1. Chapter 2 Notes “Cycles in Nature”

2. The Water Cycle The water cycle is the movement of water between the oceans, atmosphere, land, and living things.

3. Stages of the Water Cycle Evaporation – The change of a substance from a liquid to a gas, where the water is cycled back into the atmosphere. Condensation- The change of state from a gas to a liquid due to the cooling of water vapor. Precipitation- Any form of water that falls to the Earth’s surface from the clouds. It is water that moves from the atmosphere to the land and oceans- includes rain, snow, sleet and hail

4. Stages of the Water Cycle Ground Water (collection)- The precipitation that seeps into the ground, where it is stored in spaces between or within porous rocks and underground caverns. Runoff- The precipitation that falls on land that flows into streams, rivers, and lakes. Transpiration- When plants release a small amount of water vapor.

6. The Carbon Cycle The carbon cycle is the exchange of CARBON between the environment and living things (it moves from the environment into living things and back into the environment). Organic Molecules – molecules in living organisms that contain carbon

7. Stages of the Carbon Cycle Photosynthesis – The basis of the carbon cycle, in which plants use carbon dioxide from the air to make sugars. Respiration – The process by which sugar molecules are broken down to release energy. Carbon dioxide and water are released as byproducts. Decomposition – The breakdown of substances into simpler molecular substances. It’s the breakdown of dead materials into carbon dioxide and water Combustion – The process of burning a substance, such as wood or fossil fuels.

9. The Nitrogen Cycle The nitrogen cycle is the movement of NITROGEN from the environment to living things and back again because organisms need nitrogen to build proteins and DNA for new cells.

10. Nitrogen is found in the form of gas in the: Since most organisms cannot use the nitrogen gas, it is changed into usable forms by ◦ This is called Organisms get the nitrogen they require by eating When an organism dies the nitrogen is returned to land by plants or eating organisms that eat plants. Earth’s atmosphere. Bacteria/lightning. nitrogen fixation. decomposers breaking down remains.

12. Succession Succession is the replacement of one type of community by another at a single place over a period of time. There are types of succession. ◦ and 2 Primary Succession Secondary Succession

13. Primary Succession Primary succession is when a small community of living things starts to live in an area that had no soil, plants or animals. ◦ Starts with bare rock ◦ Then organisms live and die on rock ◦ Then rock slowly turns into soil

14. 1.) 2.) 3.) 4.) 5.) Bare rock is exposed where nothing lives. Steps of Primary Succession

15. 1.) 2.) 3.) 4.) 5.) Pioneer species called lichens contain acid which breaks rocks into small particles. These particles mix with remains of dead lichens to form soil. Steps of Primary Succession

16. 1.) 2.) 3.) 4.) 5.) After many years, there is enough soils for mosses to grow & replace lichens. Insects & other organisms begin to live there. When they die, their remain adds to soils. Steps of Primary Succession

17. 1.) 2.) 3.) 4.) 5.) Steps of Primary Succession Over time, soil deepens and mosses are replaced with ferns. Ferns are replaced with grass and wild flowers and eventually small trees form.

18. 1.) 2.) 3.) 4.) 5.) Over time or thousands of years, soil can deepen to support a forest. Steps of Primary Succession

19. Secondary Succession Secondary succession is the regrowth of the original plant community in an existing area that was destroyed by a natural disaster, but soil was left intact

20. 1.) 2.) 3.) 4.) After a year that a farmer stops growing crops, weeds and crab grass start to grow. Steps of Secondary Succession

21. 1.) 2.) 3.) 4.) By the second year, new weeds such as horseweed appears. Insects or the wind carries seeds. Steps of Secondary Succession

22. 1.) 2.) 3.) 4.) In 5 to 15 years, small conifers start growing among weeds and trees continue to grow. After about 100 years, a forest may form. Steps of Secondary Succession

23. 1.) 2.) 3.) 4.) As older conifers die, they may be replaced by hardwoods, such as oak or maple trees if the climate can support them. Steps of Secondary Succession