is evolution continuous or disscontinuous process
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Let's start by defining terms. Evolution is nothing more than a shift in the frequency of a gene. There are several mechanisms that can drive evolution, and the conditions for a population at any given time can give you an approximation for how "fast" or "slow" evolution might be expected to change gene frequencies. Specifically, evolution is driven by natural selection, artificial selection, genetic drift, migration, and mutation.
Now, the human population is very large. We're over 7 billion individuals on the planet now. Trying to move the needle very much with a population of that size isn't likely to happen. Furthermore, we have very long lifespans with very small numbers of offspring. All of the mechanisms for evolution that I listed are able to operate more rapidly if you have a small population with short breeding cycles and lots of young to "experiment" with.
So, are humans changing? Not very much. But if the population crashes or if we send a small group of people to colonize Mars, then the opportunity exists for relatively rapid evolution.
Now, what changes will happen? Who knows?? And anyone who tries to tell you that they know how humans will evolve in the future is talking nonsense. The only way that we will potentially be able to make any predictions about future evolution is to gain significantly more control on genetic engineering, not to mention battling through the ethics of eugenics. If we leave it to nature, 5000 years won't change us much.
But let's run the clock back 5000 years. Lactose tolerance was relatively uncommon that long ago, but it has conferred significant survival advantages upon those who possess the trait. Another good example is the sickle cell trait. Most people have only heard of sickle cell as a disease, and actually that isn't a very fair representation. It turns out that it is an adaptation to malaria. People who receive one copy of the sickle cell gene from one of their parents have an innate resistance to the worst symptoms of malaria. However, people who receive two copies typically die at a young age.
Now, the human population is very large. We're over 7 billion individuals on the planet now. Trying to move the needle very much with a population of that size isn't likely to happen. Furthermore, we have very long lifespans with very small numbers of offspring. All of the mechanisms for evolution that I listed are able to operate more rapidly if you have a small population with short breeding cycles and lots of young to "experiment" with.
So, are humans changing? Not very much. But if the population crashes or if we send a small group of people to colonize Mars, then the opportunity exists for relatively rapid evolution.
Now, what changes will happen? Who knows?? And anyone who tries to tell you that they know how humans will evolve in the future is talking nonsense. The only way that we will potentially be able to make any predictions about future evolution is to gain significantly more control on genetic engineering, not to mention battling through the ethics of eugenics. If we leave it to nature, 5000 years won't change us much.
But let's run the clock back 5000 years. Lactose tolerance was relatively uncommon that long ago, but it has conferred significant survival advantages upon those who possess the trait. Another good example is the sickle cell trait. Most people have only heard of sickle cell as a disease, and actually that isn't a very fair representation. It turns out that it is an adaptation to malaria. People who receive one copy of the sickle cell gene from one of their parents have an innate resistance to the worst symptoms of malaria. However, people who receive two copies typically die at a young age.
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