Physical Factors Affecting Organisms Flashcards
What is Osmosis?
it causes salt to move across a permeable membrane from an area of greater salinity to an area of lesser salinity.
- causes water to move to lesser salinity to greater.
- makes ratio of salt to water the same on both sides OVER TIME.
What is an example of Osmosis?
You put a white flower into water. Then you add blue dye. It causes the flower to become blue. Then you add salt to the water and the salt will cause water to come out of the flower because their are more salt in the water then there is in the flower, then the flower becomes wilted.
But what if you added blue dye and salt at the same time? It would wilt but it wouldn’t become blue. Because all the water would be coming out of the flower due to osmosis. Same reason why humans can’t drink salt water. Because there is more salt in the water than in our body so we become dehydrated.
What environmental factors do plants respond to?
- Gravity
- Life
- Stress
How does gravity affect plant growth? (and what is geotropism)
when you first plant a seed, there is no light to it when you bury it underground. It still knows to send the stem upward and the roots downward. They know to do this because of Geotropism- it is a response to gravity. Roots down towards polar gravity and the stem away from the polar gravity. Once the stem reaches the light, it changes direction of where it grows.
How does light affect plant growth? What is Phototropism?
Phototropism- method of growing when it reaches the light. Once the stem reaches the light, it changes direction where it grows.
Ex: When your plants lean towards the light is an example of phototropism. Growing towards light.
What is stress on a plant?
when there is frost or when someone steps on it, external factors can cause the plant to die.
