Chapter 1 - Scientific Thinking

Scientific Method

A process of examination and discovery of natural phenomena that involves making observations, constructing hypotheses, testing predictions, experimenting, and drawing conclusions and revising them as necessary.

Hypothesis

A proposed explanation for observed phenomena. MUST: 1. It must establish an alternative explanation for a phenomenon. 2. It must generate testable predictions.

Positive Correlation

A relationship between variables in which they increase (or decrease) together.

A powerful way to demonstrate that observed differences between a treatment group and a control group truly reflect the effect of the treatment is for researchers to

Conduct the experiment over and over again.

If you conduct an experiment that rejects your hypothesis, then

The null hypothesis was a better fit to your data.

Life

1) A complex, ordered organization consisting of one or more cells. Cells carry out the functions necessary for life. 2) The use and transformation of energy to perform work. Organisms can perform many reactions and activities, by acquiring, using, and transforming energy. 3) Sensitivity and responsiveness to the external environment. Living organisms are able to respond to stimuli—such as light, moisture, or another organism. 4) Regulation and homeostasis. Organisms are able to maintain relatively constant internal conditions that may differ from the external environment. 5) Growth, development, and reproduction. Organisms can grow and develop, and they carry information relating to these and other processes that they can pass on to offspring. 6) Evolutionary adaptation leading to descent with modification over time. Populations have the capacity to change over time. As a consequence of organisms' ability to reproduce and of evolutionary change, populations may become better adapted to their environments.

When conducting a scientific experiment, which of the following is tested?

A prediction.

Science

A body of knowledge based on observation, description, experimentation, and explanation of natural phenomena. An intellectual activity, encompassing observation, description, experimentation, and explanation of natural phenomena. A pathway by which we can come to discover and better understand our world.

The scientific method is:

A deductive process based on testable and measurable events.

Placebo Effect

A frequently observed and poorly understood phenomenon in which there is a positive response to treatment with an inactive substance.

Scientific Literacy

A general, fact-based understanding of the basics of biology and other sciences, the scientific method, and the social, political, and legal implications of scientific information.

Applying your knowledge of the scientific method, which of the following BEST explains the correct contrast between a hypothesis and theory?

A hypothesis attempts to explain natural phenomenon and can be tested through experimentation; a theory attempts to summarize a large expanse of natural phenomenon and has already been tested thoroughly without contradictory results.

Which of the following statements is CORRECT?

A hypothesis that does not generate a testable prediction is not useful.

Null hypothesis

A hypothesis that proposes a lack of relationship between two factors. -Easier to disprove

The proposed explanation for a phenomenon is BEST described as:

A hypothesis.

Independent Variable

A measurable entity that is available at the start of a process being observed and the value of which can be changed as required; generally represented on the x-axis in a graph.

Dependent Variable

A measurable entity that is created by the process being observed and whose value cannot be controlled; generally represented on the y- axis in a graph and expected to change in response to a change in the independent variable.

Many would argue that both the theory of evolution and creationism are equally probable because, after all, they are both theories. What distinction (if any) is there between a scientific theory and a conceptual one that might lead you to disagree with this argument?

A scientific theory is supported by testable and reproducible data.

Statistic

A set of analytical and mathematical tools designed to further the understanding of numerical data.

A relationship that has been established based on a large amount of observational and experimental data is:

A theory.

The scientific method can be more powerful than other ways of knowing because it is more:

All except choice D are correct.

Empirical knowledge is knowledge that is based on experience and observation. Which of the following are characteristics of reliable empirical data?

All of the above are correct.

Why would a scientist choose to state their hypothesis as a null hypothesis?

All of the above are reasons for stating a null hypothesis.

Critical Experiment

An experiment that makes it possible to determine decisively between alternative hypotheses.

Double-Blin Experimental Design

An experimental design in which neither the subjects nor the experimenters know what treatment (if any) individual subjects are receiving.

Blind Experimental Design

An experimental design in which the subjects do not know what treatment (if any) they are receiving.

Theory

An explanatory hypothesis for a natural phenomenon that is exceptionally well supported by empirical data. - Tend to be broad

Placebo

An inactive substance used in controlled experiments to test the effectiveness of another substance; the treatment group receives the substance being tested, and the control group receives the placebo.

Empirical results:

Are based on observation.

Why is it that creationism can never be accepted as a scientific explanation of the origin of life?

Because the ideas of creationism cannot be tested through experiment and observation

Science is:

Both a body of knowledge and an intellectual activity encompassing observation, description, experimentation, and explanation of natural phenomena.

In science, theories tend to be ___________ than hypotheses.

Broader in scope

Anecdotal evidence

Can appear to reveal links between two phenomena that do not actually exist.

Drug companies sometimes hire independent research laboratories to evaluate whether a drug they've discovered is effective or not in treating an illness. Companies MOST LIKELY do this to:

Demonstrate that the scientists conducting the trial are not biased in concluding that the drug is effective.

Empirical

Describes knowledge that is based on experience and observations that are rational, testable, and repeatable.

By applying scientific thinking, one should be able to:

Determine whether eating more meat makes you grow taller.

If your hypothesis is "Echinacea reduces the duration and severity of the symptoms of the common cold," what is your null hypothesis?

Echinacea has no effect on the duration and severity of the symptoms of the common cold.

Which of the following would be the most reasonable testable prediction for the hypothesis: "All birds can fly"?

Examine the list of all known species of birds and determine if any cannot fly.

Which of the following commonly used terms comes closest to the meaning of what scientists call a "hypothesis"?

Explanation

Which of the following has scientific investigation shown to be LEAST reliable in criminal prosecutions?

Eyewitness identification

If you were to design an experiment to test whether a particular pathogen caused a disease, which of the following choices would be the first step and which the last step you would make if you followed the scientific method precisely?

First: make observations; Last: Interpret data

Despite all the intellectual analyses the scientific method gives rise to and objective conclusions it makes possible, it CANNOT

Generate moral statements.

A "controlled" experiment occurs when:

Groups are kept as similar as possible and are treated identically, except for the variable of interest.

All of the following are elements of biological literacy EXCEPT:

Having read the most important books in biology.

Hierarchal Organization

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.

Pseudoscience

Hypotheses and theories not supported by trustworthy and methodical scientific studies.

In the steps of the scientific method, what is the process where a scientist writes down tentative explanations or statements about what he/she expects might happen under certain conditions?

Hypotheses formation

Treatment

In a research study, any condition applied to subjects—those in the treatment group—that is not applied to subjects in a control group.

Randomized

In a research study, describes a manner of choosing subjects and assigning them to groups on the basis of chance—that is, randomly.

Experimental Group

In an experiment, the group of subjects exposed to a particular treatment; also known as the treatment group.

Control Group

In an experiment, the group of subjects not exposed to the treatment being studied but otherwise treated identically to the experimental group.

A scientific theory is one that:

Is the foundation of all scientific experiments.

The placebo effect

Is the frequently observed, poorly understood, phenomenon that people tend to respond favorably to any treatment.

To be useful in the scientific method, an observation must be:

Measurable.

A biologist was concerned about the environmental effects of an insecticide being used in his area to kill mosquitos that carried equine encephalitis. He decided to study the environmental impact of this herbicide on blue jay reproduction. He selected two small habitats with similar vegetation and similar-sized blue jay populations (about 120 birds) with equal reproductive rates. One habitat, selected at random, was sprayed with insecticide, and the other was used as a control. Blue jay reproduction rates were measured in both habitats before and after the treatment. What is the MOST IMPORTANT flaw in this investigation?

Lack of replication

In a randomized, controlled, double-blind study:

Neither the experimenter nor the subject know whether the subject is in a control group or an experimental group.

Before experimental drugs can be brought to market, they must undergo many rigorous trials to ensure they deliver their medical benefits effectively and safely. One method that is commonly used in this process is to compare the effects of a drug to that of a neutral placebo in double-blind tests. Which of the following choices correctly describes a double-blind test?

Neither the researchers nor the study's participants know who is receiving the drug and who is receiving the placebo.

A hypothesis that states that there is a lack of relationship between two factors is called:

Null hypothesis.

You note a fuzzy growth on some of the gels in your incubator. What is the name given to this step of the scientific method?

Observation

Anecdotal Observation

Observation of one or only a few instances of a phenomenon.

In scientific thinking, which of the following are not subject to revision?

Observations

In controlled experiments

One variable is manipulated, while others are held constant.

In a scientific trial, some participants are given a pill that looks identical to a pill that contains the active ingredient being studied in the trial, but contains no active ingredient itself. Which of the following describes this pill?

Placebo

________________ makes scientific-sounding claims that are not supported by trustworthy, methodical scientific studies.

Pseudoscience

If a researcher uses the same experimental setup as another study to collect data, but uses different research subjects, it is considered

Replication

Science as a way of seeking principles of order differs from art, religion, and philosophy in that:

Science limits its search to the natural world of the physical universe.

The set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather is called

Statistics.

Steps of the Scientific Method

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.

A useful scientific hypothesis is one that is:

Testable.

Evolution

The change in genetic characteristics of a population over time, accounts for the diversity of organisms and the unity among them.

Variables

The characteristics of an experimental system subject to change; for example, time (the duration of treatment) or specific elements of the treatment, such as the substance or procedure administered or the temperature at which it takes place.

In blind experimental design:

The experimental subjects do not know which (if any) treatment they are receiving.

Superstition

The irrational belief that actions not related by logic to a course of events can influence an outcome.

Biology

The study of living things

In the late 1950s, a doctor reported in the Journal of the American Medical Association that stomach ulcers could be effectively treated by having a patient swallow a balloon connected to some tubes that circulated a refrigerated fluid. He argued that, by super-cooling the stomach, acid production was reduced and the ulcer relieved. All 24 of his patients who received the treatment were healed. Why does this fall short of qualifying as an example of the scientific method?

There was no control group with which to compare his patients who received the treatment.

What is meant by the phrase "hierarchical organization of life"?

Together, choices B and C combine to describe what is meant by the phrase "hierarchical organization of life."

Statistics are used by scientists mainly to determine:

Whether differences in results between control and treatment groups is significant and important.

Which of the following questions CANNOT be answered by the scientific method?

Which Shakespearean sonnet is the most beautiful?