BIOLOGY FINAL LAB REPORT PAPER

BIO 100A Final Lab Manual

*Adapted from Online BIO100A Survey of Bioscience Laboratory Manual Version 4.0 by

Michael Maxwell and Omar Clay.

NOTE: THIS EXPERIMENT REQUIRES SPROUTING OF SEEDS, WHICH WILL TAKE A

FEW DAYS. YOU CANNOT RUN THIS EXPERIMENT IN ONE DAY, SO PLEASE PLAN

ACCORDINGLY.

Final Lab Report

Conduct the experiment by following the detailed instructions below. Fill out the tables and

answers the questions below to guide your experiment and organize your results and conclusions.

Take pictures of your experiment prior to beginning once you have all of your equipment set up,

in the middle of the experiment and at the end of the experiment. Record your detailed

observations and results throughout the experiment. Once you have conducted the experiment

and completed the questions/tables, write a 3 page lab report in essay format (MLA)

summarizing the experiment, results and conclusions. See grading rubric.

For each lab , Create a “Student Information Card” to be pictured in each photo with:

• the name of the lab

• the date you are performing the lab

• your full name and signature

This card should be the approximate size of half of an 8x10 piece of paper, so that all information is

clearly visible in your photo. This card should be displayed in each of the lab specific photos. If you do

not include this card, you will receive 0 points on the lab report.

Materials needed

• Measuring cup

• Measuring spoon

• Water Experiment 1

• Red food coloring

• Blue food coloring

• Salt

• Celery stalk

Experiment 2

• Radish or other quick sprouting seeds (beans, pepper)

• Paper towels

• Salt

• Zip lock bags or saran wrap

• Six cups

Introduction

The abiotic (non-biological) features of an ecosystem (e.g., climate, soil quality, water

availability) are important to understanding the biological community that comprises the biotic

component of an ecosystem. Water availability is particularly important to all life.

Freshwater makes up about one percent of the world's water (Figure 6.1).

Fresh water scarcity limits the range of many terrestrial species of plants and animals. Plants,

like animals, have different tolerances to salt in their environment. All soils have some water-

soluble salts, and essential plant nutrients are absorbed in this form. High salinity in the soil (the

salt content) makes it more difficult for plants to extract water from the soil. Fresh water enters

an ecosystem in the form of precipitation, a river or lake, or an underground aquifer (Figure 6.2).

With human population growth, intensive agricultural

practices and urban water demand, water levels in many of the world's aquifers are dropping. If

fresh water is pumped out of an aquifer at a rate exceeding its natural recharge rate (from

precipitation and underground water channels) salt water and other pollutants may intrude into

the traditional aquifer basin. Salt water encroachment is a growing problem in the aquifers of

coastal communities.

Salty soil is also a problem that can arise in agriculture. As irrigation water is absorbed by plants

and evaporated by the sun, salts are left behind. Over time, salt may accumulate such that the soil

becomes too salty for many plants to grow. It is believed that the ancient population of Sumeria

first thrived with its practice of irrigation, but over many generations began to suffer reduced

crop yields due to the increasing salinity of the soil.

Experiment 1: Water Transport & Salinity

1. Obtain four cups and fill each cup with 400 ml of tap water. Use red dye to darkly stain two cups, and use blue dye to darkly stain the other two cups. Be sure that each red cup

gets the same amount of dye and that each blue cup gets the same amount of dye. Record

the drops in each. Add a spoonful of salt into each cup.

2. Label one red dye cup and one blue dye cup with an S (high salt). Add 4 spoonfuls of salt to each of these cups. Stir the solutions thoroughly.

3. Obtain two similar stalks of celery, each with some leaves at the top. Cut a 1-cm piece (about one-half inch) off the bottom of each stalk. Keep the relative lengths of the two

stalks as similar as possible.

4. Carefully, split the stalks up the middle about half-way. The stalks should each now have two “legs.” Be sure that the legs of each stock are similar sized (i.e., the left leg and right

leg are the nearly the same length and width).

5. Place the red S cup and the blue S cup together. Gently place one “leg” of one stalk into

the red S cup, and the other “leg” of the stock into the blue S cup. The celery should now

be “straddling” the two S cups (Figure 5.2.B). Place the red non-S cup and blue non-S

cup together and situate the legs of the other celery stalk into each cup (i.e., the celery

"straddles" these two non-S cups).

6. Record the time at which you place each celery into the pairs of cups as "Start time."

1.

7. Let the celery sit in the cups for 6 hours, or until you can see color in the leaves of one of the stalks. In Step 6 above, record the time when you remove the stalks as "Stop time."

8. Examine the top of the celery stalks. Are there differences between the celery in the high salt (S) and low salt (non-S) water conditions? Record your observations

9. Remove the celery from the cups (be sure to keep it clear which came from the high salt solution (S) and which came from the low salt (non-S) condition). Lay each stalk out flat.

Starting at the top, move down the stalk, making cross-sectional cuts. Stop when you first

see evidence of dye. Measure how far up each stalk the red and blue dyes climbed. In

Table 6.1, record the distance (cm) traveled by the red dye in high salt conditions (S), the

blue dye in high salt conditions (S), the red dye in low salt conditions (non-S) and the

blue dye in low salt conditions (non-S).

10. Tear apart the celery stalk. Notice the feel of the vascular tissue, and how the food coloring lies within it.

Experiment 2: Seed Germination & Environmental Conditions

In this experiment, you will investigate germination of radish seeds in environments with

different salt contents. You will prepare six germinating environments and monitor them over

four days. Each germinating environment will be a plastic-encased, water-soaked paper towel.

1. To prepare solutions of different salinity, collect 6 clean cups and label them: “1/2”, “1/4”, “1/8”, “1/16”, “1/32”, and “0”.

2. Use a measuring spoon to add salt to 50 ml of water in a measuring cup (about ¼ cup). Add 1.5 tablespoons of table salt (sodium chloride). Stir the water while adding the salt.

The solubility of sodium chloride is ~36 grams per 100 mL of fresh water at 25 C. After

vigorous stirring the solution you should still be able to see some remaining some salt

crystals at the bottom of your solution. This indicates that you have reached the saturation

point of salt in your water.

3. Pour off 40 ml of salt water into the cup labeled '1/2." Do not pour the un-dissolved salt. The “1/2” cup will then contain your saturated salt water solution.

4. Clean your measuring cup, and fill each of the remaining cups with 40 ml of plain water. 5. Add 40 ml of plain water to your salt solution in the "1/2" cup. You will then have 80 ml

of a 50% saturated saline solution in the “1/2” cup.

6. Using your measuring cup as an intermediate, transfer 40 ml the 50% saturated solution ("1/2" cup) to the cup labeled “1/4”. The “1/4” cup will then hold 80 ml of a 25%

saturated saline solution.

7. Using your clean measuring cup as an intermediate, transfer 40 ml the 25% saturated solution (“1/4” cup) to the cup labeled “1/8”. The “1/8” cup will then hold 80 ml of a

12.5% saturated saline solution.

8. Using your clean measuring cup as an intermediate, transfer 40 ml the 12.5% saturated solution (“1/8” cup) to the cup labeled “1/16”. The “1/16” cup will then hold 80 ml of a

6.3% saturated saline solution.

9. Using your clean measuring cup as an intermediate, transfer 40 ml the 6.3% saturated solution (“1/16” cup) to the cup labeled “1/32”. The “1/32” cup will then hold 80 ml of a

3.1% saturated saline solution. You have now prepared a pure water solution in cup “0”

and a 3.1%, 6.3%, 12.5%, 25%, and a 50% saturated saline solution in cups

“1/32”,”1/16”, “1/8”,”1/4”, and “1/2” respectively. See diagram below.

10. You have six solutions ranging in concentration from 0% to a 50% saturated saline solution. You can run this experiment using each solution as the basis for a germinating

environment and following the instructions as they stand. However, if you would like to

discard one or two of the salt water solutions and use two solutions of your own design in

their place, this is OK. Examples include using water with additives such as sugar,

alcohol, soda, or bleach, or even running two at the same salt concentration to get a sense

of the uncertainty. You can also use the above protocol to test the effects of even smaller

salt concentrations. If you choose to run some alternatives, you still need to run pure

water and at least three of the saline solutions, thus all of the rest of the salt concentration

experiment still applies. If you do choose to run some alternatives, simply follow the

directions below with the relevant change in mind. In the lab report, you will need to

describe your alternative experiment(s) and their outcome(s) separately. Have fun!

11. Prepare for seed germination. Take three paper towels and cut them in half. Fold each half towel in half. These towels will be the seeds' germinating environment.

12. Place a folded towel in each of the cups containing your salt solutions and possible

alternatives. Make sure that each towel gets soaked with the solution and that you do not

lose track of which one is which condition. Label one corner of each towel with the

corresponding solution (e.g., "1/2", "1/4", etc.).

13. Count out six piles of 15 or more radish seeds each. Make sure that each pile has the same number of seeds. If there are visible quality differences between seeds make sure

that each pile has similar quality as well (e.g., discard cracked, broken, or discolored

seeds).

14. Remove the soaked towels from the cups and lay the seeds from each pile out in each one of the towels (Figure 6.3). Be careful not to mix up which towel came from which cup.

Record the initial date (Day 0) in which you first put the seeds in the towels in Table 6.2

in Lab Report 6. Spread the seeds over only one half of the towel so that you can fold the

other half over the seeds. You may even want to add another fold.

15. Fold the towel up around the seeds in order to keep them wet, but you will also want to be able to unfold the towel to observe the germination process over the next four days.

Wrap each wet towel with its seeds in saran wrap or in a sealed sandwich bag. This will

insure that the water in the towel does not evaporate away. Make sure that each towel and

seed set is labeled to match the corresponding solution(e.g., "1/2", "1/4", etc.), perhaps by

marking the plastic bag or wrap, or by placing a labeled piece of paper in the bag/wrap.

16. Find a safe location where your seed sets can stay for the next four days. Make sure that each set is in identical conditions. Monitor seed appearance and growth every day for the

next four days. Unfold the wet towels carefully to avoid ripping the wet towel or fragile

sprouts. Be sure to record the number of sprouts, changes over time, and differences that

you notice between seed sets in Table 6.2 for the Final Report.

NOTE: THE FOLLOWING PAGES ARE NOT THE MIDTERM REPORT- THEY ARE YOUR

NOTES AND OBSERVATIONS. FOR THE REPORT PLEASE FOLLOW THE SEPARATE REPORT

INSTRUCTIONS.

Record Your Observations & Answer the Following Questions to Guide your Lab Report

Experiment 1.

1. Examine the top of the celery stalks. Are there differences between the celery in the high salt and low salt water conditions? Record your observations.

2. Record the distance (cm) traveled by the red dye in high salt conditions (S), the blue dye in high salt conditions (S), the red dye in low salt conditions (non-S) and the blue dye in

low salt conditions (non-S). Include +- uncertainty in your measurement.

3. From Question 2 above, did the dyes travel at the same rate? What can you conclude about the effect of salinity on water transport in celery from this experiment? Propose a

biological or physical explanation for your conclusion.

Experiment 2.

1. Observe the radish seed and sprout. Are radishes monocots or dicots? How can you tell?

2. Describe the results of your experiment in Table 6.2. How many sprouted seeds were present in each group per day? Include any other relevant observations, such as

appearance, color, etc. Include any alternative treatments or conditions.

3. From your results in Table 6.2, draw a conclusion about the effect of salinity on

sprouting success. Include conclusions drawn from alternative treatments or

conditions.