Biodiversity: Biodiversity or "biological diversity" is the diversity of species, ecosystems and genes that exist on earth.

Endangered Species: Any species of organism that is threatened by extinction, whether by natural or human-caused means.

Extinction: This occurs when the last members of a species dies. We then say the species is extinct. Recent examples of extinct animals include the dodo, passenger pigeon, and Carolina parakeet.

Reasons Why Species Become Endangered or Extinct:

a) Habitat loss - Clearcutting, farming, expansion of urban areas (cities)

b) Changing climate patterns - Global warming

c) Introduced (Alien) Species - Competition (Interspecific) by exotic or introduced species. Examples: Weeds crowd out native plants.

d) Overexploitation - Humans overfish, causing fish populations to plummet. Passenger pigeons became extinct after hunters wiped out the population in search of feathers for consumers hats and dresses.

a) Economic:

* New medicines or other commodities

* Potential new crops or farm animals.

* Ecotourism

b) Ecological:

* Native species more adapted to an area than non-native.

* If one species is endangered, others in its food webs may become endangered.

* Damage to ecosystems are widespread (climate change, erosion, flooding, etc.)

c) Ethical:

* Each species has a right to life, whether it is useful to humans or not. Each species has a cultural imortance to a regions peoples.

* Wrong to deprive future generations of the biodiversity that exists now.

d) Esthetic:

* Natural ecosystems and species are beautiful and provide us great enjoyment.

* Composers, artists & writers are inspired by the world of nature.

Advantages:

a) Species stay adapted to their habitats.

b) Species interact with each other, conserving ecosystem.

c) Allows greater genetic diversity.

d) Species maintain natural behavior

Reasons to remove from habitat:

1. So rare it isn’t safe to leave them unprotected in environment.

2. If most of the habitat is threatened, the species should be removed for preservation.

Active Management in Nature Preserves:

1. Remove alien species (those that do not belong there & may overcompete!)- Weeds, rats, cats, feral pigs, etc.

2. Restore areas damaged by human activities.

3. Prevent illegal harvest of protected species (poaching, etc.)

4. Extra measures: protect from predators, prescribed burns, protection of young, etc.

a) Zoos or Nature Parks – Captive breeding may allow some release back to wild (California condor).

b) Botanical Gardens - Special parks where plant species are cultivated and maintained.

c) Seed Banks – Seeds collected, identified and are kept in cold storage at –10¾C indefinitely, or seeds may be germinated and grown to provide replacement seed.

Many wild fish are important as a food source for humans. When a population is overexploited, the numbers of adult fish drops drastically. If the numbers drop too much, spawning fails and the population numbers remain very low. The numbers then do not support continued use as a food source, and may effect other organisms in the marine food web.

EX. – Salmon: Overfishing, El Nino, loss of spawning habitat, disruption of normal migration routes (dams), dilution of gene pool by crossbreeding with hatchery fish.

Measures to protect fish species:

1. Monitor stocks of individual species and their age and reproduction rates.

2. Quotas for the catching of species with low numbers.

3. Moratoria on catching endangered species (or catch & release).

4. Minimum net sizes (or measure caught fish) so immature fish aren’t caught).

5. Ban drift nets which catch all fish.

6. Enforcement (Coast Guard or US Fish & Wildlife Service).

International organizations have been organized to support the protection of threatened species, as wildlife do not recognize national boundaries……..

WWF: World Wildlife Fund - Privately supported, voluntary conservation organization. Involved in political lobbying, monitoring of endangered species & establishment of nature preserves. Attempts to involve local peoples in conseration projects. (http://www.wwf.org/)

CITES: "Convention on International Trade in Endangered Species" – Largest conservation convention with over 100 nations, meets every 2 years to review species of concern. Regulates trade in threatened wild plants and animals.

1. Virtual Field Trip: Biodiversity and Conservation: The Web of Life INTRODUCTION (Also click on Learning Activities (requires PDF) and Video Library for Quicktime Video presentations on diversity topics (probably requires a fast connection).

2. Biodiversity & Conservation: The Web of Life - Further investigations of biodiversity.