Practical 13: Temperature and the development of organisms

Question 1

Temperature and the development of organisms

Answer 1

1. Place 2g of sea salt into a beaker containing 100 cm of dechlorinated water.
   Stir with the stirring rod until the salt completely dissolves.
2. Put some eggs onto a sheet of paper.
3. Wet a piece of graph paper in salt water. Place it face-down onto the sheet of
   paper so it picks up some eggs.
4. Observe the graph paper under a microscope and count out 40 eggs.
5. Remove the rest of the eggs/the paper so there are only 40 eggs there.
6. Place the graph paper upside-down into the beaker and leave for 3 minutes/until
   all eggs have detached into the water.
7. Incubate the beaker at a set temperature (between about 5 and 35 degrees
   Celsius - this mimics the conditions in the wild) for 24 hours.
8. Remove the beaker from the incubator.
9. Shine a bright light on the beaker. Any hatched larvae will swim towards the
   light and can then be removed with a pipette.
   10.Return the beaker to the incubator and repeatedly remove and count hatched
   larvae.
   11.Repeat all steps at a range of temperatures.

risks- Hot liquids, Broken glass

variables-
control = sea salt + water
independent = temperature
dependent = organisms grown