Chapter 22: our impact on the ecosystem

Pollution

Water pollution

Untreated sewage + Excessive use of fertilisers

Insecticides + Inorganic waste

Def: The addition of substances to the environment that damage it, making it unfit for life

Conservation!!!!

causes eutrophication

Eutrophication: the process where water receives excess nutrients like phosphates and nitrates, which causes excessive growth of algae and water plants.

Conservation of forest

Conservation of fishing grounds

Conservation via environmental biotechnology

Reasons for conservation

Overgrowth of algae and floating water plants prevent sunlight from reaching submerged plants

  1. use of environmentally friendly fishing gear
  1. regulating catch size and fishing periods
  1. Reforestation
  1. forest reserves
  1. Use of decomposers in sewage treatment

Submerged plants die due to lack of sunlight (unable to photosynthesise). Dead plants are decomposed by aerobic bacteria and fungi

As bacteria feed on decaying matter, they use up the oxygen in the water as they grow and multiply.

  1. To maintain biodiversity by preventing the extinction of species
  • maintenance of a large gene pool is important!
  • cross breeding can be performed

Other organisms (fish and shit) die due to lack of oxygen.

causes bioaccumulation

causes bioamplification

insecticide/waste substances are non-biodegradable

It is stored in the fatty tissues of organism and cannot be excreted

  1. For scientific research
  • study of wildlife provides useful information

the more an organism consumes, the more the poison accumulates

The poison is passed from one trophic level to the next, increasing in concentration in the bodies of organisms along the levels.

  1. For economic purposes
  • major source of human food
  • provide raw materials for industries

the more it is passed along, the more the poison amplifies in the organisms

  1. To maintain a balanced and stable ecosystem
  • prevents disruption of natural cycles
  • prevents global warming
  1. To preserve natural scenery and wildlife for people to enjoy

Depleting natural resources

Deforestation

Uncontrolled fishing practises

  • soil erosion
  • flooding
  • desertification
  • climate changes
  • decrease in fish population
  • destruction of marine habitats