Trillions, maybe Quadrillions of years ago. (old answer)
On our planet, life begain about 3.8 billion years ago. Heres a timeline
http://en.wikipedia.org/wiki/Timeline_of_evolution . And for the other, Inevitably I'm sure their are way more life forms than just on earth. So I cannot say other than that. :) (ask E.T.)lol
Life on Earth is estimated to have started around 3.5 to 3.8 billion years ago, with the first microorganisms appearing in the ancient oceans. This marks the beginning of the evolutionary journey that has led to the diverse array of life forms present on Earth today.
The first life on Earth were likely single-celled organisms such as bacteria and archaea that appeared around 3.5 billion years ago. The first plants appeared around 470 million years ago, while the first animals, such as simple sponges and jellyfish, emerged around 600 million years ago during the Ediacaran Period.
The first birds are thought to have appeared in the late Jurassic period, between 150 and 200 million years ago. Modern duck species have traits that are closer to some theropods (dinosaurs) than are most land-based birds.
Abundant fossil evidence first appeared in the geologic record during the Cambrian Period, around 541 million years ago. This period is known as the "Cambrian Explosion" because it marked a rapid diversification of marine life and the emergence of many major animal groups.
The plants from long ago are like animals of long ago in a couple of ways. Both have survived through time.
The Earth is about 4.5 billion years old. Life appeared on Earth about 3.5 billion years ago. The Earth would have been about 1 billion years old at that time.
The first life developed in the oceans. That was so long ago that it has not been possible to tell where or in which ocean.
According to the fossil record, multicellular life forms first appeared about 570 million years ago. This means multicellular organisms appeared almost 3 billion years after the first evidence of life.
Slightly more than 3000 million years ago, perhaps even as long as 3500 million years ago shortly after the earth's crust cooled just enough for bodies of liquid water to accumulate on its surface.
The Earth formed about 4.6 billion years ago, and the first life forms are believed to have appeared around 3.5 to 4 billion years ago. This means there was a period of roughly 500 million to 1 billion years between the formation of Earth and the emergence of life.
Life first appeared on land around 500 million years ago during the Ordovician Period. Plants and some arthropods were among the first organisms to colonize terrestrial habitats, followed by amphibians and eventually reptiles.
Scientific AnswerThe first bacterial life to appear on Earth was 3.46 billion years ago in the Precambian supereon. The first complex life appeared around 600 million years ago just preceding the Cambrian Explosion of life 530 million years ago.
Animal life first appeared in the oceans around 600 million years ago during the Ediacaran period.
It became like this from a long, long time ago. It started when humans first appeared on Earth. Like about millions of years ago.
There is evidence to suggest that life on Earth first appeared around 3.8 billion years ago. However, there likely were periods of time when life faced significant challenges, such as during mass extinction events like the Permian-Triassic extinction around 252 million years ago.
2years ago :)
It is generally believed that life first appeared sometime around 3.8 billion years ago. The first life forms were simple, single celled organisms with no nucleus. The first photosynthetic organisms were cyanobacteria, and the evolved about 3 billion years ago. Life first began a rapid amount of diversification during the Cambrian, a little more than 500 million years ago.