Prehistoric Times- The World Before Man (1953)

[Music] Jimmy wants to be a scientist someday and he likes to go exploring along the shores of the lake where he lives he collects stones as a hobby strangest of all our small stone disks which have a hole through the center Jimmy has learned that these disks were once the stem-like part of a simple animal that lived in an ancient sea millions of years ago resembling a flower this animal was one of many forms of prehistoric life scientists can show us what these forms looked like from evidence they have found for instance this prehistoric kind of crustacean is called a trilobite geologists have found the remains of this ancient type of animal in the form of stone casts which are one type of fossil fossils are part of the prehistoric evidence that has helped geologists reconstruct prehistoric times from their studies of other kinds of evidence in the Earth's crust many scientists estimate that the earth is two or more billion years old this time of about two billion years scientists have divided into five great periods of time called geologic eras during the first billion years the archaea zoic era continents and seas were forming in the next half billion years the Proterozoic era simple forms of plants and animals appeared in the seas the Paleozoic era of 300 million years was an age of underwater animals including fishes then came the Mesozoic era 125 million years during which reptiles dominated the earth today we live in the Cenozoic era which began 60 million years ago during this time appeared mammals including man let's begin with the Archaea zoic era about two billion years ago during the first billion years continents and seas were forming and since that time the earth has been continually changing there were periods when mountains were built up from the seas by volcanic action sometimes whole mountain ranges were built by volcanic action and by other slower forces some of which pushed up rocks into great mountain folds on the other hand forces of erosion such as running water wind rain and ice were wearing down the mountains and other high regions the process of erosion is slow the land wears away bit by bit this process of building up and wearing down has been a continuous process even the oceans were changed in size and shape scientists think that during the latter part of the Archaea zoic era in the warm seawater that covered much of the land living matter appeared many scientists believe these earliest forms of life were tiny one-celled plants and animals something like the one-celled amoeba the long billion year archaea zoic era gave way to the Proterozoic era during this time there is evidence that there were more complicated forms of plants and animals probably similar to the tiny crustaceans and simple green algae we know today following the half million years of the Proterozoic era came Paleozoic times at the start of this 300 million year era there is no evidence of life on the land but beneath the surface of the warm seas the waters were teeming with prehistoric plants and animals among the early Paleozoic animals were the corals like corals of our seas today they built hard external skeletons some of them lived in colonies among other forms of life in these ancient coral reefs where animals called cephalopods some of them attained a length of 50 feet and remastered of the Seas the prehistoric cephalopods were related to the octopus of present-day times the octopus has no backbone from no outside shell however during Paleozoic times many cephalopods lived in elaborate shells important animals in the Seas of mid Paleozoic times were the fishes fish are vertebrates animals with backbones among the early fishes was the lung fish this present-day lung fish occasionally comes up to breathe air just as these prehistoric lung fish did more suited to life on the land were air breathing amphibians living both in the water and on the land the amphibians were part of the world of plants and insects of Paleozoic times dense forests of ferns and other kinds of plants grew in the warm moist climate it is from the trees and other plants of these Paleozoic forests that we get much of the coal we used today the forests grew in great swampy lowlands and when the trees died they fell into the water and were covered with mud with the passing of millions of years they were changed into the coal we find today saw this period of large coal forests has called the cold age by the end of the coal Age air-breathing lizards had appeared with the coming of these reptiles the long Paleozoic era was drawing to a close the next era the Mesozoic is often called the age of reptiles it was a time of tremendous volcanic eruptions of all the life on the land the lizards were among the animals that survived the violent upheavals gradually gigantic reptiles came to dominate the earth in the Mesozoic era the age of reptiles we call them dinosaurs the Latin word for terrible lizard this one had thick Armour like plates along its back and was about the size of elephant such huge plant eating dinosaurs were often attacked by vicious flesh-eating reptiles but the fierce dinosaurs were not the only reptiles on the earth reptiles with great webbed wings related to prehistoric birds were also part of the Mesozoic era once again changes in the Earth's surface brought this period to a close with the Cenozoic era came the age of mammals among the earliest mammals were some simple types not too different from the hedgehogs of our present-day this sloth was one of the common types of prehistoric mammals among the largest mammals of Cenozoic times were the mastodons whose bones we still find in many parts of the earth these great elephant like animals were among those that live during the severe climatic changes that happen during the Ice Age which began about a million years ago there were times when large portions of the earth were completely covered with glacial ice and snow living on the tundra near the edge of the ice fields were the woolly rhinoceros and the huge mammoths the great shaggy mammoths belonged to the elephant family they were related to the elephants on the earth today in the same way the horses that we know today can be traced to their prehistoric ancestors small horses that roamed the earth millions of years ago the story of the horse and other mammals is only part of the evidence of prehistoric life that scientists are continually finding scientists estimate the age of the earth at some 2 billion years or more the first great era is called archaea zoic the time of the formation of the Earth's crust in the next era the Proterozoic the waters of the earth contains simple forms of plants and animals during the Paleozoic era animals without backbones were most important about the middle of this time fish with backbones became abundant and near the end of the era air breathing amphibians and lizards appeared giant reptiles called dinosaurs came to dominate the earth during the Mesozoic era sometimes called the age of reptiles and in the most recent era the Cenozoic mammals appeared on the earth it was toward the end of this era during one of the warmer stages of the Ice Age that man the most highly developed mammal appeared the story of prehistoric man is the last chapter in the long record of prehistoric times [Music] [Music]