The Stuff of Ecosystems

The Stuff of Ecosystems

A. Biotic factors: the living components that can change a population

1. predators

2. food supply

The Stuff of Ecosystems

The Stuff of Ecosystems

3. spread of disease

4. population density

The Stuff of Ecosystems

5. birth rate

6. mortality

B. Abiotic factors: physical & chemical factors (nonliving) that can change a

population

The Stuff of Ecosystems

The Stuff of Ecosystems

1. intensity of wind

2. temperature

The Stuff of Ecosystems

3. water

4. light

5. soil

6. air

7. shape of land

The Stuff of Ecosystems

The Stuff of Ecosystems

• Species

• Community

• Habitat

• Ecosystem

• Biosphere

BIODIVERSITY BIODIVERSITY AT RISKAT RISK

• Number and variety of species on earth

• all plants, insects, fish, mammals, reptiles, amphibians, bacteria….etc

Our planet has Our planet has experienced experienced several mass several mass

extinctions, each extinctions, each probably caused by probably caused by a change in climatea change in climate

Number of known Number of known species is 1.4 million species is 1.4 million

(mostly insects)(mostly insects)

• Actual estimated number of Actual estimated number of species is 10 - 100 million species is 10 - 100 million

• Why such a large Why such a large variation????variation????

• Many species have yet Many species have yet to be discovered.to be discovered.

• Plant & animal species are Plant & animal species are disappearing at an alarming disappearing at an alarming rate.rate.

• Normal extinction- 1 out of Normal extinction- 1 out of every 10,000 speciesevery 10,000 species

• today-over 4000x that….today-over 4000x that….

•Why?Why?

1. Habitat destruction1. Habitat destruction–Causes 75% of all extinctionsCauses 75% of all extinctions–Most destruction in tropical rain Most destruction in tropical rain forestsforests

–22ndnd most at coral reefs most at coral reefs–Caused by huge rate of human Caused by huge rate of human population growth. (260,000 population growth. (260,000 humans per day).humans per day).

2. Hunting2. Hunting–in US no longer in US no longer a major cause a major cause of extinctionof extinction

– still a threat in still a threat in developing developing countries.countries.

3. Poaching (illegal hunting) 3. Poaching (illegal hunting) threatens animals with threatens animals with

extinctionextinction

4. Exotic/invasive 4. Exotic/invasive speciesspecies (not native to a (not native to a particular region)particular region)

• Natives have no defenseNatives have no defense• Outcompete native speciesOutcompete native species• No natural predatorsNo natural predators

FUTURE OF BIODIVERSITY

Saving individual species

• Zoos & wildlife parks carefully manage captive breeding programs

• Goal - release species back

into the wild

–EX: California condor–Cheetahs–Golden lion tamarin

• SSP-Species Survival Plan–breeding for most genetic diversity

Save plants too..?

•Botanical Garden - storehouse of genetic diversity

Save plants too..?

• Germ Plasm Bank - store germ plasm (reproductive cells) for future use in case species become extinct–frozen and stored–Cloning…?

The Ecosystem Approach•Save the entire ecosystem rather than an individual species

Protection of entire habitats most

efficient way to save many species

The Ecosystem Approach

Other Benefits from preserving ecosystems

• Forests-add oxygen, remove pollution

• wetlands-clean water, support breeding grounds

• health of biosphere!!

How much land should we protect??

• “Hot spots”-unusually large amount of biodiverity should be protected first

• Different species require different amounts of resources and habitat

What about human needs?

• Must find ways to meet human need and manage living resources at the same time.

• Developing countries-life or death conflicts between human needs and biodiversity

What about human needs?