FOR SEA Institute of Marine Science
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FOR SEA Grade 7
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How Hot Is Too Hot?

Living things must deal with changes in their environment. Things such as temperature may change a great deal. Let’s look at how different temperatures affect brine shrimp eggs.

Brine shrimp are relatives of the shrimp caught for food. They are often used as a fish food by people with pet fish. The life cycle of the brine shrimp has three stages: egg, larva, and adult.

Even as an adult the brine shrimp is less than one inch long.

In this experiment you will be observing the hatching of brine shrimp eggs.

Method

  1. Obtain three jars. Mark or label the jars: 1, 2 and 3.

  2. Fill the jars about 3/4 full with saltwater solution.

  3. Place into each jar as many brine shrimp eggs as you can put on the end of a small stick. Gently tap the stick against the side of the jar to remove the eggs from the stick.

  4. Stir the eggs into the water in each jar.

  5. Place jar #1 in the refrigerator.

  6. Place jar #2 in the spot your teacher has provided for those jars to be left at room temperature.

  7. Place jar #3 beneath the electric lamp.

  8. For the next 4 days, observe the jars using your hand lens. Record the findings in the DATA CHART on the next page. Record the estimated number of shrimp hatched and the temperature of the water. To find the temperature, put the thermometer into the jar for 1 minute then read the scale. Read the thermometer while it is still in the water.

Data Chart

Refrigerator Jar #1 Room Temperature Jar #2 Lamp Jar #3
Number
Hatched
Temperature Temperature Number
Hatched
Temperature
Day 1




Day 2




Day 3




Day 4





Hatching Results

1. a. Did any of the eggs hatch after the first day?

    b. If they did hatch, in which temperature did they hatch?

2. a. Which jar had the most shrimp hatch?

    b. What was the temperature of the jar with the most shrimp hatching?

3. a. Which jar had the fewest shrimp hatch?

    b. What was the temperature of the jar with the lowest shrimp hatching?

4. Make a general statement about the effect of temperature on shrimp hatching. (Hint: a general statement might be, “More shrimp hatch in boiling water than in ice water.”)




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