Hatching Brine Hatching Brine Shrimp Shrimp

Environments

 

Purpose

Observe and compare the hatching of brine shrimp eggs in four salt concentrations

Organize data from an experiment Determine the range of salt

tolerance for brine shrimp hatching Draw conclusions about the

optimum salt conditions for brine shrimp hatching

Design an investigation to test the viability of brine shrimp eggs.

Use scientific thinking process to conduct investigations and build explanations: observing, communicating, comparing, organizing, and relating.

Salinity: how salty water is, the concentration of salt in water

Brine Shrimp: tiny animals related to crabs and lobsters. Brine shrimp are found in salt ponds and salt lakes.

Discussion:What are the different types of

environments that we have been investigating? What organisms live in each environment?

What do you think a salt pond environment is like?

What organisms do you think might live in a salt lake or a salt pond?

Discussion: Do you think the amount of salt in the water ever changes?

Do you think the amount of water has an effect on organisms that live in the water?

•In a controlled experiment one variable (salt) is isolated and tested. All other variables are held constant (controlled).

•How can we find out if salinity affects brine shrimp hatching?

•Which environment do you think will hatch more brine shrimp?

In Your Journal

Optimum: environmental conditions are the best conditions for an organism

•What is the optimum environment for hatching brine shrimp eggs?

Part 3: Determining Viability

Get hatchery tray and make observations in your journals.

Part 3: Determining Viability

Viability: When something is alive and able to function and grow, it is said to be viable. Viable means alive or able to grow.

Part 3: Determining Viability

Do you think the eggs that didn’t hatch are viable or dead? How could you find out if the eggs that have not hatched in your cups are still viable?

Part 3: Determining Viability Each group needs to discuss a plan

to test viability. Add salt and/or water to the “extreme”

cups to bring the salt concentration within the range of tolerance for hatching.

Write out your plan in your journals including the amount of salt or water you plan to add, and the reason for adding that amount.

Re-label your cups to reflect the amount of water/salt contained in the cup.

Viability Results Were the eggs in the 0-spoon and

6-spoon cups viable? Was the hatching robust or did

only a few hatch? What advantage is it to the brine

shrimp to postpone hatching in salt solutions that are very diluted or very concentrated?

In Your Journal

Viable: means alive and able to grow

What strategies enable an organism to survive outside its range of tolerance?

Brine shrimp eggs remain viable but don’t hatch until the conditions are within the range of tolerance.

Materials:

4 plastic cups and lids 4 sticky notes 1 cup of salt, kosher 1 brine shrimp eggs in

vial 1 mini-spoon 1 spoon 5-ml 1 craft stick 1 FOSS tray 1 container 1-liter 1 beaker, 100 ml

In Your Journal

Problem: Does the amount of salt in water affect the organisms that live there?

Get 4 cups and label them as follows:0 spoons salt2 spoons salt4 spoons salt6 spoons salt

• Measure 150 ml of water into each cup • Measure salt into the labeled cups using 5-ml spoon.

Put lid on cup and swirl the water to mix the salt.

In Your Journal

Problem: Does the amount of salt in water affect the organisms that live there?

Put 1 level mini-spoon of brine shrimp eggs in each cup an gently mix.

Place all 4 cups in the recess on the FOSS tray.

In Your Journal

Part 2: Determining Range of Tolerance

Day 1 Day 2 Day 3 Day 4

Copy into your journal and answer the following.

What day of your experiment did you first notice hatching?

In which container did you first notice hatching?

0 spoons 6 spoons4 spoons2 spoon

In Your Journal

Part 2: Determining Range of Tolerance

Part 2 Copy this chart into your journal and

record the number of eggs that hatched in each cup. Make an “X ” in one box for each salt condition

0 spoons 2 spoons 4 spoons 6 spoons

MOST

SOME

NONE

Day _____________________Salt Conditions

In Your Journal

Discussion

Do brine shrimp-eggs need salt in order to hatch?

Were there cups that had conditions favorable for brine shrimp hatching? Which ones?

Were there cups that had conditions that were unfavorable for brine shrimp hatching? Which ones?

Discussion

Can you give brine shrimp eggs too much salt?

Can you determine the range of tolerance that brine shrimp eggs have for salt?

Which conditions seemed to be optimum (best) for brine shrimp hatching?