🌿 HOW PLANTS CONQUERED LAND
PAGE 1 OF 5, TRAPPED IN THE WATER
430 MILLION YEARS AGO
A WORLD WITH NO LAND PLANTS
For 400 million years after life appeared, algae ruled the oceans, but the land was completely bare. No grass. No trees. No moss. Just naked rock, sand, and barren soil baking under the sun. The entire surface of Earth was as empty as the moon.
EMPTY!
THE EDGE
🌊 Green algae clings to wet coastal rocks
🪨 Every tide brings it closer to land
🪨 Every tide brings it closer to land
THE PROBLEM
☀️ Out of water = desiccation death
💀 UV radiation destroys unprotected cells
💀 UV radiation destroys unprotected cells
PAGE 2 OF 5, THE GREEN INVASION BEGINS
470 MILLION YEARS AGO
THE FIRST LAND PLANTS ARRIVE
The first plants to survive on land were tiny, flat, hugging the ground, no taller than a fingernail. They were the ancestors of modern mosses and liverworts. They could only survive near water, soaking it in through every cell surface. But they were on land, and that changed everything.
INVADE!
ADAPTATION 1
🧈 Cuticle: waxy waterproof coating
🛡️ Stops cells drying out in the sun
🛡️ Stops cells drying out in the sun
ADAPTATION 2
🫁 Stomata: tiny pores that open and close
💨 Let CO₂ in and O₂ out for photosynthesis
💨 Let CO₂ in and O₂ out for photosynthesis
ADAPTATION 3
💨 Spores: tough airborne reproductive cells
🌍 Drift on wind to colonise new ground
🌍 Drift on wind to colonise new ground
PAGE 3 OF 5, THE VASCULAR REVOLUTION
XYLEM
💧 Xylem tubes carry water UP
🌿 From roots to every leaf and stem
🌿 From roots to every leaf and stem
PHLOEM
🍬 Phloem tubes carry sugars DOWN
🌱 From leaves to roots, feeding all cells
🌱 From leaves to roots, feeding all cells
430 MILLION YEARS AGO
COOKSONIA: THE GAME CHANGER
Around 430 million years ago, a tiny Y-shaped plant called Cooksonia appeared. It was the world's first vascular plant, containing specialised tubes to carry water upward and sugars downward, like a plant's own circulatory system. Now plants could grow tall. Now they could stand up. The invasion was unstoppable.
GROW!
PAGE 4 OF 5, ROOTS, LEAVES AND WOOD
385 MILLION YEARS AGO
THE FIRST FORESTS
By 385 million years ago, the Devonian Period, the first forests covered the land. Giant lycopsid trees towered 30 metres high. Club mosses grew as tall as buildings. Ferns spread across entire continents. Earth's bare rock was gone forever, buried beneath a spreading green world.
FOREST!
ROOTS
🌱 Roots anchor plants in soil
💧 Absorb water and dissolved minerals
💧 Absorb water and dissolved minerals
LEAVES
🍃 Leaves maximise sunlight capture
🌞 Flat surface = more photosynthesis
🌞 Flat surface = more photosynthesis
LIGNIN
🪵 Lignin: tough polymer creates wood
🌳 Allows plants to grow tens of metres tall
🌳 Allows plants to grow tens of metres tall
PAGE 5 OF 5, THE GREEN PLANET
THE LEGACY
LAND PLANTS CHANGED EVERYTHING
When plants conquered land, they transformed the planet. They broke down rock to create soil. Their roots held water and stopped erosion. They pulled carbon dioxide from the air and cooled the climate. Animals followed plants onto land, because where food grows, life follows. Every forest, every field, every garden exists because those first tiny algae made the leap.
AMAZING!
TODAY
🌿 Modern mosses are living ancestors
🏔️ Still thrive in a 470-million-year lineage
🏔️ Still thrive in a 470-million-year lineage
REMEMBER
🌍 KEY FACTS
Land plants have existed for 470 million years. The first forests appeared 385 million years ago. Plants created soil, cooled the climate, and made animal life on land possible. Without the land plant revolution, there would be no insects, reptiles, mammals, and no humans.
🌱 Algae → Land plants
🌿 Land plants → Forests
🌳 Forests → Animal life
🌿 Land plants → Forests
🌳 Forests → Animal life
🧠 QUIZ TIME!
HOW PLANTS CONQUERED LAND · 5 QUESTIONS
QUESTION 01
What is a vascular system in a plant, and why was it a game-changer?
QUESTION 02
What was the biggest challenge algae had to overcome to survive on land?
QUESTION 03
What is Cooksonia and why is it important in plant history?
QUESTION 04
What is lignin and what did it make possible for plants?
QUESTION 05
Which of these correctly describes what happened when plants colonised land?
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