Life on Earth began at the end of this period called the late heavy bombardment, some 3.8 billion years ago. The earliest known fossils on Earth date from 3.5 billion years ago and there is evidence that biological activity took place even earlier - just at the end of the period of late heavy bombardment.

Prokaryotes were the earliest life forms, simple creatures that fed on carbon compounds that were accumulating in Earth's early oceans. Slowly, other organisms evolved that used the Sun's energy, along with compounds such as sulfides, to generate their own


Millions of years ago, unicellular organism developed into multicellular organism. And first life is evolved in the water. Later, water species come to land region. And evolved themselves . Most of the species are totally exists. They don’t able to survive the circumstances. They are many reason climate change, scarcity of food, predators, disease, natural disaster,,. Some species are still alive on the Earth. 

The 10 oldest prehistoric species still alive on earth ;


10.The horseshoe shrimp;(300 Millions year old)



The horseshoe shrimp is a great example of a “living fossil” – one of the oldest species on earth that still exists today. These are hermaphroditic crustaceans with an elongated body that measures 2 to 4 mm (0.079 to 0.157 in) in length. They have a large head, the hind edge of which covers the first thoracic segment. The thorax consists of nine limb-bearing segments , followed by 10 limbless abdominal segments and a telson


9.Lampreys ;(360 Millions year old)



Lampreys evolved into existence around 360 million years ago. Before the time of dinosaurs, and their shape has stayed almost unchanged over hundreds of millions of years of evolution. Lampreys are parasitize other fish by sucking their blood and other body fluids.

8.Coelacanth;(400 Million years old)



Coelacanths first appeared during the Devonian Period roughly 400 million years ago, about 170 million years before the dinosaurs. They are estimated to live up to 100 years, based on analysis of annual growth marks on scales, and reach maturity around the age of 55; the oldest known specimen was 84 years old at the time of its capture in 1960.


7.Elephant shark ;( 450 million years old)



Such limited change means the elephant shark’s genome is the closest yet to that of the first jawed vertebrate, which lived more than 450 million years ago and gave rise to many modern animals including humans. It makes the elephant shark an important reference point for unlocking how this long-lost ancestor evolved. The elephant shark is a relic of a bygone age. Like the coelacanth, it is sometimes referred to as a “living fossil,” a creature alive today.

6.Cow shark; ( 450 - 420 million years old)



Cow sharks are considered the most primitive of all the sharks, as their skeletons resemble those of ancient extinct forms, with few modern adaptations. Cow sharks are ovoviviparous, with the mother retaining the egg cases in her body until they hatch. They feed on relatively large fish of all kinds, including other sharks.

5.Velvet worms;( 500 Million years old)



DNA evidence suggests velvet worms are closely related to crabs and spiders, possibly as a very early member of the group that gave rise to both. But fossil analysis seems to push the worm's origins much farther back, relating it to a look-alike in 540-million-year-old rocks.

4.Nautilus; (500 million years old)



 The Nautilus is like a swimming snail with tentacles. This living fossil has changed very little in the past 500 million years. Nautilus are soft-bodied creatures live inside an intricately chambered shell. A nautilus can only sense dark and light with its simple, pinhole-type eyes.

3.Jelly fish ; ( 505 Million years old)



A fossil unearthed in Canada is the oldest preserved adult jellyfish found, dating from over 500 million years ago. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles. Jellyfish are found all over the world, from surface waters to the deep sea. Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries.

2.Branchiopods; (530 million years ago).



Approximately 800 species of branchiopods are found worldwide in freshwater ponds, lakes, and inland saline waters such as the Great Salt Lake in Utah. Their fossil record includes the extinct order Lipostraca and dates back to the Devonian period (approximately 530 - million years ago).that feed on plankton and detritus.

1.Ctenophora comb jelly ; ( 700 Million years old)



Although comb jellies look like jellyfish, they are quite different from them and move through the water by using their cilia rather than tentacles. They may be found in seas all around the world and are still a vital component of the marine ecology.

Attached 1 bonus ;

Cyanobacteria; (3.5 billion years old)



Cyanobacteria commonly known as blue-green-algae, are not truly eukaryotic algae. The oldest living organisms on our planet earth are Cyanobacteria! Due to their capability to utilize CO2 and convert it into O2 (photosynthesis) they are very interesting for biotechnological purposes. Therefore, those Cyanobacteria need to be cultivated and sometimes immobilized.