Control Systems
Lesson 11
Biology 10
Objective: You will be able to
-describe how plants adjust to their
environment to maximize their chances of
survival.
-define gravitropism and phototropism
There are two specific things that plants will react
to:
1. Light – we see this when plants will bend
towards the sunlight.
2. Gravity – no matter which direction the plant
has been set, the roots always go down and the
stem always goes up.
Watch this video
The role of auxin in phototropism
Auxin is a plant hormone that causes cells to
elongate.
Look at this series of pictures and see if you
can tell where the auxin is active.
Gravitropism (geotropism)
Observe the pictures below. What can be
determined about the way plants react to gravity?
Positive gravitropism video
Negative gravitropism video
Tropism Song