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In its 4.6 billion yearscircling the sun, the Earth has harbored an increasing diversity of life forms:
- for the last 3.6 billion years, simple cells(prokaryotes);
- for the last 3.4 billion years, cyanobacteriaperformingphotosynthesis;
- for the last 2 billion years, complex cells(eukaryotes);
- for the last 1.2 billion years, eukaryotes which sexually reproduce
- for the last 1 billion years, multicellular life;
- for the last 600 million years, simple animals;
- for the last 550 million years, bilaterians, water life forms with a front and a back;
- for the last 500 million years, fish and proto-amphibians;
- for the last 475 million years, land plants;
- for the last 400 million years, insects and seeds;
- for the last 360 million years, amphibians;
- for the last 300 million years, reptiles;
- for the last 200 million years, mammals;
- for the last 150 million years, birds;
- for the last 130 million years, flowers;
- for the last 60 million years, the primates,
- for the last 20 million years, the family Hominidae(great apes);
- for the last 2.5 million years, the genus Homo (human predecessors);
- for the last 200,000 years, anatomically modern humans.
Periodic extinctions have temporarily reduced diversity, eliminating:
- 2.4 billion years ago, many obligate anaerobes, in the oxygen catastrophe;
- 252 million years ago, the trilobites, in the Permian-Triassic extinction event;
- 66 million years ago, the pterosaurs and nonavian dinosaurs, in the Cretaceous-Paleogene extinction event.
all dates are approximate
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∙ 9y ago
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Which forms of life on earth shows the greatest diversity?
Oceans
What is the oldest ecosystem?
There was no first ecosystem on Earth. There were just different ecosystems in different parts of the world.
What life forms are the simplest kind of life known on Earth?
Cells are the smallest form of life able to survive on their own.
What is brainstem?
The core of the brain - where the spinal cord attaches. Its also the thalamus - the oldest part of the brain (and the only part in old life forms like sharks).
What were the earliest life forms on the earth?
The earliest life forms were mostly different kind of bacteria and plants and other organisms.
What is proharyotes?
Single celled organisms like a bacteria and are some of Earth's oldest life forms.
What kingdoms contain the oldest forms of life on earth?
Domain Bacteria contain the oldest known fossils of cells in bacterial cells.
What type of sentence is The oldest fossils of any group of living things are simpler than the most recent fossils?
It is so because, the oldest fossils are obtained from the life forms which used to exist at that time in the oldest ages. At that time there was no so much changes in the world, the life forms being simpler. As the age of the earth advanced hence the forms of life also adapted or tried to adapt to the changes of the surrounding. The climate changed and so did the life forms. It was determined that in the older times, 1st life forms came in the water bodies and then from there the land forms developed. So as we see the later life forms are more complicated, thus the oldest fossils are more simpler compared to their most recent counterparts.
What are the oldest known forms of life?
Adam and Eve :)
What is the type of life consider the oldest in the world?
The oldest organisms in the world are still alive today. Their domain is called archaea. Archaebacteria were the very first life forms on Earth. They are single-celled and their cells have no nuclei. They reproduce asexually. Hope this helped!
What do the oldest fossil life forms resemble?
I'm not sure of the names, but sea animals. Like the underwater creatures before there were any dinosaurs roaming on Earth.
Oldest known forms of life?
SOMETHING haha i got you hehehahahoho
What is the planet with the most life forms?
Earth is the planet with the most life forms.
All life-forms on Earth are located in the .?
all life-forms are located in the biosphere
Why are scientists who are searching for life on other planets studying Archae bateria?
Archaebacteria are the oldest and most primitive forms of life on planet Earth. It is postulated that primitive life on other planets would be most likely to resemble Archaebacteria. In addition, Archaebacteria were the first life forms to exist on Earth, so studying them allows xenobiologists to postulate how life may come into being on other planets.
Would plants or animals have been the first forms of life on earth?
Unicellular plants and animals were first forms of life on Earth
Is there life in earth?
Answ2. Yes there are life forms in earth. worms, insects and bacteria. In the Antarctic, they have even found life-forms inside what appears to be solid rock.
