chapter 2

• Producer


  An organism that produces its own food through photosynthesis
• Primary Consumer


  Herbivores and omnivores that eat producers
• Secondary Consumer


  Omnivores and carnivores that eat the primary consumer
• Tertiary Consumer


  Secondary carnivores that eat a secondary consumer
• Decomposer


  An organism that breaks down dead animals and plants into simpler materials or nutrients
• Energy Flow in an Ecosystem

  1. Producer

  2. Primary Consumer

  3. Secondary Consumer

  4. Tertiary Consumer

  5. Decomposer
• Food Chain


  Used to show the feeding relationship between organisms
• Food Web


  The interconnection of a few food chains
• Energy is transferred from one organism to another organism
• Nutrient cycle


  Nutrients are obtained from a balanced ecosystem and used by living things, then returned to the environment to be used again
• Water cycle

  1. Water is absorbed by plant roots and released into atmosphere through transpiration

  2. Animals carry out respiration, defecation and excretion which increase water content in atmosphere

  3. Plant roots hold soil tightly to prevent erosion

  4. Fallen leaves reduce evaporation and prevent soil from drying
• Carbon cycle and Oxygen cycle

  1. Plants and animals carry out respiration using oxygen and releasing carbon dioxide

  2. Decay of dead plants and animals by bacteria and fungi uses oxygen and releases carbon dioxide

  3. Green plants maintain carbon dioxide and oxygen content through photosynthesis absorbing carbon dioxide and releasing oxygen
• Steps to solve problems when there is interference to the nutrient cycle

  • Create planned agricultural systems
  • Use public transport
  • Store rainwater for daily use
  • Replant trees
  • Tighten laws
• 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
• Balanced ecosystem


  The living organisms and non-living components in the environment are in a state of harmony without any external interference
• Interaction between organisms

  • Symbiosis
  • Prey-predator
  • Competition
• Symbiosis


  When two or more organisms of different species live closely together and interact with one another
• Types of symbiosis

  • Mutualism
  • Commensalism
  • Parasitism
• Mutualism


  An interaction that benefits both organisms
• Mutualism


  • 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
• Commensalism


  • 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.
• Parasitism


  • 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.
• Prey-predator


  • 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


  A method that uses organisms that are natural predators or parasites to reduce the number of pests in an area
• Biological control


  • 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
  • Change of weather
  • Changes in the ecosystem
  • Limited water supply
• Limited water supply


  • Drought season that will upset the paddy field ecosystem
• Migration


  • 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

  • The increase of pests causes the population of plants to decrease
• Role of Human in Maintaining a Balanced Nature


  How human activities impact the environment and steps to solve the effects
• Human activities on the Environment

  • Forest Logging
  • Industrialisation
  • Waste Disposal
• Forest Logging


  • Soil Erosion
  • Greenhouse Effect