Honors Biology: Unit 1 Learning Targets

For this chapter please express your knowledge of these objectives by using the scenario below (frog)s to answer questions 1-4.

  Recently aquatic biologists have reported a decline in the population of frogs in local areas.  Some scientists believe the amount of acid rain entering the lakes, rivers and streams may have an effect.

1.  Generate a question that could be investigated in the lab.

Does the amount of acid rain entering bodies of water have an effect on the population of frogs?

2.  Develop a hypothesis that you could use to design an experiment.

If there is a high level of acid in the bodies of water in which frogs live, then there will be a decline in the population of frogs.

3.  Develop a scientific investigation using the appropriate tools and techniques (selecting instruments that measure the desired quantity, length, volume, weight, time interval, temperature). Identify all variables (control, independent, dependent).  This should be a detailed explanation (step-by-step numbered procedure).

The tools needed for this scientific investigation include a pH meter to measure the acidity of the water, a large container, tub, or aquarium to house the frogs, acid, water, gloves to touch the frogs, frog food, and some sort of a journal/log to track the number of frogs. The control variable is the group of frogs not exposed to acid (or very low levels), the independent variable is the high level of acid given to another group, and the dependent variable is the overall population. Steps for the experiment are listed below.

1. Set up an environment as natural as possible for both groups of frogs to live in. You will need to acquire two separate aquariums. In one section of both aquariums, create a body of water for the frogs.

2. Divide the frogs into two separate groups, and put them in their designated aquarium. In one aquarium, you will need to expose the frogs to a high level of acid in their water. In the other, you will just put in water with a normal acidity level.

3. You will also need to ensure that the frogs have the same food and nutrition; you should feed them foods they are used to, such as insects and bugs.

4. For the next few months, you will need to track the population of the frogs by counting them and recording them in your log.

5. Observe the populations of the two groups.

4.  Make-up believable data and present it in a data table.  Use empirical evidence to explain and critique the reasoning used to draw a scientific conclusion or explanation.

Conclusion: High amounts of acid in the bodies of water in which frogs live do cause the population of frogs to decline. The population of group 1, the group exposed to the deadly levels of acid, went through a severe decline during the four months they were tracked. Since all of their other environmental conditions were stable, the high levels of acid must have played a role in some frogs’ early death. Meanwhile, group 2’s population only went through mild decline through natural deaths; they also had some population increase due to mating and reproducing. They were not affected by the absence of high levels of acid as predicted. The control group also ensures that it was really the acid that killed off more than half of group 1’s population. The population of frogs gets smaller when exposed to high levels of acid.

5. Distinguish between scientific explanations that are regarded as current scientific consensus and the emerging questions that active researchers investigate.

Scientific explanations and theories that are regarded as current scientific consensus have already been tested, experimented, and investigated many times by a wide range of scientists. So, the current scientific consensus has been agreed upon by most scientists in the field, so it is accepted as true. Emerging questions, on the other hand, are questions that could be answered through making a hypothesis, creating an experiment, recording observations and data and drawing conclusions.

6.  Why is peer review important in scientific explanations?

Peer review is so important in scientific explanations because scientists can check each other for personal biases, validity, integrity, and originality. Scientists can help each other make better, more precise, and objective papers involving scientific explanations. For example, one scientist can claim to have discovered the cause of a disease, but they actually faked the data and conclusion. If there aren’t any others to run the same experiment and refute the claims of that scientist, then people may blindly believe that the finding is accurate.

7.  Describe the distinctions between scientific theories, laws, hypotheses, and observations.

Scientific theories are hypotheses that have stood up to repeated attempts at falsification, are supported by a great deal of evidence, and enable new findings to be predicted. Scientific laws are also supported by lots of evidence and observations; however, it explains how nature will behave under certain conditions, not how nature works. Hypotheses are possible explanations based on research that must answer a question; they must also be falsifiable and testable. Observations are the information and evidence you acquire from the experiment; you can also record data that is quantitative or qualitative.

8.  How does your understanding of the scientific process allow you to make informed decisions in your everyday life?

Understanding of the scientific process allows you to make informed decisions in your everyday life by forming your beliefs and values. For example, you can tell the difference between science and pseudoscience. When you saw a video involving misinformation and a conspiracy theory, you knew better than to believe in it because the scientific method and process was not involved. There was no real evidence to support the theory at all. Understanding the scientific process can also allow you to make more observations about the world and nature around you.

9.  List the required steps for focusing a microscope on high power.

1. Center your specimen under low power and adjust the diaphragm for the best light.

2. Turn the high-power objective into the viewing position. Make sure the objective and the stage aren’t touching or too close.

3. Sharpen the focus with the fine-adjustment knob only. Do not use the coarse-adjustment knob to focus under high power, as the stage and objective may collide, damaging the microscope.

4. Readjust the diaphragm for the best light. If you can’t see the object, return to step 1 and repeat every step with more caution.

5. Continue using the fine-adjustment knob to see your specimen with the best view.

10.  What is evolution and how does natural selection explain it?

The Theory of Evolution states that all species are related, yet they change over time (living organisms are different from fossilized forms; new species evolve). Natural selection helps explain it by letting us see that organisms best suited to their environments will have higher chances of survival, living longer, and reproducing than others. Certain characteristics become more common in following generations of the species because they would be inherited.