KO: Fossils
Subject: Science | Year: 6
Name: _________________________ Class/Set: ____________ Date: ____________
1. Key Knowledge / Core Facts
- Evidence: Fossils provide a physical record of organisms that lived millions of years ago.
- Rock Type: Almost all fossils are found in sedimentary rock, formed from layers of mud and sand.
- Evolution: Scientists use fossils to see how living things have changed and adapted over time.
- Extinction: Fossils allow us to identify species that no longer exist on Earth today.
- Deep Time: Most fossilised remains belong to creatures that lived long before humans existed.
- Incompleteness: The fossil record is incomplete because many soft-bodied organisms do not fossilise.
2. Key Vocabulary
- Palaeontology: The branch of science concerned with fossilised animals and plants.
- Sediment: Natural material (sand, stones, mud) that settles at the bottom of a liquid.
- Mineralisation: The process where minerals replace the organic material in bone or shell.
- Erosion: The wearing away of rocks by natural forces like water, wind, and ice.
- Organism: An individual animal, plant, or single-celled life form.
- Preservation: The act of keeping something in its original state or in good condition.
- Specimen: An individual animal or plant used as an example of its species for study.
3. How Fossils Form (The Process)
- Death: An organism dies and sinks to the bottom of a sea or lake.
- Burial: It is quickly covered by layers of sediment, protecting it from scavengers and rot.
- Decay: Over time, the soft tissues (skin and muscle) rot away, leaving the hard skeleton.
- Pressure: Heavy layers of sediment build up, pressing down and turning the bottom layers into rock.
- Replacement: Minerals from the surrounding water seep into the bones, turning them into stone.
- Exposure: Millions of years later, Earth movements or erosion bring the fossil to the surface.
4. Types of Fossils
- Mould Fossil: A hollow 'imprint' left in the rock in the shape of the original organism.
- Cast Fossil: Formed when a mould fossil is filled with minerals, creating a solid 3D replica.
- Trace Fossil: Evidence of an animal’s life rather than its body (e.g., footprints, burrows, or droppings).
- Amber: Ancient tree resin that hardened, often trapping insects or plants with incredible detail.
- Petrified: Occurs when organic matter is completely replaced by minerals and 'turned to stone'.
5. Mary Anning (Famous Palaeontologist)
- Location: Lived in Lyme Regis, Dorset, on a stretch of coast now known as the 'Jurassic Coast'.
- Ichthyosaur: Discovered the first complete skeleton of this 'fish-lizard' aged only 12.
- Plesiosaur: Found the first nearly complete skeleton of this long-necked marine reptile.
- Legacy: Despite being a woman in a male-dominated field, she is now recognised as a pioneer.
- Method: She spent her life searching the cliffs after storms had caused fresh erosion.
6. Scientific Evidence and Discovery
- Marine Fossils: Finding sea shells on high mountain tops proves that land was once underwater.
- Climate Change: Tropical plant fossils found in the UK show the climate was once much warmer.
- Links: Fossils show the transition between species (e.g., feathered dinosaurs linking to birds).
- Dating: Scientists use the depth of the rock layer to estimate how old a fossil is.
- Coprolites: Fossilised dung (droppings) tells scientists what prehistoric animals used to eat.
Quick Recall Quiz
- Task 1: Name the specific type of rock where most fossils are found.
- Task 2: What is the name of the process where minerals replace bone?
- Task 3: Where in the UK did Mary Anning find her famous fossils?
- Task 4: What do we call a fossil that shows footprints or burrows?
- Task 5: Explain why the 'soft parts' of an animal are rarely found as fossils.
⚠ TEACHER’S GUIDANCE
💡 Pedagogical Insights & Delivery
- Delivery Context: This Knowledge Organiser is designed for Year 6 students preparing for the 'Evolution and Inheritance' unit. It is ideal as a desktop reference or a home-learning revision tool.
- Misconception Alert: Students often believe that a fossil is the original bone. Emphasise that it is actually rock (mineral replacement).
- Active Learning: Use this sheet to support a "fossilisation storyboard" activity, where students draw the six steps of the process found in Section 3.
- Greater Depth (GDS): Challenge students to explain why finding a fish fossil in the middle of a desert provides evidence for Earth's shifting tectonic plates and changing landscapes.
✅ Answer Key & Solutions
- Task 1 Answer: Sedimentary Rock.
- Task 2 Answer: Mineralisation.
- Task 3 Answer: Lyme Regis (or the Jurassic Coast / Dorset).
- Task 4 Answer: Trace Fossil.
- Task 5 Answer: The soft parts (skin, muscle, organs) usually rot away or are eaten by scavengers before they can be buried and preserved. Only the hard parts (bones, shells, teeth) last long enough for the fossilisation process to occur.