The Designs of Scientific Investigations Flashcards
When two plants, A and B, were planted together in a field outdoors, plant A produced vegetables, and plant B produced flowers which attracted pollinators. It was noted that when they were grown apart from each other, plant A did not produce vegetables, but plant B still produced flowers. Which of the following is the most likely reason plant A did not produce vegetables when planted away from plant B?
The insects that pollinated plant B also pollinated plant A.
Why is it important to keep most variables constant between experimental and control groups?
Keeping most variables constant allows the effects of a single variable to be determined more accurately.
Dissolved oxygen (DO) is an important indicator of water quality, and oxygen levels that are too high or too low can harm aquatic ecosystems. A biologist noticed that fish were dying in a local lake and was concerned that the DO levels were too low to support aquatic life due to extremely high temperatures that summer. To measure the DO levels, she brought back several lake water samples to her laboratory to measure the DO concentration as a function of temperature. To do this, she heated several samples of lake water to various temperatures and then measured the DO concentration in each sample. Some samples were kept at the outdoors temperature.
Dissolved oxygen concentration.
A group of students was studying the effects of drinking 8 oz. of milk at 9 p.m. on the amount of sleep they got. Which is the dependent variable?
The amount of sleep.
Dissolved oxygen (DO) is an important indicator of water quality, and oxygen levels that are too high or too low can harm aquatic ecosystems. A biologist noticed that fish were dying in a local lake and was concerned that the DO levels were too low to support aquatic life due to extremely high temperatures that summer. To measure the DO levels, she brought back several lake water samples to her laboratory to measure the DO concentration as a function of temperature. To do this, she heated several samples of lake water to various temperatures and then measured the DO concentration in each sample. Some samples were kept at the outdoors temperature.
To act as a control group.
Proper design of an experiment must maximize _______ and minimize ________.
accuracy and precision; bias
Which of the following is a hypothesis?
If a student gets more sleep, they will get a higher test score.
A hypothesis must be which of the following?
Testable.
A biologist hypothesized that zebras and horses evolved from the same common ancestor 4 million years ago. Which of the following pieces of evidence most strongly supports this hypothesis?
The genome of zebras and horses are very similar to the common ancestor.
Dissolved oxygen (DO) is an important indicator of water quality, and oxygen levels that are too high or too low can harm aquatic ecosystems. A biologist noticed that fish were dying in a local lake and was concerned that the DO levels were too low to support aquatic life due to extremely high temperatures that summer. To measure the DO levels, she brought back several lake water samples to her laboratory to measure the DO concentration as a function of temperature. To do this, she heated several samples of lake water to various temperatures and then measured the DO concentration in each sample. Some samples were kept at the outdoors temperature.
Temperature.
A biologist hypothesized that high humidity environments increased the growth rate of certain bacteria. Which of the following observations refutes this hypothesis?
Higher bacteria growth was observed in the Mojave Desert compared with the Everglades.
A chemist successfully synthesized an antimicrobial compound and showed that it effectively killed bacteria. The chemist then repeated this experiment two more times. What was the most likely reason for conducting this experiment three times?
To demonstrate the reproducibility of the results.
A class of students wanted to assess the effects of coffee on test scores. What would be an appropriate control?
Not drinking coffee during the test.
Which of the following is a hypothesis?
A proposed explanation based on observation that is used to conduct further studies.
Japan’s population has been declining in recent years. For this decline, which of the following must be true?
Emigration + Deaths > Immigration + Births
