The Arizona STEM Acceleration Project

How Species Change to Survive

How Species Change to Survive

An 8th grade STEM lesson

Cassandra Cordts

July 25, 2023

Notes for teachers

• I like to give each student their own materials for this activity. You could do the activity with pairs, especially if you choose to not use Skittles.
• Skittles are (usually) pretty allergy friendly. They will not meet every requirement but they are nut & gluten free. I keep a set of colored pom poms for my students with red dye allergies.
• For 160 students I usually use 3-4 party size bags of Skittles. I use a condiment cup to scoop them up and place them on student mats.
• I try to make sure their scoop is not too heavily one color.
• I ask students how we can get more accurate results and they are more than happy to tell me that more candy would be a larger sample size.

List of Materials

• Student Slides
• Teacher copy of slides
• Paper
• Colored pencils: Green, Yellow, Blue
• Skittles
• Gloves/scoop to pass out Skittles with

Standards

Core Ideas for Knowing Science:

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L2: Organisms require a supply of energy and materials for which they often depend on, or compete with, other organisms.

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L3: Genetic information is passed down from one generation of organisms to another.

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L4: The unity and diversity of organisms, living and extinct, is the result of evolution.

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Life Science:

8.L4U1.11 Develop and use a model to explain how natural selection may lead to increases and decreases of specific traits in populations over time.

8.L4U1.12 Gather and communicate evidence on how the process of natural selection provides an explanation of how new species can evolve.

Mathematical Practices:

5. Use appropriate tools strategically.

6. Attend to precision.

Objectives:

Students will model how speciation occurs as a result of geographic isolation.

Student will then analyse what other factors (not geographic isolation) could cause a species to split into two (or more) distinct groups over time.

Students will connect their learning to the real life examples.

Agenda

Objective: 1 minutes

Agenda: 1 minutes

Introduction Activity: 5 minutes

Hands on Activity: 25 minutes

Connecting Observations: 15 minutes

Assessment: 5 minutes

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Intro/Driving Question/Opening

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Driving Question:

• What happens when a group of a species is cut off from the rest of its kind?

Scaffolded Opening Questions:

• In your own words what is a ‘species’?
• What are 5 ways an individual or small group of individuals could be separated from others of their kind (ex. coyotes, birds, bears)?
• (activate prior knowledge)

Hands-on Activity Instructions - Let’s Get Started!

• This is an individual activity - HOWEVER - I encourage students to verbally help one another when they get stuck.
• Give each student a piece of paper and a blue, green and yellow colored pencil.

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1. Introduction: A species of beetles comes in a variety of colors (yellow, orange, red, purple and green). These beetles are living together on a small island. We will observe what happens to the beatles as environmental pressures act on the population.
2. On your paper label one side LEFT and one side RIGHT.
3. Wait patiently for your beetles to populate your area (wait patiently for your teacher to walk around).

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Hands-on Activity Instructions - Original Beetle Population

• Walk the class through the steps together.
• Students will count the skittles they have and begin recording that information in their slides/notebook.
• Remind students the model on the page is MY model and theirs is different.
• Students who are absent can use my model to complete the activity.

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4. Count how many beetles are living in the area. How many total beetles do you see?
5. Record how many beetles you see of each color under Initial Population on data table 1.
6. To calculate the percentage of color, divide the number of beetles by the total. Round to the nearest whole number and record your answer.

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Hands-on Activity Instructions - Speciation Round 1

• Walk the class through the steps together.
• Students will split the beatles into two approximately even groups, pushing them to either side of the paper. Have them draw a river down the center of their paper.
• Remind students the model on the page is MY model and theirs is different.
• Students who are absent can use my model to complete the activity.
• Have students answer the “Round 1 of Speciation” and “Looking forward to Round 2” questions on their slides.

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7. Oh No! A large storm brings flood waters to the area. The water carves out a river that separates the betweele population into two groups.
8. How many total beetles are on the left side of the river?
9. How many total beetles are on the right side of the river?
10. To calculate the percentage of each color, divide the number of beetles by the total. Round to the nearest whole number and record your answer.

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Hands-on Activity Instructions - Speciation Round 2

• Walk the class through the steps together.
• Have students draw a grassy field on the left and a sandy beach on the right.

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Hands-on Activity Instructions - Speciation Round 2

• Walk the class through the steps together.
• Give students the following scenario and have them ‘eat’ the beetles that were ‘spotted’.
• Scenario: As a predator, you will spot the beatles easily that are not able to camouflage. To the left of the river, delete 2 beetles of each color (if available) except the green beetles.

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Hands-on Activity Instructions - Speciation Round 2

• Walk the class through the steps together.
• Have students calculate how many beetles are left and what percentage they make up of each population.
• Have students answer the ‘Review Round 2 of Speciation” questions.
• Walk the room and check on any students who seem lost.

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11. How many total beetles are on the left side of the river?
12. How many total beetles are on the right side of the river?
13. To calculate the percentage of each color for Data Table 3, divide the number of beetles by the total. Round to the nearest whole number and record your answer.

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Assessment

At this point in the unit student should be able to explain an example of how species can get split into two groups.

Students should have worked with the model to see how population traits can change in just a few generations and hypothesize how they could continue to change.

Student notebooks/observations are also a great formative assessment at this point.

It would be relatively easy to create a quick summative assessment. It would need to include scenarios of speciation and have students identify them and the opportunity for them to explain/define what a speciation is in their own words.

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Differentiation

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Pair students as needed for extra support.

Provide extra resources like books and videos for students to have multiple examples.

Provide an extra model example for students to experience.

Remediation

Extension/Enrichment

Students can look into real life examples of speciation and look into how long ago it happened and why. They can create a Google Slides presentation to report what they found.

Looking at species such as Pizzly Bears, Narlugas, or Ligers is also an interesting and relevant topic to the world today. Ask students whether this is speciation or something else.

Student Work Slides

I use Google Slides to create a digital notebook with my students. Most days I use a copy of the same presentation that i have added animations and extra informational slides to if necessary. I have attached my student slides for this lesson to the slides that follow.

Investigation 97.2 Wonders of the Galapagos

FQ: What happens when a group of a species is cut off from the rest of its kind?

When we completed the ‘battling beaks’ activities with the different tined forks representing beaks did one type of ‘beak’ collect the most food? Why?

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Type here…

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Does this happen in real life? Are certain individual in a species better at living and reproducing (and therefore passing on their genes/traits) than other individuals? Explain your answer.

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Type here…

The man in the cartoon is Charles Darwin. Explain what you think might have happened in real life to inspire this cartoon. Check out the book link to see if you were correct!

Speciation

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When a group within a species separates from other members of its species and develops its own unique characteristics,

forming a

new species.

In your own words define the word “species”

Type here…

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Activate your prior knowledge! What are 5 ways individuals in a species can become isolated from others of their kind?

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5. Type here…

Introduction: A species of beetles comes in a variety of colors (yellow, orange, red, purple and green). These beetles are living together on a small island. We will observe what happens to the beatles as environmental pressures act on the population.

Introduction: A species of beetles comes in a variety of colors (yellow, orange, red, purple and green). These beetles are living together on a small island. We will observe what happens to the beatles as environmental pressures act on the population.

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On your paper label one side LEFT and one side RIGHT.

Left

Right

Wait patiently for your beetles to populate your area (wait patiently for your teacher to walk around).

Count how many beetles are living in the area. How many total beetles do you see?

Type here.

Directions: Record how many beetles you see of each color under Initial Population on data table 1.

To calculate the percentage of color, divide the number of beetles by the total. Round to the nearest whole number and record your answer.

If you are in class you will use your own beetle model to complete this activity. If you are working on this at home you will use the pictures provided to complete the activity.

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Oh No! A large storm brings flood waters to the area. The water carves out a river that separates the beetle population into two groups.

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On your paper draw a river down the center.

Left

Right

Speciation Round 1: Oh No! A large storm brings flood waters to the area. The water carves out a river that separates the beetle population into two groups.

How many total beetles are on the left side of the river?

Type here.

How many total beetles are on the right side of the river?

Type here.

If you are in class you will use your own beetle model to complete this activity. If you are working on this at home you will use the pictures provided to complete the activity.

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How did the population change to the left of the river compared to the initial population?

Type here…

How did the population change to the right of the river compared to the initial population?

Type here…

On the left side of the river, there are a lot of grassy areas. Which color beetle will survive the best in this habitat? Explain your answer.

Type here…

Review Round 1 of Speciation:

Looking forward to Round 2 of Speciation:

On the right side of the river, there are a lot of sandy areas. Which color beetle will survive the best in this habitat? Explain your answer.

Type here…

On your paper draw a grassy field on the left and a sandy beach on the right.

Left

Right

On your paper draw a grassy field on the left and a sandy beach on the right.

Left

Right

Eat 2 green from this side

Eat 2 red from this side

Eat 2 orange from this side

Eat 2 purple from this side

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DO NOT EAT YELLOW FROM THIS SIDE

Eat 2 yellow from this side

Eat 2 red from this side

Eat 2 orange from this side

Eat 2 purple from this side

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DO NOT EAT GREEN FROM THIS SIDE

Speciation Round 2: As a predator, you will spot the beatles easily that are not able to camouflage. To the left of the river, delete 2 beetles of each color (if available) except the green beetles.

How many total beetles remain on the left side of the river?

Type here.

To the right side of the river delete 2 beetles of each color (if available) except the yellow beetles.

How many total beetles remain on the right side of the river?

Type here.

If you are in class you will use your own beetle model to complete this activity. If you are working on this at home you will use the pictures provided to complete the activity. Use the black dots below to ‘eat’ beetles (cover them) according to the instructions.

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How did the population change to the left of the river compared to the initial population?

How did the population change to the right of the river compared to the initial population?

Suppose in 100 years the beetles from the left side of the river come back into contact with the beetles on the right side of the river. Do you think they will be able to reproduce with each other or will they be separate species? Explain your answer.

Review Round 2 of Speciation:

What traits would you expect to be eliminated on the grassy side of the river in a few generations? What about the sandy side?

The beatles were split up by a geographical change in their environment. What are other things that could separate a group from the rest of its species?

What are some examples of real species that have had speciation happen? What caused them to separate and stay separated? (you can have a friend help but you need to explain the process in your own words).

Analysis Questions: