Question

In Darwinian evolution, which do you think appeared first - the Host or the virus?
Explain your answer in depth.

Answer 1

As per the Darwins theory first evolved organisms are simplest forms of life. The simple organisms gave rise to more complex forms of life. There are number of evidences to prove that the life evolved in to complex forms by the process of natural selection and evolution. Paleontological evidences when the earth is escavated proves the fact that the simplest unicellular organisms are the ones which evolved first. Gradually multicellular forms and more and more complex multicellular forms have evolved. HUmans are the most recent and highly evolved organisms present ont he earth. The whole process of evolution is led by natural selection if Darwinian theory is only considered.

So in that sense Virus must have evolved first since it is the organism which most simplest and is intermediate between living and non living. So it links the living system to the non-living world by being intermediate between the two.

But to accept this theory of virus evolving first, there are some questions that arise. Viruses can't reproduce outside the host cells. Viruses do not have any cellular machinery other than the genetic material (DNA/RNA) and a protein coat. It replicates only when it enters in to the living cell which can be a plant cell, animal cell or a fungal cell. Virus hijacks the cellular machinery form the host and makes its own proteins and vial particles to increase their numbers. Once the numbers increase in the host cell, they break open the host cell to come out and infect more host cells. So without the host viruses can't reproduce and increase their numbers. If the viruses can't reproduce they can't continue as a group or they will be extinct.

So, if we study the life cycle of the virus, it appears to be highly unlikely that the viruses may have evolved first.

DEfinitely the host has evolved first as there is no way that the viruses could have replicated without the presence of the host.