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Comment by TehCorwiz | Hacker News Reader

Evolution IS selective breeding. The members of a species most fit for their environment are successful in procreation. The female elephants without tusks are surviving at higher rates which is resulting in more offspring with no tusks. This causes a shift in the population where a trait previously with no or little benefit becomes advantageous and the shift in genetic makeup of the whole population evolves.

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But we don't commonly run around saying Arabians and Morgans are different because of evolution. Neither do we say that chihuahua's and labradors have evolved into their present form.

In my humble opinion "evolution" refers to speciation, which takes very many generations.

We already have a term for speciation though. Evolution is more broad.

> Neither do we say that chihuahua's and labradors have evolved into their present form.

They 'evolved' into their present forms because they were forced/accelerated by the hand of humans through selective breeding.

The distinction between one species and another is pretty arbitrary in many cases. Exact species boundaries, or even the concept of "species" itself, are something humans determine, by convention. Evolution is something that happens regardless.

> Evolution is defined as the change in the inherited traits of a population of organisms through successive generations… When particular genetic sequences change in a population (e.g., via mutation) and these changes are inherited across successive generations, this is the stuff of evolution… One can distinguish between two general classes of evolutionary change: microevolution (change below the level of the species) and macroevolution (change above the level of the species)… These [micro-evolutionary] processes can, but do not necessarily, lead to the formation of new species over time but instead result in fluctuating frequencies of traits within populations tracking ever-changing selective pressures.

https://www.nature.com/scitable/knowledge/library/evolution-...

Thanks for the thoughtful response. Good link.

So in this case, evolution is the correct term. Microevolution is more correct.

Macroevolution is more correct when describing speciation.

It’s just selective evolution. We just use a different word for it to convey more information. It’s the same process though albeit randomly.

> Neither do we say that chihuahua's and labradors have evolved into their present form.

This is artificial selection. When it occurs naturally, it's called Natural selection & it's the basis of evolution. The mechanism of both artificial and natural selection is the same -- increase of a trait in the population by selecting only animals with that trait to reproduce. Speciation is merely a result of this process.

Btw the pulitzer winning book "The beak of the finch" discusses how evolution actually doesn't need many generations to happen. What it needs is selection pressure -- events (such as severe draught) that force natural selection to happen within a handful of generations. It's a fascinating book on a fascinating study.

Selective breeding is an important component of evolution. But evolution is certainly not just selective breeding. Population diversity whether it's through random chance, genetic drift, horizontal transfer etc. is also a key component of evolution. Equating evolution with just selective breeding is incorrect.

For what it's worth, he could have said "Selective breeding IS evolution" and his comment would read the same. The point is that selective breeding is a subset of evolution, so attempting to ask, "Isn't this just selective breeding?" would be answered with a, "No, because selective breeding is a subset of evolution."

"Is this a rectangle or just a square?" "A square IS a rectangle."

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