Evaluating Scientific Studies and Basic Biology Concepts

Evaluating Scientific Studies

When evaluating scientific studies reported in the media, it's crucial to understand the scientific process.
Just because a study makes a claim, doesn't mean it's valid.

Science uses a method to observe, answer, and acquire knowledge through observation and experimentation.
Evidence from experimentation is crucial.
Anecdotal evidence can be a starting point for scientific investigation.
- Example: Observing the effect of a skin cream; however, a controlled experiment would obtain more reliable results.

A hypothesis must be falsifiable (able to be proven untrue).
Evidence either supports or rejects a hypothesis.
The term "proven" is not used in science with a hypothesis.
Hypotheses are never proven true with absolute certainty because it’s impossible to test every scenario.
Experiments and data analysis either support or refute a hypothesis.
Repeated experiments and confirmation by other researchers increase the likelihood that a result isn't a fluke.

Scientific evidence is compiled over time by numerous researchers.
A hypothesis confirmed many times through extensive testing without being disproven becomes a theory.

It's important to distinguish between causation and correlation.
Correlation doesn't equal causation.
Causation: one event causes another.
Correlation: two events are associated but one doesn't necessarily cause the other.
Observational studies track variables without manipulation; doesn't imply causation.
- Example: Case control study (Interphone) on cell phone use and brain tumors

Exercise caution when interpreting science in the news, especially nutrition related results that are often correlation based.
When considering risks, compare collective data to confirmed cases (e.g., cigarette smoking).
Be wary of omitted details in headlines.
Findings can be lost in translation from lab to media.
When looking at studies consider:
- Sample size: Is the study confined to animals? Then, it may not apply to humans.
- Replication: Have the results been repeated and confirmed by others?
- Funding source: Who funded the study and might they have a bias (e.g., industry with financial gain at risk)?

One epidemiologist states that cancer is inevitable in a society where people live long enough, because the longer you live the more likely mutations will occur.
Cellular reproduction is constantly happening to replace old cells, for example with healing a paper cut. Cell reproduce more, healing you.

Living organisms respond to stimuli in their environment.
- Example: Plant leaves turning towards the sun (sunlight is the stimulus)
Living things must obtain and use energy.
Living organisms are able to reproduce.
- Example: A mule is alive but sterile and cannot reproduce (sexually).

Atoms have a nucleus containing protons and neutrons.
Electrons orbit the nucleus in electron shells.
The first electron shell holds up to two electrons; subsequent shells hold more (typically eight).

Protein denaturation: alteration of a protein's shape (e.g., frying an egg).
- The liquid egg albumin transforms into a solid when heated, and cannot be reversed.
Proteins function as enzymes, which are biological catalysts.

Unsaturated fats: liquid at room temperature.
They can be mono- or polyunsaturated (depending on number of double covalent bonds).