CHAPTER 1 ENVIRONMENTAL CHANGE AND TRAIT DISTRIBUTION

CHAPTER 1 ENVIRONMENTAL CHANGE AND TRAIT DISTRIBUTION

1.4.1: WARM-UP Observing Populations at Two Generations The histograms below show the distribution of fur-level traits in a population at two different points in time. Review the two histograms and answer the questions below. The distribution of the traits changed over time. 1. Do the two histograms show the same amount of variation in the population at both generations? 2. Do the two histograms show the same distribution of traits at both generations? YES NO YES NO

1.4.1: WARM-UP Observing Populations at Two Generations The histograms below show the distribution of fur-level traits in a population at two different points in time. Review the two histograms and answer the questions below. 1. Do the two histograms show the same amount of variation in the population at both generations? NO 2. Do the two histograms show the same distribution of traits at both generations? NO

1.4.1: WARM-UP Why did the distribution changed from mostly individuals with traits for low and medium levels of fur to mostly individuals with high levels of fur? The population started with most ostrilopes having low amount of fur. The population at this time had a high variation 7 different fur traits. At Generation 50, the distribution was different since most of the ostrilopes had a high amount of fur. There was also less variation since there were only 4 fur traits.

1.4.2: SIM UTILIZE SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Investigation Question: What makes the distribution of traits in a population change? In the next activity, you will use the Natural Selection Sim to begin thinking about what made the distribution of fur traits in the Ostrilope population change over time.

Let s examine some more controls in the SIM 1.4.2: SIM UTILIZE SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Temperature Slider - Observe the changing visuals. - Only make ONE temperature change to make conclusions. COLD MILD HOT TEMP.

Traits Histogram Window Run - Run Sim by pressing NEXT - Then hit RUN in the build setup menu. - Collect a few generations of data - Open Traits Histogram Window (Bottom Left icon) - Observe real-time histograms of different features 1.4.2: SIM UTILIZE SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM

Speed Controls - Use drop down to collect many generations of data more quickly. 1.4.2: SIM UTILIZE SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM

Histograms in Analyze - Use Analyze in Build Setup menu. - Move generation slider. - Note the stripes show the starting generation histogram. 1.4.2: SIM UTILIZE SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM

Starting histogram Fur and Temperature A Mode Press Build, then Rebuild Click on Ostrilope Look at starting Ostrilope population 1.4.2: SIM FUR AND TEMP A OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Note that it has the same distribution of fur traits as in the Generation 1 Histogram from the Warm-Up. These ostrilopes have been living in a warm environment, but that students are going to change the environment to be colder.

1.4.2: SIM FUR AND TEMP A OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Set the environment to cold (Level 1), using the Temperature slider, and observe what happens over 50 generations. Zoom into the environment and select different ostrilopes to observe individuals with different traits. Each bar tells us how many individuals in the population have a particular trait. After 50 generations have passed, students should press ANALYZE to compare the Generation 50 histogram with the Generation 1 histogram.

1.4.2: SIM FUR AND TEMP A OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Launch the Sim and make sure you do the following: 1. Begin by setting the environment to cold (Level 1). 2. Observe individuals with different fur traits while the Sim is running. 3. Use the Traits Histogram Window while the Sim is running. 4. Press ANALYZE to compare histograms. 5. Upload a screenshot of the fur-trait histogram for Population A after 50 generations. 6. Answer the questions on their Amplify Science screens. 7. Time Permitting: Reset SIM and repeat your test to see if you get the same results. Entire Screen Specific Area of the Screen

1.4.2: SIM FUR AND TEMP A OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Discuss your responses to the questions with a partner.

Let s review your work 1.4.2: SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM "The population started with ostrilopes that had low, medium, and high levels of fur. I saw that the ostrilopes with the low level of fur shivered and died in the cold environment, but the ones with the high level of fur survived. " The high fur-level trait became more common because individuals with this trait could survive in the cold environment.

1.4.2: SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Use your interpretation of the data to hypothesize that the change shown in the data was caused by the environmental change cold environment. When a bar gets shorter, it means that individuals died because they did not have enough fur to survive in the cold environment.

1.4.2: SIM OBSERVING FUR TRAITS AND TEMPERATURE IN THE SIM Traits for high fur became more common and the traits for low fur became less common. The ostrilopes with lower fur-level traits shivered and died in the cold environment. The ostrilopes with higher fur-level traits survived in the cold environment. More fur helped them survive, and they became more common.

environment: everything (living and nonliving) that surrounds an organism Each of these environments includes many living things, such as plants and animals, and nonliving things, such as rocks and water. From left to right: Craters of the Moon National Monument, Idaho; Denali National Park, Alaska; Guadalupe Mountains National Park, Texas; Channel Islands National Park, California.

adaptive trait: a trait that makes it more likely that an individual will survive in a specific environment non-adaptive trait: a trait that makes it less likely that an individual will survive in a specific environment

1.4.2: SIM INTRODUCING ADAPTIVE AND NON -ADAPTIVE TRAITS What were the adaptive traits in this Sim mode? In other words, which traits helped individual ostrilopes survive best in the cold environment? Higher fur-level traits What were the non-adaptive traits in this Sim mode? In other words, which traits made it less likely that an individual ostrilope would survive in the cold environment? Lower fur-level traits Were individuals with the non-adaptive traits able to change to an adaptive trait in the middle of their lifetime? No, they shivered and died

GOAL Fur vs. Temp A 1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Show how and why Population A changed after the environment changed from warm to cold. You will be learning how to model your ideas about changes in the distribution of traits in populations using the natural selection simulation model. Remember: Scientists create models to communicate ideas about how things work to other people.

Types of Models: Physical models, like a globe or a model of a cell. Computer programs, like a computer model that predicts weather or the Natural Selection Simulation. Visual representations, like a food web or a diagram of the water cycle. You will be using a special tool called a Modeling Tool to make visual models that show your thinking about why populations change over time. 1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Histograms: There are two histograms that represent the same population at two different points in time.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Timeline: There is a timeline at the bottom of the image that shows what points in time these histograms represent.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Environment labels: There are labels below each histogram that describe aspects of the environment and whether the environment is changing.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Trait labels: There is a legend that shows symbols and what those symbols mean.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Examine the Starting Population Histogram More likely to survive The environment is changing from warm to cold, just like in the previous Sim activity. Which Ostrilopes would be more likely to survive and which would be less likely to survive in the cold environment?

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS These histograms are the same as the histograms you saw in the Warm-Up. In the Sim and the Warm-Up, we observed that the distribution of traits changed over time. This example modeled the change we saw in the Sim.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS We learned that traits for higher fur levels are adaptive traits in a cold environment because they help ostrilopes survive in cold environments. Lower fur-level traits make it difficult to survive in a cold environment. This means traits for lower fur levels are non-adaptive traits in cold environments. You will continue to investigate what causes the distribution of traits in a population to change as you create another model.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS You will receive one copy of the Modeling Tool: Fur and Temperature, Population B

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS POPULATION A POPULATION B Share what similarities and differences you notice between Population B and Population A and their environments.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS POPULATION A POPULATION B Like Population A, most of the ostrilopes in Population B have low fur-level traits. There is much less variation in fur-level traits in Population B compared to Population A. Both populations experience an environment that gets colder suddenly.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS In our next activity, we will test our predictions using the SIM. Let s discuss making predictions. We do not yet know how the distribution of traits in Population B will change as a result of the environment becoming cold.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS We will make a visual model to predict how Population B will change in a cold environment. You will be able to check your predictions in the Sim in a few minutes.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Turn to a partner and discuss the following. Do you think Population B will respond differently than Population A did to an environment that changes from warm to cold?

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS Complete your models individually. You do not have to make perfect predictions, but you should show your best guess at what might happen to this population by shading in the bars for the Population After 50 Generations Histogram.

1.4.3: MODELING TOOL MODELING CHANGES TO THE DISTRIBUTION OF TRAITS

Open Fur and Temperature B mode in the Natural Selection Simulation. Press the Ostrilope icon and point out the Fur-Trait Histogram for the ostrilope population. Note that it has the same distribution of fur traits as the Generation 1 Histogram from the Modeling Tool activity. 1.4.4 TESTING PREDICTIONS IN THE SIM

Setting Up The Sim activity. Set the temperature of the environment to cold (Level 1) and observe what happens over 50 generations. While running the Sim, you should zoom into the environment and observe several individuals with different traits. When complete, press ANALYZE to compare the Generation 50 Histogram with the Generation 1 Histogram. 1.4.4 TESTING PREDICTIONS IN THE SIM

1.4.4 TESTING PREDICTIONS IN THE SIM Entire Screen Specific Area of the Screen

Discuss with a partner whether your predictions are correct. 1.4.4 TESTING PREDICTIONS IN THE SIM Did population B change the way you had predicted? Individuals cannot change traits midlife, so the population died out.

1.4.4 TESTING PREDICTIONS IN THE SIM Did Population B change in the way you predicted? Why or why not? Population B died out because it did not have high levels of fur that were required for a cold environment.

1.4.4 TESTING PREDICTIONS IN THE SIM

POPULATION A: Individuals with high fur levels were able to survive in the cold environment. The individuals with low fur levels shivered and died. Since more individuals with high fur levels survived, the high fur-level trait became more common in Population A over time, and the low fur-level trait became less common. The high fur-level trait was an adaptive trait. 1.4.4 TESTING PREDICTIONS IN THE SIM

Since Population B did not start out with variation that included individuals with the adaptive trait of a high fur level, none of the individuals could survive. POPULATION B: In the second Sim, the distribution of traits in Population B could not shift like Population A did - toward more individuals with high fur level. This is because new traits cannot appear in a population just because they would be helpful for survival. 1.4.4 TESTING PREDICTIONS IN THE SIM

1.4.5 HOMEWORK R E A D A N D A N N OTAT E T H R E E A RT I C L E S A B O U T D I F F E R E N T O R G A N I S M S I N O R E G O N S TAT E PA R K. In order to help Dr. Alex Young and to apply your understanding of variation, traits, and changes in trait distribution, you will be reading articles about different organisms living in Oregon State Park.