revision

• How to Maintain and Conserve Biodiversity?


  1. ban the killing or trade of endemic or endangered animals or plants through the Wildlife Protection ACT 1972
  2. protecting the habitat through creating national parks, forest reserves and wildlife sanctuaries
  3. undertaking reproductive programmes such as seedling nurseries to help with reforestation and turtle hatcheries
• INvertebrates

  Without legs and Without segmented bodies

  • sponge
  • sea anemone
  • corals
  • planaria
  • snail
• Invertebrates

  With segmented bodies

  • Earthworm
  • Leech
  • Tapeworm
• Invertebrates

  With 3 pairs of legs

  • Ant
  • Butterfly
  • Cockroach
• Invertebrates

  With more than 3 pairs of legs

  • Spider
  • Prawn
  • Centipede
  • Horseshoe crab
  • Scorpion
• Moss

  • reproduce by producing spores
  • non-vascular
• Fern

  • reproduce by producing spores
  • vascular
• Conifer

  • reproduce by bearing cones
  • vascular
• 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
• Water cycle

  • 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
• Water cycle

  • 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
• Carbon Cycle and Oxygen Cycle

  • Plants and animals carry out respiration which uses oxygen and releases carbon dioxide
• Carbon Cycle and Oxygen Cycle

  • The decay of dead plants and animals by bacteria and fungi in the soil uses oxygen and releases carbon dioxide
• Carbon Cycle and Oxygen Cycle

  • Green plants maintain the content of carbon dioxide and oxygen in the air through photosynthesis which absorbs carbon dioxide and releases oxygen
• Human activities that disrupt the nutrient cycle

  • Unrestricted logging
  • Burning of fossil fuels
  • Overconsumption of water resources
• Steps to solve interference to the nutrient cycle

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

  • A habitat is the natural surroundings or home of an organism
• Species

  • A species is a group of organisms that have common characteristics and can reproduce to breed offsprings
• Population

  • A population is a group of organisms of the same species that live in the same habitat
• Community

  • A community is a few populations of different organisms that live together in one habitat and have mutual interaction with one another
• Ecosystem

  • An ecosystem is 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
• Forest logging

  • Extinction of flora and fauna species
  • Soil erosion
  • Greenhouse effect
• Industrialisation

  • pollution of air, water and soil
  • greenhouse effect
  • acid rain
• Agriculture

  • pollution of water due to overuse of pesticides and fertilisers
  • soil loses minerals due to non-sustainable agriculture
• Waste disposal

  • pollution of water and ground
  • flash floods
  • foul odour
• Steps to solve effects of human activities

  1. enforce laws
  2. increase public awareness
  3. practise Refuse, Reduce, Reuse, Recycle, Repurpose (5R)
  4. use biological control
• Vitamin A

  Source: milk, egg yolk, fish oil

  Importance: helps with night vision, maintains skin health

  Effects of deficiency: night blindness, skin diseases
• Vitamin B

  Source: yeast, liver, eggs

  Importance: Maintains the function of the nervous system, formation of red blood cells

  Effects of deficiency: beri-beri, anaemia
• Vitamin C

  Source: fruits, vegetables

  Importance: Fights diseases, maintains the health of gums and mouth, Effects of deficiency: scurvy (bleeding gums)
• Vitamin D

  Source: butter, eggs, fish oil, also produced through sun exposure

  Importance: helps in the absorption of calcium, strengthens tooth enamel, maintains skin health

  Effects of deficiency: rickets, toothache, skin diseases
• Vitamin E

  Source: grains, green vegetables

  Importance: maintains the functions of reproductive system

  Effects of deficiency: sterility, foetus miscarriage
• Vitamin K

  Source: milk, egg yolk, fish oil

  Importance: speeds up the blood-clotting process

  Effects of deficiency: prolonged bleeding