Impacts of humans on ecosystems

1
Impacts of humans on ecosystems

• Rainforest- need to conserve them because
• Ecological
• Economical
• Ethical
• Kudzu- Japanese plant that ate the south
• Zebra mussels-population increases
• Prickly pear-population increases rapidly.

2
Impact of humans on ecosystems

• Impacts
• Interspecific competition
• Predation
• Species extinction
• Biological control of pest species
• Control
• Different species have different drawbacks to the
  ecosystem thus need to be controlled different
  ways.

3
Impact of humans on ecosystems

• Biomagnification  increase in concentration of a
  chemical substance (pollutant) from one trophic
  level to the next in a food chain.
• The causes for biomagnification is DDT as it was
  released to kill mosquitoes and other insect
  pests - mosquitoes are disease vectors for
  malaria.

4
Impacts on humans on ecosystems

• Ultraviolet radiation effect
• Cancer
• Sunburn
• Chlorofluorocarbons effect
• Due to the depletion of the ozone layer, the
  amount of UV radiation reaching the Earth's
  surface has increased.
• Ozone in the stratosphere absorbs UV radiation

5
Conservation of biodiversity

• Situ conservation in species
• For captive breeding, animals kept in zoos or
  parks are allowed to reproduce in order to give
  them a chance to increase in number.
• Botanic gardens are sites where many plant
  species are planted in controlled
• Seed banks are where seeds are kept in cold and
  dry storage, since they stay in good condition
  for hundred of years.

6
Population ecology

• R strategies reproduce rapidly
• K strategies show the caring of the off spring.

7
Population ecology

• Lincoln index
• statistical measure used
• in several fields to estimate
• the number of cases that
• have not yet been
• observed, based on two
• independent sets of observed
• cases.

8
Population ecology

• Estimating aquatic population
• Fish catch data-look at volume of the type of
  fish catched
• Lincoln index- similar to previous page
• Technology- estimate the shoal size

9
Population ecology

• Maximum sustainable yield- largest yield (or
  catch) that can be taken from a species' stock
  over an indefinite period.