Echinoderm Biology as an Underlying Theme of Our Biology Course

SueAnn Bryant, Ashley Cooper, Dana Grooms, Carl Reichenberger

Objective:

To incorporate local echinoderms, their anatomy and reproduction, into existing topics we teach in our 10^th grade CP/S and 9^th grade H biology class.

Introduction:

The curriculum in our biology class in the past has been text book driven, with little emphasis on continuity of topics between the chapters. Sea urchins seem to us, to be a familiar yet unique organism with which to grab the student’s attention and to act as a unifying factor to help the students realize the interrelationship of topics in biology. We feel that this approach will help our students at all levels achieve better success in biology.

Curriculum

The following is a list of topics in which we can insert labs or activities using echinoderms and a short description of the activities we have in mind.

a. Echinoderm observation lab—a class introductory activity in which the students will be given 3 echinoderms (sea star, sea urchin, and sea cucumber) with which to make detailed observations.

b. Microscope lab—we will add a component to our existing lab in which students will observe, draw and measure sea urchin gametes.

c. Osmosis lab—we will add a component to our existing osmosis and diffusion labs in which students will expose sea urchin eggs to different concentrations of sea water and observe the effects on the eggs. The effect of the different salinities on fertilization will also be examined.

d. pH lab—we will add a component to our existing pH lab in which the students study the effect of an acidic or basic pH on fertilization rate.

e. Mitosis/meiosis/development—observing the fertilization and early development of a zygote

f. Evolution—a dissection lab of 3 different echinoderms comparing form to function. Here we will also have a discussion of phylogeny. Using Biology Workbench, we can examine the DNA or amino acid sequence of proteins from different organisms to see how closely related they are.

g. Ecology lab—examine the effects of heavy metals, acid rain, oil spills, pesticides and global warming on sea urchin fertilization rates.

Resources:

Some of the lab activities can be found on the following pages.

Echinoderm Observation Lab

Objective: Students will be able to identify common external physical characteristics of Echinoderms. Students will accurately illustrate and be able to differentiate between the various echinoderm species. Students will be able to recite the common characteristics of the Phylum Echinodermata.

Materials: •multiple specimens of a sea star, a sea urchin, a sea cucumber, a bat star, brittle star, a sand dollar, or any other available readily available echinoderm species

•white paper

•colored pencils

•metric ruler

Time for Activity: 1 – 2 class periods.

Prior Activities: •The students will have read information in their text books introducing the classification of the Phylum Echinodermata and the associated physical characteristics.

•The teacher will lecture on the four major shared characteristics of Echinoderms: the endoskeleton, pentaradial symmetry, water-vascular system, and coelomic circulation and respiration.

Procedure: The lab will be set up in a rotating station format around the lab tables in the classroom. Each student will have a few sheets of paper and colored pencils. The teacher will assign the lab partners which station to begin at and will allow 10 minutes at each station for the partners. The students will observe the specimen and transcribe detailed notes that describe their observations. The students will use their ruler to make measurements of the specimen’s appendages and unique land marks. The students will use the colored pencils to draw the Echinoderm specimen as true to life as possible. The partners will collaborate to discuss and assist each other in identifying key physical characteristics.

After the lab activity, the teacher will lead a discussion to highlight the important physical characteristics of the Echinoderm species. The students will be able to ask questions to clarify their observations.

Assessment: The students will take their drawings home and use either the text book or Internet to help identify the physical characteristics in their illustrations. The student drawings will be assessed according to accuracy in the illustration and

the identification labels.

Activity Expansion: •The students will make a T-chart that lists common Echinoderm characteristics displayed by the specimen in one column and in the other column the student will list the physical characteristics that are unique to this echinoderm sample.

•The students will list the adaptations that they observe and then describe why that adaptation has evolved for that particular specimen.

OSMOSIS: THE EFFECT OF SALINITY ON SEA URCHIN EGGS

PROBLEM: How are sea urchin eggs affected in shape & size by different salinity levels of sea water?

What will happen to sea urchin eggs placed in water with different salinity levels, as occurs naturally, often based on conditions such as location and ocean depth?

You will examine two sets of data: your sea urchin eggs at the onset of the lab, and the same specimens 24 hours later (the next day of class). You will have an opportunity to use the microscope in the process. Be prepared to observe lysis (explosion) and/or crenulation (shriveling) of your eggs. At the end of period one, you may also be able to examine the effect of different salinities on fertilization, for which you will need another lab sheet.

MATERIALS: sea urchin eggs, 3 plastic cups (labeled: “3.5% salinity” for the control, “0% salinity,” and “5% salinity.” It may be useful to add a bit of green dye to the 0% solution and a bit of red dye to the 5% solution to help differentiate between solutions.), microscope, and pipette.

PROCEDURE:

1. Obtain specimen (a drop) of sea urchin eggs; examine under the microscope. Draw, measure, & record the average diameter of 10 sea urchin eggs. Count 50 eggs in a field of view, and record whether the eggs are normal, lysed, or crenulated.

2. Place .5mL of sea urchin eggs in each of the labeled cups, each cup containing 20mL of the appropriate degree of salinity: 3.5% salinity (control), 0% salinity, and 5% salinity.

3. After 24 hours, prepare another microscope slide. Repeat step one: drawing, measuring, and recording the average diameter of 10 sea urchin eggs. Count 50 eggs in a field of view, and record whether the eggs remain the same (are normal), are lysed, or are crenulated. Compare the percentage of each (normal, lysed, and crenulated) in the various solutions between day one and day 2, and record your results in a data table.

DATA TABLE

	“0% salinity”	“0% salinity”	“35% salinity”	“3.5% salinity”	“5% salinity”	“5% salinity”
	1^st Day	2^nd Day	1^st Day	2^nd Day	1^st Day	2^nd Day
Egg diameter
%, Normal
%, Lysed
%, Crenulated

ANALYSIS QUESTIONS:

1. What is the relationship between salinity and changes in shape and size of the sea urchin eggs?

2. Plot on a graph the number of eggs in each category from the three specimens on Day 1 and on Day 2 on a piece of graph paper. Predict the water concentration at which the sea urchin eggs would not change in shape or size.

3. Describe an experiment that would test your prediction.

4. Has this investigation answered the question posed in this experiment? Explain.

TITLE: EFFECT OF pH ON THE FERTILIZATION OF PURPLE SEA URCHINS (Strongylocentrotus purpuratus)

PURPOSE: Students will investigate the use of fertilized sea urchins ova for differing pH levels between 5.0 – 8.0 (neutral sea water) to simulate what effects environmental pollution (i.e. acid rain) has on embryonic development.

MATERIALS:

Sea Urchins- eggs and sperm. Follow procedure of core lab.
Instant Ocean
Citric acid or acetic acid to lower pH to desired levels
Microscopes
_PH paper or pH meter
Glass slides
Pipettes

METHODS:

Place 2 drops of 8.0 salt water (control) on glass slide
Add one drop of eggs to the salt water
Add one drop of sperm to the eggs and salt water
Observe with 100x magnification
After 5 minutes, record the number of fertilized and unfertilized eggs out of the first 50 eggs seen
Record results in data table
Repeat 2x for same pH
Repeat steps 1-7 using the following pH: 5.0, 6.0 and 7.0
Complete Data Tables and compare results with other groups

Name _______________________

EFFECT OF pH ON THE FERTILIZATION OF THE PURPLE SEA URCHIN

DATA TABLE

Percent of Fertilized and Unfertilized Eggs for Different pH

Trial Number	_PH of Salt Water	Number of Eggs	Number of Fertilized Eggs	Percent of Fertilized Eggs	Number of Unfertilized Eggs	Percent of Unfertilized Eggs
Trial 1	8
Trial 2	8
Trial 3	8
Trial 1	7
Trial 2	7
Trial 3	7
Trial 1	6
Trial 2	6
Trial 3	6
Trial 1	5
Trial 2	5
Trial 3	5

Average Number of Fertilized and Unfertilized Eggs and Average Percents of Fertilized and Unfertilized Eggs

_PH of Salt Water	Average Number of Fertilized Eggs	Average Percent of Fertilized Eggs	Average Number of Unfertilized Eggs	Average Percent of Unfertilized Eggs
8
7
6
5

CONCLUSION:

What pH had the greatest percent of unfertilized eggs? Was this much different than your other results?

What inferences can be drawn from your results?

What extrapolations can you derive from the results and use them in real world situations?

Echinoderm Evolution Lab

We will conduct a dissection lab of 3 different echinoderms (sea star, sea urchin, sea cucumber) to compare their anatomical structures. The links listed below have lab procedures outlined to use as individual teachers desire. We will also have an investigation of the phylogeny of echinoderms.

Starfish dissection:

http://www.d91.k12.id.us/www/skyline/TEACHERS/ROBERTSD/starfish.htm

Introduction to echinoderms:

http://www.tulane.edu/~bfleury/diversity/labguide/echinchor.html

Dissection of all types of echinoderms:

http://faculty.uccb.ns.ca/jfoulds/courses/invertebrate/labmanual/web/chpt11.htm

Dissection of a sea cucumber:

http://www.lander.edu/rsfox/310cucumariaLab.html

Starfish dissection:

http://www.villagegreen.net/vg/teachers/sikes/starfishdissect.pdf

Sea urchin dissection:

http://www.hoala.org/marine%20biology/SeaUrchinLab.html

Pictures and phylogenetic tree of echinoderms:

http://www.sfu.ca/~fankbone/v/lab11.html

Part 2 of the investigation will use Biology Workbench to compare amino acid sequences of proteins found in different organisms to see how closely related they are.

1. Students will use Biology Workbench to find and compare sequences of proteins.

a. Go to the Biology Workbench site: http://workbench.sdsc.edu/ and register to access the program

b. Click on SESSION TOOLS and NEW. Name it “proteins”. Click on START A NEW SESSION.

c. Click on PROTEIN TOOLS

d. Click on NDJINN ( a search engine)

e. Check the boxes by PDBFINDER and PIR

f. Change the hits per page to ALL

g. Type in the name of your protein and click SEARCH

h. Check the boxes of the proteins you would like to compare. Choose different types of organisms to look at (ideally 5 or more). Make a data table to record the names and symbols of your organisms. (look at the example at the end of the procedure)

i. Click on IMPORT SEQUENCES

j. Check the boxes of the sequences you want to compare.

k. Click on CLUSTAWL and SUBMIT

l. Scroll down to look at your sequences and the tree diagram produced by your sequences.

m. Complete the chart to compare sequences. Which of the organisms is most closely related? Why?

Data table

Organism	code number	# of matching amino acids	# of non-matching amino acids	% of conserved amino acids

California Science Content Standards for Biology/Life Science achieved through our Echinoderm Biology Unit

1.) Echinoderm Observation Lab:

Investigation and Experimentation: Scientific progress is made by asking meaningful questions and conducting careful investigations.

*Select and use appropriate tools and technology to perform tests, collect data, analyze relationships, and display data.

*Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions.

*Formulate explanations by using logic and evidence.

*Recognize the usefulness and limitations of models and theories as scientific representations of reality.

2.) Microscope Lab:

Cell Biology: The fundamental life processes of plants and animals depend on a variety of chemical reactions that occur in specialized areas of the organism’s cells.

*Students know cells are enclosed within semipermeable membranes that regulate their interaction with their surroundings.

*Students know how prokaryotic cells, eukaryotic cells, and viruses differ in complexity and general structure.

*Students know the central dogma of molecular biology outlines of the flow of information from transcription RNA in the nucleus to translation of proteins on ribosomes in the cytoplasm.

*Students know how eukaryotic cells are given shape and internal organization by a cytoskeleton or cell wall or both.

3.) Osmosis Lab:

Genetics: Mutation and sexual reproduction lead to genetic variation in a population.

Ecology: The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time.

*Students know new mutations are constantly being generated in a gene pool.

*Students know variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions.

*Students know a great diversity of species increases the chance that at least some organisms survive major changes in the environment.

4.) pH Lab:

Chemistry – Acids and Bases: Students know the observable properties of acids, bases, and salt solutions.

*Students know how to use the pH scale to characterize acid and base solutions.

Ecology: The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time.

*Students know biodiversity is the sum total of different kinds of organisms and is affected by alterations of habitats.

*Students know how to analyze changes in an ecosystem resulting from changes in climate, human activity, introduction to nonnative species, or changes in population size.

5.) Mitosis/Meiosis/Development Lab:

Investigation and Experimentation: Scientific progress is made by asking meaningful questions and conducting careful investigations.

*Select and use appropriate tools and technology to perform tests, collect data, analyze relationships, and display data.

*Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions.

*Formulate explanations by using logic and evidence.

*Recognize the usefulness and limitations of models and theories as scientific representations of reality.

Genetics: Mutation and sexual reproduction lead to genetic variation in a population.

*Students know meiosis is and early step in sexual reproduction in which the pairs of chromosomes separate and segregate randomly during cell division to produce gametes containing on chromosome of each type.

*Students know only certain cells in a multicellular organism undergo mitosis.

*Students know how random chromosome segregation explains the probability that a particular allele will be in a gamete.

*Students know why approximately half of an individual’s DNA sequence comes from each parent.

*A multicellular organism develops from a single zygote and its phenotype depends on its genotype, which is established at fertilization.

6.) Evolution:

Evolution: The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time.

*Students know variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions.

*Students know how natural selection determines the differential survival of groups organisms.

*Students know the effects of genetic drift on the diversity of organisms in a population.

*Students know how to use comparative embryology, DNA, or protein sequence comparisons, and other independent sources of data to create a branching diagram that shows probable evolutionary relationships.

Investigation and Experimentation: Scientific progress is made by asking meaningful questions and conducting careful investigations.

*Select and use appropriate tools and technology to perform tests, collect data, analyze relationships, and display data.

*Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions.

*Formulate explanations by using logic and evidence.

*Recognize the usefulness and limitations of models and theories as scientific representations of reality.

Genetics: Genes are a set of instructions encoded in the DNA sequence of each organism that specify the sequence of amino acids in proteins characteristic of that organism.

*Students know the general structure and function of DNA, RNA, and protein.

*Students know proteins can differ from one another in the number and sequence of amino acids.

7.) Ecology Lab:

Cell Biology: The fundamental life processes of plants and animals depend on a variety of chemical reactions that occur in specialized areas of the organism’s cells.

*Students know cells are enclosed within semipermeable membranes that regulate their interaction with their surroundings.

Genetics: Mutation and sexual reproduction lead to genetic variation in a population.

Ecology: The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time.

*Students know new mutations are constantly being generated in a gene pool.

*Students know variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions.

*Students know a great diversity of species increases the chance that at least some organisms survive major changes in the environment.