NEET BIOLOGY

Detailed explanation-1: -The first fossils of prokaryotic (bacterial) cells are known from 3.5 and 3.4 billion years ago. These bacteria were photosynthetic (although non-oxygen producing) so it is likely that simpler non-photosynthetic bacteria evolved prior to this (Schopf, 1987; Beukes, 2004).

Detailed explanation-2: -We now know that prokaryotes were likely the first forms of cellular life on Earth, and they existed for billions of years before plants and animals appeared. The Earth and its moon are dated at about 4.54 billion years in age.

Detailed explanation-3: -The first cells were most likely primitive prokaryotic-like cells, even more simplistic than these E. coli bacteria. The first cells were probably no more than organic compounds, such as a simplistic RNA, surrounded by a membrane.

Detailed explanation-4: -The eukaryotes developed at least 2.7 billion years ago, following some 1 to 1.5 billion years of prokaryotic evolution.

Detailed explanation-5: -Prokaryotic cells would have evolved first. These are much more primitive cells that would be much more likely to form spontaneously. A single cell was likely to give rise to all other life and arose in a primordial soup of organic compounds near a heat source.