Sharks are older than trees and dinosaurs The earliest evidence of shark fossils dates back as far as 450 million years, which means these creatures have been around at least 90 million years before trees and 190 million years before dinosaurs.
Sharks are among Earth's most ancient creatures. First evolving over 455 million years ago, sharks are far more ancient than the first dinosaurs, insects, mammals or even trees.
Sharks are one of the most popular marine species today, but did you know the earliest fossils date around 450 million years? Even more impressive is the elusive, deep-sea Greenland shark which is one of the oldest living species.
Jellyfish have been around for more than 500 million years. That means they appeared more than 250 million years before the first dinosaurs.
Today's sharks are descended from relatives that swam alongside dinosaurs in prehistoric times. In fact, the largest predator of all time was a shark called a Megalodon. It lived just after the dinosaurs, 23 million years ago, and only went extinct 2.6 million years ago.
Sharks have survived many mass extinction during their presence of 450 million years on Earth. Scientists believe that their ability to repair damaged DNA has helped them survive over the years. Their presence on the planet over millions of years have earned them the title of living fossil.
Cyanobacteria
What is this? Cyanobacteria are the oldest existing species in the world. These bacteria are believed to be the Earth's oldest known life form.
For approximately 120 million years—from the Carboniferous to the middle Triassic periods—terrestrial life was dominated by the pelycosaurs, archosaurs, and therapsids (the so-called "mammal-like reptiles") that preceded the dinosaurs.
Around 240 million years ago, during the Cretaceous period, the earth looked pretty different. It was a time when dinosaurs roamed freely and crocodiles coexisted alongside them. In fact, crocodiles are one of the only animals that are thought to have survived the asteroid that wiped out the dinosaur population.
Crocodiles are not dinosaurs, but both crocodiles and dinosaurs came from the crown group Archosaurs. Archosaurs were reptiles that included birds, crocodiles, pterosaurs, and dinosaurs. Modern-day birds are descendants of feathered dinosaurs, evolving over the last 65 million years.
The earliest shark-like teeth we have come from an Early Devonian (410-million-year-old) fossil belonging to an ancient fish called Doliodus problematicus. Described as the 'least shark-like shark', it is thought to have risen from within a group of fish known as acanthodians or spiny sharks.
Coelacanth – 410 MYA
The Coelacanth is one of the oldest known fish still alive today. There are two species, one living near Africa and the other near Indonesia. The oldest Coelacanth fossils are only 410 million years old, predating dinosaurs, trees, and sharks by a large margin.
Sharks have roamed the Earth's oceans for more than 400 million years. In the process, the animals have survived five mass extinction events, including the one that wiped out the dinosaurs. This latter extinction event occurred around 66 million years ago, marking the end of the Cretaceous period.
Scientists already know that an asteroid—or perhaps a comet—struck Earth off Mexico's Yucatán Peninsula. The resulting 110 miles/80 kilometers wide Chicxulub crater is thought to have caused a decades-long “impact winter” that killed the dinosaurs.
Although megalodons existed many millions of years in the past, they can't truly be considered dinosaurs, who died out around 66 million years ago.
Sharks have existed on Earth for approx. 450 million years. Whereas crocodiles have only existed for roughly 200 million years. Shark ancestors existed before the dinosaurs ? and trees ?!
Australia has two species of crocodiles, the saltwater or estuarine crocodile, Crocodylus porosus and the freshwater crocodile, C. johnstoni. Readable and well-illustrated reviews of the biology of world crocodilians may be found in Webb & Manolis (1989) and Ross (1989).
In an evolutionary sense, birds are a living group of dinosaurs because they descended from the common ancestor of all dinosaurs.
There are two main reasons. First, crocodiles can live for a very long time without food. Second, they lived in places that were the least affected when the asteroid hit Earth.
Frogs & Salamanders: These seemingly delicate amphibians survived the extinction that wiped out larger animals. Lizards: These reptiles, distant relatives of dinosaurs, survived the extinction. Mammals: After the extinction, mammals came to dominate the land.
No! After the dinosaurs died out, nearly 65 million years passed before people appeared on Earth. However, small mammals (including shrew-sized primates) were alive at the time of the dinosaurs.
Known as an ichthyosaur, the animal lived about 205 million years ago and was up to 85 feet long—almost as big as a blue whale, say the authors of a study describing the fossil published today in PLOS ONE.
Today there are two living coelacanth species, known as Latimeria, which have basically remained unchanged over the past 100 million years. Horseshoe crabs are ancient creatures that first appeared at least 480 million years ago during the Ordovician Period and don't appear to have changed much since.
By many metrics, the most successful animal species is Homo sapiens: it has conquered the world and can fly around it in a matter of hours; it can live at the polar regions and the equator; plus, it is able to dive the depths of the sea, climb the highest mountains and even go to the moon.