-this lab can take anywhere between 3 to 6 months for observations so you may want to get this started at the beginning of your unit.
-present students with notes on the ocean life zones so they can relate the organsims they will be looking at from here on out with where they live in the ocean.
-set up aquariums and slowly acclimate crab larvae to tanks
-label each tanks as to what each set of larvae will be eating
-crabs should be feed 4x-5x a day (you could set up a feeding schedule for your students to come in and feed the crabs before or after class each day. You may want to talk to your principle about how might be here at school on the weekend how could possibly take responsibility for feeding the crabs if you cannot make it in. I had a member of the custodial staff do it on Saturdays I came in one day to show him how, and a member of the church that meets in the gym on Sundays.)
-Salinity and pH should be taken on Mondays and Fridays.
-The heat lamps should be on timers and set to be on for about 16 hours a day. It is best to have them come on during the night when the sun is not out and the lights in the room are off to help maintain temperature.
-explain lab objectives and procedures to students
-have students come up with a hypothesis (use if, then format)
-show students how to properly care for the larvae
-at a set time (2x a week) of the week students should be given class time to record data on the larvae. Students should be measuring the width of the larvae, taking 3 samples of larvae for each aquarium to get a good range of larvae into measure. Students should be recording the number of larvae in each sample and totaling the numbers for each day of sampling for each aquarium. Students should also be estimating a percentage of the tank that food still occupies in the tank on the day of sampling. For example, if there is no food left in the tank then students should record 0%.
-Students should come up with a relationship to the type of food, the number of mortalities, and the rate of growth of the larvae.
-Students will graph all 3 aspects above and answer conclusion questions. They will also be drawing and identifying each larval stage.
-If possible allow students to take photographs of the larvae at each stage. This is possible if your school has an attachment for the microscope to use a digital camera or a microscope that can take pictures/video.
-Discuss with students results of lab on a periodic basis.
-Explain to students the threats, trials, and survival rate that larvae in the environment have. You may also want to discuss the need for larval transportation before they become nekton.
-set up aquarium field trip
-before you take students on the field trip to the aquarium, have students prepare the same Semantic Feature Analytic Grid with the same questions they came up with in class. Instead of classifying pictures they will be classifying 60 live organisms.
-as students go through the aquarium they should record the names of 60 organisms and then use their questions to categorize them into the correct phylum.
-collect and check for accuracy
-While students are going through benthos lab, they should also be making observations as to at what point the crabs stop being plankton. When the larvae can swim independently on their own, (usually at the end of the megalops stage) they have become nekton.
-Students should be making these observations when they sample for the Benthos lab.