Variation in biology

Just a quick post on my thoughts about evolution by natural selection……

I think evolution is an incredibly amazing idea courtesy of Charles Darwin and Alfred Russel Wallace, and makes our lives so incredibly fulfilled through the knowledge of how we got here.

My one confusion is how the variation occurs. I think it is kind of a paradox how one species, say a platypus, would always give birth to the same species, i.e. another platypus, and so then this species would give birth to another and another and another and so on. In this way an evolutionary chain is set up whereby all the generations should be the same species, but they aren’t, obviously since we have so many life forms from a single cell billions of years ago.

I find it hard to understand this, but I suppose if you think of it as gradual changes over a huge period of time, then the ‘species’ will change so much from its ancestors that it could not longer interbreed with them to create fertile offspring, if they were both alive at the same time.

Feel free to write your own comments about evolution, I would be very interested 🙂


2 thoughts on “Variation in biology

  1. The key to variation is mutation. For a whole host of reasons, the genes of a child can differ markedly from their parents’ genes. Sometimes these mutations are negligible. Sometimes they produce something not so subtle and grossly different. Eventually, as you said, gradualism comes into play. Minute changes in DNA wouldn’t immediately produce a new species…however, the accumulation of DNA mutations over a long period of time could produce a sufficient number or new or different genes to have created an entirely new species.

    • Thanks for the reply! I think I just need to make it clear in my mind that there is never a discrete change in species from generation to generation, only very gradual changes. I also think it would be good for me to understand what makes it impossible for two different species to produce fertile offspring (incompatibility of gametes?) This would probably also show me how it is possible to create hybrids and why there can be so much variation within a species, like how chihuahuas are so different to st bernards 🙂

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