The Story of Life

By researching and introducing the story of the Earth you also have an opportunity to introduce a project on the story of life.

In the primary Montessori classrooms this is studied with the help of a timeline made of coloured ribbon representing the different eons and eras of life. The timeline is made to scale to help children imagine the length of time before human beings came to live on Earth and the very short time we have been here. You can see an example timeline here: bit.ly/2OF1OzC

You can help to inspire the students in your class to engage with the story of life by creating a physical timeline with them using ribbon or a painted till-roll. This will help you make the story come alive as each new eon/era is introduced.

To make the timeline cut lengths of ribbon or paint a paper till-roll using the following colours:

• ▶  Hadean & Archaean Eons (Black) 2.75 m long;

• ▶  Proterozoic Eon(Pale Blue) 7.10 m long;

• ▶  Palaeozoic Era (Yellow) 1.00 m long;

• ▶  Mesozoic Era (Orange) 0.41 m long;

• ▶  Cenozoic Era (Green) 0.15 m long.
  Scale: 10 million years = 0.025 m (approximately one inch)

  Useful links:

• ▶  TheFiveGreatLessonsoftheElementaryCurriculum:bit.ly/317kmuX

• ▶  Lifetimeline:bit.ly/2OF1OzC

• ▶  The coming of life video: bit.ly/2p9YVfk

• ▶  Note: Often the Hadean, Archaean and Proterozoic eons are represented as one, the Precambrian supereon, but it’s useful here to separate them to highlight the time it took for life in water to evolve, shown here: bit.ly/35sOvba

Proterozoic Eon

It took a very long time for the water on Earth to first show signs of life. Tiny little organisms appeared, they were neither plants or animals. Some of them used the light of the sun to grow and became the plants whilst others found their nourishment in the plants and became animals. As they grew and multiplied the plant-like organisms released oxygen helping to support the development of other life. Some of these organisms such as the blue green algae can be found today in the oceans and continue to be a major source of oxygen in the water and the air.

As the oxygen in the water increased more complex creatures started to develop, among them sponges, corals and jellyfish. Descendents of these animals can be found in most of the seas today and because of their fragility we need to make sure that the right conditions for their life continue.

Palaeozoic Era

Life in the water continued to develop and the seas became busy. We know from the fossils we can find today, that animals with shells such as the trilobites existed - they came in many sizes. As the seas lapped against the rocks they brought with them some of the algae and bacteria which grew into the first plants on land such as mosses, ferns and horsetail – descendents of which can still be found across the Earth today.

This is a time of incredible change on Earth as new forms of life appeared in the seas and on the land. New types of animals could be found in the seas: they were very different to the others because they had a backbone – they were the first fish and there were many different types of them, including the ancestors of the sharks. Other types of fish (similar in some ways to modern lungfish or mudskippers) made a move from the water onto land. They gradually adapted to life away from the sea, developing fully formed legs whilst still returning
to the water to lay their eggs, just like frogs do today. These animals (known as tetrapods) were the ancestors of all the vertebrates we see today - that’s all the modern amphibians (like frogs), reptiles (like lizards), birds (like doves) and mammals (like you!).

Also on the land the ferns and horsetails grew bigger creating forests. Fossils tells us of giant insects that buzzed through these forests, including dragonflies with a wingspan of 70cm!

Mesozoic Era

The reptiles came to rule the land, some of them were the largest land animals ever to live on Earth, the dinosaurs. Reptiles lay their eggs out of water and need a lot of sun to keep their bodies warm. Reptiles roamed the entire Earth; their fossils can be found today in many places across the globe. They came in many shapes and sizes, such as Dimetrodon (a synapsid that lived and died long before the dinosaurs) and Brachiosaurus (a truly massive dinosaur). Some reptiles ate plants (like the dinosaur Stegosaurus) whilst others ate other animals, such as the Velociraptor (another dinosaur). Some reptiles continued to swim (Plesiosaurus) and live in water whilst others developed wings and learned to fly such as Pteranodon. The plants on the Earth were also changing and some had flowers such as the magnolia tree.

Cenozoic Era

At the end of the Mesozoic era a dramatic event occurred that resulted in many forms of life dying out rapidly, including the dinosaurs and other large reptiles. Today, scientists think this was most likely caused by the Earth being hit by a big comet or asteroid, which threw so much material into the atmosphere that it caused a long, dark cold spell
that many species of plants and animals could not cope with. Other animals managed the change and survived, they had hair and fed their babies with mother’s milk – the mammals. Like the dinosaurs before them they found homes all over the Earth, eventually evolving into the mammals you see today, including you!

Afterword

Today, scientists believe that this story of plants and animals has taken over 4.5 billion years, and that life continues to change and evolve given the time it needs.

When environmental changes happen rapidly as at the end of the Mesozoic era animals and plants do not have the time to adapt. It is for these reasons that we need to care for and respect all life on the planet, act responsibly and look after the treasure of life entrusted to our care.

Resources

Book resources to extend your own knowledge and bring the story closer to the children.

• ▶  David Attenborough, Life on Earth. Comprehensive guide to this story for adults and older chidlren

• ▶  EricMadden,EarthStory

• ▶  Eric Madden, Life story. Very clear and simple interpretations of

  evolution which we have used as basis for our story.

• ▶  Meredith Hooper, The Pebble in my Pocket. This story brings evolution closer to the children of today as they follow the history of a pebble found on a beach.

• ▶ Catherine Barr, Steve Williams and Amy Husband, The Story of Life: A First Book about Evolution. More recent version of the stories presented by Eric Madden, the book is rich in text and images

• ▶ Ruth Symons and Katie Scott, The Story of Life – Welcome to the Museum. This recently published book has spectacular illustrations.

• ▶ Anna Claybourne and Wesley Robins, Amazing Evolution: The Journey of Life. 2019 publication with amazing illustrations full of incredible facts.