science topic 6-7

• Succession


  The gradual process by which some species replace other species in an ecosystem
• Primary succession


  1. Gradual growth of organisms in an area that was previously bare, such as rock

  2. Lichens, mosses, and ferns first appear on bare rock

  3. As they become established and grow, they change the conditions of the area

  4. New conditions allow other plants and animals to grow and survive
• Secondary succession


  1. Gradual growth of organisms in an area that previously had a number of organisms

  2. Regeneration of a burned forest area

  
• Succession can take place in any kind of area, large or small, in a short period of time or over many years
• Humans affect the environments around them in many different ways
• Changing an ecosystem sometimes results in unexpected environmental changes
• Biological control


  Using the natural enemies of pests to control them, which can limit or eliminate the need for pesticides
• Whenever a new organism that is not native to the area is introduced to an ecosystem, there is always a risk that it will cause harm
• Many species have been accidentally introduced into new environments, often with disastrous consequences
• Biological methods are being used to control insect or plant pests
• Introduced species occur naturally in another part of the world, and are controlled by predators and other natural controls there
• Exotic species have a large impact on the environment into which they are introduced
• If exotic species are able to survive and reproduce better than naturally occurring species, they become invasive and can take over a particular ecosystem
• Habitat loss is now the main reason why so many species are threatened with extinction
• Introduced species is a serious problem that will one day replace habitat loss as the main cause of extinction
• Other causes of species extinction include overuse, pollution, and climate change
• Factors that can lead to the extinction of a species

  • Habitat loss
  • Introduced species
  • Overuse
  • Pollution
  • Climate change
• The difference between a threatened species and an endangered species
• Environmental monitoring is a way to check the condition of an ecosystem by comparing the results of investigations done at different times
• Types of environmental monitoring

  • Physical monitoring
  • Climate, temperature, and weather patterns monitoring
  • Chemical monitoring of air, soil, and water
  • Biological monitoring of organisms or populations
• Volunteers are often an important part of monitoring programs
• Environmental monitoring can begin after a disturbance has occurred or before a disturbance occurs
• Amphibians are considered indicator species that can help monitor the overall health of the environment
• Amphibians


  • Salamanders
  • Frogs and Toads
• Salamanders


  • Body covered with scales
• Frogs and Toads


  • Body does not have scales
• Baseline data can also be used to predict changes in the environment
• Environmental Impact Assessment


  A report that outlines how an activity will affect the environment
• The impact of human developments was considered as well