Why Are Plants Important?

On the first day of our plant study, we mentioned things like crops, medicine,

oxygen, food chains, shelter, and others. What one process allows plants to be this

important?

PHOTOSYNTHESIS

A Big Picture Review…A Big Picture Review…

CC66HH1212OO66 + 6O + 6O2 2 + 6H+ 6H22OO Glucose Oxygen WaterGlucose Oxygen Water

We’ve looked at the left side of We’ve looked at the left side of the equation, now let’s look at the equation, now let’s look at what happens to the products…what happens to the products…

What’s What’s needed?needed?

Energy + 12HEnergy + 12H22O + 6COO + 6CO22 Sunlight Water Carbon Sunlight Water Carbon DioxideDioxide What’s What’s

produced?produced?Illuminating Photosynthesis Website:

What happens to the water?

• It evaporates out of the stomata in the leaves (helps “pull” water through the plant) and becomes a part of the atmosphere, or…

• It is used to restart photosynthesis.

What happens to the glucose?

• What is glucose?– Glucose is a monosaccharide.– The product of photosynthesis is always

glucose, but glucose molecules can be combined to make other substances.

– Ex. Starch in a potato– Glucose (or some form of glucose) is used

by cells to complete respiration, the process that creates ATP for the body.

So, glucose can be… •Used by plant cells to complete respiration (Glucose made in the leaves moves to all parts of the plant through tubes called phloem)

•Stored in a plant for later use. •Ex: potato, carrot, turnip…

•Eaten by a heterotroph (animals, humans, etc.) so they can complete respiration.

The oxygen exits through stomata in the leaf.

What is the role of oxygen in the environment?

What happens to the oxygen?

A different perspective on oxygen…

• Does the oxygen we breath come only from plants?

• More than half of Earth’s oxygen is produced by tiny phytoplankton in the ocean!

• What is phytoplankton?– Plant-like protists and bacteria

Phytoplankton: plant-like organisms

• Most phytoplankton are too small to see with the naked eye.

• Phytoplankton live on the surface of the ocean where light is available for photosynthesis

Phytoplankton bloom in the South Atlantic (February 15, 2006) HI from space

The Photic Zone: the area of ocean that gets light• Sunlight does not

reach deep water, its reach depends on how clear the water is

• In coastal areas where there is sediment and living things in the water, the light does not reach as deep as 200 meters

• The same is true for rivers, streams and ponds

The Role of Phytoplankton

• Phytoplankton are the base of the marine food web

• Phytoplankton tell us a lot about a marine ecosystem, including its health and availability of food

Marine Food Web Example

• As we have just discussed, phytoplankton are an incredibly important part of life as we know it. They produce a huge amount of the oxygen we breathe, and they are the basis of the marine food chain.

• Where are these phytoplankton blooms found in the ocean?

• Scientists use satellite technology to see where chlorophyll is in the ocean. You can assume that the concentration of chlorophyll is a direct indicator of how many phytoplankton there are in an area. We will use these satellite images to investigate this topic further…

The Importance Of Phytoplankton