Hows does evolution take place? I understand that its an accumulation of changes to adapt to an environment, but how does it change generation to generation? Is the set of traits that will be passed down to an offspring predetermined or does it change depending on how my environment is? Its seems too fascinating that my environment may change the set of dna that is passed down, or is that not the case?
In: Biology
Basically, every individual has slight genetical variation compared to its parents. One slight modification, mutation, can sometimes lead to a different caracteristic. Mutations can provide an advantage (e.g make you more robust), be neutral or be disadvantageous (e.g makes you genetically ill). Now the interesting part is that if one individual has a disadvantageous mutation, they will be less likely to transfer this mutation to offspring. Imagine a mutation that makes a rat flashy green : the poor rat will be easily seen and eaten by predation, thus he dies and its mutation as well. On the opposite, a mutation that makes the color of a rat change and that increases its ability to hide will makes it more likely that the rat survives, reproduces, and transmits its mutation. The non-mutant type, with time, would then disappear. This is natural selection. Other type of selection exist, like sexual selection.
The mutations that are transmitted depend of the environment in which they appear. But the mutations themselves do not depend of the environment.
Now you add different evolutive mechanisms like natural selection, you keep in mind that multiple mutations can be selected at the same time, and you remember that this process occurs over the course of hundreds of generations, and you understand how evolution works.
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