RNA and DNA are necessary for reproduction
False. Catalytic reactions reproduce by spreading to adjacent power sources, liposomes by growing larger and splitting, polypeptide micro-spheres by growing denser and budding. These processes are precursors to the elements of cell reproduction associated with enzymes, membranes, and genes respectively.
Working in conjunction (a polypeptide core in a lipid bubble containing catalysts and raw material) this pre-life can synthesize PNA chains which will mutate and interact with other chemicals in a variety of ways. The development of the ribosome is what leads to the predecessor of "life as we know it" known as the RNA world. Further transcription error by RNA in the presence of thymine produces DNA, a more stable compound for storage purposes, which allows the RNA to specialize in transcription and enzyme management.
These earliest life forms (archaea) require a radiant power source or simple sugars, they do not eat in a modern sense. Further mutations lead to true bacteria, which are not so dependent, as they can eat each other. This causes them to begin sharing genes laterally, as a bacteria which has been consumed is an infection and thus core material is accrued. This is a preliminary to what will become breeding/conjugation, in which organisms of the same species exchange genetic material; bacteria don't distinguish between species, whatever they eat they potentially gain genes from.
One of these co-infective bacteria, the ricketsia family, specializes in invading other organisms, developing methods for breaching the cell membrane and living on inside their host without lateral absorption. And one of these specialists, the proto-mitochondrion, works its way back down the chain and successfully infects a more sophisticated version of archaea, producing the ancestor of the earliest eukaryotes.
Bacteria and now protozoans have already developed in many cases into tissue-like cultures but because of lateral transfer there is no reason to expect the members of such a culture to be genetically identical. Then one group of eukaryotes develop, and share laterally and conjugationally, a series of homeotic genes which make it possible for individual cells to specialize. Organisms which are already differentiating via anterior asymmetry and external irregularities like flagella are thereby enabled to grow larger and fill more niches by using different cells for each separate function instead of confining it all to a single unit. Further tissues which develop after this point share the same genetic makeup, and lateral transfer begins to become less relevant, but never disappears.
Worms, grubs, fish, salamanders, lizards, shrews, lemurs, monkeys, apes, us.
Edited by Iblis, : jot and tittle
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