Test 1 Review
The 4 areas of focus of the 2 major themes are:
1. The chemical, cellular, and energetic foundations of life 2. The genetics, evolution, and behavior of individuals 3. The staggering diversity of life and the unity underlying it 4. Ecology, the environment, and the subtle and important links between organisms and the world they inhabit
What is the alternative hypothesis?
A statement that is contrary to the null hypothesis. Example: If I do X, then there was a change. -It is, however, impossible to prove a hypothesis is absolutely true. You can prove it right but not 100%.
If you wanted to test if antibacterial soap worked better than regular soap, which answer has the strongest experimental design? D.
A. Have people in the experiment wash with antibacterial soap first and later with regular soap and compare. B. Have two groups of people wash with either antibacterial soap or regular soap and compare. C. Have two groups of people wash with either antibacterial or regular soap, without knowing which type of soap is being used, and compare. D. Have two groups of people wash with either antibacterial or regular soap, with neither the researchers nor the groups knowing which type of soap is being used, and compare. -This helps us get away from biases.
What is an experiment?
An experiment is devised to show that if the hypothesis is not true, our experimental results will cause us to reject the hypothesis - Use previous knowledge during the critical experiment
Anecdotal evidence: Characteristics
Based on only one or a few personal observations, people conclude that there is or is not a link between two things.
Drawing conclusions from the experiment
Based on the results of experimental tests, we can revise a hypothesis and explain the observable world with increasing accuracy. A great strength of scientific thinking, therefore, is that it helps us understand when we should change our minds.
Why is the scientific thinking empirical?
Because it is based on experience and observations that are rational, testable, and repeatable.
Experimental designs
Blind experimental design • The experimental subjects do not know which treatment (if any) they are receiving. Double-blind experimental design • Neither the experimental subjects nor the experimenter knows which treatment the subject is receiving.
Well-designed experiments are essential to testing hypotheses because:
Controlling variables makes experiments more powerful
Independent variable vs. Dependent variable
IV: Some measurable entity at the start of a process and can be changed - generally the x-axis DV: Created by the process being observed and whose value cannot be controlled - generally the y-axis
Pseudoscience characteristics:
Individuals make: - Scientific-sounding claims NOT supported by a trustworthy, methodical scientific studies
An observation must:
Look for cause-and-effect relationships or interesting patterns
How are pseudoscience and anecdotal evidence similar?
Pseudoscience and anecdotal observations often lead people to believe that links between two phenomena exist, when in fact, they don't.
Science vs. Technical innovations and development
Some things seem scientific, but they are not. Rather, some things are technical innovations and developments (such as construction of new engineering marvels or the heroic surgical separation of conjoined twins). While they frequently rely on sophisticated scientific research, they represent the application of research findings to varied fields such as manufacturing and medicine to solve problems.
What is a randomized study?
When subjects are randomly assigned into experimental and control groups.
Placebo effect
Phenomenon in which people respond favorably to any treatment Placebo effect highlights the need for comparison of treatment effects with an appropriate control group.
What is the null hypothesis?
- A negative statement that proposes that there is no relationship between two factors. Example: If I do X, then nothing should change. - Both null and alternative hypotheses are equally valid, but the null is easier to disprove. This is because a single piece of evidence or a single new observation that contradicts a null is sufficient for us to reject it and conclude that an alternative hypothesis must be considered.
What is statistics?
- A set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather. - The more participants, the better if you want to draw general conclusions about natural phenomena. - Statistics can help us identify whether relationships exist between variables. - Because much variation exists in the world, statistics can help us evaluate whether any differences between a treatment group and a control group can be attributed to the treatment rather than random chance.
Common visual displays of data used in biology
- Bar graph - Line graph - Pie chart
Why and when do people develop superstitions?
- Because of anecdotal evidence (seen once or twice but never really been tested). This is often unreliable and untested. - We develop behaviors that we think are necessary for certain outcomes. - This is not part of a natural phenomenon and so it has no part in biology due to its irrationality.
Why do we have to seek to stay away from biases?
- Because they can influence our behavior, including our collection and interpretation of data. - With careful controls, it is possible to minimize such biases.
A hypothesis must:
- Clearly establish mutually exclusive alternative explanations for a phenomenon - Generate testable predictions
What is another hallmark of an extremely well-designed experiment?
- Combing blind/double-blind strategies in a randomized, controlled, double-blind study.
What does scientific thinking enable us to do?
- Helps us make wise decisions - Statistics also help us make decisions
What are two unifying themes in the diversity of living organisms?
- Hierarchical organization: Life is organized on many levels within individual organisms, including atoms, cells, tissues, and organs. And in the larger world, organisms themselves are organized into many levels: populations, communities, and ecosystems within the biosphere. - The power of evolution: Evolution, the change in genetic characteristics of individuals within populations over time, accounts for the diversity of organisms, but also explains the unity among them.
Difference between hypothesis and theory
- Hypothesis: Proposes an explanation for a phenomenon; leads to testable predictions. - Theory: Hypothesis for natural phenomena that is exceptionally well-supported by empirical data; it has withstood the test of time and is unlikely to be altered by any new evidence. This is often seen as a "fact".
What is a superstition?
- Irrational belief that actions that are not logically related to a course of events can influence its outcome.
Why does visual display of data is important?
- It helps us understand and explain phenomena - It condenses large amount of information into a more easily digested form - It helps readers think about and compare data, ultimately helping them to synthesize the information and see useful patterns
Why are repeated experiments important?
- It increases our confidence - Science can be misleading because once is not enough - We also want to watch out and minimize biases
What are some characteristics of science?
- It is curious - Asks questions about how the world works - Seeks answers
What is science?
- It is not simply a body of knowledge or a list of facts to be remembered - Science is an intellectual activity, encompassing observation, description, experimentation, and explanation of natural phenomena (does not deal with supernatural)
Devising a testable prediction
- Keep in mind several possible explanations could be true - Devise a prediction from your hypothesis
What is pseudoscience?
- Literally means "false science" - Pseudoscience and misleading anecdotal evidence may obscure the truth
Controlling variables
- Most important feature of a good experiment - The attempt to minimize any differences between a control group and an experimental group other than the treatment itself
What does the scientific thinking consist of?
- Observe a phenomenon - Propose an explanation - Test the explanation with experiments
What are the limits of science?
- Science is not the only way to understand nature - Science cannot address every question posed by man - Cannot prove/disprove God's existence, cannot objectively determine elegance or beauty - Cannot give us insights into the generation of value judgments and other types of non-quantifiable, subjective information.
Characteristics of statistics
- The greater the difference between two groups & the smaller the variation, the more confident we are about our conclusion - We may find positive correlations - Statistical analyses can help us organize and summarize information
What is the scientific method/thinking?
- The process of examination and discovery - This is a flexible, adaptable, and efficient pathway to understanding the world because it tells us when we must change our minds.
What is one of the most common functions of visual data?
- To present the relationship between two variables, such as in a graph
The goal of a prediction is
- To propose a situation that will give a particular outcome if your hypothesis is true, but that will give a different outcome if it is not - To use "if" and "then" types of statements (scientific thinking)
The 4 elements common to most experiments are:
- Treatment: Experimental condition applied to research subjects - Experimental group: A group of research subjects who are exposed to a particular treatment - Control group: A group of research subjects who are treated identically to the experimental group with the one exception that they are not exposed to the treatment (aka, placebo group) - Variables: Characteristics of your experimental system that are subject to change
What is biological literacy?
- Uses the process of scientific inquiry to think creatively about real-world issues - Communicates thoughts to others so that it makes sense - Integrates these ideas into your decision making - Involves big issues, abstract ideas and personal matters
How do we understand the world?
- We wonder why something is the way it is, and then we decide to try and find out the answer
How do you know if it is true?
- You have to ask questions about the things you see, and the things that are advertised: does it have scientific proof or evidence? - You got to think scientifically
How do we correctly draw conclusions?
-It is essential to hold constant all those variables we are not interested in. - Control and experimental groups should differ only with respect to the treatment of interest. - Differences in outcomes between the groups can then be attributed to the treatment.
Null and alternative hypothesis example
Statement: Echinacea reduces the duration and severity of the symptoms of the common cold. - Null: If I take echinacea while I have the common cold, then nothing should happen; all symptoms will remain the same - Alternative: If I take echinacea when I have the common cold, then the severity and symptoms will be reduced.
What are the basic steps in the scientific thinking?
Step 1: Make observations. Step 2: Formulate a hypothesis. Step 3: Devise a testable prediction. Step 4: Conduct a critical experiment. Step 5: Draw conclusions and make revisions. - This process proceeds in a straight line. Conclusions, for example, lead to new observations and refined hypothesis.
What is scientific literacy?
This is - Thinking scientifically - Using knowledge to make wise decisions - Important in our lives - Important in matters of biology because it looks at how things affect you
Positive correlations
When one variable increases/decreases, so does the other variable