chapter 1

Victoria, who is 10 years old, wants to be a zoologist when she grows up because she loves animals. So, she decided to begin her training by "doing something scientific." Specifically, she weighed and measured the lengths of all the earthworms she could find in her yard and recorded the data in a notebook. She then made a graph showing the maximum, minimum, and average weights and heights of the earthworms. Was she doing something scientific?

No, because she had no hypothesis to direct her data collection or interpretation.

Scientific understanding can always be challenged, and even changed, with new ways of observing and with different interpretations. For example, new tools and techniques have resulted in new observations and the discovery of additional information. This has resulted in revised ways of understanding how molecules are moved across the plasma membrane of cells. Hence, there is no certainty in science, only degrees of probability (likelihood) and potential for change. In light of this understanding, which of the following statements is most meaningful?

Scientific knowledge is necessarily contingent knowledge.

Which of the following would be a theory?

Specific pathogens are directly responsible for specific diseases and conditions.

Dr. Blehert took 117 healthy bats into his laboratory. He exposed 83 of them to the fungus suspected of causing white-nose syndrome (WNS) while the rest of the bats were not exposed to the fungus but otherwise kept under the same environmental conditions. All of the bats were monitored for symptoms of WNS. What was the dependent variable in Dr. Blehert's experiment?

The dependent variable in this experiment was development of WNS symptoms in the healthy bats.

A newly discovered microscopic structure is hypothesized to be a living organism. Which of the following combinations of characteristics would best support this hypothesis?

The microscopic structures are single celled, contain replicating DNA, maintain a constant internal environment while responding to the external environment, and are reproducing by fission.

The roots of a sunflower plant growing downwards while the shoot grows upwards and the flower turns towards the sun are examples of what characteristic of all living organisms?

They sense the environment and respond to it.

Some questions fall outside the realm of science. Which of the following questions could NOT be answered using the scientific method?

Why is it unethical to test newly developed drugs in animals?

A hypothesis can be supported, but no amount of testing can prove a hypothesis is correct with absolute certainty. Is this statement accurate?

Yes, because there may be other, unmeasured or unobserved reasons that influence the predictions made by the hypothesis.

You are coughing and producing a wheezing sound as you breathe; you also have a fever. You go to the doctor who listens to your chest, takes X-rays of your chest, and determines that you probably have something called croup. Which of the following are the facts in this scenario?

You are coughing, wheezing, and have a fever.

A group of researchers conducted an experiment and collected the data presented in the graph below. Was one of the treatments more lethal than the others?

a. Yes, the group of bats injected with the European fungus died off before any of the bats in the other two treatment groups.

Which of the following sequences correctly represents the biological hierarchy of a multicellular organism?

cells > tissues > organs > individual

The genetic material used for reproduction by those organisms conventionally considered to be living is ________.

dna

I scored an 80 percent or higher on my test every time I take a nap before the test. This observation ______ a cause and effect relationship between napping and scoring well on a test.

does not support

A scientific hypothesis must be potentially ________. It must make predictions that can be clearly determined to be correct or incorrect.

falsifiable

Living organisms respond to both internal and external stimuli to maintain constant conditions inside of the organism. This state of steady conditions is known as

homeostasis.

You often experience numbness and pain in the thumb and first two fingers on your right hand. You go to the doctor who suspects that carpal tunnel syndrome is the reason for the numbness and pain. The doctor then orders a simple test to see how fast nerve impulses are moving up and down your arm. The doctor's preliminary diagnosis of carpal tunnel syndrome is a(n)

hypothesis

New medications undergo extensive human testing before receiving FDA approval. These tests represent an experiment and variations in the dosage given to participants represents the

independent variable.

Scientists are human beings and are, like all human beings, susceptible to personal and group biases that may influence how they interpret evidence. Before original research work is accepted and added to a growing body of scientific understanding, perhaps even contributing to our understanding of an important scientific theory, it must be scrutinized by experts in the field who have no direct connection to the research under review. The main mechanism for doing this is

peer-reviewed publications.

Which of these characteristics of living organisms are present in viruses?

reproduce using DNA (or RNA); sense their environment and respond to it; can evolve as groups

When analyzing patterns in observational or experimental data, scientists use a special branch of mathematics to help them quantify the reliability of the data and determine how well any patterns support the hypothesis. This special branch of mathematics is known as

statistics