science f2 chap 2.3-2.4

• • Habitat
  • The natural surroundings or home of an organism.
• • Species
  • A group of organisms that have common  characteristics and can reproduce to breed offsprings
• • Population
  • A group of organisms of the same species that live in the same habitat.
• • Community
  • ​​​​​​​A few populations of different organisms live together in one habitat and have mutual interaction with one another.
• • Ecosystem
  • ​​​​​​​​​​​​​​A few communities that live together in one habitat and have mutual interaction with one another,  including all the non-living components such as water, air and soil.
  • An ecosystem is said to be balanced if the living organisms and non-living components in the environment are in a state of harmony without any external interference.
• • Symbiosis happens when two or more organisms of different species live closely together and interact with one another. 
  • Symbiosis includes mutualism, commensalism and parasitism.
• Mutualism

  An interaction that benefits both organisms

  Example: Lichens are algae and fungi that live together
• Commensalism

  The interaction between two organisms which only benefits one organism without harming or benefitting the other

  Example: The remora fish (commensal)  latches on the shark (host)
• Parasitism

  An interaction that benefits one organism and only and harms the other. The parasite gets benefit and host is harmed.

  Example: Tapeworm(parasite) that lives in the human intestine(host)
• PREY-PREDATOR

  • Involves one organism that eats another organism
  • Prey is the organism that is eaten by the predator
  • Predator is the organism that hunts another organism for food
  • Example : Lion(predator) and deer(prey)

   
• COMPETITION

  • Competition happens when organisms in one habitat compete for a limited supply of basic needs such as light, space, water, food and mates
• Biological Control

  • Biological control is a method that uses organisms that are natural predators or parasites to reduce the number of pests in an area.
  • Example: Owls are kept in palm oil plantations to control the population of rats
• Factors that Influence Population Size in an Ecosystem: Disease , Presence of predators , Source of food and Change of weather
• Changes in the Ecosystem

  • Limited water supply
  • Example: Drought season that will upset the paddy field ecosystem
  • Migration
  • Example: The cattle egret migrates to Kuala Gula from September to April every year.
  • As a result, the number of insects decreases as they are eaten by the egrets
  •  Change in population size
  •  Example: The increase of pests causes the population of plants to decrease
• Forest Logging Effects :

  • Soil Erosion
  • Greenhouse Effect
• Industrialisation Effect :

  • Acid Rain
  • Greenhouse effect
• Waste Disposal Effect :

  • Flash floods
  • Pollution of water
• Steps to solve the effects of human activities on the environment

  1. Enforce laws
  2. Increase public awareness
  3. Practise Refuse, Reduce, Reuse, Recycle, Repurpose(5R)
  4. Use biological control