DOCUMENT RESUME

ED 103 233 SE 018 514

TITLE Brine Shrimp and Their Habitat, An EnvironmentalInvestigation.

INSTITUTION Minnesota Environmental Sciences Foundation, Inc.,Minneapolis.; National Wildlife Federation,Washington, D. C.

PUB DATE 72NOTE 21p.; Related documents are SE 018 515-534AVAILABLE FROM National Wildlife Federation, 1412 16th Street, W.V.

Washington, D.C. 2003G (Order No. 79169, $1.50)

EDRS PRICE MF-S0.76 HC-$1.58 PLUS POSTAGEDESCRIPTORS Elementary Education; *Elementary School science;

Environmental Education; *Instructional Materials;Investigations; Learning Activities; NaturgqResources; *Science Activities; *Science Education

IDENTIFIERS * Brine Shrimp

ABSTRACTThis environmental unit is one of a series designed

for integration within the existing curriculum. The unit isself-contained and students are encouraged to work at their ownspeed. The philosophy of the unit is based on an experience-orientedprocess that encourages independent student work. This unit explorestae life cycle of brine shrimp and the effects of the environment onthat cycle. The unit contains a series of related activities thatillustrate basic ecological principles of interrelationships. Teacherinformation such as materials needed, background information, andadditional topics is given. The unit is designed for students, grades1-5. More sophisticated investigations are given at the end of theunit. A bibliography is included. (MA)

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THE ENVIRONMENTAL UNITS

Uhl" is one ot ai group Of Envuonmental Units written by the Environmental Science Center and published by the

National Wildlife Federation.

In both theory and prat. lice education is the essential base for long-range local. regional and national programs

to improve and maintain the quality of environment necessary for tnan's welfare and survival. Citizens must be aware

of ecological relationships in order to recognize. appreciate and fulfill constructive roles in society. This awareness

should be launched through the existing educational process in classroom and related school activities. No special

courses on ecology can replace the need to integrate ecological learning throughout the existing curricula of our school

systems. Furthermore, the lite-styles and value-systems necessary for rational environmental decisions can best be

acquired through repeated exposure to ecological learning which pervades the total educational experience.

It was with these thoughts that we developed these curriculum materials. They were designed for the classrcom

teacher to use with a minimal amount of preparation. They are meant to be part of the existing curriculumto rom-

plement and enhance what students are already experiencing. Each unit is complete in itself, containing easy-to-fo!low

descriptions ot objectives and methods. as well as lists of simple materials.

The underlying philosophy throughout these units is that learning about the environment is not a memorization

process. but rather an experience-oriented. experiment-observation-conclusion sort of learning. We are confident that

students at all levels will arrive at intelligent ecological conclusion; if given the proper opportunities: to do so, and it

not forced into "right" answers and precisely "accurate" names for their observations. It followed in principle by the

teacher, these units will result in meaningful environmental education.

In the process ot development. these units have been used and tested by classroom teachets, after which they have

undergone eyaluatims, revisions and adaptations. Further constructive comments from classroom teachers are en-

couraeyd in the hope that we may make even more improvements.

A list of units in this group appears on the inside hack cover.

About the National Wildlife Federation-1412 Sixteenth Street, N.W., Washington, D.C. 20036

Founded in 1936, the National Wildlife Federation has the largest membership of any conservation organization in

the world and has affiliated groups 'n each of the 50 states, Guam, and the Virgin Islands. It is a non-profit, non-

governmental organization devoted to the improvement of the environment ai.d proper use of all natural resources.

NWF distributes almost one million copies of free and inexpensive educational materials each year to youngsters, edu-

cators and concerned citizens. Educational activities are financed through contributions for Wildlife Conservation

Stamps.

About the Environmental Science Center-5400 Glenwood Avenue, Minneapolis, Minnesota 55422

The Environmental Science Center, established in 1967 under Title III of the Elementary and Sec midary Education

Act is now the environmental education unit of the Minnesota Environmental Sciences Foundation, Inc. The Center

works toward the establishment of environmental equilibrium through educationeducation in a fashion that will

develop a conscience which guides man in making rational judgments regarding the environmental consequences of

his actions. To this end the Environmental Science Center is continuing to develop and test a wide variety of instruc-

tional materials and programs for adults who work with youngsters,

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Brine Shrimp and Their HabitatAn Environmental Investigation

BY

NATIONAL WILDLIFE FEDERATION

MINNESOTA ENVIRONNIENTAL SCIENCES FOUNDATION, INC.

Design and Illustrations byMN BLYLER

Eggs, environment, regenerationa cycle. The citizen-ecologist must be concerned with how things relate, how theydevelop, and how they will continue to do so. A good way forthese concerns to sustain power and effectiveness is for themto be grasped early and become part of a person's way of life.We need to help children become more aware of the environ-ment and their relationship to it if we want them to take careof it.

Brine Shrimp and Their Habitat attempts to get childreninterested in the life cycle of brine shrimp and how environ-ment affects this cycle. The children will observe the eggs ofbrine shrimp and then the shrimp themselves. We hope theseactivities will convey some basic ecological principles andinitiate some better understandings about environmental in-ter-relationships. We also hope the activities will be fun for yourstudents.

We leave it to you to use this unit as a jumping off pointfor further discovery about the environment.

Table of Contents

Introduction 3

Materials 3

Brine Shrimp Eggs 4

Hatching Brine Shrimp

After Hatching 6

I. Observations and Investigations 6

Additional Topics 7

Effects of Environmental Variables 8

I. Hatching in Various Liquids 8

II. Hatching in Various Salt Concentrations 9

Hatching Eggs Under Various Conditions 10

IV. The Effect of Light on Live Brine Shrimp 11

V. Conditions Needed for Brine Shrimp to Grow 11

VI. The Effect of Various Liquids on Live Brine Shrimp

VII. Examining Dead Brine Shrimp 12

The Back of the Book 13

I. Background Information 14

I Hatching, Feeding and Caring for Brine Shrimp 14

III. Bibliography 15

0 1972by National Wildlife Federation

5

INTRODUCTION

Brine Shrimp and Their Habitat contains a series of environmentallyrelated activities. Hopefully, most of the experiences your students willgain from these activities will spring from their own interests and motiva-tions rather than from specific directions set forth in the body of this unit.One activity will merge into another and several will be concurrent.Throughout it all, each child should be allowed to proceed at his own pace.

The unit is introduced by contronting the children with rather mys-terious brown objectsthe brine shrimp eggs. The children's own observa-tions will probably help to generate questions. These questions, in turn,will lead to closer observation and manipulation of the eggs. The eggs willbe hatched and the shrimp raised to adulthood, at which time more eggsmay be produced. Once the cycle is complete, the children will have otherquestions to investigate. Let them experiment as much as your scheduleallows and as long as the activities hold their interest. The content of theunit will accumulate as the children discover the answers to their ownquestions. (We have provided some background information for you inthe back of the book.)

The second half of the unit contains activities for older children(grades 3 -5). The children will investigate some of the variables of environ-ment which affect egg viability, population growth, and organism size. Asin the beginning sections for younger children, the emphasis in this secondpart is on student-generated activities. As the students' investigations be-come more sophisticated, you will need to provide extra guidance.

Some of the activities in this unit can be coordinated with other areasof the curricu:um. Brine shrimp drawings, for example, could be madeduring an art class. Reports of the students' results could be incorporatedinto language arts. You may find that the children want you to read themstories about the shrimp or other marine animals. Or they may want to tellyou stories of what they have observed. In short, as the children engagein the activities of Brine Shrimp and Their Habitat, take every opportunityto practice any related skills that might ordinarily be developed in otherareas of your curriculum.

MATERIALS

brine shrimp eggs (available froma biological supply house or pet store)

medicine droppers or soda strawsnon-iodized salt or crushed rock saltiodized saltbabyfood jars with capslarger jars or gallon jugs1 cup measuresteaspoons and tablespoonshand lens (preferably with a low and

high manification lens)stereo-binocular microscopeswell slides (depression slides)

light sources (microscope lamps,flashlights, or pen lights)

overhead projectorpetri dishes or other low,

flat, transparent containersgrid paperconstruction paperbrewer's yeastmicroscopestest tubes, corksmicroprojectorcrayonspaper

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Brine Shrimp and Their HabitatBrine Shrimp Eggs

This section introduces the students to the mate-rial tt.ey will be using for the next several weeks.First, they will observe the brine shrimp eggs, andmany will try to guess what these might be. Thisguessing and observing could continue over a periodof sev "ral days. As the children become acquaintedwith the material, they will begin to identify someproblems they would like to investigate. You willprobably want to make note of their plans.

Encourage the children to begin making recordbooks. Pictures, drawings, and short, written obser-vations can be entered into these booklets. Whenthe booklets are completed, the children will be ableto take them home

Your objective in this first section will be to providethe type of classroom atmosphere conducive toquestion-asking.

Before you start, set up one or more binocularmicroscopes somewhere in the room. Also, preparea well-slide of eggs for each microscope, using justthe dry eggs without water.

Begin the activity by sprinkling some of the eggsonto pieces of paper placed on each child's desk.Do this without comment. The eggs are easily blownaway, S3 you might caution the children not tobreathe heavi!y on them. The class Will probablybegin questioning you immediately,

After the children have had a few minutes to ex-amine the eggs, discuss any guesses made aboutwhat these "things" might be. there may be oneor two children who have fish tanks at home wherethe eggs are used as food for trr pica! fish. Butthere probably won't be many children who haveseen them before,

Take note of your students' guesses, and thensuggest they look more closely at the objects in thewell-slides with the hand lenses. How do any newcomments compare with their first guesses? Have

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them describe what they see. You might want themto suggest some physical characteristics of the eggssuch as color, size, form, etc. Record these com-ments and then introduce the binocular micro-scopes to the children. Make sure each child getsto see the eggs through a binocular.

During the next several days, encourage moreobservation and record-taking. The children mightbegin their record books or notebooks with a set ofthree drawingsone representing what they see withtheir eyes alone, one of what they see through thehand lens, and finally, their view through the binoc-ular. If a quick sketch of each "optical system" (eye,lens, binocular) appears next to the drawing for eachsystem, there will be little confusion about what eachpicture represents.

The children might want to try testing some oftheir guesses about the objects' identity. If one orseveral children suggested that the eggs were seeds,for example, have them plant the "seeds" and ob-serve the results.

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At some point, someone may suggest that these"things" are eggs. Since you cannot expect most ofthe students to know they are brine shrimp eggs,you might now disclose this, but try to avoid describ-:ng the eggs' appearance.

Hatching Brine ShrimpA bit of mystery surrounding the identity of the

round, brownish eggs may now have disappeated.But enthusiasm can be regenerated by the prospectof hatching the eggs. (Before the class gets involved.you will want to become familiar with the hatch-ing procedures yourself by actually hatching someof the brine shrimp eggs. See the back of the book,page 14, for detailed instructions.)

Encourage close observation on the part of thechildren. This will be best accomplished if eachchild has his own eggs for hatching. A personalsupply is also helpful in case the children wantto compare their cultures,

Permit the children the freedom of making somemistakes. Possible sources of error can be discussedwhen they are making comparisons between theirresults. The children will have a base for these com-parisons if they keep careful records or drawingsof their procedures.

MATERIALS

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When the time seems appropriate to begin hatch-ing eggs, assemble the materials and display thembefore the class, As the materials are viewed andas questions about them arise, you may wish todiscuss the use for each item. Inform the childrenthat each student will be responsible for hatchinghis own eggs and tell them how you have done it.Demonstrate the procedure for them. You may haveto repeat the directions several times.

Supervise the procedure but try to limit do's anddon't's to a minimum. For hatching the eggs, eachchild may obtain his own babyfood jar from thematerials on the table ant! his own supply of water.

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Have each child add the necessary amount of salt,put the cap on the jar, and shake it. Ask what hap-pened to the salt. Next, each child should place a"pinch" of eggs into his brine mixture. Finally, thechildren can put their names on their jars, usinga grease pencil.

STEP 1Make BrineMixture

STEP 2Add EggsTo BrineMixture

STEP 3Put NamesOn Jars

At this point you might ask the students whenthey think something will happen. You might wantto have each child estimate at what time he thinkschanges will take place in his jar. List the variousestimates on the board with the corresponding name.

Make up several of your own cultures to insurea continuing supply. Encourage the children to drawpictures of the procedures as they make their owncultures.

When they are finished, have them discuss whatthey think is going to happen. Have them imaginewhat the eggs will develop into and then have themdraw pictures of their imagined ideas, to compareand discuss. Perhaps each child could also tell astory about why he thinks the hatched eggs willlook like his drawing.

Observations of the eggs can be made at inter-vals during the next two days. Some of the childrenmay wish to view several eggs with the binocularmicroprojector, the binocular microscope, or thehand lens. To use this equipment the children willhave to remove some of the eggs from the baby-food jars and place them on well slides. Have them

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the! a edi- dropper or soda straw to place.4 .0t1' one drop of water containing eggs into the

pry .sion on the slides. They should then placeslides on the equipment. Demonstrate how toe soda straw as a pipette by placing it in theto the desired depth (about 14 inch), placing

across the upper opening, and then liftingaw. Straws may be cut in halves or quarters tomodatt. small fingers.

W n the first egg hatches have the class try to'.-te tine how long it took in hours. Each childAoki!;1 record this figure for his own set of eggs.lot! may need to help.)As more and more eggs hatch, the children will

you with questions. Answers to many of these;tiestionis (an be found by the children themselves,,hro:igh observation and investigation. Ask the chil-dren if the appearance (the look) of the shrimp.surprises them. Do any of their drawings resemblethe shrimp?

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After HatchingWhen all the children have successfully hatched

some shrimp, you will have to nandle their ques-tions. guide their investigations, and promote fur-ther observation. You can expect a wide variety ofquestions ranging from "Are they alive?" to "Whatdo we feed them?" Within reason, permit the chil-dren to explore all the possible answers to theirquestions. Try to avoid imposing too much structureon their investigations. Some possible categoriesof observations and investigations follow. The dis-cussions that accompany the observations and in-vestigations, together with the background informa-tion on brine shrimp (see the back of the book, page14), should provide you with the data needed toguide the children through their activities.

NINTERIALS

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i. Observations and Investigations

A. Physical CharacteristicsThese are easily observed through the hand lensor binocular microscope. The shrimp have twoeyes, various numbers of jointed appendages (de-pending on their age), and a jointed tail section.

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B. MaintenanceThe back of the book, page 14, tells how to prop-erly feed and care for the shrimp. If the childrenwish to try food other than the yeast, permit themto do so, but recommend tiny portions.

C. Behavior and response to the environmentShrimp behavior, like that of all organisms, de-pends upon both internal and external environ-mental conditions. Positive and negative reac-tions to light can be observed using the lightsource. The light could be shown for a few min-utes on one side of a jar containing brine shrimpand then the light could be removed. Note anyreactions of the shrimp. Perhaps the children canalso determine if the shrimp react to varying saltconcentrations, to each other, to temperaturechanges, etc. (See page 8.) One aspect of be-havior easily observed is the means of locomo-tion. The shrimp swim on their backs using theirappendages as we would use oars.

D. ReproductionTry to maintain a culture long enough for theshrimp to reproduce. A female's first set of off-spring will be born as tiny shrimp. Her next setwill be born as eggs. (See page 14.)

E. Life requirementsSome children may want to know if the eggs willhatch in non-salt water or another liquid. Allowthem to experiment. They might also ask whetheror not the shrimp will live in non-salt water. (Seepage 12.) Transfer some live shrimp to tap waterand have the children observe the results. Ifsomeone asks, "Do they breathe "' transfer oneshrimp to a small container and have the childobserve one closely to see if he can detect any-thing he thinks is evidence of breathing. Try toget the child to observe a single shrimp eating.How does he know it is eating?

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F. Population factorsSome cultures will contain more shrimp thanothers. One reason could be the initial numberof eggs placed in the water. There are always livebaby shrimp being produced, but there will be anincreasing reserve of eggs which must be driedin order to hatch. Other reasons for differences inpopulation density might be the salinity of thewater, overcrowding. etc. See if a child can counthis own shrimp. If so, he may wish to transfer aknown number of them to water containing differ-ent amounts of salt to see if salinity has anyeffect on the populations. (See page 9.)

During the course of the activities encourage draw-ings, stories, and as much discussion of observa-tions as possible. When it seems appropriate, youmight ask the children if they have reported whatthey have seen to their parents or to brothers orsisters. This might be one indication of interestleveI.

II. Additional TopicsThese topics for discussion and investigation rep-

resent several levels of difficulty. Select only thosewhich could be discussed and investigated by mostof the students in your class.

A. Salt LakesMany of the children will wish to know wherethe shrimp live. They are collected from saltlakes, mostly in Utah and Southern California.and you might wart to indicate these locationson a map. Here is an opportunity to involve theclass in some geography. Try to get them to seethat salt lakes exist only in certain parts of thecountry and that there are relatively few of them.The children might want to discuss possible rea-sons for why the salt lakes are found where theyare.

B. Other ShrimpBring to class some unshelled edible shrimp.Discuss similarities and differences betweenthese and the brine shrimp. There is also a tinyfresh water shrimp called a fairy shrimp. Thoughrarely found around metropolitan areas, you maybe lucky enough to collect some from ponds inthe spring and compare them with the brineshrimp.

C. Food ChainsIf you have an aquarium with tropical fish, youmight demonstrate something about food chainsby feeding the shrin p to the tropicals. First, washthe shrimp under tap water by placing them in avery fine mesh net (nylon hose will work well).Remind the children that the shrimp eat tiny

plants found in water. Finally, have them suggestpossible predators of the small tropical fish. Thechildren might want to draw pictures of this foodchain and enter them in their record books.

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O. Color, Temperature, and LightMaintain several brine shrimp cultures over thryear. A numbev of interesting experiments can betried. For example, the class might try hatchingand raising several generations of shrimp in com-plete darkness or contir'uous fight. Keep someshrimp in the refrigerator to note the effects ofcooling. Also, students might place non-toxic foodcoloring in the water to discover some of theinternal structure of the shrimp. This can be doneby placing the shrimp in colorless water after theyhave absorbed the food coloring from the firstcontainer.

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Effects ofEnvironmental Variables

In the pieceding activities. the children havehatched brine shrimp eggs and have made someinitial observations. In this next section, the chil-dren will carry out some investigations relating tothe shrimp's response to its environment. You willprobably want to select several of the activities in-cluded in this section for the entire class to do, or,have ditferent groups select for themselves the ac-tivities that especially interest them. In addition, youwill want to have the students devise some of theirown experiments to add to those from the unit.

Should two or more groups do the same experi-ment, have them compare their results and discusstheir findings with one another. If they do not getthe same results, encourage them to seek reasonsfor the dIfforonces. Stress the record-keeping aspectof these activities so that accurate comparisons canbe made.

When the class has completed its investigations,the students might wish 'o compile a class notebookcontaining descriptions of their experiments, results,and conclusions. The notebook would provide a val-uable reference for the children, especially if theyreturn to their textbooks for background reading.By relating their experiences with brine shrimp totext material, they will broaden their exposure tolife cycles and environments.

I. Hatching in Various Liquids

INATIMALS

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Have students assemble or prepare about one cupof each of the following liquids and solutions:

1. Unsalted tap water2. Unsalted pre-boiled water3. Tap water, properly salted with iodized salt,'

teaspoon of salt per every ounce (2 table-spoons) of water. (See the back of the book,page 14.)

4. Preboiled water, properly salted with iodizedsalt

5. Tap water, properly salted with non-iodizedsalt

6. Preboiled water, properly salted with non-iodized salt

7. Tap water that has as much iodizej salt in it

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as it will dissolve- (saturated with the salt. Asaturated solution is one in which the salt nolonger dissolves but precipitates out of thesolution).

8. Preboiled water. saturated with iodized salt9. Tap water, saturated with non-iodized salt

10. Preboiled water, saturated with non-iodizedsalt

11. Vinegar12. Alcohol13. Salad oil14. Other combinations of liquids and solutions

Assign each student or team of students a solu-tion in which to try to hatch the eggs. Have the stu-dents place approximately the same amount of eggsin each solution. A level eighth of a teaspoon mightbe a convenient amount. The students might wantto make their own measuring device. Whatever theydecide upon, all students should use the sameamount of eggs per jar.

Place the containers in approximately the samelocation to keep external conditions as nearly thesame as possible. Have the students make guessesas to which liquids will best hatch the eggs. Stimu-late guesses by asking questions like, "Do you thinkthe eggs will hatch in all the containers?" Havestudents record their guesses. This is a good placeto discuss the value of hypothesizingmaking in-telligent guessesin science.

Label each container and check every few hoursfor live brine shrimp. Have the students keep accu-rate records. After two days, compare the numberof hatched brine shrimp in each container. Discussways of counting the hatched shrimp so that accu-rate comparisons can be made between jars.

It would be good if the students themselves coulddevise a method of counting or estimating the num-ber of hatched brine shrimp in a jar. Again, what-ever procedure is decided upon, each student orgroup should use that same method. In this way,comparisons between jars will be more meaningful.

One way to estimate live shrimp population in ajar would be to take a measured sample of theliquid, count the number of shrimp in the sampleand multiply that number times the number of liquidmeasures in the entire jar. For example, you mightfind that the jars your class is using each holdtwenty-five thimblefuls of liquid. If you take a thim-bleful of the solution, count the number of liveshrimp in that thimble sample and then multiplyby twenty-five, you will get an estimated shrimppopulation for the whole jar. Whichever method thechildren decide to use, they should mix their solu-tions gently before sampling (possibly by cappingand shaking slightly), so that the shrimp will beevenly distributed throughout the solution.

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BEST COPY AVAILABLEtainers in similar locations (regarding temperatureand light) and make sure that the teams keep rec'rdsof their observations.

After two days, compare the number of live shrimpin each t ontainer. This time arrange the containersin order of salinity. You may simplify the record-keeping by establishing a scale and symbols for esti-mating the number of live shrimp. A zero (0) mightstand for no live shrimp; one plus sign ( ) mightrepresent very few shrimp (1.10); two plus signs( ). many shrimp; and three plus signs ( 4

l ),

very many shrimp. Constructing a histogram withthis scale to record the results at the end of two daysmight help the students zero in on the important con-cepts without getting bogged down in statistical data.

ASK THE STUDENTS:Were there solutions or liquids in which no eggshatched?Were there some containers in which more eggshatched than in others?Was there much difference in number of eggshatched between the tap water solutions and thepreboiled water solutions?Did the amount of salt seem to make a difference?Did the iodized salt keep eggs from hatching?Can you make any general statements about thesolutions in which brine shrimp eggs will hatch?

Do not allow students to make statements thatare not supported by the evidence. Repeat portionsof the experiment that your students .eel were riotconclusive. New would be a good time to discussthe value of experimentation where results are notdefinite and general statements cannot be made.

Have students compare the results of the experi-ment with the guesses or hypotheses they madeearlier. Discuss how scientists must sometimes giveup **pet" ideas when the results of their experimentsdo not support these.

Have the class continue to observe for two weeks.Ask: Are there any live shrimp in solutions wherethere were none before? If so. what does this indi-cate about the time it takes brine shrimp eggs tohatch? Did any statements have to be revised?

Hatching in VariousSalt Concentrations

MATERIALShor m0000sod amounts

lad wader of brio* shrimpoggsnotWodized set salt measure

In this section, the students will experiment withhatching the brine shrimp eggs in solutions withdifferent salt concentrations. Divide the class intoteams of two students each, and provide each teamwith a container (for example, a babyfood jar.). Makesure that there is an equal amount of pre-boiledwater in each of these containers.

Now have each team dissolve a different amountof salt into the water of its container. The range ofsalinity in the , lassroom should be from unsalted tosaturated. The students should decide what quantityof salt they wish to test, as well as a standard meansof measuring the quantity so that they may comparetheir results.

When this has been accomplished, an equalamount of brine shrimp eggs should be placed ineach container. Have the students store the con-

The following sample shows one method the stu-dents could use for plotting their information on ahistogram. The information used is intended as asample and does not necessarily reflect the data thestudents would find. The horizontal axis representsthe relative degrees of salinity, ranging from no saltto a saturated solution. The actual amounts of saltthat each relative number represents will depend onthe amounts the students have chosen for their dif-ferent solutions. The vertical axis indicates relativenumbers of live shrimp, ranging from none to verymany. Information plotted for the various solutionswill provide the histogram.

129

HATCHING AT VARIOUS SALT CONCENTRATIONS

0 2 4 6 8 10 12 14

TEASPOONS SALT PER CLIP OF WATER

(AT ROOM TEMPERATURE)

Discuss the results with tho students. Can theymake any general statements as to how salinityaffects the hatching of brine shrimp eggs? Have themcontinue to observe and record for two weeks. Theycan make histograms showing the results after oneweek and again after two weeks.

ASK THE STUDENTS:Were there containers in which no eggs hatched?Were there containers in which few eggs hatched?How did the salinity affect the time it took the eggsto hatch?Might a longer period of observation produce newdata?

III. Hatching Eggs Under Various Conditions

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Do brine shrimp eggs need air, light, or warmth inorder to hatch? For this activity, the hatching solution should have been stored in full, sealed con-tainers, prior to use, so that almost no air will re-enter the solution after the air has been removed byboiling.

Have the students place the same amount ofhatching solution in each of eight containers, sothat each is filled nearly to the brim. Next, have thestudents place a small, equal amount of eggs in eachcontainer and then add enough more hatching solu-tion so that each jar is brimful,

aiiIMIMM11

Then have the students place one of the eight con-tainers uncovered in a warm, light location. A secondcontainer should be placed next to it, but the airmust be excluded by putting a cap on the jar. (Inorder to exclude as much air as possible, you maywant to cut out a cardboard spacer disk to fit insidethe cap and to take up any extra air space). Have thestudents place two more containersone with andone without a capin the same location as the firsttwo, but exclude light from the second two by cover-ing them with boxes of black construction paper.Have the students also place two more of the con-tainers, (one capped and one not) in a refrigeratorand the last two (one capped and one not) in a coldplace where they will receive light. You will probablybe able to have these last two conditions only duringthe cooler months of the year when you can place thecontainers in tne sun outside a window. Label eachcontainer appropriately as follows :

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CONDITION CHART,--womemmism

Condition 1: Warm, J.ight, Air

Condition 2: Warm, Light, No Air

Condition 3: Warm, Dark, Air

Condition 4: Warm, Dark, No Air

Condition 5: Cold, Dark, Air

Condition 6: Cold, Dark, No Air

Condition 7: Cold, Light, Air

Condition 8: Cold, Light, No Air

At regular intervals (perhaps once a day) for twoweeks. have the class observe the eggs under thepreceding conditions.

ASK THE STUDENTS:In which container did the eggs hatch first?Were there containers in which no eggs hatched?Compare the containers thz t were warm with thosethat were cold. Does temperature affect the hatchingof eggs?Compare the containers that were in tie light withthose that were in darkness. Is light necessary forthe hatching of eggs?Compare those containers which were exposed tnair with those from which the air was excluded. Dothe eggs need air to hatch?

In the last comparison, be sure to make a distinc-tion between hatching ano continuing to live. Eggsmay hatch without air. but live shrimp soon die.

IV. The Effect of Light o.-aLive Brine Shrimp

MATERIALS

test tubes with corks(any small, long,narrow, transparentcontainer will do)

black constructionPaPer

live brin e shrimpflashlights

Divide the class into teams and provide each teamwith a flashlight and a test tube. Have each team fillits test tube within one-half inch of the top with solu-tion containing Iive brine shrimp, Have each teamcork its tube tightly and place it on its side, support-ing it so it will not roll. Then each team should shinea flashlight on the tube at right angles so that thebeam illuminates only one end of the tube. The lightshould be left shining on one end for several minuteswhile the behavior of the shrimp is being noted. Nowthe flashlight should be moved so that it illuminates

the other ',nd of the tube. Ask the students whatthey Does the light appear to have anyeftse,t shr imp:'

T..11111116.

Have the students make a black constructionpaper sleeve and cover orie end of the test tube withit. Make sure they leave the other half of the tubein daylight. Have the students lay the test tube onits side, supported so it will not roll. They shouldcarefully remove the sleeve after one-half hour andcompare the number of shrimp in each half of thetube. Discuss the results.

V. Conditions Needed forBrine Shrimp to Grow

On the day you wish to begin this next section,have the students, as a group, set up one class set(eight jars) of the same eight conditions as thosedescribed in Part Ill, "Hatching Eggs Under VariousConditions." (See page 10.) But this time, place anequal number ef life shrimp in each jar using shrimphatched according to the instructions in the back ofthe book. These eight jars are control groups. In theactivities which follow, they will be used by the stu-dents as standards for making comparisons. At thispoint, you will probably want to explain what a con-trol group is and why it is needed in a scientificexperiment.

11

BEsT copy AVAILABLENi:.. have .. h team of two students make up

one jar usim; will, never one of the eight environ-mental conditions they wish. They will need to fol-low directions given in Part III with regard to tern-per,thire. light, air iio,htness, and so forth. Also, eachteam must put the same number of live shrimp intoits jar as is contained in each control group jar.

One team may decide to have a Warm, Light, NoAir condition for its jar, another a Cold, Dark, Aircondition. etc. In this way. the members of eachteam will be able to compare the concitions in theiron jar with conditions in three of the other controljars For example. a team with a Warm, Light, No Aircondition should compare the life in its jar with theWarm, Light, Air control jar. or with the Warm, Dark,No Air control jar, or Cold, Light, No Air control jar.Each comparison would involve a single variable.Hopefully by making suco comparisons, the studentswill be able to arrive at some preliminary generali-zation: and conclusions, based on their own ob-servations.

Have the teams keep records of their observationsover a two-week period. Discuss the results. Havethem grapo their findings where possible. You willwant to ask such questions as: How long did theshrimp survive without air? Did darkness affect theshrimp in two weeks? How long did the refrigeratedshrimp survive? (See the back of the book for 1'2"and 3/4" grids that can be reproduced.)

These investigations should establish some of theconditions necessary for brine shrimp to grow. Nowwould be a good time to discuss conditions underwhich various other organisms prosper. Discuss theneed of all living things for air and food. Discussthe importance of temperature. (You might want torefer to Fish and Water Temperature, another unitin this series.)

Set up a "shrirnparium." Any large jar will do. Ifpossible, aerate the solution with an aquarium aera-tor. Try to raise shrimp until they produce a newbatch. It might be interesting for the class to seehow large brine shrimp get.

VI. The Effect of Various Liquids onLive 3rine Shrimp

12

Have the students place one drop of alcohol intoa container of shrimp, and have them observe theshrimp for a few minutes. Then have them repeat thiswith other liquids in other containers. They shouldcontinue to add liquids, one drop at a time. Ask:Which liquids affected the brine shrimp mostquickly? Did all liquids finally kill the shrimp?

VII. Examining Dead Brine Shrimp

MATERIALS

mkroprojector or microscope wellmicroscope slide

vinegar live brine wimpmedicine dropper

Have the students place a drop of water contain-ing dead brine shrimp on a slide. Have them placethe Glide under magnification and observe theshrimp. Ask: What body parts can you identify?Have them notice the black spot on the head, theorange portion of the body, the antennae, and thetwo large "legs." Have the students draw picturesof a brine shrimp.

FOR DISCUSSION:How are the brine shrimp adapted for their environ-ment? Where would you expect to find brine shrimpin nature? What factors affect their life-span?

15

The Beek of the Book

1613

Background Information

The brine shrimp (Artemia solaria) is a member ofthe phylum Arthropoda and the class Crustacea.Arthropods share the common characteristic. ofjointed, movable appendages. All crustaceans havea chitinous exoskeleton which is typified by theexternal coverings of crayfish and lobsters. With theexception of lobsters and the king crab, most crus-taceans are small, not exceeding one eighth to one-half inch in length. Fresh water relatives of brineshrimp are the fairy shrimp (a "look-alike" organismfound in most ponds), and Daphnia, which is alsofound in ponds and is used as fish food.

Sant lakes, sinks, and ponds in the western por-tion of the United States are the primary sources ofbrine shrin p eggs. They are found less frequently inthe ocean The Great Salt Lake in Utah is an espe-cially rich source of shrimp eggs where, blown bythe wind and consequent wave action, they accu-mulate on the lee side of the lake. There the eggsare gathered and packaged for pet supply storesand biological supply houses.

An adult female will produce young in your cul-tures when cultivated under optimum conditions.Her first batch will be born as tiny immature forms(baby shrimp): her second will be produced as eggs.Examination of the eggs reveals them to be small,indented. spherical structures which must be driedbefore they will hatch. Drying is a means of survivalfor these organisms. Their ability to withstandiengthy periods of drought insures the preservationof the species. It has been estimated that somedried eggs may remain viable for periods of ap-proximately ten years.

Upon soaking in a salt solution (brine) the eggsswell, burst, and a tiny pre-adult form of the shrimpcalled a Nauplius emerges. Increasing the salinityof the water shortly after the shrimp are hatchedprovides a more favorable environment and con-tributes to the rapid growth of the organisms. Suc-cessive molts produce a mature adult whose formand behavior is somewhat different from the Naup-lius. With proper care and feeding, the adult mayreach an overall length of one-half inch within sixweeks after hatching if the temperature is kept atapproximately 28 degrees C. or 82.4 degrees F. (Theorganisms are killed by heat in excess o; thisamount.)

If you examine a mature brine shrimp with astereo-binocular microscope, you will see that itcharacteristically swims on its back, exposing sixto eight pairs of appereAges. These structures func-tion both as a means of locomotion and as gills for

14

breathing. The number of appendages increases withthe age of the shrimp.

Upon hatching, the young shrimp will gather wherethe most light is available. A shrimp has two com-pound eyes which are thought to perceive light,shadow and movement, but not images as do verte-brate eyes. The adults, however, respond negativelyto light. It is interesting to speculate upon the sur-vival value of various responses to light at differentstages in the development of the organisms.

1. Hatching Feeding, and Caring forBrine Shrimp

In order to hatch the shrimp, a general "recipe" tofollow would be to use sixteen teaspoons of non-iodized salt per one quart of water. (A simplified ruleof thumb is to use 1/2 teaspoon of salt per everyounce, or 2 tablespoons, of water.) It is a good ideato age or pre-boil the water to remove chlorine, andto do the mixing in a large, flat (2" depth) containerfor aeration. Non-iodized salt may be found in mostgrocers but if it is not available, rock salt used formelting ice in the winter will also work.

After the sdlt and water are mixed, sprinkle theeggs onto the surface of the water. Depending on thetemperature of the room, the eggs will hatch in 24 to48 hours. The higher the temperature, the more rapidthe hatching. Some sources recommend tempera-ture around 80 F. for the most rapid hatching. Stirthe eggs from time to time to insure proper aeration.

The eggs will hatch into a Nauplius stage of de-velopmenta form many crustaceans take beforedeveloping. through successive molts, into an adultform. If you have success in getting the shrimp toreproduce, the first set of new organisms will beborn as baby shrimp, the second set (from the origi-nal mother) will be produced as eggs. These eggswill need to be dried before they can be induced tohatch.

After the shrimp hatch, they will live for sometime before they require food, but this does notmean they need not be fed at all. The most easilyobtainable food is brewer's yeast. Small pinches ofit may be fed once or twice a week. For best re-sults in obtaining large adult shrimp, make certainthe cultures are not crowded. Over-population ofthe culture results in decreased oxygen supply, anaccumulation of wastes and undersized shrimp.Small (1/2 teaspoon) amounts of bicarbonate of sodamaintains the alkalinity of the water, counteractingthe effects of accumulated carbon dioxide producedby the breathing organisms.

17

111. Bibliography

Teacher

Buchsbaum, Ralph, Animals Without Backbones.Chicago, University of Chicago Press, 1948.

Buchsbaum, Ralph, and Lorus Milne, The LoverAnimals: Living Invertebrates of the World. Gar-den City, N.Y. Doubleday and Co., 1966.

Carthy, J. D., Animals and Their Ways: The Scienceof Animal Behavior. Garden City, N.Y. NaturalHistory Press, 1965.

Engel, Leonard, The Sea: (Life Nature Library). NewYork, Time, Inc. 1963.

Feldman, S. E., Experiments in Biologic.. Design.New York. Holt, Rinehart and Winston, Inc., 1965.

Tinbergen, Niko, Animal Behavior: (Life NatureLibrary) New York, Time, Inc., 1965.

Student

Engel, Leonard, The Sea: (Life Nature Library). NewYork, Time, Inc. 1963.

Headstrom, Richard, Adventures with a Hand Lens.Philadelphia, Lippincott Co., 1962.

Ray, Carleton, Wonders of the Living Sea. NewYork, Parents Magazine Press, 1963. (grades 4-8)

Ray, Carleton and Elgin Ciampi, Underwater Guideto Marine Life. New York, A. S. Barnes, 1956.(grades 4-6)

Reed, William M. and Wilfred S. Bronson, The Seafor Sam. New York, Harcourt, Brace and World,1960.

Selsam, Millicent E Greg's Microscope. New York,Harper Row, 1963.

Selsam, Millicent E., Underwater Zoos. New York,Wm. Morrow and Co., 1961.

1815

3/4- AND1

" GRAPH PAPER FOR UPL GATING

16 19

THE ENVIRONMENTAL UNITS

Below is a list of the first titles in the Environmental Discovery Series.The ones with order numbers next to them are available as of January, 1972.The others are in preparation and will be available in the coining weeks.Also, ten additional units will beannounced soon.

Next to the titles, we have suggested the grades for which each is mostappropriate. We emphasize that these are suggested grade levels. Theteacher is encouraged to adapt the activities to a wide range of grade levels,and subject areas depending upon the interests and abilities of the students.

OrderNo. Title

GradeLevel Price

OrderNo. Title

GradeLevel Price

79007 Plants in the Classroom 3-6 $1.50 79132 Soil 2-9 $1.50

79016 Vacant Lot Studies 5-9 1.50 79141 Tile Patterns and Graphs 1-2 1.00

79025 Differences in Living Things 4-8 1.00 79150 Plant Puzzles 1-6 1.50

79034 Shadows 1-8 1.00 79169 Brine Shrimp and Their Habitat 1-5 1.50

79043 Wind 3-6 1.50 Nature's Para in Art 3-6

79052 Snow and Ice 1-6 1.50 Change in a Small Ecosystem 5-9

79061 Man's HabitatThe City 4-9 1.50 Micro-Communities 3-9

79070 Fish and Water Temperature 4-9 1.50 Plants Outside the Classroom 3-9

79089 Oaks, Acorns, Climate and Squirrels 1-6 1.50 Contour Mapping 4-9

79105 Nature Hunt Spec. Ed. K-1 1.00 Stream Profiles 4.9

79098 Sampling Button Populations 3-9 1.00 Color and Change K-2

79114 The Rise and Fall of a Yeast Community 6-9 1.00 Water Quality 5-9

79123 Genetic Variation 4-9 1.50 Outdoor fun for Students 1-12

If you would like a free brochure describing activities in the individual units, write:

The National Wildlife FederationEducational Servicing1412 16th Street, N.W.

Washington, Co. C. 20036

Written and developed by:

NWTJames D. DavisKathleen Di Blasi°Wendy KayB. J. MitchellPhil NicholsonTom L SmithJohn Cary Stone

MESFEdmund BrayBarbara ClarkRobert CollinsJoann CurrentJohn HeitkampDavid Jones

Karen JostadEdward LandisRichard MyshakMichael NaylonRobert O'HaraNoreen TeachoutCarl Vogt

NATIONAL WILDLIFE FEDERATION1412 Sixteenth Street. N.W.Washington. D.C. 20036