AP Biology Practice 4 - Data Collection Strategies

Summary

In this AP Biology Science Practice video, Mr. Andersen discusses the importance of data collection in scientific inquiry, emphasizing the scientific method's role alongside observational and historical sciences. He illustrates the process with an example of an enzyme experiment and explains the significance of controlling variables. The video also covers how to justify data collection strategies, design experiments, collect specific data to answer questions, and evaluate given data, using examples from evolution, free energy, information, and systems.

Takeaways

• 🌟 Science is fundamentally about asking questions and gathering data to understand the objective reality governed by natural laws.
• 🏀 The scientific method is a powerful tool in science, but it's not the only approach; observational and historical sciences are also important.
• 🔍 In designing a controlled experiment, it's crucial to identify the independent and dependent variables and control other variables to ensure valid data collection.
• 🌡 An example of an experiment is measuring the effect of temperature on enzyme activity using catalase, where temperature is the independent variable and enzyme action speed is the dependent variable.
• 🧪 Control variables in an experiment should be carefully considered to maintain consistency, such as pH and solution concentration.
• 📊 College Board expects students to understand data collection in the context of the four big ideas of AP Biology: evolution, free energy, information, and systems.
• 🐟 An example of data collection in evolution could be measuring changes in stickleback fish pelvis length over time as they adapt to different environments.
• 🌱 Data related to nutrient cycling, such as nitrogen levels, could be collected to understand free energy in ecosystems.
• 🔬 Historical data, like Fredrick Griffith's experiment on bacterial transformation, is valuable for understanding information in biology.
• 🧬 To determine if two plant species are the same, one could collect data on their ability to interbreed, DNA sequences, or chromosome numbers.
• 🔴 The Hershey-Chase experiment used radioactive sulfur and phosphorus to differentiate between protein and DNA, leading to the discovery that DNA is the genetic material.

Q & A

What inspired Mr. Andersen when he was young, and how has that changed over time?

When Mr. Andersen was young, he was inspired by Michael Jordan and had posters of him everywhere. However, today he is more inspired by academics rather than athletic achievements.

What ties together the scientists mentioned in the video?

The scientists mentioned in the video, including Darwin, Mendel, Louis Pasteur, E.O. Wilson, and Jane Goodall, are tied together by their ability to ask questions and gather data to answer those questions, which is a fundamental aspect of science.

What is science according to Mr. Andersen?

According to Mr. Andersen, science is the belief in an objective shared reality that is governed by natural laws. These laws can be discovered through observation and experimentation.

What are the different types of science mentioned, and how do they differ?

The different types of science mentioned are the scientific method, observational science, and historical science. The scientific method is a powerful tool involving controlled experiments, observational science involves gathering data through observation, and historical science looks at data collected over time.

In the enzyme activity experiment described, what are the independent and dependent variables?

In the enzyme activity experiment, the independent variable is the temperature of the enzyme, and the dependent variable is how fast the enzyme acts.

Why is controlling variables important in an experiment, and how is this achieved in the classroom?

Controlling variables is important to ensure that the data collected is valid. In the classroom, students are asked to come up with about ten control variables to ensure consistency in the experiment, such as maintaining the same pH, concentration of solutions, and using fresh hydrogen peroxide each time.

What example does Mr. Andersen use to illustrate the concept of evolution and data collection?

Mr. Andersen uses the example of the stickleback fish in the glacial lakes of Alaska, which quickly adapt to their local environment. He suggests measuring their pelvis length over time as they move from areas with many predators to areas with fewer predators to observe evolution.

How does Mr. Andersen suggest students approach a question involving data collection strategies?

Mr. Andersen suggests that students should first identify the data collection strategies, justify them, and then design a plan for collecting their own data. He emphasizes the importance of identifying independent and dependent variables, discussing the procedure, and considering statistical analysis.

What approach does Mr. Andersen recommend for designing an experiment, and what should students focus on?

Mr. Andersen recommends that students should identify the independent and dependent variables, briefly discuss the procedure, consider statistical analysis, and include multiple trials. He emphasizes that students should focus on thoroughly formulating how they would conduct the experiment.

What is the significance of the Hershey-Chase experiment, and why were specific isotopes used?

The Hershey-Chase experiment was significant because it identified DNA as the transforming factor in genetics. Radioactive sulfur and phosphorus were used because phosphorus is found in DNA, while sulfur is found in protein. This helped distinguish which molecule was responsible for the genetic transformation.

Outlines

00:00

🔬 Science as Inquiry and Data Collection

Mr. Andersen introduces the concept of data collection strategies in AP Biology, emphasizing the importance of asking questions and gathering data to understand natural laws. He highlights the role of observation and experimentation in science, distinguishing between the scientific method, observational science, and historical science. The paragraph discusses the process of designing a controlled experiment, using the example of studying the effect of temperature on enzyme activity with catalase. Key points include identifying independent and dependent variables, and the challenge of controlling other variables to ensure valid data collection.

05:03

📊 Designing Experiments and Hypothesis Testing

This paragraph delves into the process of formulating hypotheses and designing experiments to test them, using the kangaroo rat and its adaptation to varying precipitation levels as an example. Mr. Andersen explains the importance of identifying independent and dependent variables, outlining the experimental procedure, and considering statistical analysis and multiple trials. He also discusses the types of data that can be collected to answer specific biological questions, such as species identification through pollination, DNA analysis, or chromosome number comparison. The paragraph concludes with an evaluation of the Hershey-Chase experiment, emphasizing the significance of selecting appropriate isotopes to determine the transforming factor in genetic material.

Keywords

💡Data Collection

Data collection refers to the process of gathering information to answer specific questions or test hypotheses. In the video, it is emphasized as a fundamental aspect of scientific practice, where different strategies are employed to observe, experiment, and analyze. The importance of data collection is illustrated through examples such as measuring enzyme activity and analyzing historical data, showcasing its role in validating scientific experiments.

💡Independent Variable

An independent variable is the factor that is intentionally varied or manipulated in an experiment to observe its effect on a dependent variable. In the context of the video, the independent variable is highlighted through the example of varying temperature to measure its effect on enzyme activity. Understanding and controlling the independent variable is crucial for conducting valid scientific experiments.

💡Dependent Variable

A dependent variable is the outcome or response that is measured in an experiment, influenced by changes in the independent variable. The video explains this concept using the example of enzyme activity, where the speed at which the enzyme acts is the dependent variable being measured. It is essential for determining the effect of the independent variable in scientific research.

💡Controlled Variables

Controlled variables are factors that are kept constant in an experiment to ensure that the results are due to the independent variable alone. The video underscores the importance of controlling variables such as pH and solution concentration in an enzyme activity experiment, ensuring the validity of the collected data. Proper control of variables is critical for drawing accurate conclusions in scientific studies.

💡Scientific Method

The scientific method is a systematic approach to investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. While the video acknowledges it as a powerful tool, it also clarifies that science encompasses more than just this method, including observational and historical sciences. The scientific method's structured approach helps in developing controlled experiments and gathering reliable data.

💡Hypothesis

A hypothesis is a proposed explanation or prediction that can be tested through experimentation or observation. In the video, the concept is discussed in the context of designing an experiment to test a hypothesis about the kangaroo rat's mass in relation to precipitation. Formulating a clear hypothesis is the first step in scientific inquiry, guiding the direction of the experiment.

💡Experimental Design

Experimental design refers to the process of planning an experiment to test a hypothesis, including the identification of independent and dependent variables, control of variables, and data collection methods. The video highlights the importance of a well-thought-out experimental design, using examples such as enzyme activity experiments and the kangaroo rat study. A strong experimental design ensures that the results are valid and reliable.

💡Observational Science

Observational science involves gathering data through direct observation rather than through controlled experiments. The video mentions this approach as part of the broader scientific practice, alongside the scientific method and historical science. Observational science is particularly important in fields where controlled experiments are not feasible, such as astronomy or certain aspects of ecology.

💡Historical Science

Historical science involves the study of past events and phenomena by analyzing existing data and records. The video references historical science when discussing how scientists use previously collected data, such as Fredrick Griffith's experiment on bacterial transformation, to draw conclusions. This approach is crucial for understanding processes and events that cannot be replicated in a lab.

💡Control Experiment

A control experiment is a standard against which the results of an experiment are compared. It includes all the factors of the experiment except the one being tested. In the video, control experiments are discussed in the context of maintaining validity in data collection, with examples like Mendel's pea experiments. Control experiments are essential for isolating the effects of the independent variable and ensuring that the results are due to that variable alone.

Highlights

Science is about asking questions and gathering data to answer those questions.

The scientific method is powerful, but science also includes observational and historical methods.

In controlled experiments, identifying independent and dependent variables is crucial, along with controlling other variables.

Data collection strategies are essential in understanding biological processes like evolution, free energy, and enzyme activity.

AP Biology emphasizes justifying data collection strategies, designing experiments, and evaluating data.

Example experiment: measuring how temperature affects enzyme activity by controlling variables like pH and concentration.

Evolution example: studying stickleback fish in Alaskan lakes to understand rapid adaptation.

Photosynthesis example: tracing oxygen-18 to understand the process of water splitting in light reactions.

Designing experiments involves identifying independent and dependent variables, creating hypotheses, and considering statistical analysis.

Open-ended questions in biology require considering various data types, such as cross-pollination for species identification.

Hershey-Chase experiment: used radioactive sulfur and phosphorus to identify DNA as the genetic material.

Understanding controlled experiments is key to conducting valid scientific research.

Mendel's work with peas is a classic example of experimental science leading to genetic discoveries.

Data analysis in biology can involve comparing DNA sequences, chromosome numbers, and hybrid viability.

Science relies on repeated experimentation and observation to uncover natural laws.

Transcripts

Hi. It's Mr. Andersen and this is AP Biology Science Practice 4. It's on

data collection strategies. When I was young I was inspired by Michael Jordan. So I had

posters of him everywhere. Today I am more inspired by the academics rather than the

athletic achievements and so this poster might be on my wall today. We've got the biologists

that jump out, like Darwin, Mendel. Here's Louis Pasteur. We've got E.O. Wilson and Jane

Goodall. But we also have physicists, chemists on here. But what ties together all of these

great scientists is their ability to ask questions and then gather data to answer those questions.

And that's what science is. It's this belief that we have this objective shared reality.

It's not subjective. It's governed by natural laws. And then we can discover these natural

laws through observation and experimentation. A lot of people think that the only thing

scientists do is the scientific method. Now that's a powerful tool and it's a part of

science, but we also have observational science. We also have historical science where we look

through the work of others. And we look through data that was collected through time. And

so it's just one part of it. But when you're coming up with a controlled experiment, there

are really two parts to that. So let's say I ask you to develop an inquiry lab where

you're going to measure how the temperature effects the enzymes activity. And let's say

I frame it a little bit by saying that I want you to use catalase, which is an enzyme that

breaks down hydrogen peroxide into water and oxygen. Now this is a lab that we do. We use

chads of filter paper. We dip them in different concentrations of enzyme and see how long

it takes to float in a beaker filled with hydrogen peroxide. But if we're changing it

to temperature, now we're going to have to vary the temperature. So what's our independent

variable? It's going to be the temperature of the enzyme. And then what's going to be

our dependent variable? Well it's going to be how fast it acts. And so those first to,

this idea of what are we going to change and what are we going to measure is only part

of the experiment. The more difficult part is actually controlling all of the other variables.

We have to make sure, for example, that the pH stays the same. That the concentration

of the solution stays the same. That we're getting new hydrogen peroxide each time. And

so in my class I have kids come up with about ten control variables. And once they do that,

then they're going to be able to collect data that's pretty valid. So in College Board what

they want you to do is be able to collect data or understand the collection of data

in each of the four areas. Or the four big ideas. So in evolution a great example could

be evolution in the stickleback. So the stickleback fish, remember is a fish found in these glacial

lakes of Alaska. They're quickly adapting to their local environment. And so we could

measure that by collecting for example, collecting data on their pelvis length over time. And

as they move from an area where there's a lot of fish that prey upon them to no fish,

we're going to see quick evolution. If we look at free energy, it could be data related

to the nutrients cycling. In this case looking at the amount of nitrogen. If we're looking

at information, we could even go back and look at historical data. And so Fredrick Griffith

did this famous experiment where he was looking at different types of bacteria, virulent - nonvirulent,

and then measuring how transformation takes place. Or if we're looking at systems, we

could be looking at enzymes. And measuring how lowering that activation energy can increase

the action of the enzymes. And so you have to be good at understanding how to collect

data. And then see when good data is collected. And so what kind of questions are you going

to get asked? Well, you're going to get asked question in four areas. The first one is in

your ability to justify data collection strategies. And so here is the formula for photosynthesis.

That should jump out to you right away. In this question they're saying if the input

water is labelled with a radioactive isotope for oxygen, oxygen 18, then the oxygen gas

released as the reaction proceeds is also labelled with oxygen 18. Which of the following

is the most likely explanation for that? And this is a real common type question where

they want to make sure you understand where all of the atoms are going in that formula.

And so they're going to label one. So which of the following, this would be like a multiple

choice question, which of the following is going to be correct? Well let me show you

how I would go at this question. I know that water is going to be split in the light reaction.

So I immediately could rule out C & D. And now I have to, I'm kind of down to A & B.

In this one they're saying during the light reaction hydrogen atoms combine with carbon

dioxide. I know the carbon dioxide doesn't come in until the Calvin Cycle. And so I would

circle B as the right answer. And so in this case you're looking at the data that was collected

and then you're justifying the use of that data. Let's go to the next one. They want

you to be able to design a plan for collecting data of your own. And so this is an essay

type question that was asked a few years ago. They're giving you data on the kangaroo rat.

Try to pull yourself away from how cute the kangaroo rat is to look at the data for a

second. We've got the mean annual precipitation down on the bottom. And then we have the average

mass on the side. And you can see that there's an increase in average mass when we have this

kind of a sweet spot here of around 40 millimeters of annual precipitation. And so they want

you to do two thing. Number one, develop a hypothesis that would explain the data. And

then number two, design an experiment that would test the hypothesis. And so the first

part is going to be easy because you can come up with a lot of ideas. Maybe the parasites

are going to do better at those different amounts of water. But probably a better guess

is to look at, what is the kangaroo rat eating? What is it's food supply? And maybe this is

like the perfect food supply. Or in other words the perfect amount of water for the

food supply, maybe the seeds that are being produced by grasses to do well. So it doesn't

matter what your hypothesis is. On that first one you just have to choose one. And after

you've done that we have to design an experiment. Now when you see design an experiment, I mean

light bulbs should go off. And you could say, really start thinking about how many points

am I going to get on this essay question. So I'm going to identify what's my independent

variable, what's my dependent variable. I'm briefly going to talk about the procedure.

I'm going to talk about statistical analysis and lots of trials and each of those are going

to get you a point. And so remember you don't have to do the experiment, you just have to

formulate how you would do the experiment. And so really shoot for the moon. Let's go

to the next one. You have to be able to collect data to answer a specific question. And so

in this one this is a practice test. They're saying that we've got a population of plant

species that are found growing in the mountains. And then another species that have been found

in the same mountains at lower altitude. So what they're asking you to do is to describe

two types of data that could be collected to answer the question, Do these growing above

and below represent a single species? And so again they're kind of opening it up for

you. And so what would be one thing that starts for me would be looking, okay what is a species?

How am I going to compare these two? If they can interbreed and produce fertile offspring,

in other words, I would start pollinating them, cross-pollinating them and see if I

could produce viable seeds. And so if I can then that would suggest they're a single species.

Maybe I could start looking at hybrids between the two groups. Or maybe I could look at the

DNA. That would be another type of data that I could collect. I could look at the nucleotide

sequences and then see how similar they are by comparing them. Like using blast analysis.

Or I could look at their chromosome number. There's lots of ways. And so you really have

to start, this is an open ended question where you're looking at what kind of data would

I collect? And then finally you have to be able to evaluate data that they're giving.

And so this is the famous Hershey-Chase experiment. Remember they were looking at bacteriophages.

Injecting their DNA into bacteria. And so what they're asking in this essay is why were

radioactive sulfur and phosphorus used in the Hershey-Chase experiment? And so why are

those great choices? Remember it's because the phosphorus is dying the phosphate that's

found in the DNA. And we don't have sulfur in our DNA. Likewise the sulfur is going to

make those, especially disulfide bonds in the protein, but we're not going to have the

phosphorus inside that. So they were able to choose properly which atoms they should

use to answer the question that they were looking at. Which was, what is the transforming

factor? And that's how they discovered that it was DNA. And so really what makes science

science is our ability to again ask questions and then gather data. And we have to do that

over and over and over. And a great example of that would be Mendel. Mendel's ability

to figure out how genetics works just through experimentation and on peas. Over and over

and over again. And so again, when you get stuck, look back on that controlled experiment.

What things are required to do that. And I hope that was helpful.