Prehistoric: Dinosaurs, Megalodons and Other Fascinating Creatures of the Deep Past
CONTENTS ANTHROPOCENE PRESENT DAY HOLOCENE 10,000 YEARS AGO PRESENT DAY PLEISTOCENE 2 6 MILLION 10,000 YEARS AGO NEOGENE 23 MILLION 2 6 MILLION YEARS AGO PALEOGENE 66 MILLION 23 MILLION YEARS AGO END-CRETACEOUS EXTINCTION 66 MILLION YEARS AGO CRETACEOUS 145 66 MILLION YEARS AGO JURASSIC 201 145 MILLION YEARS AGO TRIASSIC 252 201 MILLION YEARS AGO END-PERMIAN EXTINCTION 252 MILLION YEARS AGO PERMIAN 299 252 MILLION YEARS AGO CARBONIFEROUS 359 299 MILLION YEARS AGO DEVONIAN 419 359 MILLION YEARS AGO SILURIAN 443 419 MILLION YEARS AGO ORDOVICIAN 485 443 MILLION YEARS AGO CAMBRIAN 541 485 MILLION YEARS AGO EDIACARAN AND BEFORE 4 6 BILLION 541 MILLION YEARS AGO GLOSSARY INDEX 6 8 10 12 14 16 18 22 24 28 30 32 34 36 38 40 42 44 45
HOLOCENE 10,000 YEARS AGO PRESENT DAY Humans evolved during an ice age For most of this time life was tough Temperatures were low The polar ice caps were more than just caps they were more like ice cloaks But around ten thousand years ago Earth entered a warming spell scientists call the Holocene and the ice sheets began to shrink This was good for humans Before long people were living all around the globe wandering across prairies through forests and along coastlines in small groups They hunted and fished for food or gathered roots nuts and fruits to eat while they traveled As the climate continued to warm some groups settled in small villages and began to farm the land They chose places where the soil was good for growing crops and with plenty of fresh water nearby in rivers or lakes Over time some of those villages grew into the first towns and cities Today most people live in urban areas Even with this warming we are actually still living in an ice age today It may not feel like it on a hot summer day but as long as there’s at least some ice and snow at the North and South Poles scientists say it’s an ice age 8
HOLOCENE YEARS PRESENT DAY AGO 10,000 Large mammals such as woolly mammoths mastodons and woolly rhinos still roamed the Earth at the beginning of the Holocene But within a couple of thousand years they were all extinct Along with the changing climate humans hunting with early weapons may have been partially responsible for their disappearance Earth today during ice age conditions Earth during the warm Cretaceous Period 70 million years ago ICE AGES The Ice Age during which we evolved began 2 6 million years ago Since then the Earth has alternated between times of warming and cooling But throughout this time the Earth’s poles have always been covered by ice sheets There have been four other ice ages before the current one Around 650 million years ago the Earth may have been so cold that it was totally frozen over Ice sheets stretched all the way to the Equator This period is called Snowball Earth Snowball Earth 650 million years ago
