Biology Review Flashcards
What is at the heart of science?
- Inquiry
Ex. What causes stomach ulcers?
What are the two main steps to inquiry?
- making observations
- forming hypotheses
How are we able to describe natural structures and processes?
- through observations and analysis of data
What is data?
- Recorded observations
What is qualitative data?
- Observations with your senses
What is quantitative data?
- Measured using instruments
What is inductive reasoning?
- Deriving generalizations based on a large number of specific observation
What is a hypothesis? GENERALLY
- Prediction that can be tested by recording more observations or experiments
What is the structure of a hypothesis?
- often heard as “if … , then …, (because)” but not mandatory
If = manipulated variable
Then = responding variable
Because = optional explanation
What does the results say about the hypothesis?
- results could either support or refute the hypothesis
- Never say the hypothesis is correct, say the data supports/refute the hypothesis
What is deductive reasoning?
Specific results derived from general premises
Ex. All athletes workout. John is an athlete, therefore he works out.
- deductive is a lot more elaborate, kind of like a step-by-step putting generalized ideas together
What type of hypothesis should you always start with?
Null hypothesis
What is a null hypothesis? (2)
Ho Is a hypothesis which is the researcher tries to disprove/project/nullify.
- The hypothesis that shows there is no difference between two groups of data, and the observations are due to chance
Ex. There is no difference in headache relief between individuals who take Tylenol, and those who don’t
What is an alternative hypothesis?
H1 is made after the null hypothesis
- start with H1 and continue listing H2… As many necessary for the experiment
Ex. Tylenol will allow for relief when consumed by patients with headaches
What is a hypothesis, how is it tested? (3)
- An explanation to a question
- tested by experiment or continued observation
- can be disproven, but cannot be proven true
What is a theory?
- Summarizes a group of hypotheses
What are the characteristics of a theory? (4)
- broader in scope (more data or info collected)
- new hypotheses can be generated from it
- supported by massive body of evidence
- can never become a law
What is a scientific law?
- statement of fact, usually as a mathematical formula (ex. Newton’s law of gravity)
What are characteristics of a scientific law?
- describes an observation (not “how” or “why”)
- generally accepted to be true and universal
- Basis for scientific method
What should you use in an experiment? (4)
- start with an observation and a hypothesis
- use control groups (+ and/or -) and experimental groups
What do well-designed experiments include? (5)
- independent variable
- dependent variable
- Control group (+ and/or -)
- Constants
- Number of trials (acceptable in science is 3)
What is the difference between a variable and a constant?
- A veariable is something that is changed in the experiment, while a constant is something that does not change through the experiment
What is an independent variable and what does it represent?
- The one factor that is changed by the person doing the experiment
- represents a quantity that is being manipulated in an experiment
What is a dependent variable, and what does it represent?
- The factor which is measured in the experiment
- represents a quantity whose value depends on how the independent variable is manipulated
What are constants?
- all the factors that stay the same in an experiment
- examples depend on experiment but could include temperature, height, location, weight
What is a comparison between control group and experimental group?
- Control groups are your expected results, while experimental group are your experimental results
Why are control groups essential elements of an experiment?
- they help eliminate experimental error and biases of researchers
- Results of the control experiments validate the statistical analysis of the experiment
REMEMBER CONTROLS ARE NOT CONSTANTS
Why is statistical analysis necessary in regards to control groups?
- necessary to determine whether or not the data is significant
- Reliability of the experiment increases
What are positive control groups? (2)
- Group that is not exposed to the experimental treatment or independent variable
- but, it is exposed to a treatment known to produce the expected effects
What does the positive control group ensure?
- ensures that there is an effect when there should be an effect
- It’s the positive control does not produce the expected results, there may be something wrong with the experimental procedure
What is a negative control group? (3)
- Group not exposed to any treatment or exposed to a treatment that is known to have no effect
- group where nothing is expected to happen
Note that you do not need both positive and negative control groups
What does the negative control group ensure?
- ensures that there is no effect when there should be no effect
Why do scientists use positive control groups?
- When they are trying to induce a positive result
Why are negative controls used? (3)
- negative control can be a way of setting a baseline
- ensures that no cofounding or outside variable has affected the results, or to factor in any likely sources of bias
- it uses a sample that is not expected to work, or it is not exposed to anything such as a placebo
