Ecosystem

• Green plants convert light energy from the Sun into chemical energy through the process of photosynthesis. The chemical energy is transferred to primary consumers and then to secondary and tertiary consumers in the food chain and food web.
• A producer is an organism that produces its own food through photosynthesis. Most plants are producers.
• A consumer is an organism that eats another organism. Primary consumers are herbivores and omnivores that eat producers. For example, caterpillars.
• A secondary consumer is an omnivore and carnivore that eats the primary consumer.
• A tertiary consumer is a carnivore that eats secondary consumers. For example, a lion.
• Producers convert light energy from the Sun into chemical energy through the process of photosynthesis.
• Producers are organisms that produce their own food through photosynthesis, such as green plants.
• The chemical energy produced by producers is transferred to primary consumers and then to secondary and tertiary consumers in the food chain and food web.
• A tertiary consumer is a secondary carnivore that eats a secondary consumer. The size of a tertiary consumer is usually bigger than a primary or secondary consumer.
• Some examples of decomposers are mushrooms that grow on decaying wood, mould that grows on food as well as E.coli bacteria that break down food molecules in the large intestine of human
• A decomposer is an organism that breaks down dead animals and plants into simpler materials or nutrients. This interaction is known as saprophytism.
• A food chain can be used to show the feeding relationship between organisms.
• The interconnection of a few food chains is called a food web.
• Energy is also transferred from one organism to another organism in the food web. In reality, some of the energy is lost because it is used by the organism to move and carry out the life process of respiration. Apart from this, energy is also lost in the form of heat energy or chemical energy through undigested food, or faeces.
• The role of living things in the water cycle

  • Water is absorbed by roots of plants in the ground and released into the atmosphere through transpiration. Animals carry out respiration, defecation and excretion (sweating and urination). All of these increase the water content in the atmosphere.

  • Roots of plants hold the soil tightly and make the structure of the soil more compact. This slows down the flow of water underground and prevents soil erosion.

  • Leaves that fall from trees and cover the surface of the earth will reduce the rate of evaporation and prevent the soil from becoming dry.
• The role of living things in the carbon cycle and oxygen cycle

  • Plants and animals carry out respiration which uses oxygen and releases carbon dioxide.
  • The decay of dead plants and animals by bacteria and fungi in the soil uses oxygen and releases carbon dioxide.
  • Green plants maintain the content of carbon dioxide and oxygen in the air through photosynthesis which absorbs carbon dioxide and releases oxygen.
• human activities such as unrestricted logging, burning of fossil fuels and overconsumption of water resources for agricultural and domestic purposes have negatively affected the nutrient cycle.
• When the population of tertiary consumers decreases, the number of secondary consumers (prey) increases due to less number of predators 


  When the population of secondary consumers increases, this will cause the number of primary consumers to decrease due to the increase in the number of predators

  Then, the number of producers will increase because of the lack of predators (primary consumers)
• Respiration is the movement of oxygen from the outside environment to the cells within tissues and the transport of carbon dioxide in the opposide direction
• Decomposition is the process by which organic substances are broken down into simpler organic matter
• Energy is transferred from one organism to another in a food chain or food web, but some energy is lost as heat or used by organisms for respiration.
• A food web is a network of interconnected food chains that shows the feeding relationships between different organisms in an ecosystem.
• Producers are organisms that convert light energy from the Sun into chemical energy through the process of photosynthesis.
• Producers play a crucial role in the food chain by providing energy to other organisms.
• Transpiration is a process when the plants absorb the water by the roots in the ground and release it into the atmosphere through the leaves
• Fungi are an example of decomposers that break down dead organic matter into simpler nutrients.
• Decomposers help recycle nutrients in an ecosystem by breaking down dead organisms and returning essential elements to the soil.
• The greenhouse effect happens because of the increase in the amount of greenhouse gases such as carbon dioxide and nitrogen in the atmosphere which prevents heat from being released.
• The impact of the greenhouse effect are:

  • Ice melting
  • Increasing of sea level
  • Increase temperature
• Ecosystem services make human life possible by, providing

  nutritious food, clean water, and a stable climate, and by providing habitats for wildlife, regulating disease, supporting pollination of crops and soil formation, providing recreational, cultural and spiritual benefits.
• Carbon and Oxygen Cycle

  A) Respiration

  B) Respiration

  C) Decay

  D) Photosysthesis

  
• Water Cycle

  A) Condensation

  B) Underground

  C) Absorbed

  D) Transpiration

  E) Evaporation

  F) Excretion

  
• Importance of conserving water:

  • to preserve our environment
  • reduce the energy required to process and deliver water
  • reduce pollution and conserve fuel
  • to have water available in the future for daily purposes
• Importance of conserving fossil fuels:

  • fossil fuels are non-renewable materials
  • reduce air pollution
  • reduce release of carbon dioxide and climate change
  • for future use
• Acid rain: when sulphur dioxide from factories combines with rainwater in clouds.
• Flash flood is caused by littering
• Extinction of flora fauna is caused by excessive logging activities
• Water and soil pollution is caused by the usage of pesticides
• Substances that cause river pollution include: fertilisers, pesticides, oil, sewage, industrial waste and domestic waste.
• The effects of water pollution on aquatic life includes: death of fish, algae bloom, loss of oxygen, and contamination of food chain.