Living Environment Translated Arabic 2014 | Page 84

24.Water cycles through the environment using several pathways.
 Evaporation- liquid water changes into water vapor and
enters the atmosphere
 Condensation- the process of changing from a gas to a
liquid. This occurs in the water cycle when water vapor
( gas) comes into contact with colder air.
 Precipitation - water falling from the atmosphere in various
forms ( rain, snow, sleet)
 Transpiration- the release of water vapor through the
leaves of plants
 Surface water- water found on the surface of the Earth such
as lakes, rivers, oceans
 Groundwater- water stored under ground
25. In the nitrogen cycle some types of bacteria can form nitrogen
compounds. These compounds enter plants, which are then
consumed by other organisms.
26. During the Carbon-Oxygen Cycle :
 Producers (green plants) remove CO2 from the air during
photosynthesis and produce O2 during photosynthesis.
 Consumers remove O2 and produce CO2 during respiration.
27. Ecosystems change:
 Ecological succession is the gradual change from one plant
community to another.
 Primary succession begins in a place where no plants were
before.
 Secondary succession begins in a place that has soil and
was once the home of living things.
 A climax community has reached a stable stage of
ecological succession.