Question

explain phototropism and geotropism with example. Is there any such example in animal world also

Answer 1

Tropism are of many types, they can be growth related or non growth related. Phototropic movements are the movements shown by plants towards the source of light. There are many other forms like chemotropic(responsiveness to certain chemicals), gravitropic(responsiveness to gravity), etc. now, activities like placing a plant in a box with a small window to allow to the sunlight to pass and placing one in open sunlight can be done to prove the directional change due to sunlight, and placing a plant on an inclined plane and or on it's side can prove the directional change in plant growth due to gravity.

Answer 2

the orientation of a plant or other organism in response to light, either towards the source of light ( positive phototropism ) or away from it ( negative phototropism )

If you put a plant in a window, you may notice that, after a few days, it has bent toward that window. This is because the plant needs sunlight to make energy, so it grows toward the light. The growth of a plant toward any stimulus is called tropism, and the growth of a plant toward a light stimulus is called phototropism - photo means light.

Plant roots also exhibit gravitropism, which is growth in response to gravity. Sunflowers are a great example of positive phototropism, because not only do their stems curve toward the light but their flowers turn to face the sunlight as well. As mentioned above, your houseplants also likely exhibit phototropism.