Eco Multi-Lab Overview

Ecology Multi-Lab Overview

Photosynthesis and Respiration

photosynthesis and respiration diagram

Photosynthesis is a process that plant use to make sugar (glucose) that they can later use as an energy source to live and grow.

The raw materials to make the sugar (glucose) are Carbon Dioxide (CO₂) from the air and water (H₂O) usually from the ground. Sunlight is the ENERGY used to run the reaction! The sunlight DOES NOT BECOME sugar!!

The Sunlight is the energy needed to run a series of reactions inside the plant that we call photosynthesis. The energy from the sunlight is CONVERTED from light (electromagnetic energy) into Chemical Energy (stored in the sugar!)

This is the growth chamber for the Ecology Multi-Lab Biomass Lab. The plants are grown hydroponically, meaning plants get the nutrients they need from a liquid solution rather than from the soil.

In this chamber the plants are given all the light they need, all the nutrient they need, all the water they need and all the air they need... basically EVERYTHING they need!

The only thing they have to do is grow! As they grow the mass of plant will increase, this is biomass! We are studying how efficient this plant is at converting the energy of light into stored energy in the plant and making plant matter (biomass).

We measure the mass of nutrient solution used by the plant compared to the control (which has no plants in it!) to control for water loss due to evaporation. The difference between the nutrient solution used by the control and the one with plants in it should be the mass of solution that went through the plant.

When we harvest the plants we measure the mass of the plant wet, and then dry. The difference should be the amount of water contained in the plant!

By dividing a measure of the amount of light used to grow the plants (in Watts) by the mass of plant matter produced (biomass) we get a number that represents how efficient the plant is at converting CO₂ from the air, H₂O and nutrients from the solution using light to run the reaction (photosynthesis).

students measure nutrient solution in the Biomass Lab

In the previous photographs students carfully measure and record the amount of nutrient used by the plants in their growth chamber.

testing quality of light in 'Which Color is best'

In this photo we see different colored bottles with plants growing in them. The different colors filter out different wavelengths of light from the continuous spectrum emitted by the sun.

The plants recieve all the water and nutrient they need and all the air they need. the only thing that is different is the color of light they receive.

By observing and comparing the growth of plants in the the different bottles students discover which wavelengths have the energy for optimal plant growth.

The colorless chamber acts as the control. All wavelengths of light pass through the colorless bottle. By comparing the conditions of the plants in the colored bottles to the plants in the colorless one, students can determine if color of light (the quality of the light) has an effect on plant growth.

testing the effect of gas exchange on plant growth

This plant has had petroleum jelly smeared on the top and bottom of a portion of a leaf, effectively sealing the pores from the air around them.

This plant gets all the water and nutrient and all the sunlight it needs, the only thing that is missing for the "greasy Leaf" is CO₂ from the air!

In the Ecology Multi-Lab we have:
	Studied how efficiently plants use light
	Studied the impact of different wavelengths of light on plant growth and development
	Studied the impace that the air has on plant growth.
	Looked at all of the components necessary for photosynthesis to occur (except water. What do you think would happen if a plant did not get water? (duh!) )

The main point to all of this is that energy from the sun (in the form of wavelengths of light) is converted into chemical energy stored in sugar (glucose) in the plant.

All of the energy that you and I and all of the animals in the world rely on to live is chemical energy stored in glucose by plants ! We are COMPLETELY DEPENDENT upon the PLANTS!

We will see as we progress that energy is "lost" as we move up the food pyramid.

We have seen that the plants are not very efficient at converting sunlight into chemical energy, so some of the sunlight is "lost" (converted to heat rather than usable chemical energy)

As an animal eats the plant, most of the energy in the plant is lost as heat as the animal digests and uses the energy from the plant.

If an animal eats another animal, even more of the original energy is lost.

These energy relationships are the subject of another series of labs and activities.

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