Question

5 explain what jan van helmont learned from his experiment. 6 how do autotrophs get energy? how do heterotrophs get energy? 7 how does water enter the plant? how does it leave? 8 explain how the opening and closing of stomata can regulate the amount of water in the plant.

Explanation:

1. Jan van Helmont's experiment led him to believe that the mass of a plant comes mainly from water, as he grew a willow tree in a measured amount of soil and added only water over several years, and the tree's mass increased while the soil mass decreased very little.
2. Autotrophs get energy through photosynthesis, using sunlight, carbon - dioxide and water to produce glucose and oxygen. Heterotrophs get energy by consuming other organisms, either plants (herbivores), other animals (carnivores) or both (omnivores).
3. Water enters the plant through the roots via osmosis, moving from an area of high water potential in the soil to an area of lower water potential in the root cells. It leaves the plant through transpiration, mainly through the stomata in the leaves.
4. Stomata can open to allow water vapor to escape (transpiration), reducing the water content in the plant. When they close, they prevent water loss, thus regulating the amount of water in the plant.

Answer:

1. He thought plant mass mainly came from water.
2. Autotrophs: photosynthesis; Heterotrophs: consume other organisms.
3. Enters through roots by osmosis, leaves by transpiration.
4. Open: water loss; Close: prevent water loss.