Science · Year 6 · Evolution and Inheritance · Spring Term

Fossils as Evidence of Past Life

Using fossils to understand that living things have changed over time and to learn about ancient life.

• National Curriculum Attainment Targets
• KS2: Science - Evolution and inheritance

About This Topic

Fossils provide concrete evidence of ancient life, revealing how organisms have changed over millions of years. In Year 6, students examine fossil formation: rapid burial in sediment protects remains from decay, followed by hardening into rock through mineral replacement or impressions in mud. They interpret clues like tooth shapes for diets, leaf structures for climates, and layered strata for timelines, addressing key questions on past environments and evolutionary shifts.

This topic anchors the evolution and inheritance unit, linking to variation in living things and adaptation. Students sequence fossils to visualise life's progression from simple to complex forms, honing skills in evidence analysis and chronological thinking central to scientific literacy.

Active learning excels with fossils because students handle replicas, mould their own casts, or excavate simulated sites. These methods bridge vast timescales to everyday actions, deepen engagement through discovery, and build confidence in using observations to form conclusions.

Key Questions

1. Explain how fossils are formed and what they tell us about living things from the past.
2. Describe how a fossil can provide clues about an animal's diet or environment millions of years ago.
3. Discuss how the discovery of new fossils can change our understanding of past life.

Learning Objectives

• Classify different types of fossils based on their formation process (e.g., cast, mold, imprint).
• Explain how specific fossil features, such as tooth shape or leaf venation, provide evidence about an organism's past environment and diet.
• Analyze the chronological order of fossils found in different rock strata to infer the relative ages of ancient life forms.
• Synthesize information from various fossil discoveries to construct a narrative about evolutionary changes in a specific lineage over time.

Before You Start

Rocks and the Rock Cycle

Why: Understanding the formation of sedimentary rocks is fundamental to grasping how fossils are preserved within them.

Life Cycles of Organisms

Why: Familiarity with the life cycles of current organisms helps students compare them to the inferred life cycles of extinct organisms found as fossils.

Key Vocabulary

Fossil	The preserved remains or traces of an organism that lived in the past, typically found in rock.
Sediment	Loose particles of sand, silt, and clay that accumulate over time and can eventually harden into rock, often preserving fossils.
Mineralization	The process where organic material in a fossil is replaced by minerals from the surrounding groundwater, turning the remains into rock.
Mold Fossil	An imprint left in the sediment by an organism. The original organism is gone, but its shape is preserved.
Cast Fossil	Forms when a mold fossil is filled in with minerals or sediment, creating a three-dimensional replica of the original organism.

Watch Out for These Misconceptions

Common Misconception

Fossils are just bones or skeletons turned to stone.

What to Teach Instead

Most fossils form as moulds, casts, or traces like footprints, not direct bone replacement. Creating plaster casts in pairs lets students see the moulding process firsthand, while group discussions clarify preservation types and dispel magic transformation ideas.

Common Misconception

All past animals were exactly like those today.

What to Teach Instead

Fossils reveal extinct species with unique features, showing change over time. Comparing replica trilobites or ammonites to modern animals in stations prompts students to spot differences, fostering evidence-based arguments during rotations.

Common Misconception

Fossils form quickly after death.

What to Teach Instead

Formation requires slow burial and millions of years of rock hardening. Layering sediment models in digs helps students grasp timescales, as they build and 'age' layers collaboratively to mimic geological processes.

Active Learning Ideas

Hands-On Fossil Making: Plaster Casts

Give pairs soft clay and natural objects like shells or leaves. Students press objects into clay to form moulds, pour plaster of Paris over them, and wait for drying. They then carefully excavate casts and discuss similarities to real fossils.

40 min·Pairs

Fossil Dig Simulation: Excavation Challenge

Bury replica fossils and small artefacts in sand-filled trays or boxes. Small groups use brushes, trowels, and sieves to excavate slowly, sketch findings, and note positions. Groups present discoveries to the class.

45 min·Small Groups

Stations Rotation: Fossil Clues Stations

Prepare stations for diet analysis (teeth/jaws), environment clues (rock types), formation models (layered sediments), and timelines. Groups rotate every 10 minutes, recording inferences on worksheets before sharing.

40 min·Small Groups

Whole Class Timeline: Life Through Time

Display fossil images or replicas chronologically. Students add cards with habitat or diet notes to a large timeline mural, debating placements based on evidence. Conclude with a class vote on key changes.

50 min·Whole Class

Real-World Connections

• Paleontologists at the Natural History Museum in London study fossils to reconstruct ancient ecosystems and understand the history of life on Earth, informing conservation efforts for modern species.
• Geologists use fossils found in rock layers to date geological formations, which is crucial for resource exploration, such as identifying potential sites for oil and gas reserves or understanding groundwater systems.

Assessment Ideas

Exit Ticket

Provide students with images of three different fossils. Ask them to write one sentence for each, identifying the type of fossil (mold, cast, imprint) and one piece of information it reveals about past life.

Quick Check

Present students with a diagram showing several layers of rock (strata) with different fossils in each. Ask: 'Which fossil is the oldest? How do you know?' and 'What might the environment have been like when the fossil in the top layer was alive?'

Discussion Prompt

Pose the question: 'Imagine a new fossil is discovered that contradicts what scientists previously believed about a dinosaur's appearance. How should scientists react to this new evidence?' Facilitate a discussion on the scientific process of revising understanding based on new data.

Frequently Asked Questions

How are fossils formed?

Fossils form when organisms die and are quickly buried by sediment like mud or sand, shielding them from air and scavengers. Over time, minerals replace organic material or form moulds around remains as sediment turns to rock. Rare cases preserve soft tissues in amber. Students grasp this best through layered models showing burial stages.

What do fossils tell us about ancient diets?

Fossil teeth, beaks, and jaws reveal diets: sharp teeth suggest carnivores, grinding molars indicate herbivores. Stomach contents or coprolites provide direct evidence. Analysing replicas at stations helps students infer feeding habits and link to modern animal comparisons, building inference skills.

How can active learning help students understand fossils?

Active approaches like moulding plaster fossils or excavating sand trays make deep time tangible for Year 6 students. Handling replicas builds observation skills, while group digs encourage careful evidence collection and peer debate. These methods boost retention by 30-50% over lectures, as students connect actions to abstract formation processes.

How do new fossil discoveries change our understanding?

New finds like feathered dinosaurs refine evolutionary trees, showing transitions such as birds from reptiles. They fill gaps in the fossil record, challenge old views on timelines or habitats, and spark scientific revision. Class timelines updated with recent examples teach students science evolves with evidence.