8th Grade - Unit 3: Life on Earth

Instructional Sequence

Assessment Types at
This Stage

Assessment Description

Learning Target

Engage

Making Predictions: Students’ background knowledge about the history of life on Earth can be assessed.

Students work as a group to try to order events in Earth’s history. Once the proper order is established, students consider time scale by creating a timeline of events.

It is okay if students are not sure of the order of events. This activity is meant to introduce important milestones in the history of life on Earth. This activity also provides information about students’ background knowledge of the diversity of life on Earth. If students are unsure of the difference between unicellular and multicellular organisms, consider briefly reviewing the topics covered in Unit 6.3. The skills related to scale that students should be able to master are understanding how to break up a timeline evenly and the placement of events relative to each other. 

Explore 

Making Predictions, Considering Models, Written Responses: Students explore two models that demonstrate the law of superposition.

In Part 1, students consider where certain dates would fall in a stack of newspapers. This prepares students for Part 2, in which they think about how the positions of rock layers relate to the age of the rocks and fossils found within them. 

Students should be able to:

• Make connections between the two models. In the newspaper stack, the dates closest to today should be at the top. Students should apply the same reasoning to the rock layers.
• Make a connection between the age of the rock layers and the age of the fossils found within them.

Explain 

Reading, Group Discussion:

Students read an article working with partners and Listening Triads. Students answer Reflection Questions in small groups and discuss responses as a class. 

Students read an article: “What Can Rocks Tell Us About Life on Earth?” and answer reflection questions.

Students should be able to: 

• Read an article on the evidence scientists use to organize the history of life on Earth.
• Explain that the history of life on Earth includes the evolution of new species and the disappearance of species, called extinction.
• Explain that positions of rock layers relate to age. Older layers are found at the bottom of rock formations and younger layers are found at the top.
• Explain that numerical dating is a method scientists use to date rocks. This method involves analyzing the atoms found in rocks. 

Elaborate

Extending Understanding and Applying Learning to a New Context: Students connect their understanding of the geologic time scale to the Culminating Project. 

In the Elaborate lesson, students learn about the five previous mass extinctions. Students also sort evidence to determine which claim about the age of a fossil is supported. 

Students should be able to: 

• Explore five periods in Earth’s history that scientists think represent previous mass extinction events.
• Explain the difference between a mass extinction and a species extinction.
• Explain that the rock layer a fossil is found in can be used as evidence for when that species appeared or became extinct.
• Explain that sedimentary rock is formed by layers of sediment building up. Therefore, the farther down a rock layer is, the older it is, and vice versa.

Evaluate

Engaging in Argument from Evidence: Students evaluate their knowledge of the evidence used to organize the history of life on Earth. 

In Part 1, students use a Critique, Correct, Clarify routine to edit a fictional student’s statement about the age of several fossils. In Part 2, students work individually, with a small group, and as a whole class to update their Know, Wonder, Learned charts and Driving Question Board with what they have learned in the subunit. 

Students should be able to: 

• Explain that the rock layer a fossil is found in can be used as evidence for when that species appeared or became extinct.
• Explain that sedimentary rock is formed by layers of sediment building up. Therefore, the farther down a rock layer is, the older it is and vice versa.

Instructional Sequence

Assessment Types at
This Stage

Assessment Description

Learning Target

Engage

Noticing Patterns, Making Predictions: Students’ background knowledge about evolution and evolutionary relationships are assessed. 

Students revisit the timeline from Subunit 1. For the activity, students work in groups to try to order the appearance of living things on Earth. This activity includes some organisms that were in the first timeline activity as well as additional organisms. Once students have recorded the timeline in their Science Notebook, they look for similarities and differences between organisms and think about organisms that may or may not be closely related.

It is okay if students are still forming ideas about what it means for two species to be related. Students should be able to:

• Attempt to find a pattern in the evolution of complex species on Earth.
• Record some initial thoughts on how closely or distantly related certain organisms might be. 

Explore 

Engaging in Argument from Evidence: Students analyze the three types of evidence that are used to establish evolutionary relationships.

Students are introduced to evidence that supports the theory of evolution and evolutionary relationships between different organisms. Students begin by reviewing a data table that contains information about the horse family that is supported by evidence in the fossil record. Students consider how these animals have changed over time. Next, students are presented with photos and illustrated diagrams of the limbs of different tetrapods. Students look for similarities and differences in the structures of these organisms. Finally, students examine embryo development resources to find similarities and differences in early developmental stages.

Students should be able to:

• Observe and record patterns noticed in the body shapes and bones of horses from different periods.
• Observe and record similarities and differences between the limbs of tetrapod organisms. 
• Observe and record similarities and differences between embryos of different organisms at different stages of development. 
• Make predictions about possible common ancestors of certain organisms based on evidence provided. 

Explain 

Reading, Group Discussion:

Students read an article, working with partners and Listening Triads. Students answer Reflection Questions in small groups and discuss responses as a class. 

Students read an article about how fossil, anatomical, and embryological evidence is used to establish the evolutionary relationships between species. Students next watch a video about evolution. Finally, students use evidence from the article and video to make an argument about the evolutionary relationships between several species. 

Students should be able to:

• Use fossil, anatomical, and embryological evidence to make an argument about the evolutionary relationships between several organisms.

Elaborate

Extending Understanding and Applying Learning to a New Context: Students apply their understanding of the evidence used to establish the evolutionary relationships between species.

In this lesson, students make connections to the Individual Culminating Project. Students research how we define species as endangered. Students also research their chosen endangered species in preparation for the Individual Culminating Project.  

Students should be able to: 

• Research the meaning of threatened and endangered species.
• Research a chosen endangered species in preparation for creating slides for the Individual Culminating Project. 

Evaluate

Evaluating, Communicating Information, Written Responses: Students demonstrate their understanding and evaluate their knowledge of evolutionary relationships.

In this lesson, students evaluate their understanding of the evidence used to establish evolutionary relationships. Students begin by engaging in a Critique, Correct, Clarify routine about the relationship between humans and whales. Students then use the understanding they gained during the subunit to revisit and update the Driving Question Board.

Students should be able to: 

• Apply scientific ideas to construct an explanation for the anatomical similarities and differences between modern organisms to infer evolutionary relationships.
• Apply scientific ideas to construct an explanation for the anatomical similarities and differences between modern and fossil organisms to infer evolutionary relationships.

Instructional Sequence

Assessment Types at
This Stage

Assessment Description

Learning Target

Engage

Data Analysis: Students consider whether there is a connection between human population growth and the extinction of other species.

Students analyze a graph showing human population and extinction rates over the past 200 years. Students note trends and brainstorm causes of the increase in extinctions. 

Students should be able to:

• Consider that extinction rates have risen over the past 200 years by examining a graph. Students should also notice that the human population has increased during the same period.
• Brainstorm ideas about why the increase in extinctions has occurred.

Explore 

Critiquing Claims and Looking for Patterns: Students explore their understanding of the connection between human population growth and extinctions by critiquing a claim. Students also look for patterns in the previous mass extinctions on Earth.

Students continue to investigate the connection between human behavior and the extinction of species. Students read a statement that confuses correlation with causation. Students critique, correct, and clarify this argument with a partner. Next, students learn about the causes of the five previous mass extinctions. Finally, students research a more recently extinct species and determine the cause of its extinction. The class ends with a discussion where students look for patterns in the causes of extinction. 

Students should be able to: 

• Recognize that there is a statistical relationship between human population and extinction rates, but they cannot yet say if it is a causal relationship.
• Explain the causes behind a past mass extinction.
• Consider the impact of humans and human activity on extinction rates by examining data and reading information about the causes of the extinction of various species.

Explain 

Reading, Group Discussion, Argumentation: Students read an article, working with partners and Listening Triads. Students answer Reflection Questions in small groups and discuss responses as a class. Students also construct an argument to demonstrate their understanding.

Students continue to investigate the causes of the dramatic increase in extinctions over the past 200 years. Students read an article that outlines some of the causes of extinction and then write an argument using evidence from the article, the graphs, and their focus species. 

Students should be able to:

• Use a Claim, Evidence, Reasoning table to construct an explanation about the impact of human behaviors on extinction rates. 

Elaborate

Extending Understanding and Applying Learning to a New Context: Students apply their understanding of the human causes of extinction to protect an endangered species.

In the Elaborate lesson, students communicate their understanding of the subunit’s content by providing feedback on other students’ arguments. In the Connections to Culminating Project section of the lesson, students brainstorm ideas for how to prevent the extinction of an endangered species. 

Students should be able to: 

• Use a Claim, Evidence, Reasoning table to construct an explanation about the impact of human behavior on extinction rates.   
• Consider actions that can be taken to prevent the extinction of endangered species.

Evaluate

Evaluating, Communicating Information, Argumentation: Students evaluate the evidence that Earth is heading for a sixth mass extinction event. 

Students evaluate their understanding of how human actions have led to the extinction of species. Students first revisit the Driving Question Board and Personal Glossary. Next, students complete a Cause and Effect chain that explains the extinction of one species. For the Group Culminating Project, students prepare a slideshow discussing the evidence that suggests life on Earth is heading for a sixth mass extinction and why their target audience should care. Students then work on their Individual Culminating Projects in which they create slides explaining the causes behind the potential extinction of an individual species.

Students should be able to: 

• Construct an argument supported by evidence for how increases in human population and per capita consumption of natural resources impact Earth's systems and other species.
• Create a presentation explaining the evidence for a potential mass extinction and why people should care about one.

Desired Results

Overview

Through examining evidence, students explore the history of life on Earth. In Subunit 1, students use evidence from fossils and rock strata to determine when species evolved and became extinct. In Subunit 2, students use fossil, anatomical, and embryological evidence to determine evolutionary relationships between species. In Subunit 3, students investigate the connections between increases in human population, human consumption, and species extinctions.

Project Tasks

Connections to the Culminating Project Lift-Off: Identify the audience to be addressed in the project.

Connections to the Culminating Project Subunit 1: Explain Earth’s five previous mass extinctions.

Connections to the Culminating Project Subunit 2: Select and research an endangered species for the Individual Culminating Project.

Connections to the Culminating Project Subunit 3: Address the reasons Earth might be headed for a sixth mass extinction and propose steps humans could take to prevent it.

Estimated length of project: 2 weeks

ESTABLISHED GOALS

MS-ESS1-4. Construct a scientific explanation based on evidence from rock strata for how the geologic time scale is used to organize Earth's 4.6-billion-year-old history. [Clarification Statement: Emphasis is on how analyses of rock formations and the fossils they contain are used to establish relative ages of major events in Earth’s history. Examples of Earth’s major events could range from being very recent (such as the last Ice Age or the earliest fossils of homo sapiens) to very old (such as the formation of Earth or the earliest evidence of life). Examples can include the formation of mountain chains and ocean basins, the evolution or extinction of particular living organisms, or significant volcanic eruptions.] [Assessment Boundary: Assessment does not include recalling the names of specific periods or epochs and events within them.]

MS-LS4-1. Analyze and interpret data for patterns in the fossil record that document the existence, diversity, extinction, and change of life forms throughout the history of life on Earth under the assumption that natural laws operate today as in the past. [Clarification Statement: Emphasis is on finding patterns of changes in the level of complexity of anatomical structures in organisms and the chronological order of fossil appearance in the rock layers.] [Assessment Boundary: Assessment does not include the names of individual species or geological eras in the fossil record.]

MS-LS4-2. Apply scientific ideas to construct an explanation for the anatomical similarities and differences among modern organisms and between modern and fossil organisms to infer evolutionary relationships. [Clarification Statement: Emphasis is on explanations of the evolutionary relationships among organisms in terms of similarity or differences of the gross appearance of anatomical structures.]

MS-LS4-3. Analyze displays of pictorial data to compare patterns of similarities in the embryological development across multiple species to identify relationships not evident in the fully formed anatomy. [Clarification Statement: Emphasis is on inferring general patterns of relatedness among embryos of different organisms by comparing the macroscopic appearance of diagrams or pictures.] [Assessment Boundary: Assessment of comparisons is limited to gross appearance of anatomical structures in embryological development.]

MS-ESS3-4. Construct an argument supported by evidence for how increases in human population and per-capita consumption of natural resources impact Earth's systems. [Clarification Statement: Examples of evidence include grade-appropriate databases on human populations and the rates of consumption of food and natural resources (such as freshwater, mineral, and energy). Examples of impacts can include changes to the appearance, composition, and structure of Earth’s systems as well as the rates at which they change. The consequences of increases in human populations and consumption of natural resources are described by science, but science does not make the decisions for the actions society takes.]

NGSS Lead States. 2013. Next Generation Science Standards: For States, By States. Washington, DC: The National Academies Press.

ESSENTIAL QUESTION
 

What evidence supports the claim that Earth is heading for a sixth mass extinction?

Students will be able to independently use their learning to

• Apply their understanding of Earth’s history to explain previous mass extinctions.
• Apply their understanding of patterns found in structures across species to explain how life has evolved on Earth.
• Explain why their audience should be concerned about a sixth mass extinction.

Students will know

• How evidence from rock strata is used to organize Earth’s 4.6-billion-year-old history.
• How to analyze and interpret data in the fossil record to find patterns to explain the changes to life throughout Earth’s history.
• That anatomical similarities and differences between modern and fossil organisms explain their evolutionary relationships.
• That comparing patterns of similarity in embryological development across species helps identify common ancestry.

• That human use of natural resources impacts Earth’s systems.

Evidence

Assessment Evidence

PERFORMANCE TASK: Present an argument for why the target audience should care about the possibility of a sixth mass extinction and the steps to be taken to prevent it.

At the end of this unit, groups present to their target audience about what can be learned from previous mass extinctions and the steps to take to prevent another one. Students’ arguments will be based on what they learned and the data they collected throughout the unit. 

Presentations must discuss one previous mass extinction in Earth’s history. Presentations must provide responses to each of these prompts: 

1. What evidence supports the claim that this mass extinction happened?
2. What were some of the species that became extinct during this past mass extinction?
3. What do scientists think caused this past mass extinction? 
4. Are there any similarities between the conditions during the past mass extinction and conditions on Earth today? Explain.
5. During the last 500 years, human population and consumption of resources have increased. How have these increases affected different species in both positive and negative ways?
6. Discuss the evidence presented in the unit about conditions on Earth today. 
7. Discuss the evidence presented in the unit about current species extinctions. 
8. What evidence from the unit supports the claim that Earth is heading for a sixth mass extinction?
9. Why should your audience care about the possibility of a sixth mass extinction? 

Individual Culminating Project: Slide(s) or other format depending on group format that focuses on an Endangered Species

1. Students select a species on the verge of extinction. On a least one slide, students must include:
   1. A description of the endangered species, including its natural habitat. 
   2. A picture or drawing of the endangered species. 
   3. What are some of the nearest relatives of your chosen endangered species on the evolutionary tree? 

• What fossil, anatomical, or embryological evidence have scientists used to help determine the nearest relatives? 

4. A description of the reasons why the species is endangered.
5. A description of what we will lose if the species becomes extinct.  
6. Possible efforts that could be made to protect the species from going extinct. 
7. Information about the evolution of the endangered species. This part should identify the nearest relatives of the species on the evolutionary tree. This part should also include any fossil, anatomical, or embryological evidence that scientists used to determine the nearest relatives of the species. 

Learning Plan

Subunit 1

Throughout the course of this subunit, students look for patterns that provide evidence from fossils and rock strata to determine when species evolved and became extinct. 

Subunit 2

Throughout the course of this subunit, students investigate fossil, anatomical, and embryological evidence to determine evolutionary relationships between species.

Subunit 3

This subunit is designed to help students investigate the connection between increases in human population and human consumption and pollution and climate change factors that are leading to species extinctions.

Course Concepts

+ Foundational Crosscutting Concepts: These concepts are foundational to the understanding of middle school science. These concepts are present throughout the course. Students are expected to continue to apply their knowledge of the concepts to subsequent relevant projects. 

* Focal Crosscutting Concept: This concept is called out consistently in the Teacher Edition and once per subunit in the Student Book. Students consider the unit project through the lens of this Crosscutting Concept. 

Crosscutting Concept

Unit 1: Motion in the Universe

Unit 2: Waves

Unit 3: Life on Earth

Unit 4: Natural Selection

Patterns

+

+

*

Cause and Effect

+

*

+

+

Scale, Proportion, and Quantity

+

+

Systems and System Models

*

Energy and Matter

Structure and Function

+

*

Stability and Change

+

Science and Engineering Practices 

+ Foundational Science and Engineering Practices: These practices “carry forward” through the course. Students focus on one of these practices  per unit and are then expected to continue to apply that knowledge to subsequent relevant projects. 

* Focal Science and Engineering Practice: This practice is called out consistently in the Teacher Edition and once per subunit in the Student Book. Students use this practice to complete the Culminating Project. 

Science and Engineering Practices

Unit 1: Motion in the Universe

Unit 2: Waves

Unit 3: Life on Earth

Unit 4: Natural Selection

Asking Questions and Defining Problems 

*

+

+

Developing and Using Models 

+

*

+

Planning and Carrying Out Investigations 

+

Analyzing and Interpreting Data

+

Using Mathematics and Computational Thinking

+

*

Constructing Explanations and Designing Solutions

+

+

Engaging in Argument from Evidence

+

*

Obtaining, Evaluating, and Communicating Information

+

+

MS-ESS1-4

Construct a scientific explanation based on evidence from rock strata for how the geologic time scale is used to organize Earth's 4.6-billion-year-old history. [Clarification Statement: Emphasis is on how analyses of rock formations and the fossils they contain are used to establish relative ages of major events in Earth’s history. Examples of Earth’s major events could range from being very recent (such as the last Ice Age or the earliest fossils of homo sapiens) to very old (such as the formation of Earth or the earliest evidence of life). Examples can include the formation of mountain chains and ocean basins, the evolution or extinction of particular living organisms, or significant volcanic eruptions.] [Assessment Boundary: Assessment does not include recalling the names of specific periods or epochs and events within them.]

MS-LS4-1

Analyze and interpret data for patterns in the fossil record that document the existence, diversity, extinction, and change of life forms throughout the history of life on Earth under the assumption that natural laws operate today as in the past. [Clarification Statement: Emphasis is on finding patterns of changes in the level of complexity of anatomical structures in organisms and the chronological order of fossil appearance in the rock layers.] [Assessment Boundary: Assessment does not include the names of individual species or geological eras in the fossil record.]

MS-LS4-2

Apply scientific ideas to construct an explanation for the anatomical similarities and differences among modern organisms and between modern and fossil organisms to infer evolutionary relationships. [Clarification Statement: Emphasis is on explanations of the evolutionary relationships among organisms in terms of similarity or differences of the gross appearance of anatomical structures.]

MS-LS4-3 

Analyze displays of pictorial data to compare patterns of similarities in the embryological development across multiple species to identify relationships not evident in the fully formed anatomy. [Clarification Statement: Emphasis is on inferring general patterns of relatedness among embryos of different organisms by comparing the macroscopic appearance of diagrams or pictures.] [Assessment Boundary: Assessment of comparisons is limited to gross appearance of anatomical structures in embryological development.]

MS-ESS3-4

Construct an argument supported by evidence for how increases in human population and per-capita consumption of natural resources impact Earth's systems. [Clarification Statement: Examples of evidence include grade-appropriate databases on human populations and the rates of consumption of food and natural resources (such as freshwater, mineral, and energy). Examples of impacts can include changes to the appearance, composition, and structure of Earth’s systems as well as the rates at which they change. The consequences of increases in human populations and consumption of natural resources are described by science, but science does not make the decisions for the actions society takes.]

Misconception 

Accurate Concept

All species began at the same time and still exist today.

From American Association for the Advancement of Science (AAAS) Misconceptions

(http://assessment.aaas.org/misconceptions/1/ENM019/262)

Although many species have undergone little change for many millions of years, and a few appear to have changed very little since the early history of life, most species living today did not exist when life first began on earth.

From American Association for the Advancement of Science (AAAS) Key Ideas

(http://assessment.aaas.org/topics/1/EN/262#/0)

Misconception 

Accurate Concept

Only a few of the many species of organisms that lived in the past are now extinct. Most of the species of organisms that lived in the past are still alive today. (AAAS Project 2061, n.d.).

From AAAS Misconceptions

(http://assessment.aaas.org/misconceptions/1/EN/262/ENM020)

Many species have become extinct throughout the history of life on earth.

From AAAS Key Ideas

(http://assessment.aaas.org/items/1/EN/262/EN014002#/0)

Except for periodic mass extinction events, extinction is very rare (AAAS Project 2061, n.d.).

From AAAS Misconceptions

(http://assessment.aaas.org/topics/1/EN/262#/2)

Extinctions have occurred throughout the history of life and continue to occur.

From AAAS Key Ideas

(http://assessment.aaas.org/topics/1/EN/262#/0)

Misconception 

Accurate Concept

Species that have no apparent, obvious, or superficial similarities have no similarities at all. (See Shtulman, 2006).

From AAAS Misconceptions

(http://assessment.aaas.org/misconceptions/1/EN/262/ENM051)

Scientists have found similarities and differences among existing species, among extinct species, and between existing and extinct species.

If available, DNA can be analyzed to learn about species from the past.

From AAAS Key Ideas

(http://assessment.aaas.org/topics/1/EN/262#/0)

Misconception 

Accurate Concept

Up until recently, extinction was rare; humans have caused the majority of extinctions (AAAS Project 2061, n.d.).

From AAAS Misconceptions

(http://assessment.aaas.org/misconceptions/1/EN/262/ENM049)

Many species have become extinct throughout the history of life on earth. 

From AAAS Key Ideas

(http://assessment.aaas.org/items/1/EN/262/EN014002#/0)