agents of habitat alteration and degradation in the world Alien species from around the world now threaten native species throughout the Great Lakes 13.17 Diseases Pathogens may also be considered predators – – To be successful, a pathogen must establish a balance in which it can reproduce, but does not destroy its host Dutch elm disease caused towns to lose all of their trees Pollution Toxic pollutants can have disastrous effects on local population of organisms Lead pellets have been ingested by bottom feeding waterfowl, which ultimately results in lead poisoning Genetic Assimilation Genetic Assimilation: The disappearance of a species as its genes are diluted through crossbreeding with a closely relate species Hatchery raised trout often are introduced into streams and lakes where they genetically dilute indigenous stocks The Endangered Species Act Endangered Species: Species considered to be in imminent danger of extinction Threatened Species: Species that have declined significantly in total numbers and may be on the verge of extinction in certain localities Vulnerable Species: Species that are naturally rare or have been depleted by human activities to a level that puts them at risk Recovery Programs Species Recovery Plan: Describes how species can be restored to numbers that permit its delisting from the endangered species list Minimum Viable Populations Island Biogeograghy: A species composed of a small number of individuals can undergo catastrophic declines due to environmental change, genetic problems, or random events when isolated in a limited geographic range. Founder Effect: Occurs when a few individuals establish a new population Demographic Bottleneck: Arises when only a few individuals survive some catastrophe Genetic Drift: A reduction in gene frequency in a population due to unequal reproductive success Inbreeding: Mating of closely related individuals resulting in recessive deleterious mutations Habitat Protection In Hawaii, where more than 50% of the land is federally owned, many vegetation types occur completely outside of natural preserves 13.23 Gap Analysis: Wildlife managers and conservationists look for unprotected landscapes that are rich in species Captive Breeding and Species Survival Plans Most mammals in North American zoos are produced by captive breeding programs instead of being captured in the wild