| A | B |
|---|
| habitat | the natural home of an organism where it lives and reproduces |
| environment | the climate of a place where an organism lives. the environment plays an important part in determining the types of organisms that live there |
| light | all green plants use light energy from the sun to make their own food. as other forms of life on earth depend directly and indirectly on green plants for survival, they thus depend on light for survival as well |
| temperature | the heat from the sun greatly influences the temperature of a place. most organism are active from 0 to 45 degrees celcius |
| water | water is essential fro life and is thus present in every environment of every organism. the distribution of land organisms corresponds closely to the distribution of water over the land surface |
| minerals | minerals are needed by plants for healthy growth. nitrates, for example are used by plants to make protein. |
| pH value | the pH value of water determines the types of aquatic organisms that can live in it. fresh water organism need a pH value of about 7 to live while s\marine organism in the sea need a pH of about 8 |
| oxygen | all organism need oxygen to survive and for respiration. oxygen can be taken in from the air as well as from the water, where it has dissolved |
| herbivores | animals that feed only on plants |
| carnivores | animals that feed only on animals and other organisms |
| omnivores | animals that consume both plants and other organisms |
| scavengers | animals that feed on dead organic matter |
| mutualism | a relationship between 2 organisms in which both benefit |
| commensalism | a relationship between 2 organisms in which one benefits while the other neither benefits nor is harmed by it |
| paracitism | a relationship involving 2 kinds of organisms, the paracite and its host. the paracite benefits in living off its host whle the host is harmed by the paracite |
