Water and Carbon cycle

• How long has life on Earth existed?

  For billions of years
• Why has life on Earth been possible?

  Because it recycles molecules and atoms
• What are some molecules recycled on Earth?

  Water and carbon dioxide
• What happens to atoms over millions of years?

  They can be reused to make different organisms
• How many atoms are estimated to be in a human body?

  Six octillion atoms
• Where have the atoms in your body been recycled from?

  Oceans, volcanoes, other animals, and humans
• What are the two cycles covered in the study material?

  • Water cycle
  • Carbon cycle
• What initiates the water cycle?

  Energy from the sun causing evaporation
• What forms of water can evaporate?

  Water from lakes, oceans, and soil
• What is transpiration?

  Evaporation of water from plant leaves
• What happens to water vapor in the sky?

  It condenses into clouds
• What is precipitation?

  Water falling back to Earth as rain
• What can happen to water after precipitation?

  It can seep into soil or flow into rivers
• What are the main components of the carbon cycle?

  • Carbon dioxide in the air
  • Carbon in plants
  • Carbon in soil
  • Carbon in fossil fuels
  • Carbon in animals
• What is the primary process of the carbon cycle?

  Photosynthesis by plants and algae
• What do plants convert carbon dioxide into?

  Biological molecules like glucose
• What happens to carbon in plants after photosynthesis?

  It can be released by respiration or consumed by animals
• What occurs when organisms die in the carbon cycle?

  They can decay or become fossil fuels
• What happens during microbial respiration of decayed organisms?

  Carbon is released as carbon dioxide
• What conditions lead to the formation of fossil fuels?

  Anaerobic conditions without oxygen
• What can fossil fuels be burned to produce?

  Carbon dioxide
• What additional process can be included in the carbon cycle?

  Burning of plants or biofuels
• What are the key points of the water cycle?

  1. Evaporation of water by sun's energy
  2. Condensation into clouds
  3. Precipitation as rain
  4. Water seeps into soil or flows into rivers
  5. Cycle repeats
• What are the key points of the carbon cycle?

  1. Carbon stored in air, plants, soil, fossil fuels, and animals
  2. Photosynthesis converts CO2 to biological molecules
  3. Respiration releases CO2 back to the atmosphere
  4. Decay of organisms releases CO2
  5. Anaerobic decay can form fossil fuels