Prehistoric Times

Prehistoric Times:

Even long before humans evolved, our oceans and lands were home to some of the most bizarre creatures ever to have lived. Let's step back in time to some of the most amazing eras in the history of our planet and meet these unusual creatures and plants of the Earth. Note that an audio recording pronouncing the dinosaur name is available above each dinosaur image. Also, be sure to click on the individual images for better quality viewing. So, let's step back in time and journey to some of the most amazing "lost worlds" ever known. Enjoy!

College Humor:

The Geologic Time Scale

According to scientists, the Earth formed around 4.567 billion years ago. During the first 800 million years, much of Earth's surface was made of hot liquid rock. Gradually, it began to cool forming islands of land surrounded by hot oceans and a poisonous atmosphere. Since the Precambrian Period, many life forms have come and gone. Feel free to use this time scale when referring to the plants and animals that existed throughout time.

Precambrian -- primitive life forms (bacteria) appeared.
Cambrian -- trilobites and all life forms inhabited water.
Ordovician -- primitive corals, arthropods, star fish and sea shells evolve.
Silurian -- first land plants appear and take root.
Devonian -- fish and amphibians ruled.
Carboninferous -- swamps, plants, fishes, and reptiles were abundant.
Permian -- advanced reptiles, such as Dimetrodon ruled the Earth.
Triassic -- advanced reptiles and early dinosaurs lived side-by-side.
Jurassic -- bony fish and variety of dinosaurs reigned.
Cretaceous -- world of the dinosaurs, first gymnosperms (flowering plants).
Tertiary -- first primates make the seen and branch off in different directions.
Paleogene -- more modern herbivores and ground birds roam the Earth.
Neogene -- evolving horses and many modern mammals fluorish.
Quaternary -- hominids, such as Australopithecus afarensis, Homo habilis, Homo erectus, Neanderthals, and Homo sapiens evolve.

Prehistoric Life:

Ammonite: Time (Devonian to Late Cretaceous Period)

The Ammonites were shell fish that could be found in all of the seas and oceans around the world. These carnivorous sea creatures came in different sizes. They ranged from 1 inch to 8 feet in diameter. In the ancient seas, giant ammonites lived for millions of years as a successful invertebrate. There were many hundreds of ammonite species, and they adopted a wide variety of shapes and lifestyles. However, the one thing they all had in common was a coiled shell, the inside of which was subdivided into several chambers. Only the outermost chamber was occupied by the animal itself.

Anomalocaris: Time (Cambrian Period)

Measuring three feet in length or sometimes greater, this apex predator of the seas was the largest animal living in the Cambrian Ecosystem. As a soft-bodied creature rarely preserved, Anomalocaris was first discovered in the Burgess Shale in British, Columbia, Canada. The animal's head had two large eyes, each resting on a stalk-like structure. It also had a pair of segmented downward-curving appendages with spiny projections on the underside. Its mouth was also situated on the underside and consisted of a circle of elongated plates, and its body was divided into 8 segments giving them fast-speed in the water.

Archaea: Time (Precambrian Period)

Archaeans are organisms similar to bacteria, yet most are anaerobic -- that is they require no oxygen. Pyrococcus furiosus, shown here, thrives on sulfur in near-boiling sea water. Such organisms as these were probably the first life forms on Earth. Archaeans today, can live in extreme habitats, such as thermal vents, hot springs, alkaline or acidic waters. They may be extremely abundant in environments that are hostile to all other life forms. However, these unique organisms are not restricted to such environments. New research is showing that they are also quite abundant with the various plankton of the open seas. Much is still to be learned about these fascinating microbes.

Archaeopteryx: Time (Jurassic Period)

From beak to tail, Archaeopteryx was approximately 1 foot long. It had a wingspan of 1.5 feet and weighed around 11 to 18 ounces. Amazingly well-preserved fossil remains of this creature have been found in fine-grained Jurassic limestone rock in southern Germany. Paleontologists view Archaeopteryx as a transition between dinosaurs and modern birds. With a combination of avian and reptilian features, it is believed to be the oldest known bird ever found. Unlike modern birds, it had teeth, three claws on each wing, a flat breastbone, belly ribs, and a long, bony tail. Like modern-day birds, Archaeopteryx had feathers, a light-built body, and hollow bones. Unlike dinosaurs, Archaeopteryx could fly.

Arsinoitherium: Time (Oligocene Epoch)

Arsinoitherium was a rhino-like but gentle giant that lived in the North African coastal mangrove swamps, where it would have spent most of its time wading around in the water. This herbivorous mammal stood about 6 feet tall and lived from 36 to 30 million years ago. Because its hind legs were permanently bent and pointed outwards, paleontologists speculate that Arsinoitherium not only spent a great deal of time wading in the water but actually swimming. The legs were not ideal for walking on land. More recently, its awkward gait has been confirmed by the discovery of its fossilized footprints in Egypt. Its most obvious feature was its hollow, giant double horn.

Australopithecus afarensis: Time (Pliocene Period)

According to many scientists, Australopithecus afarensis was an early species of hominids, and thus a distant relative of our own species, Homo sapiens. Like us, they walked upright as bipedals (two-legged) most of the time. By walking upright, this allowed them to appear taller and more intimidating to predators, see above the grasses for long distances, mate face-to-face, walk longer distances more efficiently, and free their arms to hold infants and other objects (food, clubs, rocks, etc). Although bipedal, they still relied on the safety of the trees when predators approached and during the night time while sleeping. During the day time hours, Australopithecus had keen eyesight with colored vision, but at night they had limitations of seeing in the dark. Their diet consisted of soft fruits, nuts, insects, and leaves. At times, when food supplies were low, they scavenged off of dead carcasses, and by doing so, the protein from the meat caused their brains to grow and develop. The bodies of Australopithecus resembled that of Homo sapiens, but the head looked more like that of a modern ape. Their hands were well-developed, having four fingers and a thumb which allowed them to manipulate objects.

Cooksonia: Time (Silurian Period)

Evolution of the first land plants was a major event in the history of Earth. The first plants to appear during the latter part of the Silurian Period were that of Cooksonia and some species of fungi that grew in clumps near to streams and rivers. They reached a height of only 4 inches or so. While Cooksonia plant fossils are distributed globally, they are found most commonly in Britain. These unique and hardy plants are the oldest known plants to have a stem with vascular tissue. Cooksonia specimens occur in a range of sizes and vary in stem width. Specimens of different sizes were probably different species rather than fragments of larger plants. Observations made of the root system suggests that the plant was able to attach at a shallow depth within the soil.

Deinotherium: Time (Miocene Epoch)

At about 13 feet tall and weighing in around 10 tons, Deinotherium was the second largest land mammal to exist on Earth. It is the cousin of the modern elephant and had many of its characteristics including: tusks, thick hide, long legs, and a trunk. Aside from its size, its most noticeable characteristic was two downward-pointing tusks. The tusks were in the lower jaw -- unlike modern elephants, and they were probably used for stripping down the bark from trees. Deinotherium may have also used the tusks for self-defense and sexual display. These unique mammals would have been roaming the open plains of Afrca and Eurasia. Artist's interpreation of this creature is by Walter Myers (http://www.arcadiastreet.com).

Dimetrodon: Time (Permian Period)

Up to 11.5 feet long, this early synapsid reptile lived during the Permian Period and fed on other animals. Dimetrodon was a carnivore, and it is the ancestor to all modern mammals. Years ago, and sometimes even to this day, school teachers inform their students that Dimetrodon was a dinosaur. This is simply not true. Dinosaurs are in a different class of their own and did not appear until the Triassic Period. The most obvious feature of Dimetrodon was its large sail. The sail on its back was not just for display but also for regulating body temperature. Dimetrodon had acute eyesight and probably was an active hunter. It usually lived in low, swampy regions, but could survive in a wide range of environments, including harsh mountain areas. This unique reptile was one of the first animals to have teeth of different sizes, which allowed it to catch its prey and eat different types of animals.

Dunkleosteus: Time (Devonian Period)

Dunkleosteus was a large fish that lived during the Devonian Period (380 to 360 million years ago). This alien-looking creature could grow up to almost 33 feet long, making it the largest predator of its time. It's head was encased with a solid and inflexible armor-plating, and just below this region was a muscular body that was streamlined much like our modern-day sharks. Instead of having true teeth, Dunkleosteus had two razor-sharp shearing plates made from bone. These teeth had a scissor-like motion which allowed them hunt larger animals. The younger ones had straighter-edged teeth that functioned very much like a guillotine. As they grew older and continued to actively hunt in the Devonian seas, their teeth slowly wore down to fangs. As a full-grown adult weighing around 40 tons, it probably had very few predators to battle with for territorial rights.

Helicoprion: Time (Carboniferous to Early Triassic Period)

This bizarre-looking creature lived from the Carboniferous to Early Triassic time. It is thought that the strange lower jaw slowly revolved over a life time, bringing new, sharp teeth into position. The fossilized teeth are serrated; therefore, it was indeed a carnivore. An alternate hypothesis posits that the whorl could be enrolled like a party favor, snaring and grasping fish as it reeled them in. Such specimens have been found in eastern Idaho, northern Utah, and the far central western part of Wyoming. This unusual shark was 10 to 15 feet long, and it survived the intense Permian-Triassic Extinction. This is quite notable, because 95 percent of all life forms died out at the end of the Permian Period.

Leptictidium: Time (Eocene Epoch)

Leptictidium was a fast-moving, medium-sized mammal (about 2 to 3 feet long) that lived in the dense jungles of Central Europe. This furry little creature had long back legs that were initially a puzzle to paleontologists who could not determine how it walked. With more fossils to observe, paleontologists were able to conclude that this small creature must have moved about by hopping on both back legs like a kangaroo. Leptictidium was a carnivore preying on insects and smaller mammals that it probably plucked from low branches or found by digging around the leaf litter on the forest floor. The long snout of Leptictidium was sensitive to smell and probably twitched back and forth constantly very much like a mouse's behavior.

Mosasaur: Time (Late Cretaceous)

Now this extinct vertebrate (animal with a backbone) was not a dinosaur. Dinosaurs did not swim in the water. Mosasaurs lived during the Cretaceous Period roughly 87 million years ago. They were the apex predators of their time, and a good, healthy Mosasaur had nothing to fear in the shallow seas of Kansas. The largest of the Mosasaur marine reptiles measured 50 feet in length and weighed 15 or more tons. Mosasaur skeletons and teeth are found mostly in the western part of the state.

Opabinia: Time (Cambrian)

Opabinia was one of the strangest animals to ever exist in the shallow, Cambrian seas. This small creature had five prominent eyes and a long, flexible trunk-like feature called a proboscis that extended from the front of its head. The proboscis ended in a pod-shaped organ with small spines that were used to grasp and capture their prey. Opabinia would have used its proboscis to pass its prey up to its underside mouth. It was a good swimmer -- it had 16 individual segments, each of which possessed a flap-like lateral lobe with gills on the underside. Also, its tail had three flaps that projected from each side. The only Cambrian creature that Opabinia would have feared was Anomalocaris.

Pachyrhachis: Time (Early Cretaceous)

This strange sea creature is an extinct genus of a snake with well-developed hind limbs. Most fossil remains are from limestone beds of the Middle East (modern day Israel). This Late Cretaceous marine reptile possessed unmistakably snake-like body complete with scales, as well as a python-like head, and of course, its tiny limbs. The legs included a hip, knee, and ankle joint. The total length of this sea creature was about 3.2 feet long. Animals as diverse as whales, snakes, and ostriches are all essentially tetrapods (four-limbed creatures) descended from a land-living ancestor that used its limbs for walking.

Paradoxides: Time (Mid Cambrian Period)

Paradoxides was one of the largest known genera of trilobites that existed during the Mid-Cambrian Period. Based on its structure and swimming appendages, this trilobite was at the top of the food chain during the "Cambrian Explosion". Paradoxides had long spines with a long tail. Also, it is one of the pieces of fossil evidence for "continental drift" that was first proposed by Alfred Wegener. He argued that most trilobites lived in saltwater seas, but Paradoxides lived in freshwater and it could be found on both sides of the world several hundreds of miles away.

Quetzalcoatlus: Time (Late Cretaceous)

Well now, your eyes are not deceiving you. You do see a dinosaur hanging from the mouth of this creature. However, it is a baby sauropod dinosaur. This colossal Late Cretaceous pterosaur, Quetzalcoatlus, was one of the largest flying reptiles of all time. Its wingspan was around 39 feet long, which made it larger than many small planes and it had a skull which measured over 8 feet in length. It stood as tall as a modern-day giraffe and despite its monstrous size, it weighed no more than 550 pounds -- thanks to a complex system of air sacs inside most of its bones. Based on the morphological characteristics of its arms and legs, this unusually large pterosaur could walk slowly on land and take off "on a dime" without needing to run. A pterosaur this size could not survive on fish alone. It needed to fuel its enormous metabolic needs by stalking and feeding on baby and young dinosaurs. Quetzalcoatlus was named after the serpent Aztec god Quetzalcoatl, who was the patron god of Aztec priests. This creature's fossil remains have been found in Mesoamerica and the United States of America.

Scutosaurus: Time (Permian Period)

This giant reptile, Scutosaurus, was one of the strangest looking animals of the Permian Period. Resembling a rocky surface texture, its bulky body and face were covered in bony lumps and protrusions, which at least to our eyes made it look somewhat aggressive and ugly. Such features would have helped protect itself from attack and possibly even intimidate predators. With its short, elephant-like legs, this plant-eating reptile moved slowly across the surface of the semi-arid deserts. To ensure that it could find plenty of plant material and water, it would spend most of its time near the river banks and coastlines.

Stethacanthus: Time (Devonian Period)

Stethacanthus was a Devonian shark that measured 2.4 to 6.5 feet long. These early sharks had sleek-shaped bodies and sharp teeth, both of which made them formidable hunters in the seas. As you can see in the image depicting Stethacanthus, the males had an unusual dorsal fin. Such anvil-shaped fins were probably used for mating rituals or frightening prey. A few Stethacanthus fossils have been preserved in extraordinary detail showing the outline of the shark and its biological detail. With the exception of its dorsal fin, such prehistoric sharks resembled that of our modern-day sharks. They had wide mouths, streamlined bodies, sharp teeth, and smooth swimming action. More than likely, it hunted by chasing down its prey.

Stromatolites: Time (Precambrian Period to Present)

How did oxygen form in the oceans and in the atmosphere?

It was in the oceans nearly 3.5 billion years ago that photosynthesizing bacteria called cyanobacteria began to release oxygen into the water through tiny bubbles. As thebacteria excreted its waste, it precipitated (mineralized) mounds or mats of mineral deposits known as stromatolites.

Stromatolites are believed to be the oldest living organisms on the planet. Stromatolites are still present on the Earth. This particular photo was taken in Shark's Bay, Australia.