During the period when living things appeared on Earth, the surface level of ultraviolet (UV) radiation is believed to have been much higher than current levels, because oxygen levels were too low to form an ozone layer. This UV radiation would have damaged living cells that were not protected, suggesting that the earliest life was in warm water around deep-sea volcanic vents.
However, some scientists have theorized that a hydrocarbon haze in the atmosphere could have compensated for the lack of upper level absoption, while providing the surface heat necessary for living organisms.
During the period when living things appeared on Earth, the surface level of ultraviolet (UV) radiation is believed to have been much higher than current levels, because oxygen levels were too low to form an ozone layer. This UV radiation would have damaged living cells that were not protected, suggesting that the earliest life was in warm water around deep-sea volcanic vents.
However, some scientists have theorized that a hydrocarbon haze in the atmosphere could have compensated for the lack of upper level absoption, while providing the surface heat necessary for living organisms.
During the period when living things appeared on Earth, the surface level of ultraviolet (UV) radiation is believed to have been much higher than current levels, because oxygen levels were too low to form an ozone layer. This UV radiation would have damaged living cells that were not protected, suggesting that the earliest life was in warm water around deep-sea volcanic vents.
However, some scientists have theorized that a hydrocarbon haze in the atmosphere could have compensated for the lack of upper level absoption, while providing the surface heat necessary for living organisms.
There was too much UV radiation
UV radiation
he evolved from a monkey No, he evolved from an ape.
Scientists thing protists evolved from archaea, which are simply single celled organisms.
Modern man evolved a long time ago. There has never been a time in all the years that man has been upon the earth that has, to him, has not been a modern time. From the time of Adam to the present day there have been thousands of modern times. If there is one aspect of the evolvment of mankind it is through knowledge. Man began life as a man and not some ameba crawling out of the sea. Science will never be able to proove that man was nothing less than a man when the earth was first inhabited.
If we're evolving and evolved from monkeys or apes then why is there still monkeys and apes. We did not evolve from apes or monkeys. We branched off a common line. Humans did not evolve from apes. Humans and apes had a common ancestor . Apes evolved in one direction and we evolved in another. We probably looked a lot alike at first.
As the first photosynthetic organisms increased in number, the concentration of oxygen in Earth's atmosphere began to increase. Organisms that could respire aerobically would have evolved and thrived. The sun's rays would have converted much of the oxygen into ozone molecules that would then have formed a layer that contained more ozone than the rest of the atmosphere.
eff the time in wich life first evolved on earth!!
To Much UV Radiation! :)
They didn't come to earth they evolved here
Impossible to say. Comets have been striking the earth since before life evolved on the earth
Cat didn't "come to Earth". They evolved here about 25 million years ago.
the first lifeforms probably some sort of algae evolved in the sea millions of years ago.
Biblical AnswerAdam and Eve were the first two people on earthRational AnswerNo one knows as there was no one to record the event.That depends upon whether you want a scientific answer or a religious answer. The bible reports that Adam was the first person to walk on the Earth. From the perspective of evolutionary biology, when the human race first evolved about half a million years ago, nobody was keeping records of those events, and it is unlikely that the very first person to walk the Earth even had a name, since language as we know it wasn't invented yet.
No, the first vertebrates evolved long before the Mesozoic. The first vertebrates, small jawless fish, evolved around 520 million years ago. Land animals had even evolved long before the Mesozoic Era.
Oxygen evolved for first time. Many compounds were oxidised
I believe Echinoderms evolved first.
Scientists think that the first life forms appeared on Earth about 3.6 billion years ago. These were simple cells that eventually evolved into the abundance of life we see today.
The oldest plant form on the Earthis algae. Larger plant forms evolved from green algae.Algae and/or diatoms