Lesson 2 — Weighing Competing Explanations: The Classic Maya Collapse

Summary

Learners evaluate competing explanations for one major historical change — the Classic Maya collapse (roughly 800–950 CE) — weighing three explanations (drought, warfare, environmental stress) and the evidence for each, then supporting a reasoned judgment. They learn that historians weigh evidence, and that several causes often work together.

Objectives

• Evaluate competing explanations for one major historical change and support a reasoned judgment with evidence. (D08.S1.08.01)

Connection

When something big goes wrong at school or at home — a garden fails, a team loses, a friendship breaks — people often give different reasons: “it was the weather,” “it was a bad decision,” “it was too much at once.” Usually it is not one thing; it is several, working together. Historians face the same puzzle about the past. Today you act as a historian and weigh the rival explanations for one great change, deciding what the evidence best supports.

Materials

• Evidence-and-explanation sheet
• Evidence cards

Preparation

• Copy the evidence-and-explanation sheet and the evidence cards.
• Retrieval: from Grade 7, recall that a major change has multiple causes and consequences (D08.S1.07.02) and that a claim needs evidence.

Facilitator note

This lesson is written to the learner (“you”). The idea to land: historians evaluate competing explanations by weighing evidence, and a reasoned judgment says which explanation the evidence best supports — often several causes working together. The worked historical example: the Classic Maya civilization flourished from about 250 to 900 CE across Mesoamerica (present-day southern Mexico, Guatemala, Belize, Honduras, and El Salvador), building great cities (Tikal, Calakmul, Copán, Palenque) with writing, astronomy, and a precise calendar (S-378, S-204). Then, beginning around 800–950 CE, many southern-lowland cities were abandoned — the “Classic Maya collapse.” Three competing explanations: (1) drought — evidence from lake-sediment cores (for example, gypsum and oxygen-isotope records at Lake Chichancanab) points to severe, repeated droughts around 800–1000 CE; (2) warfare and political instability — monuments and inscriptions record mounting war between rival city-states; (3) environmental stress and overpopulation — intensive farming and growing populations may have worn down fragile tropical soils (S-378). Most scholars today hold that these worked together, with drought as a trigger that magnified the others (S-378). The ethics lens: it is honest and respectful to say “we are not certain; the evidence supports several causes” rather than pretending to one clean answer. The egalitarian lens: the Maya did not “vanish” — Maya peoples live today in the millions across the region, speaking Maya languages and carrying their traditions; the “collapse” was the decline of certain lowland cities, not of a people. The global lens: the Classic Maya are one of many brilliant civilizations (Mesoamerica, the Andes, West Africa, the Indian Ocean world) in this unit — the human story is many stories. The environment lens: a changing climate (drought) is a reminder that environmental change has shaped human history for thousands of years — a thread we will pick up later in the unit. Keep it honest: this is documented scholarship, and where scholars disagree, we hold the disagreement as a question, not a verdict (philosophy §11).

Procedure

1. Recall (5 min). From Grade 7: why does a major change usually have more than one cause? Today you weigh rival explanations for one change.
2. Meet the change (8 min). The Classic Maya built great cities in Mesoamerica with writing, astronomy, and a precise calendar (about 250–900 CE). Then, around 800–950 CE, many southern lowland cities were abandoned. Historians do not all agree on why — and that is our job today.
3. Meet the three explanations (10 min). Read the three candidate explanations: (1) drought — the rains failed; (2) warfare — rival cities fought until the system broke; (3) environmental stress — too many people and too much farming wore out the land. A good historian does not pick a favorite; a good historian asks: what is the evidence?
4. Sort the evidence (12 min). In a group, sort the evidence cards under the three explanations. Notice: some evidence fits more than one explanation. Note the strongest piece of evidence for each.
5. Make a reasoned judgment (12 min). Write your judgment: which explanation does the evidence best support — and is it just one, or several working together? Back it with at least two pieces of evidence. You may say “the evidence supports several causes.”
6. Close (8 min). Share judgments. Notice that many scholars now hold the same view most learners reach: drought, warfare, and environmental stress worked together, with drought as a trigger. And remember: the Maya peoples did not vanish — millions of Maya live today.

Differentiation

• Support: Provide the three explanations pre-written and ask learners to match each piece of evidence to an explanation, then choose one piece of evidence to support a simple judgment.
• Extension: Apply the same weighing skill to a second change — the fall of the Western Roman Empire — and name two competing explanations with one piece of evidence each.

Assessment

• Formative (observation): Can the learner weigh at least two explanations against evidence and state a judgment with a reason?
• Portfolio artifact: The completed evidence-and-explanation sheet with a reasoned judgment, kept in the portfolio.

Home connection

Ask at home: when something changed in your family’s life, did one cause explain it, or several? Compare with the Maya collapse.

Resources

• On the Classic Maya, the collapse, and the competing explanations (drought, warfare, environmental stress): Encyclopaedia Britannica, “Maya” (Dates, Collapse, Civilization), https://www.britannica.com/topic/Maya-people (S-378).
• On Maya astronomy, writing, and the calendar (context for the civilization): Smithsonian Institution, writing systems, the wheel, and Maya astronomy (S-204).
• On explicit instruction and worked examples: Kirschner, Sweller & Clark (2006), https://doi.org/10.1207/s15326985ep4102_1 (S-011).