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4 billion
Zackery Schumm
Wiki User
∙ 11y agoSingle-celled organisms have lived on Earth for about 4 billion years!
Wiki User
∙ 11y agoFrom the beginning of live up to half a billion years ago ...
so a fair estimate would be 4 billion years.
Wiki User
∙ 9y agoThere has never been a time when multi-celled life consisted only of single-celled life.
If all life is single-celled, then there won't be a lot of multi-celled life.
Wiki User
∙ 12y ago3.5 billion years ago
Wiki User
∙ 16y agoit depends
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Are there more single-celled or multi-celled organisms on earth?
multi-celled organisms have more than 1 cell.But a singe-celled organism does not.
What important role do unicellular organisms play in sustaining life on Earth?
Single celled lifeforms constitute most of the life on Earth. They are the majority of the producers in Earth's ecological system. They are major contributors to the processes that replenish our atmosphere, and form the basis of the marine food chain. On a smaller scale, single celled organisms perform equally important roles: they are a major part of the digestive system of most advanced animals. In humans, they are present in our intestines to aid in the breakdown of foodstuffs. Without them, we would not survive. Without single celled organisms, no life would be possible on Earth.
What events occured that allowed single celled organisms to evolve into more complex organisms at the end of the precambrian time?
the ozone layer began to develop shielding earth from ultraviolet rays, this was hypothesized that these changes allowed species of single celled organisms to evolve into more complexed organisms
What were organisms that lived doing Precambrian time?
Animals that lived during the Precambrian times were single celled animals such as stromatolites,(blue-green algae).The earliest forms of invertebrae animals were also in the Late Precambrian.
What other kingdom has single celled organisms?
There are currently millions of species of single-celled organisms, and million of others that were once here and are now extinct. Which of these would BEST describe the first, most primitive organism to arise on Earth from which all other life evolved?
Are there more single-celled or multi-celled organisms on earth?
multi-celled organisms have more than 1 cell.But a singe-celled organism does not.
Where did the immigration happen first?
When a commet containing single celled organisms, or the basic materials needed for single celled organisms to develope, hit the earth.
What were the first types of creatures on earth?
Single-celled organisms, bacteria...algae
Which creature first born on Earth?
Single celled organisms were the first creatures.
What organisms first introduced oxygen into earth's atmosphere?
Colonies of algae-like single celled organisms called stromatolites
What is proharyotes?
Single celled organisms like a bacteria and are some of Earth's oldest life forms.
What type of organisms first appeared on earth?
Earth's first organisms were the Single- Celled organismsBacteriaFungiAnd Protozoa
What events occurred that allowed single - celled organisms to into more complex organisms at the end of the precambrian time?
the ozone layer began to develop shielding earth from ultraviolet rays, this was hypothesized that these changes allowed species of single celled organisms to evolve into more complexed organisms
What important role do unicellular organisms play in sustaining life on Earth?
Single celled lifeforms constitute most of the life on Earth. They are the majority of the producers in Earth's ecological system. They are major contributors to the processes that replenish our atmosphere, and form the basis of the marine food chain. On a smaller scale, single celled organisms perform equally important roles: they are a major part of the digestive system of most advanced animals. In humans, they are present in our intestines to aid in the breakdown of foodstuffs. Without them, we would not survive. Without single celled organisms, no life would be possible on Earth.
What event occurred that allowed single celled organisms to evolve into more complex organisms at the end of the Precambrian time?
the ozone layer began to develop shielding earth from ultraviolet rays, this was hypothesized that these changes allowed species of single celled organisms to evolve into more complexed organisms
What events occurred that allowed single celled organisms to evolve into more complex organisms at the end of the Precambrian time?
the ozone layer began to develop shielding earth from ultraviolet rays, this was hypothesized that these changes allowed species of single celled organisms to evolve into more complexed organisms
What event occurred that allowed single-celled organisms to evolve into more complex organisms at the end of the Precambrian time?
the ozone layer began to develop shielding earth from ultraviolet rays, this was hypothesized that these changes allowed species of single celled organisms to evolve into more complexed organisms
