core prac 13 Flashcards
1
Q
What are the independent variables for the brine shrimp prac?
A
The temperature of each sample
2
Q
What are the dependent variables for the brine shrimp prac?
A
the number of hatched shrimpos
3
Q
What are the control variables for the brine shrimp prac?
A
- amount of sea salt used
- volume of water used
- number of brine shrimp eggs
- light intensity
- time left to grow
4
Q
What temperature is the control kept at for the brine shrimp prac?
A
25 degrees since that’s room temp
5
Q
Ethical issues in brine shrimp prac…
A
- no consent available so have to minimise suffering.
- shrimp should be returned to natural habitat after use.
- shrimp should be stored in an environment that replicates their natural habitat.
- working at good pace to minimise the time shrimp are under stress.
- turn off bright light when not in use.
- don’t use excessive temperature.
6
Q
What’s the method for the brine shrimp prac?
A
- set up water baths at 10-30degrees (increase by 5 each time)
- place 2g of sea salt into a 100cm3 beaker, add 100cm3 of de-chlorinated water and stir until salt is dissolved.
- label beaker with sea salt and temperature it’s incubated at.
- place tiny pinch of egg cysts onto large sheet of white paper, wet the piece of graph paper using a few drops of salt water.
- dab the paper onto the white sheet to pick up 40 eggs (use magnifying glass to count them)
- put paper with eggs into beaker egg side down, after 3mins, use a pair of forceps to gently remove from the water making sure that all the egg cysts have washed off into the water.
- incubate beakers at different temperatures and control light exposure.
- the next day count the number of hatches larvae in each of the beakers, to do this place a bright light next to them and any larvae will swim towards the light.
- using a fine glass pipette catch the brine shrimps and place them in a small beaker with salt water.
- record number of larvae that have successfully hatches at each temp and plot a graph.
