Unit 3 - Investigative Biology Flashcards
What is science?
Science is the organisation of testable and reproducible knowledge.
What is meant by ‘The current best explanation’?
Since current theories could potentially change following processes of evaluation and further experimentation we treat theories as ‘The current best explanation’
What are negative results?
Negative results are when a scientist fails to find an effect.
How can conflicting data be resolved?
Conflicting data can be resolved with further evaluation or more creative study.
What is a Null Hypothesis?
A hypothesis that you aim to disprove to further prove your hypothesis, it states that two variables are unrelated.
What should you do with one-off results?
Treat them with caution.
When can new theories be accepted?
After independent verification.
What methods exist for sharing scientific findings?
Seminars
Conference talks
Publishing in scientific journals
What is a peer review?
When specialists in the same field of science carry out a critical review of research. These are important to ensure that findings are suitable to be published.
What is a critical review?
An assessment of the quality, reliability and validity of a paper.
What is a review article?
When a lot of work has been carried out by a group of scientists in the same field, an author may pull all the ideas and findings together in one article.
Why are scientific findings often misinterpreted in the media?
The reporters that publish the findings often don’t have much (if any) knowledge of the subject.
What must be considered when experimenting on human subjects?
- Seeking informed consent
- They have the right to withdraw data
- Confidentiality of data
When experimenting on animal subjects what must be considered?
- Reduce the number of animals used
- Replace the used of animals with something else if possible
- Refine procedures to that minimal harm is caused to animals
What are the four factors that influence scientific research?
Legislation
Regulation
Policy
Funding
What is a pilot study?
A study carried out that tests experimental procedures before commencing study. Allows evaluation and modification of experimental procedures.
What can assessments be about when performing a pilot study?
- The effectiveness of technique/ allows the experimenter to become proficient.
- The range of values of the independent variable.
- Identification and control of confounding variables.
- The number of repeats/replicates required
- Suitable timescales for the procedure.
What is a discrete variable?
Only takes on certain individual values e.g.
- Number of pages in a book
- Shoe size
What is continuous variable?
Can take on any value in a certain range e.g.
- Length of film
- Temperature
What 3 types of data do discrete and continues variables give rise to?
Quantitative
Qualitative
Ranked
How are discrete and continues data represented?
Discrete - Bar graph
Continuous - Line graph
What is simple experimental design?
1 variable is changed
Control of lab conditions is easier than in the field.
Usually ‘in Vitra’ (easy to control)
What is multi-factorial experimental design?
More than 1 variable is changed
Combination of treatments
Usually ‘in Vivo’ (difficult to control)
Lots of data obtained that can show complex interactions.
What is an observational study?
Using groups that already exist so there are not any true independent variables as the observer is not causing any change. This can determine correlation but not causation.
What are the two types of control?
Positive control
Negative control
What is positive control?
Control group is not exposed to the experimental treatment but is exposed to a treatment of known effect.
Used to produce standardisation curves.
What is negative control?
Control group is not exposed to the experimental treatment or any other known treatment.
When is a representative sample taken?
If it is not practical to sample every single individual in a population .
What does sample size depend on?
The natural variation in a population.
Large populations require a large sample size.
Small populations require a small sample size.
What are the 3 types of sampling?
Random
Systematic
Stratified
What is random sampling?
Each individual has equal chance of being selected.
What is systematic sampling?
Population is sampled at set intervals.
What is stratified sampling?
Sample split (male, female) then sampled proportionally.
Why may variation of experimental results occur?
Reliability of measurements
Natural variation in specimens
In terms of ensuring reliability, what is accuracy?
How close the data is the the true value.
In terms of ensuring reliability, what is precision?
How close data values collected are to the data values being collected.
How is the natural variation in living material determined?
By taking a sample of the population and repeating measurements to find the mean.
Why is an independent replicate required?
To increase reliability of an experiment.
How can an experimental design be considered valid?
The aim or hypothesis must be tested.
A control should be compared with a treatment group.
Confounding variables should be controlled.
Representative samples should be taken, and sample size should be sufficient.
