Question 1

The best experimental design _____.

Accepted Answer

The best experimental design should have a large number of replicates to ensure statistical significance, a control to compare the results with the experimental condition, and only alter one condition between the controls and experimental condition to isolate the effect of that condition. Therefore, choice D is the best option as it includes all these criteria.

Question 2

Agrobacterium is a type of bacteria that infects plants and causes them to form tumors.You are asked to determine how long a plant must be exposed to the bacteria to become infected.Which of the following experiments will provide the best data for that question?

Accepted Answer

Option D would provide the best data for determining how long a plant must be exposed to Agrobacterium to become infected. This experiment would involve exposing plants to Agrobacterium for different time intervals and then counting the number of tumors formed. By comparing the results from plants exposed to different lengths of time, the minimum exposure time needed for infection can be determined. Options A, B, and C may provide useful information but are not directly related to determining the time required for infection.

Question 3

Recall the caterpillar experiment,where caterpillars born in the spring looked like flowers,and caterpillars born in the summer looked like twigs.What is the most likely selective advantage for this difference in body shape?

Accepted Answer

Looking like their food source allows the caterpillars to blend into their surroundings and avoid predation. This would increase their survival rates and provide a selective advantage.

Question 4

A friend of yours calls to say that his car would not start this morning.He asks for your help.You say that you think the battery must be dead,and that if so,then jump-starting the car from a good battery will solve the problem.In doing so,you are _____.

Accepted Answer

The statement includes both a specific hypothesis (the battery is dead) and a prediction of the hypothesis (jump-starting the car will solve the problem).

Question 5

Figure 1.1
The following experiment is used for the corresponding question(s).
A researcher discovered a species of moth that lays its eggs on oak trees.Eggs are laid at two distinct times of the year: early in spring when the oak trees are flowering and in midsummer when flowering is past.Caterpillars from eggs that hatch in spring feed on oak flowers and look like oak flowers.But caterpillars that hatch in summer feed on oak leaves and look like oak twigs.
How does the same population of moths produce such different-looking caterpillars on the same trees? To answer this question,the biologist caught many female moths from the same population and collected their eggs.He put at least one egg from each female into eight identical cups.The eggs hatched,and at least two larvae from each female were maintained in one of the four temperature and light conditions listed below.
  
Figure 1.1
In each of the four environments,one of the caterpillars was fed oak flowers,the other oak leaves.Thus,there were a total of eight treatment groups (4 environments × 2 diets).
-Refer to Figure 1.1.In every case,caterpillars that feed on oak flowers look like oak flowers.In every case,caterpillars that were raised on oak leaves looked like twigs.These results support which of the following hypotheses?

Accepted Answer

The experiment manipulated the diet of the caterpillars, feeding some oak flowers and others oak leaves. The results showed that the diet triggered the development of different types of caterpillars, supporting the hypothesis that differences in diet are responsible for the different appearances of the caterpillars. The other answer choices (A, B, and D) are not supported by the evidence presented in the experiment.

Question 6

Louis Pasteur's experiment had a good design because _____.

Accepted Answer

The answer of Louis Pasteur's experiment had a good design...

Question 7

On an evolutionary tree,any group that includes a common ancestor and all of its descendants is called monophyletic ("one-tribe").Recall the current evolutionary tree for Bacteria,Archaea,and Eukarya.According to this tree,are all organisms alive today monophyletic?

Accepted Answer

All organisms alive today are monophyletic, as they all have a common ancestor that is represented by the root of the evolutionary tree.

Question 8

Use the following information when answering the corresponding question(s).
In 1668 Francesco Redi did a series of experiments on spontaneous generation.He began by putting similar pieces of meat into eight identical jars.Four jars were left open to the air,and four were sealed.He then did the same experiment with one variation: Instead of sealing four of the jars completely,he covered them with gauze (the gauze will exclude the flies while allowing the meat to be exposed to air).In both experiments,he monitored the jars and recorded whether or not maggots (young flies)appeared in the meat.
-Refer to the paragraph on Redi's experiments.In both experiments,flies appeared in all of the open jars and only in the open jars.Which one of the following statements is correct?

Accepted Answer

Redi's experiment supports the hypothesis that maggots arise only from eggs laid by adult flies because the flies appeared only in the open jars where adult flies could lay eggs on the meat, and not in the sealed jars or jars covered with gauze where they were excluded.

Question 9

Current evolutionary data groups land plants with green algae and red algae.Brown algae,which you often find in the same habitat as red and green algae,is part of a distantly related group that includes the diatoms.This suggests that _____.

Accepted Answer

The term "algae" is a general term that includes various groups of photosynthetic organisms that are not necessarily closely related, indicating that it does not represent a single taxonomic group.

Question 10

Figure 1.1
The following experiment is used for the corresponding question(s).
A researcher discovered a species of moth that lays its eggs on oak trees.Eggs are laid at two distinct times of the year: early in spring when the oak trees are flowering and in midsummer when flowering is past.Caterpillars from eggs that hatch in spring feed on oak flowers and look like oak flowers.But caterpillars that hatch in summer feed on oak leaves and look like oak twigs.
How does the same population of moths produce such different-looking caterpillars on the same trees? To answer this question,the biologist caught many female moths from the same population and collected their eggs.He put at least one egg from each female into eight identical cups.The eggs hatched,and at least two larvae from each female were maintained in one of the four temperature and light conditions listed below.
  
Figure 1.1
In each of the four environments,one of the caterpillars was fed oak flowers,the other oak leaves.Thus,there were a total of eight treatment groups (4 environments × 2 diets).
-In Figure 1.1,which of the following is not a plausible hypothesis to explain the difference in caterpillar appearance observed in this population?

Accepted Answer

The hypothesis related to differences in air pressure due to differences in elevation is not a plausible explanation for the difference in caterpillar appearance observed in this population. There is no mention of any differences in elevation in the experiment or the background information provided. The other three hypotheses are all plausible explanations based on the information provided.

Question 11

Recall the experiment on ant navigation.What parameters would have to be held constant for the test group of 75 ants in order to run a controlled experiment?

Accepted Answer

To run a controlled experiment, all variables except the one being tested (leg length, and therefore stride length) should be held constant to ensure that any observed effects on navigation are due to changes in leg length.

Question 12

Which of the following observations led to the conclusion that the food competition hypothesis for giraffe neck length might not be correct?

Accepted Answer

The answer of Which of the following observations led to...

Question 13

What is the difference between experimental replicates and experimental controls?

Accepted Answer

Experimental replicates are repeat samples taken under the same experimental condition, in order to ensure the accuracy and reliability of the results. Experimental controls, on the other hand, are samples used to ensure that any observed effects are due to the experimental treatment and not other factors. The two terms are not interchangeable, and serve distinct purposes in experimental design. Option B is incorrect because replicates actually increase the sample size, which improves statistical power. Option C is incorrect because replicates can be found both under control and experimental conditions. Option D is incorrect because replicates should be identical in all factors except for the variable being tested, so as to eliminate unwanted variation.

Question 14

You find yourself standing next to a beautiful rosebush.Based on the current evolutionary data,which of the following do you and the rose have in common?

Accepted Answer

The only option that is correct is A because both humans and roses are multicellular organisms. Option B is incorrect because humans have a membrane-bound nucleus in their cells, while plants have a cell wall to surround their cells. Option C is incorrect because neither humans nor plants are prokaryotic, as they are both eukaryotic organisms. Option D is incorrect because there are certainly some biological similarities between humans and plants, particularly at the cellular level.

Question 15

Agrobacterium is a type of bacteria that infects plants and causes them to form tumors.You determine that tumor formation requires a huge amount of the plant's energy for tissue formation.How might this change the number of offspring a plant produces,and what is the most likely explanation for this change?

Accepted Answer

Since tumor formation requires a huge amount of the plant's energy, it is likely that the plant will devote less of its energy towards producing offspring. As a result, the number of offspring produced by the infected plant is likely to decrease.

Question 16

Use the following information when answering the corresponding question(s).
In 1668 Francesco Redi did a series of experiments on spontaneous generation.He began by putting similar pieces of meat into eight identical jars.Four jars were left open to the air,and four were sealed.He then did the same experiment with one variation: Instead of sealing four of the jars completely,he covered them with gauze (the gauze will exclude the flies while allowing the meat to be exposed to air).In both experiments,he monitored the jars and recorded whether or not maggots (young flies)appeared in the meat.
-Refer to the paragraph on Redi's experiments.What hypothesis was being tested in the initial experiment with open versus sealed jars?

Accepted Answer

The hypothesis being tested in the initial experiment with open versus sealed jars is that maggots do not arise spontaneously, but from eggs laid by adult flies, which is known as the principle of biogenesis.

Question 17

Your colleague proposes to test the mechanism of ant navigation by placing a food source 7 m from the nest.She will then pick up the ants from the nest and move them 4 meters from the nest (3 m from the food source).Based on the previous data,when do you expect the ants to start searching for their nest on their return trip?

Accepted Answer

The ants will start searching for their nest after they have traveled 3 meters from the food source because they will have traveled the same distance from the nest as they did on their outward journey.

Question 18

Recall the giraffe experiment that suggested longer necks gave a reproductive advantage to males.Which of the following could counteract or negate this advantage?

Accepted Answer

If females prefer short-necked males, the reproductive advantage of longer necks would be negated, as reproductive success would be more influenced by female choice rather than neck length.

Question 19

For many years,no one bothered to test the food-competition hypothesis for why giraffes have long necks.Why?

Accepted Answer

The food-competition hypothesis was widely accepted as plausible, leading to a lack of questioning or testing.

Question 20

Figure 1.1
The following experiment is used for the corresponding question(s).
A researcher discovered a species of moth that lays its eggs on oak trees.Eggs are laid at two distinct times of the year: early in spring when the oak trees are flowering and in midsummer when flowering is past.Caterpillars from eggs that hatch in spring feed on oak flowers and look like oak flowers.But caterpillars that hatch in summer feed on oak leaves and look like oak twigs.
How does the same population of moths produce such different-looking caterpillars on the same trees? To answer this question,the biologist caught many female moths from the same population and collected their eggs.He put at least one egg from each female into eight identical cups.The eggs hatched,and at least two larvae from each female were maintained in one of the four temperature and light conditions listed below.
  
Figure 1.1
In each of the four environments,one of the caterpillars was fed oak flowers,the other oak leaves.Thus,there were a total of eight treatment groups (4 environments × 2 diets).
-Refer to Figure 1.1.Recall that eggs from the same female were exposed to each of the eight treatments used.This aspect of the experimental design tested which of the following hypotheses?

Accepted Answer

The experimental design, where eggs from the same female were exposed to different treatments, was used to test if the differences in caterpillar types are genetic. If all offspring from the same female develop into the same type of caterpillar regardless of treatment, it would suggest a genetic basis.

Quiz 1: Biology and the Tree of Life