Biodiversity and Threatened Ecosystems

Question 1

Definition of biodiversity

Answer 1

Refers to an intricate complexity of life contained within an ecosystem. It is reflective of:

		- Genetic diversity within species
		- The variety of species
		- The diversity of ecosystems

Question 2

Extinction of species

Answer 2

There is a natural rate of extinction. Man has accelerated extinction primarily through destruction of habitats, but also through over-exploitation. There is no accurate assessment of species lost, nor close estimate of total global species.

A study of animal extinctions since 1600 found:
39% arose mainly from the introduction of alien species (US has >7,000 alien invasive species)
36% from habitat destruction
23% from hunting or deliberate extermination

Question 3

Biodiversity preservation

Answer 3

Humans don’t always have a negative impact on biodiversity. Our activities, while destructive of some species, create new ecological niches for many forms of wildlife.
With global transportation, England now has more species of flowering plants than ever before.

As recent as 50 years ago, China grew 10,000 wheat varieties, and Andean farmers bred 3,000 varieties of potato. >6,000 of the 7,000 apple varieties grown in the US in the 19th century are now extinct, and just two make up half the national crop.

Question 4

Impacts that are threatening coral reefs

Answer 4

• Pollution – agricultural runoff, sewage, cyanide (fish harvesting), ship and industrial discharges, infectious diseases
• Acidification – Increased atmospheric CO2 decreases ocean pH, inhibiting shell formation in corals, plankton, and shellfish.
• Climate change – warming water causes coral death (“bleaching”).
• Physical damage – from boats, divers, dynamite (fish harvesting), and storms. Overfishing - rate of fishing exceeds rate of natural production of species.