Investigative Question

How did the environment influence the migrations of early humans? How did early humans adapt to new environments and climate changes?

In the first unit, students learn about the emergence and migrations of early humans, the gathering and hunting way of life, and the emergence of village agriculture and pastoral nomadism. To frame the topic of the emergence and migrations of early humans, the teacher uses these questions: How did the environment influence the migrations of early humans? How did early humans adapt to new environments and climate changes? For millions of years, the genetic ancestors of humans, known as hominins (or hominids), used stone tools and lived on foods found by gathering and hunting. Archaeological evidence shows students that our earliest forebearers evolved in eastern Africa and that small bands of those ancestors migrated into Eurasia about 1.9 million years ago, driven by population gains and increased competition for food. Around 800,000 years ago, early humans discovered how to control fire, allowing them to cook food, keep away predators, and burn areas of land in order to flush out game. Homo sapiens, that is, anatomically modern humans, evolved in Africa around 200,000 years ago. Modern humans adapted well to new environments, developing increasingly diverse stone and bone tools for collecting and processing food. About 100,000 years ago, our species developed the capacity for language, which accelerated technological change. Spoken language and the evolution of pro-social mental and social structures enabled humans to teach complex skills to each other, cooperate with others, pass down ideas to the next generation, and talk about their world and the cosmos. After leaving Africa 90,000 to 100,000 years ago, humans may have reached Australia 60,000 or more years ago and Europe 40,000 years ago. In the Middle East and Europe, humans encountered Neanderthals, a related hominid species, who became extinct about 28,000 years ago. Early humans reached the Americas from Eurasia at least 12,000 years ago, possibly earlier. Students use maps to identify the patterns of early human migration and settlement that populated the major regions of the world. … To understand the gathering and hunting way of life and appreciate the linguistic and cognitive advantages of Homo sapiens, students analyze primary sources from this long time period before written language. Our knowledge of this era depends on evidence from material remains, especially from bones and stone tools, and, more recently, from research on human DNA and long-term climatic and geological change.

Because there are no written sources recording the experience of prehistoric people, our understanding of where and why they migrated, how they lived, what they believed, and how they thought is based on four types of evidence. The social science of archaeology provides the first type of evidence. Evidence from archaeology includes artifacts (things made by early humans); human and animal remains; marks of human activity on the land; and evidence of geological, environmental, and climate changes. Finds of ancient hominid bones in Olduvai Gorge in Africa are evidence supporting the interpretation that all hominid species came from Africa, for example. This source set contains visuals of tools, human structures, and prehistoric artwork found by archaeologists.

The second type of evidence comes from linguists and anthropologists, who study the similarities and differences among languages. They use evidence from words, syntax, and grammar to determine how languages are connected in language families or phyla (groups more distantly connected than families) and how long ago two groups speaking related languages parted from each other. Linguists use this evidence and scientific methods to reconstruct ancient proto-languages and paths of migration taken by groups who spoke those languages and descendant languages. A map of the language families of California indigenous people gives linguistic evidence about migration. Pre-Columbian California Indians spoke 78 mutually unintelligible languages, almost one-third of all languages spoken in North America, an incredible diversity that provides evidence for the waves of migration into California.

The third type of evidence has emerged only in recent decades with the advancements in research into DNA. Biomolecular analysis of isotopes and mitochondrial DNA provide evidence about the movements of individuals whose bones have survived and the genetic markers they share with modern groups. Scientists use the same methods to analyze food sources, plants, and diseases.

Another type of evidence comes from stories told by descendants of early human groups recorded in historical time. These stories about creation, the history of the group, the gods, animals — often called legends, myths, fables, etc. — were passed down orally perhaps for centuries before they were written down. There is significant debate about whether these sources are really evidence of an earlier time before they were recorded. Some social scientists reject them altogether, while others think the stories can be evidence of the ways that people thought and things that were important to them. This set does not contain any stories as sources, but teachers may choose to add a creation story to the set if they want to introduce students to the issues involved in using stories as historical evidence.

Although these types of evidence are increasingly sophisticated, there are significant limits to what we know about early humans. Many common assumptions about early humans are interpretations based on little evidence and subject to continual debate. In addition to learning about the first three types of evidence and current interpretations about the migrations of early humans, students should understand the limits of those interpretations. Interpretations are not facts to be accepted uncritically.

Since this source set is the first for grade 6, it is intended as an introduction to inquiry in history-social science as well as an investigation of prehistoric migration. Students will learn about and examine the key parts of the process of inquiry, such as primary and secondary sources, evidence, and interpretation. They will understand what evidence is available about early humans and compare it to the interpretations that social scientists — archaeologists, anthropologists, historians, economists, etc. — make about early humans. Students should use their textbooks along with the source set in the suggested activity. The suggested activity has two stages. In the first stage students should read a textbook summary and study a map of prehistoric migration. Next they will learn the definitions of a primary source, a secondary source, evidence, and interpretation and will identify examples of each (Student Handout 6.1.2). They will categorize all of the sources in the set (and their textbook) as either primary or secondary sources and distinguish between evidence and interpretation. In the second stage, students should analyze the primary sources to form their own interpretation to answer the investigative question.

Literacy Strategy for Source 8: Ancient DNA Reveals Complex Migrations of the First Americans

California English Language Development Standards for Grade 6

Part I. Interacting in Meaningful Ways

B. Interpretive

6. Read closely literary and informational texts and view multimedia to determine

how meaning is conveyed explicitly and implicitly through language.

7. Evaluate how well writers and speakers use language to support ideas and opinions

with details or reasons depending on modality, text type, purpose, audience, topic, and

content area.

8. Analyze how writers and speakers use vocabulary and other language resources for specific purposes (to explain, persuade, entertain, etc.) depending on modality, text type, purpose, audience, topic, and content area.

Teacher Background

This literacy strategy makes space for class conversation around some potentially challenging scientific concepts and words related to DNA analysis for archaeological purposes. Its primary focus, however, is on the concept of modality: how speakers/authors modulate their expressed positions in terms of probability and confidence. This supports the set focus on the difference between evidence and interpretation by asking students to consider the way this distinction is or isn't communicated by the level of certainty expressed in the language choices in a secondary source text. It will enhance their ability to critically read secondary sources and make them more thoughtful about the appropriateness of their own language choices when presenting information with various levels of certainty.


  1. Provide context. Explain to students that the aim of this literacy activity is to (1) better understand the differences between evidence and interpretation, (2) give them an opportunity to understand how DNA evidence has been used to make interpretations about the past, and (3) understand how researchers and secondary source authors make small word choices that imply various levels of certainty about the information expressed in texts (and reflect on how this connects to the concepts of evidence and interpretation).

  2. Interpret and discuss text.

    a. Begin with an initial whole-class reading of the text to help students understand its basic content. Discuss some of the more challenging words and concepts using the vocabulary at the bottom of the handout. Make sure students can answer comprehension questions about the text: What was the environmental challenge in the Andean highlands for the people who migrated there about 9,000 years ago? When did the Andes highland and lowland people split into two groups? What is different about the genome of the highland people (the Aymara)?

    b. Using the second section of the student handout, tell or remind students of the difference between evidence and interpretation and have a class conversation about what this looks like in this particular text. See if students can point out a few pieces of evidence and a few pieces of interpretation. This discussion will reinforce understanding of the relationship between the two in this text as well as provide space to talk about the role of DNA evidence in social science research.

    c. Move to the third section of the student handout to guide students through an analysis of modality language choices.

    i. Explain to students that the words chosen to report the evidence can imply higher or lower levels of confidence or certainty in the information being expressed. Model filling out the chart with the first word, shows, looking at the context in which it appears, thinking about what level of certainty it expresses, and brainstorming words that could express higher or lower levels of certainty. Note for students that determining whether a word expresses "higher," "lower," or "medium" certainty is relative and that it can come into focus more as they brainstorm alternative choices. Explain that shows expresses relatively high certainty that "people started living permanently in the Andean highlands about 9,000 years ago."

    ii. Have students work in pairs or small groups to analyze the other two words/phrases on the chart, perhaps assigning half of the class to work on each. As a class, debrief their opinions about the relative strength of each word/phrase, possible alternative words/phrases, and ideas being expressed (with varying levels of certainty) with these words.

    iii. Have students write and talk or talk and write about the last two questions, which will help them connect their analysis of this text to ideas about evidence and interpretation, and the implications this has for them as critical readers and writers.

  3. Extend the learning.

    a. You could choose to have students analyze words that express higher or lower modality in other secondary sources they've encountered throughout the unit and discuss the advantages and disadvantages of these choices given the information that is being expressed.

    b. You may also encourage students to be thoughtful about the appropriateness of their own modality choices in the writing they do about primary sources in this set.


6.1 Migration Student Handout 1

6.1 Migration Student Handout 2

6.1 Migration Teacher Key

  • The Library of Congress. The Library of Congress’ Primary Source Analysis Tool supports an inquiry model of instruction by asking students to first observe, then reflect, then question. Their customizable tool includes specific prompts for student interrogation of books and other printed materials, maps, oral recordings, photographs and paintings, and many other types of primary sources.

  • The National Archives and Records Administration (NARA). NARA has developed a vast collection of document analysis worksheets, ready for classroom use. Their website offers teachers a wide collection of customizable tools – appropriate for working with photographs, maps, written documents, and more. NARA has also customized their tools to meet the needs of young learners, and intermediate or secondary students.