4.2: Evaluating biodiversity and vulnerability

4.2.1: Identify factors that lead to loss of diversity.

Loss of diversity:
  • Nature hazard: meteor impact and volcanoes
  • Loss of habitat: clearing of rainforest
  • Fragmentation of Habitat: large ecosystem been broken to small ecosystems which cause them to be more vulnerable
  • Pollution: acid rain and climate change
  • overexploitation: affect the environment had been cause by growing human population and introduction of new technologies
  • Introduction of new species: cause old species to be vulnerable
  • Disease: mad cow diseases, can greatly damage the diversity of species
  • Agriculture practices: use of chemicals and genetic engineering

Rate of loss varies from country to country and are depended on:
  • the ecosystem present
  • protection policies
  • environmental viewpoints
  • Stage of economic development

4.2.2: Discuss the perceived vulnerability of tropical rainforests and their relative value in contributing to global biodiversity.

Tropical Rainforest:

  • Located within many developed countries, meaning that it would face more human disturb
  • Very complex structure with high diversity
  • Play an important role in reducing the effects of global warming
  • Having many economic value and demands e.g. timber
  • Due to human destruction, the rainforest need a long time to recover and have poor soils
  • The destruction of rainforest has been regard as a key mobilser of the enivonrmental movement nad green policies

4.2.3: Discuss current estimates of numbers of species and past and present rates of species extinction.
external image MassExtinction.jpg

Mass extiniction: a large proportion of the total nuber of species on Earth wiped out
  • There had been 5 mass extinction with 100 million years interval, some suggested that we are currently in the 6th one, and is caused by human.
  • the total number of species on Earth today remain poorly understood, but is estimated around 5-100 million. However only 1.8 million have been identified.
  • The background extinct rate is 10-100 species per year
  • Human had increase this rate, e.g. in the rainforest, 27000 species is lost annually

  • Asteroids or comet impact
  • Volcanic eruption
  • Earthquakes
  • Turmoil
  • Development of agriculture and clearance of native ecosystems
  • Over-population
  • Invasive species
  • Over-exploitation
  • Pollution
  • Global Warming
File:Extinction intensity.svg
File:Extinction intensity.svg

4.2.4: Describe and explain the factors that may make species more or less prone to extinction.

external image mass-extinction_1077_600x450.jpg

Low Numbers
When population numbers drop to very low they are at risk e.g. Javan rhino
High degree of specialization
Species that have require a highly specialized niche can become endangered if there is environmental change, e.g. Giant Panda
Species with a restricted distribution are more prone to extinction e.g. golden-brown mouse
Reproduction potential
Species that are K-stagiest are most prone to extinction if population are hunted above sustainable yields, e.g. blue whale
Species that are sensitive to the presence of human or disturbance by human prone to extinction, e.g. European otter
Trophic level
Species at a high trophic level are more prone to extinction as they naturally exist at low density, requiring more habitat space to survive, e.g. tigers

Outline the factors used to determine a species’ Red List conservation status.

external image conservation_status.png

Red List conservation status
Determine by
  • Total Population Size
  • Change in population Size
  • Numbers of mature individuals
  • Geographic range and degree of fragmentation
  • Habitat quality
  • Area of occupancy
  • Probability of extinction
  1. Extinct
  2. Extinct in Wild
  3. Critically Endangered
  4. Endangered
  5. Vulnerable
  6. Conservation Dependent
  7. Near Threatened
  8. Least Concern
File:IUCN Red List 2007.svg
File:IUCN Red List 2007.svg

http://www.iucnredlist.org/ (Further Reading)

4.2.6: Describe the case histories of three different species: one that has become extinct, another that is critically endangered, and a third species whose conservation status has been improved by intervention.

You can find your own example or use the following

Summary of causes
Socio-Political and Economic Pressures
Consequences to biodiversity
Schomburgk's deer
-Hunting and habitat destruction
-Failed to conserve
-The deer were hunted to be possessed into beautiful antlers
-Habitat destroyed for paddy fields
-Catalyst for the need of conservation of other animals
-Help the establishment of conservation department
Critically endangered
South China tiger
-Habitat degradation and fragmentation
-Low prey density
-Removal of tigers as pests
-Government policy of prompting economic development by transforming forests into farmland
-Reduce of genetic diversity
Previously extinct in the wild
Arabian oryx
-Hunted by their resources
-Reintroduced into the wild through breeding programs

4.2.7: Describe the case history of a natural area of biological significance that is threatened by human activities.

You can find your own example or use the following (which is very brieft)

Case Study: the seasonal evergreen forests of Northern Thailand
Threat: commercial deforestation for resources; clearing of land for crops and easier for hunting; show power and imply ownership of territory; small hill tribes clearance
Consequences: air quality; local extinction of larger mammals and birds due to habitat destruction and hunting pressure, for economical values; disruption of hydrological function