Organisms and their environment

• Producers make their own food by photosynthesis

  they contain chlorophyll which traps and converts light energy into chemical energy
• Decomposers such as bacteria and fungi feed on decaying organisms

  • obtain energy by breaking down dead bodies of organisms, faeces
  • in this process, nutrients are returned to the environment
• 90% of energy is passed on From one trophic to another.

  • lost as heat energy through respiration
  • lost as chemical energy trapped in egested and excreted material and in dead organisms
• The shorter the food chain, the less energy is lost to the environment. more energy is available for last trophic level. Hence, shorter food chains are more efficient than longer ones
• carbon cycle

  1. Photosynthesis , plants absorb carbon dioxide
  2. Feeding, animals obtain carbon from feeding on plants or other animals
  3. Respiration , plants and animals respire, releasing carbon dioxide into atmosphere.
  4. Decomposition. Decomposers such as bacteria and fungi break down dead organic matter and release carbon dioxide
  5. Combustion, dead bodies of organisms buried produce fossil fuels such as coal and natural gas. Combustion of fossil fuels release carbon dioxide into environment
• Carbon cycle is important as it ensure continuous supply of carbon dioxide for photosynthesis. It enables enrrgy flow through the ecosystem through chemical energy stored in organic compound. It regulates the amount of carbon dioxide in atmosphere
• Carbon sink is an area that stores more carbon than it releases.

  • Oceans Are the largest carbon sinks. Carbon dioxide dissolved in ocean water used by aqu plants for photosynthesis
  • fossil fuels buried in seabeds
  • forests are carbon sinks
  • carbon dioxide taken in by plants during photosynthesis
  • carbon compounds stored In trees are buried in the ground when they die and form fossil fuel
• What are the three categories of organisms in any ecosystem?

  Producers, consumers, and decomposers
• What is the role of producers in an ecosystem?

  • Make their own food through photosynthesis
  • Include plants, algae, and photosynthetic bacteria
  • Contain chlorophyll to convert light energy into chemical energy
• What do consumers obtain energy from?

  Feeding on other organisms
• What are the types of consumers in an ecosystem?

  • Primary consumers: feed on producers (plants)
  • Secondary consumers: feed on primary consumers
  • Tertiary consumers: feed on secondary consumers
• What do decomposers feed on?

  Decaying organisms
• What is the function of decomposers in an ecosystem?

  • Break down dead bodies, faeces, and excretory products
  • Return nutrients (e.g., mineral salts) to the environment
• What is a food chain?

  A series of organisms through which energy is transferred

  
• What is a food web?

  An interlinked series of food chains
• What is a trophic level?

  Each stage in a food chain
• How many trophic levels do food chains generally have?

  No more than five trophic levels

  
• What happens to energy as it is passed from one trophic level to another?

  90% of the energy is lost as heat and in egested material

  
• Why are longer food chains less efficient?

  They have insufficient energy to support many trophic levels
• What do ecological pyramids represent?

  • Food and energy relationships in ecosystems
  • Producers at the bottom, consumers in the middle, and tertiary consumers at the top
• What does the pyramid of numbers show?


  The number of organisms present in each trophic level
• Can the pyramid of numbers be inverted?

  Yes, it can be either inverted or upright
• What does the pyramid of biomass show?

  The dry mass of organisms at each trophic level

  
• Is the pyramid of biomass always upright?

  Yes, it is always upright
• What is the carbon cycle?

  The processes by which carbon is removed from and released into the environment

  
• Why is the carbon cycle important?

  It ensures a continuous supply of carbon dioxide for photosynthesis

  
• What are carbon sinks?

  • Areas that store carbon compounds for a long time
  • Store more carbon than they release
  • Examples include oceans and forests

  
• What is the largest carbon sink on Earth?

  The oceans
• How do oceans act as carbon sinks?

  They dissolve carbon dioxide and use it for photosynthesis
• How do forests act as carbon sinks?

  They absorb carbon dioxide during photosynthesis

  
• What are the undesirable effects of deforestation?

  • Extinction and reduction in biodiversity
  • Soil erosion leading to floods
  • Desertification of land
  • Contribution to global warming
• What is global warming?

  The increase in global temperature due to greenhouse gases
• How does global warming differ from climate change?

  Global warming refers to the rise in temperature, while climate change refers to long-term weather pattern changes
• How can human actions reduce the effects of enhanced global warming?

  • Reduce fossil fuel use and switch to renewable energy
  • Save electricity with efficient devices
  • Use hybrid or electric vehicles
  • Reduce consumption of resources
  • Implement forest management practices

  
• What are some forest management practices to prevent global warming?

  • Conservation of forests
  • Prevent indiscriminate felling of trees
  • Reforestation efforts
  • Control of forest fires
  • Conduct education programs on forest importance