BiodiversityBiodiversity

                                                                                                                                                                                                                                               

 

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

tailed frog: only in cold, clear mountain streams sensitive to siltation, warming

leopard frog: found in lakes, rivers, ponds, streams, wetlands

Species Diversity

Giant kelp bed

Close to the surface

On the bottom

Tropical Rainforest

Deciduous Forest

                                                                                                                                                                                                                                               

 

Artificial Selection has a GoalNatural 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