2. Section 6.3
Biodiversity

3. Why is biodiversity important?
Biodiversity – total of all the genetically based variation in all organisms in the biosphere
3 types
Ecosystem diversity
Species diversity
Genetic diversity

4. Biodiversity as a natural resource
Biodiversity and medicine
Many medicines come from wild species
e.g. aspirin, antibiotics
Genetic information in species is like a natural library from which we have much to learn
Biodiversity and agriculture
Many crop plants have wild relatives, like potatoes
Wild plants carry genes that may be useful for crop plants – e.g. gene resistance
Biodiversity and ecosystem services
Number and variety of species can influence an ecosystem’s stability and productivity

5. Threats to biodiversity
99 %of all species that have existed are now extinct
Humans are causing the greatest wave of extinctions since the dinosaurs
Current rate – 1000 times the typical rate
Humans reduce biodiversity by:
Altering habitats
Hunting
Invasive species
Pollution
Climate change

6. Altering habitats
When natural land is developed for farms or cities, species are threatened
Development often splits ecosystems into smaller pieces – habitat fragmentation
Habitat, or biological islands
The smaller the island the fewer species it can support and the more susceptible it is to a disturbance

7. Hunting
1800s the passenger pigeon and the Carolina parakeet were wiped out
Many countries protect endangered species, but not all
Laws are difficult to enforce in remote areas
Animals can be hunted for
Meat
Products e.g. hide, medicinal properties
Pets – e.g. parrots
Fragmentation increases access to hunters and limits hiding spaces

8. Introduced species
Introduced organisms can become invasive and threaten natural biodiversity

9. Pollution DDT for example prevented birds from laying healthy eggs
Acid rain can place stress on organisms
Carbon dioxide is making oceans more acidic, threatening coral reefs

10. Climate change
Organisms are adapted to their environment and have specific tolerance ranges
If conditions change, organisms must move or face extinction
Fragmented habitats are a key problem – as organisms may not be able to move
If increase of 2.5 °C, 30 % of studied species are likely to face an increased threat of extinction
If increase of above 3.5 °C, 40 – 70 % likely to face extinction

11. Conserving biodiversity
Should we focus on specific organisms, or entire ecosystems?
We must do both, but also take into account humans
Make it worth their while
Preserving species
Captive breeding program
Mating pairs managed to ensure survival of species
Goal is to reintroduce to the wild
Preserving ecosystems
Goal to preserve interactions of many species
Land set aside as parks and reserves
National parks and national forests
Marine sanctuaries

12. Ecological hotspots
Area must contain 1500 species of native vascular plants
And it must have at least 70 % of it’s natural habitat
Current hotspots include 50 % of worlds plants and 42 % of worlds vertebrates

13. Local interests
Often local inhabitants need to change their way of life
In USA, tax credits exist for solar panels or hybrid cars
Many countries use national parks for tourism
Internationally, a system of carbon credits exist
Companies can buy or sell carbon
Pollution is capped