Explodapedia: Evolution E-Book

Ben Martynoga

• Herausgeber: David Fickling Books
• Kategorie: Für Kinder und Jugendliche
• Serie: Explodapedia
• Sprache: Englisch
• Veröffentlichungsjahr: 2023

Seitenzahl: 145

Beschreibung

The story of evolution began billions of years ago. It's an epic tale that links us humans to all other life on planet Earth. And it's not over yet! Creatures are still evolving today - constantly seeking new ways of growing, thriving and surviving.Filled with up-to-the-minute science, Evolution uncovers the myths and mysteries surrounding biology's most extraordinary story. Meet some surprising ancient relatives - discover your similarities and differences - and find out what the evolution of our brains has meant for life as a whole.How will our past shape our future?

Leseprobe

Welcome to

Explodapedia

, the indispensable guide to

everything you need to know!

This series is packed with in-depth knowledge you can trust;

it gives you the tools you need to understand the science

behind the wonders of our world. Read on to discover the

story of how we became the way we are, in

Evolution . . .

‘Extraordinary discoveries are explained in this book in

a way everyone can understand.’

Sir Paul Nurse, Nobel Prize winner

‘The perfect balance between charm, quirkiness and

wonder . . . for kids and adults alike.’

Siddhartha Mukherjee, Pulitzer Prize winner

‘A totally fascinating book, brimming with amazing scientific

knowledge and fab illustrations.’

Greg Jenner

‘Successfully blend[s] appealingly humorous drawings . . .

with text that combines clarity and accuracy.’

Professor Richard Fortey

‘Both accessible and funny . . . a clever way to introduce . . .

our understanding of all life today.’

Professor Venki Ramakrishnan, Nobel Prize winner

BM: To Ghyll, the most up-to-date evolutionary prototype in our

family. Keep asking those great questions. x

MA:

To Connor and Spencer, thank you for evolving so beautifully.

EXPLODAPEDIA: EVOLUTION

First published in 2023

by David Fickling Books, 31 Beaumont Street, Oxford, OX1 2NP

This ebook edition first published in 2023

All rights reserved

Text © BEN MARTYNOGA, 2023

Illustrations © MOOSE ALLAIN, 2023

The right of Ben Martynoga and Moose Allain to be identified as the author

and illustrator of this work has been asserted in accordance with Section 77 of

the Copyright, Designs and Patents Act 1988.

This ebook is copyright material and must not be copied, reproduced, trans-

ferred, distributed, leased, licensed or publicly performed or used in any way

except as specifically permitted in writing by the publishers, as allowed under

the terms and conditions under which it was purchased or as strictly permitted

by applicable copyright law. Any unauthorised distribution or use of this text

may be a direct infringement of the author’s and publisher’s rights, and those

responsible may be liable in law accordingly.

ISBN 978–1–78845–251–9

Italic type is used in

Explodapedia

to highlight words that are defined

in the glossary when they first appear, to show quoted material and

the names of published works. Bold type is used for emphasis.

Contents

Consider the Fly

7

Chapter 1: How Evolution Works

17

Chapter 2: Bugs, Birds, Beasts and Bellyaches

30

Chapter 3: Natural Selection

40

Chapter 4: It’s in the Genes

53

Chapter 5: The Rise of the Replicating Robots

74

Chapter 6: Why Should Anyone Care?

86

Chapter 7: Seeing the Light

105

Chapter 8: All Kinds of Everything

120

Chapter 9: You’re History, Sunshine

137

Is This the End, or the Beginning?

152

Timelines

160

Glossary

163

Index

169

Acknowledgements

172

About the Author and Illustrator

173

6

Bzzzzzzz.

Not until you apologize.

Never gonna catch me!

S’pose not. As long as it’s only to

marvel at my sleek physique.

Consider the Fly

What’s the point of flies? They’re annoying. They buzz. And,

of course, they hang out in the most disgusting filth – then

come and land smack bang in the middle of your dinner.

Oh, great. Here’s a fly now. Get lost!

A

talking

fly?! Go on, zip it, or you’re getting squashed.

OK, OK, you’re right. You flies

are

practically impossible to

swat. And, actually, what we really want to do is take a closer

look at you. Do you mind?

W

hy

y

ou

’

ll

N

ever

C

atCh

a

h

ousefly

With

y

our

B

are

h

aNd

First, let’s check out those eyes. They might look fairly ordinary

at first, but they’re actually two compound eyes:

That’s why flies can see what’s going on all around them –

and see

you

coming a mile off.

Just like the cells in the

retinas

at the backs of your eyes, cells

in a fly’s compound eyes contain tiny, highly sensitive detectors

made from proteins, which convert light into electricity. When

the fly ‘sees’ something – like a rolled-up newspaper rushing

towards it – those electrical signals zip along nerve-

cell

‘wires’

and into the brain, which decides what to do about the threat.

8

One compound eye –

made up of 3,000

miniature eyes

Each miniature eye

works brilliantly

‘Corneal lens’ protects eye

and focuses light

‘Retinular’

cells detect

light

Nerve cells carry

signals to brain

Nerve

cells carry

signals to

brain

‘Cornea’

protects

eye

‘Lens’ focuses light

‘Retina’

detects light

But all this happens extremely quickly. Flies process visual

information

seven times faster

than you do. From a fly’s point

of view, each tick of a clock’s second hand feels like it takes

seven whole seconds. So, to a fly, we humans look like we’re

moving in slooowwww motion.

Which is why flies always seem to . . .

fly

off, extremely

quickly.

Also, for their size, flies are vastly stronger than we are.

Because they have an

exoskeleton

, which basically means a

skeleton on the

outside

of their bodies, they can pack more

muscle power

inside

their bodies.

Exoskeleton made from an

ultralight yet super-strong

chemical called ‘chitin’

And that gives me

ages

to react.

Muscles can contract ten

times faster than yours

Even the fastest human

hand is no match for a

humble housefly

Wings beat 200

times per second (a

pro sprinter takes

about five strides per

second)

10

Fair point!

Next time you spot a fly, watch it for a moment. You’ll see it

wiping itself down with its front legs. Flies rely on their senses.

They use chemical sensors embedded in their legs to ‘taste’

their world – constantly. If they don’t keep those sensors, as

well as their compound eyes, nice and clean, they’ll get lost

and confused.

And, actually, it’s worth knowing that if flies –

– didn’t join forces with all the other

detritus

-eating

beasties that gobble up and recycle dead and decaying

waste, that waste would just hang around for ever. And

our world would stink a whole lot worse.

Maybe that was a little harsh.

Take a proper look at any living thing and you’ll find that

So, who, exactly, were you calling pointless?

OK, so flies’ bodies are

awesome, but they’re still

filthy little creatures.

How dare you! We’re

always grooming

ourselves!

And all our cute little maggot babies.

11

it’s amazingly well-suited to its surroundings. Its body parts

seem tailor-made to do all the work needed to keep it alive and

able to multiply itself, whenever it gets a chance.

Think about the grass in your local park that’s constantly

being mowed, nibbled, scuffed, stomped and peed on. It just

keeps on growing back. Incredible, eh? And all it needs to stay

alive is a bit of sunlight, the occasional splash of rain and a thin

layer of soil.

That soil is even more amazing.

Just one teaspoonful can contain up to

120 billion

microscopic living things.

That’s the same as the number of people

it’s estimated have been born across all

human history

We definitely have a point!

We get knocked down . . .

But we get up again!

12

They absolutely do. These minute underground creatures

are utterly crucial. Without them there’d be no soil. And

without soil there’d be no plants and, therefore, no plant-

eating animals – which means there’d also be no ‘us’.

If you could peer into the minuscule bodies of those

soil

microbes

, your mind would be truly boggled. You’d see

thousands of intricate,

molecule

-sized machines, all working

away 24/7. Together, they perform the elaborate chemical

reactions needed to break down the waste other living things

leave behind, keep themselves going and make the fertile soils

plants need. Though these

microbes are tinier than the

smallest specks of dust, their

moving parts all look every bit

as carefully constructed as the

much larger bodies of plants

and animals.

Now look in the mirror.

Whether or not you like what

you see, there’s no denying

that the human head is fitted

I’ll never take soil for granted again!

13

with some impressive equipment. Most of us are lucky enough

to have a set of hungry sense organs, which are constantly

gobbling up information about the world around us.

OK, so we don’t have wings. But that’s exactly the

point: different bodies are purpose-built for life in different

environments

. It doesn’t make any sense to say that some bodies

Sharp eyesight,

capable of 3D-vision

And in between those ears is a brain that’s more than a

match for any manmade supercomputer. It uses all that sense

information to livestream the most addictive, fully immersive,

multi-sensory virtual reality computer game ever. Only it’s not

virtual reality, it’s your actual reality.

Highly attuned

hearing

Can detect

one trillion

different smells

Touch- and

heat-sensitive

skin

2,000–4,000

tastebuds

You can’t fly though,

can you, big head?!

are better than others. And, besides, we don’t need wings.

Thanks to our brains, we can fly . . . in aeroplanes.

That’s a question people have been pondering for as long as

they’ve been able to ponder. We’re lucky enough to live in an

age where we

know

the answer.

Here’s what it boils down to: all living things have been

carefully crafted, over aeons of time, by the extraordinary, and

often incredibly creative, process we call

evolution

!

t

he

P

laNet

-s

ized

i

NNovatioN

l

aB

Evolution basically means ‘gradual change’. So, when we say a

living thing has evolved, we mean it is a modified version of a

different living thing that existed in the past.

14

Human being today

Tch. So lazy. So slow.

But

how

did all these creatures get bodies

that are so good at doing their stuff?

Homo habilis

: human

being’s relative two million

years ago

15

Evolution modifies living things through a never-ending

process of ‘trial and error’. In each new generation, some

organisms

grow and behave in ways that differ slightly from

their parents. Some of these differences make creatures’ lives

harder. But successful ones produce individuals that are

better at surviving and reproducing within their particular

surroundings. Over many, many generations, success has built

on success, gradually creating all the different creatures that

creep, swarm, sprout, spread, ooze, bloom, squawk, flap and

buzz across every corner of our planet.

Evolution has been running these ‘experiments’ for an

eye-wateringly massive amount of time. In fact, biologists now

know for certain that all

species

around right now are related

Whale today

Millipede today

(from 0.32 cm to

around 27cm)

Ambulocetus

: whale’s four-legged

relative 49 million years ago

Arthropleura:

millipede’s relative

300 million years ago

It was six metres long!

16

to the very first

living things

that spluttered into life on our

planet back in the deep shadows of time. That means they’ve

all

been evolving for around

four

billion

years!

Life has had its ups and downs, however. On several

occasions things got so bad that it was almost

snuffed out

entirely. But some living things have always found a way to

persevere and, thanks to evolution, adapt themselves to their

new circumstances whenever the world has changed. That’s

why you can actually think of today’s life forms – including

you – as the most up-to-date prototypes to have emerged from

a planet-sized innovation lab. It’s a lab that has been tinkering

with its designs, non-stop, for thousands of millions of years.

We’re all works in progress, actually, Fly. Your type of body

will gradually be altered. And future flies might even evolve

into something that isn’t a fly at all. That’s evolution for you

– everything that’s alive is, and always will be, in a state of

change. Now, sit tight, because we’re about to find out how it

actually happens.

Hey, there’s no improving

on

this

design.

17

CHAPTER 1

How Evolution Works

s

urviviNg

aNd

t

hriviNg

iN

a

W

orld

that

K

eePs

oN

C

haNgiNg

Sixty-seven million years ago, the planet

teemed with a breathtaking array of reptiles.

Pterosaurs

soared through the air on claw-tipped

wings. Fearsome, saw-toothed predators called

plesiosaurs

ruled the waves. And, on dry land,

the

dinosaurs

held sway. All these creatures had

been evolving alongside each other over tens of

millions of years, their bodies gradually adapting

as they tussled and hustled for survival.

Then, around sixty-six million years ago, a massive, ten-

kilometre-wide meteorite slammed into our planet, detonating

an explosion with the same energy as

one billion

atomic

bombs.

18

The seas literally boiled and the shockwave and

mega-

tsunamis

that followed slaughtered dinosaurs and their reptilian

cousins in their countless millions. The reign of the giant

reptiles came to an abrupt and very messy end.

Some living things managed to survive the hellish blast,

but the new world they had to live in was truly abysmal. The

oceans turned dangerously acidic and the sun disappeared

behind a thick cloud of toxic soot; smoke, dust and blazing

hot debris encircled the planet and occasionally rained fire on

the creatures below. Plants, seaweeds and

plankton

couldn’t

properly harness the sun’s energy, so Earth’s

food chains

collapsed. In total, scientists think three-quarters of all species

19

alive at the time died out completely.

Not one of the pterosaurs or plesiosaurs survived, but the

dinosaurs weren’t

all

wiped out. A small fraction of them made

it through the catastrophe. In fact, they eventually turned one

of the greatest natural disasters of all time into an

opportunity

,

and they’ve been evolving ever since. That’s the incredible thing

about evolution, it means living things can change, generation

by generation, and at least stand a fighting chance of coping

with whatever nasty surprises the world might throw at them.

Here’s one of the dinosaurs whose

ancestors

lived through

the utter havoc the meteorite wreaked all those millions of

years ago:

Yup, biologists agree that chickens – and all of today’s birds

– are dinosaurs. Believe it or not, they all evolved from a small,

feathered dinosaur that lived around 150 million years ago. By

the time the meteorite struck, however, some of its descendants

looked much more like today’s birds.

Eh?

ROAR!

Long before the meteorite:

Nobody knows for sure, but even 66 million years ago, birds

had evolved a whole range of

characteristics

that biologists think

may have saved their skin after the meteorite turned Earth into

a living hell:

1. Since most land animals died and the forests had burned

down, food was suddenly very scarce. Thanks to their

beaks

,

birds could peck at the tough seeds and nuts, pick at carcasses

and gouge grubs out of decaying wood.

2. Birds were

smaller

than most other dinosaurs. They needed

20

But how come the bird-like dinosaurs made it

through and T- rex and the rest didn’t?

Slightly bigger brain

(relative to smaller body)

Boney tail

When the meteorite struck:

Wings that can fly

Feathers

Egg-laying

Walks on two legs

Warm-blooded

No wings

Feathery tail

Beak

Teeth

less food and would have found it easier to hide when trouble

loomed.

3.

Wings

were great for getting out of trouble and searching for

better places to live.

*

4. Compared to their body size, bird

brains

are generally

bigger

than reptile brains, and therefore better at solving problems

and remembering where to find food, etc.

They evolved them, through an awesomely powerful process

called

natural selection

.

That’s what built the dinosaurs’

incredible bodies – and what turned some of them into birds.

The basic idea of natural selection is pretty straightforward:

in a population of living things, individual organisms vary, and

the ones that happen to be best at surviving and

reproducing

…

survive and reproduce more than all the others.

The ways in which individuals vary are usually quite small

and subtle. Just think about your family, or your neighbours.

They’re all people, obviously. But they have different eyes, hair,

skin, facial features and so on – because they’re all

individuals.

21

*

Though some scientists think the birds that survived the meteorite were not able to fly.

So being ‘bird-

brained’ is a

good thing!

Well, maybe . . . But

I don’t get how your

early bird ancestors

ended up with all those

handy features.

That’s how it is for all living things: every organism is an

individual.

Biologists call the small differences that distinguish one

individual from another

variations

. If a variation proves even

a tiny bit helpful when it comes to surviving and reproducing

– and if it gets passed on to the next generation – it might

combine with other variations to trigger more dramatic

evolutionary changes. That’s how it must have been for some

of the maniraptoran dinosaurs, way back at the start of the

birds’ evolutionary journey. Some of them will have had snouts

that were just a tiny bit ‘beak-like’, arms that were slightly ‘wing-

like’ and so on. And, crucially, those little variations must have

given them some kind of advantage.

Because lots and lots of little changes over a huge amount

of time

add up

to truly monumental changes. In fact, that

chicken we met earlier can show us how it works.

22

But if the variations were so tiny, how

could they

possibly

lead to massive

changes like whole sets of actual wings?