Biology Quiz 1

Suggest a control treatment for each of the following experiments. a. To investigate if spots on butterfly wings scare off songbirds, scientists expose birds to butterflies with large spots.

Butterflies with plain wings

Treatment that eliminates the independent variable or sets it as a standard value

Control

Review the major components of an experiment by matching the following terms to the correct definition: Control, Controlled variables, level of treatment, dependent variable, replication, procedure, prediction, hypothesis, independent variable. a. Variables that are kept constant during the experiment (variables not being manipulated)

Controlled Variables

Propose an experiment and suggest a control treatment for each of the following questions. a. Do bearded dragons that are genetically male change into females if eggs are incubated at temperatures above 32 C?

Experiment: Have a group of eggs (a group of them in incubators with temperatures above 32 C and some in room temperature). After the eggs hatch, obtain the DNA and see which ones were genetically males and are now females. Identify how each incubator differs due to the information received. Control: The room temperature eggs

Is the cause of colic in newborns related to the microbial community in their intestines?

Experiment: There will be a group of newborn (those with colic and those without). A small sample from the intestine of each newborn from both groups will be obtained. Microbial lévela from both intestines will be observed and tested/identify how they differentiate. Control: Newborns without Colic

c. Female waterbugs lay their eggs on the backs of male waterbugs who care for the eggs. Do female waterbugs prefer to mate with male waterbugs with large number of eggs?

Experiment: there will be two groups composing of 1 male with eggs on his back and 1 with no eggs on his back. 1 Female will then be placed in the container with both of the males and observations will be made to indicate which one she chooses/mates. This will be replicated multiple times to obtain reliable data. Control: Males with no eggs

b. To investigate if night lights foster depression, a group of hamsters is kept in chronic dim light throughout the night.

Hamsters kept in complete darkness

b. Tentative explanation for an observation

Hypothesis

c. What the investigator varies in the experiment (for example, time pH, temperature, concentration)

Independent Variables

c. Researchers use a molecular tool called CRISPR to modify a gene in 35 beagle embryos to test if the modified gene will increase the amount of muscle produced by the dogs.

Independent: CRISPR implemented into the genes of 35 beagle embryos Dependent: The amount of muscle that is produced

Identify the dependent and independent variables in the following investigations. (Circle the dependent variable and underline the independent variable.) a. Scientists inject 50 people with an experimental vaccine immediately after exposure to Ebola and 50 different people after a 21-day delay. The number of people who contract Ebola are counted.

Independent: Time of vaccination (21-day delay) Dependent: number of people who contract Ebola

b. Coral reefs compete for light and space with seaweeds that may cover the coral like a lawn. Scientists measure the percent of coral covered with seaweed and the rate of coral growth in test plots with and without goby fish present.

Independent: measure of percent of coral covered with seaweed Dependent: rate of coral growth (There are 2 independent variables which might interfere with the reliability of the information recurved)

Appropriate values to use for the Independent variable

Level of treatment

5. A recent study of 59,806 Caucasian women reports that women who take aspirin for five or more years are 30% less likely to develop melanoma than women who do not use aspirin. List other variables that would be important to control in this study (controlled variables).

Melanoma is related to skin cancer so the amount of time individuals spent in the sun, the usage of sun screen all the time the went outside, tanning practices, and other factors that may affect the development of skin cancer.

Statement of the expected results of an experiment based on the hypothesis

Predictions

d. process used to measure the dependent variable

Procedure

What is the essential feature of science that makes it different from other ways of understanding the natural world?

Science is observation and proving it based on experiments. The proof will be mathematical and collected vigorously with data that may be repeated various times to show its consistency. Along with this, the hypothesis can never be proven true, it is just supported with information collected. Further, with new technology obtained as years go on, new observations may develop from previous experiments that were not seen there before. - It is measurable, repeatable, and objective.

6. A study of the effects of vitamin D in the body has shown that persons with lower levels of vitamin D are more likely to have chronic diseases such as cardiovascular disease, breast cancer, colds, and flu. Can you conclude that vitamin D prevents these chronic diseases? What other possible explanations for this correlation can you suggest?

Vitamin D is essential for growth and development and lacking Vitamin D can result in weak bones and a weak immune system. It is recently found that having low levels of this in the human body are found to be linked with chronic diseases like cardiovascular diseases, breast cancer, colds, and flu. 25(OH) D which is an important pre-hormone that is synthesized by the liver from the hydroxylation of vitamin D and it is found to be associated with chronic diseases. Deficiency of 25(OH) D is directly linked to the deficiency of vitamin D in the body. Further, the study should have isolated on the disease it was observed to obtain full attention towards that disease and how vitamin D affected it. Although we might understand this, other factors may have factored into this life family history, diets, health care, and much more.

What the investigator measures, counts, or records; what is being affected in the experiment

dependent variable

Number of times the experiment is repeated

replication