sensory and motor mechanism

• Tropism - a biological mechanism that enables plant to move toward (positive tropism) or against (negative tropism) the source of a stimulus.
• Geotropism - gravity causes a response in a plant's growth;
• hydrotropism - the way plants grows or bends in response to water;
• thigmotropism - plants bend or grow because of touch;
• phototropism - the way plant grows or bends in response to light.
• ground - Plants do not have the ability to move from one place to another, as plants are rooted into the
• Plants do not have the ability to move from one place to another, as plants are rooted into the ground, exceptions are Volvox and Chlamydomonas.
• photoreceptors - responds to light;
• Mechanoreceptors - respond to physical stimuli such as sound or touch;
• Chemoreceptors - detect chemicals;
• Thermoreceptors - respond to temperature;
• pain receptors - detect possible tissue damage.
• Animals can move from one place to another freely, and exceptions are Sponges and Corals.