Biology - Controlled Assessment P2 Flashcards
Did you have any anomalies?
Yes
Identify anomalie
What’s its value?
Say that it doesn’t fit the pattern or line of best fit
What was the range of the independent variable and was it appropriate?
IDV: concentration of acid
Range: 0 mol/dm3 - 0.1 mol/dm3
Yes, the range was appropriate as it allowed me to find a pattern which was that, as the concentration of acid increased, the number of germinated seeds decreased.
Why do we repeat experiments?
To calculate an average (closer to the true mean) by adding all the results and dividing by the number of values.
It also helps to identity and avoid the use of anomalous results.
If another class were to repeat the experiment, why may they get different results?
May have used a different method
- Suggest something they could have done something differently: Type of seeds Type of acid Concentrations of acid Environments of seeds
- Explain why it caused a difference e.g. Different seeds may react differently to different acids or some may germinate better in acidic conditions. Different seeds are affected by acids differently.
Different acids may affect germination differently as different acids will react with enzymes differently in the seeds which may affect germination
How do you draw a sketch graph?
Label the axis with units
Draw a line
- a scale isn’t necessary.
Do case study 1, 2 and 3 support the hypothesis?
Explain a simple statement about whether it is supporting the hypothesis or not.
Detailed description of pattern which each one shows. State if the IDV is different.
Use examples of data from each c.s. And describe any anomalies.
Example:
C.s. 1 supports the hypothesis as it demonstrates that, as the pH of the soil increases, the number of germinated seeds also increases manning as the acidity of water decreases, more seeds germinate. We see this as, at pH 1, 0 seeds germinate whereas at pH 6, 20 seeds germinate.
C.s. 2 supports the hypothesis despite using sulphur dioxide. This shows that, as the amount of SO2 increases, increasing the acidity of acid rain the number of germinated seeds decreases. However there was an anomalous result found in trial 2 at 100ppm.
C.s. 3 supports the hypothesis as it shows the affects of different acids on the germination of seeds. It demonstrates that ‘no-acid’ results in the highest percentage of germinated seeds after 7 days (82%) however less seeds germinate when am acid is used. Sulphuric acid affects germination the most, only 2% germinated and ethanoic acid affected it the least however the rate of germination decreased after 4.5 days.
(Example Case Study 4 Question)
Farmer Giles wants to switch from rearing beef cattle to growing crops. He looks at the data in C.S. 4 and decides to grow potatoes.
What should he consider before making his decision?
The pH of the soil Costs for fertilisers and pesticides Need for fertilisers Yield Time Selling price Presence of other minerals Seed cost Cultivation cost
Different acids may affect germination differently as different acids will react with enzymes differently in the seeds which may affect germination
Did your results support the hypothesis?
Yes/no, reference to pattern, data
Yes our results support our hypothesis as they demonstrate that, as the concentration of the acid increases, the number of seeds which germinated after 3 days decreased. (Examples of the pattern). We also identified a anomalous results: X
