If all scientific knowledge were to suddenly disappear and we were to start from square one, it would all reappear exactly like it is.

Three competing theories of evolution arose, independently, in our world - one from British and European scientists studying the tropics, another from Russian and US scientists studying Siberia and northern North America, and a third by a Japanese scientist studying statistics and genetics. While the current consensus in evolutionary biology is that all three are true (at different timescales), the vast majority of people (and even other scientists) only know the first. This is partly because Darwin got there first, and partly because a lot of powerful people benefit from spreading social Darwinist woo.

Ironically, in a post-apocalyptic world, the powers that be would probably support the symbiotic theory, with Darwinism frowned upon as selfish individualism.

however the process of science will ensure that the truth comes to light eventually.

As Keynes said, in the long term we are all dead. Science is probably the best tool we currently have to find the truth (assuming there is a truth), but it is always important to remember that it is produced by humans, funded by interests and (mostly, though this is changing) published by for-profit journals. When reading a paper, always read the conflict of interest and funding details, and hope the authors are being honest.