1. 7 th Grade Unit 1: Organism Response to the Environment Lesson 2: Seedling Science Vocabulary of Instruction:

2. Gravity The force that pulls objects toward each other.

3. Stimuli Something causing or regarded as causing a response.

4. Response A change in an organisms surroundings that cause the organism to react.

5. Tropism Is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus.

6. Geotropism Is the term applied to the consequent orientation response of growing plant parts.

7. Hydrotropism Is a directional growth response in which the direction is determined by a stimuli in water concentration.

8. Phototropism Is directional growth in which the growth is determined by the direction of the light source.

9. Thigmotropism Is a movement in which an organism moves or grows in response to touch or contact stimuli.