Temperature and development of organisms

Question 1

What are the controlled variables of this practical? (using animals)

Answer 1

Number of eggs in each sample
Length of time incubated
Temperature of incubation

Question 2

How can the level of development of organisms be measured?

Answer 2

After incubation, shine a light to attract all hatched larvae to swim towards the light and be counted.

Question 3

How can organisms be treated ethically during the practical?

Answer 3

Minimize exposure to stressful testing conditions, and release into salt water when the practical is complete.

Question 4

Outline the procedure to this practical using plants.

Answer 4

1. Label 5 Petri dishes with a range of t°. Place 20 seedlings in each Petri dish on top of cotton wool.
2. Use a measuring cylinder to add 30cm3 of water to each dish and then place the dishes in the corresponding environments.
3. Every 24 hours, add more distilled water to each dish.
4. Count the number of germinated seeds for each temperature, record the results in a suitable table.

Question 5

What are the controlled variables for the practical using plants?

Answer 5

Volume of water added
Number of seedlings
Species of seedlings
Time interval between adding water
Light intensity