Question

1.How did life first exist on earth ?
2.How long did it take ?
3.What led to evolution of different
types of organisms ?

Answer 1

1.Stromatolites, like those found in the World Heritage Area of Shark Bay,Western Australia, may contain cyanobacteria, which were most likely Earth's first photosynthetic organisms. The earliest evidence for life on Earth arises among the oldest rocks still preserved on the planet.

2.Earliest life forms. Fossil evidence informs most studies of the origin of life. The age of the Earth is about 4.54 billion years; the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago. There is evidence that life began much earlier.

3.Evolution is the process of change inall forms of life over generations, andevolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms' observable traits.