CapZone Letter to Kids

The first life forms were very simple organisms not unlike the algae we see today in our fish tanks.

Modern day algae

They appeared about 3.8 billion years ago. These plants, called stromatolites, formed the basis for all life to come.

Next came the Paleozoic Era, which began about 700 million years ago and lasted until 225 million years ago (the date ranges may differ according to what reference book you use). Around 570 million years ago, trilobites and other sea creatures such as brachiopods, corals, and sponges first appeared.

A trilobite

Fish came a bit later (about 100 million years or so later, that is). Some of these guys still exist today. Now that is a long family tree!

The Paleozoic Era is also the time when the majority of the earth's supply of oil was formed. The largest amount of oil formed in deep sedimentary rocks in the Middle East (mainly Saudi Arabia). Although the original amount formed was huge, humans have been actively using up the oil since it was first discovered.

Humans need to understand that the earth no longer produces oil. It is like drinking a big glass of water with a straw. You can take little sips for hours, but once it is gone, it is gone! This time period is when the first primitive fish (Acanthodians and Placoderms), the first bony fish, Osteichtyses (a goldfish is a modern example), Chondrichthyes (sharks, skates, and rays - these guys have no bones, only cartilage like the material your nose is made of), and Amphibians (e.g., the modern frog) appeared on the planet.

And then around 225 million year, the all-time kids' favorite arrived... The Age of the Dinosaurs! The dinosaurs were present in what geologists call the Mesozoic Era, which consisted of three parts: the Triassic, the Jurassic (you probably have heard of this one somewhere), and the Cretaceous.

These huge creatures (you know them well, Tyrannosaurus Rex, Brachiosaurous, and Triceratops, just to name a few), roamed the earth for about 160 million years, until about 65 million years ago.

Tyrannosaurus Rex (oh my...run as fast as you can!)

Most scientists now believe that these big guys went extinct because of a combination of two factors: (1) a gigantic meteor that hit the earth and covered the atmosphere with dust, blocking out the suns rays (which supports all life); and (2) massive erupting volcanoes that spit deadly gases into the air.

But just so you don't think that dinosaurs were the only animals living on the planet during this period, you should know that flying reptiles (Pterodactyls...talk about a big, ugly flying meat-eater. This is what nightmares are made of) and small mammals co-existed with the giant beasts.

Pterodactyl (a flying reptile about the size of a small airplane ...wings but no feathers ...watch out for this predator!)

Well, as everyone knows, the dinosaurs are long gone (except in movies and our imaginations). So, what came next?

The time period of the gigantic animals was over, and the Age of Mammals began 65 million years ago. The beginning of Cenozoic Era saw the rise of many animals you see now. This is when animals like horses, opossums, tapirs, lemur-like monkeys, camels, and other mammals (including Capzbear's relatives) began to dominate. Not that early Cenozoic animals all look exactly like their present-day cousins. Some were larger. Some were smaller. Some were hairier. Most were probably meaner.