79 votes
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Do beneficial viruses exist? If so, what examples are there?

Do they exist? Yes What are they called? Marilyn Roossinck calls them viral mutualistic symbiotes. She has an excellent review here. What are some examples? My personal favorite is GB-Virus C, or ...
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77 votes

Why do some bad traits evolve, and good ones don't?

During the process of selection, individuals having disadvantageous traits are weeded out. If the selection pressure isn't strong enough then mildly disadvantageous traits will continue to persist in ...
47 votes
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How could a species be engineered to go extinct?

Short answer The article in particular that you reference is discussing the possibility of using a mechanism called gene drive. The concept of gene drive breaks the normal "rules" of inheritance and ...
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42 votes
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Is there a biological mechanism for evolution encoded into our DNA?

This entire answer will be long, so read the short part first, then read the rest if you (or anyone else) is curious. Citations are included in the long section. I can include additional citations in ...
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37 votes

Why do some bad traits evolve, and good ones don't?

There's always the most obvious: Evolution is chance. Some traits allow an individual to have a higher chance to produce offspring. That doesn't mean individuals with that trait have more offspring, ...
28 votes

Why are there species instead of a continuum of various animals?

Mathematician/computer programmer's answer here: There is a continuum of different animals — in fact it's pretty fair to say that every animal occupies a different place on this continuum. They're ...
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  • 378
25 votes

Do beneficial viruses exist? If so, what examples are there?

Another good virus would be a Bacteriophage, a virus that infects and kills illness-causing bacteria. From Wiki: A bacteriophage also known informally as a phage, is a virus that infects and ...
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  • 551
23 votes

Why do some bad traits evolve, and good ones don't?

Because evolution is an effect, not a cause. That is, there's no "God of Evolution" out there deciding that this or that trait would be beneficial to a species, and deciding to add it. Evolution ...
19 votes
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Why are there species instead of a continuum of various animals?

Short answer Why are there species rather than a long continuum? Three important reasons I could think of are sex, non-uniform adaptive landscape and ancestry. Long answer I am not sure I'll ...
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18 votes

Is Mutation Theory still "valid" for complex organisms?

Change in genetic variance From what I have been taught, Natural Selection (or even Artificial Selection) is great for panning favorable genes from a species and bringing them to the fore, however, ...
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18 votes

Do beneficial viruses exist? If so, what examples are there?

I would say that if any "good" viruses exist, they are already within us. Retrotransposons are genetic elements in our DNA that were likely ancient viruses and they move around from time to time ...
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18 votes

Do beneficial viruses exist? If so, what examples are there?

We have engineered a few good viruses to treat certain diseases Per my comment and response: The most current example (at this time and based on my recollection) is the virus we have engineered to ...
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16 votes
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The evolutionary process in bird wings, especially with regard to winglets

I looked up winglets so I had context for this answer. I'm interpreting winglets as the vertical tips at the end of airplane wings. If so, then you are correct. The spread primary feathers of soaring ...
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16 votes

Why do some bad traits evolve, and good ones don't?

Below are the reasons I can think of. The list is not exhaustive and there are some conceptual overlaps. The trait seems advantageous but it is not, maybe due to its effect on another component of ...
14 votes

Do beneficial viruses exist? If so, what examples are there?

Cowpox and smallpox viruses structurally similar, and catching one confers immunity to both by immune system response, but one was a deadly disease and the other almost harmless. Once this was ...
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14 votes
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What is the definition of "Natural Selection"?

Official definition Is there an official definition of natural selection that is adopted by biologists nowadays? and what is that definition exactly? I don't think there is such a concept as an "...
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13 votes
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How does Darwinian Evolution work?

I accidentally wrote a lot! I first discuss the term Darwinian evolution. I then describe the main evolutionary processes insisting on the two elements of interest in your question, that is mutations ...
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13 votes

What is the difference between the evolution of fins in whales and fish?

I agree with you that the question is ambiguous, and also that the most sensible answer would be C. However, one could make a more or less reasonable argument in favor of several other answers, too. ...
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12 votes

Why are there species instead of a continuum of various animals?

Nothing happens to them. Organisms exist. They breed with other organisms who are genetically compatible. We humans might try to categorize them according to certain traits, but our labels are just ...
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12 votes
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Where are the evolutionary "inbetweeners"?

More specifically, the lack of observable gradual change between species. Most significant phenotype differences occur over several thousand generations, which means several thousand years on up. ...
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12 votes

Is there a biological mechanism for evolution encoded into our DNA?

About your question This kind of very basic question has the drawback to need a very long answer. In consequence, your question might get some close vote. I'll do my best to help but you might want ...
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12 votes

Why do some bad traits evolve, and good ones don't?

Evolution occurs by a change in gene frequencies, with gene frequencies potentially affected by four mechanisms (mutation, migration, drift, and selection). The answer to the question Why does the ...
12 votes

Is Mutation Theory still "valid" for complex organisms?

You're right that the mutation must be in a germ cell in order to be passed on. Most errors are introduced during DNA replication (at a rate of around 10-10), which occurs a number of times between ...
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12 votes

Are there real world examples of one way isolation between two populations?

You might want to look for asymmetric dispersal. Asymmetric dispersal has been found in many freshwater fishes (such as bullhead; Junker 2012), freshwater mussel (Terui et al., 2014) and in marine ...
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11 votes

The evolutionary process in bird wings, especially with regard to winglets

The logical assertion "winglets have not happened in a long time, therefore they are not advantageous" is incorrect. It is possible for an advantageous trait not to evolve even when advantageous, if ...
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11 votes

What is meant by `individuals do not evolve, populations do`?

The statement individuals do not evolve, populations do is rooted in the (classical population genetic) definition of evolution. Here is this definition: ...
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10 votes

Why are there species instead of a continuum of various animals?

Typically when both new and old species still exist it is because evolution pushed the new one into a different habitat or role. As a hypothetical example reef fish vs. deep water fish and their ...
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10 votes
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Why has grey hair evolved?

Presumably this means that at least some grey haired humans have noticeable reproductive advantage, or maybe they had it in the recent past. No it doesn't. Natural selection is not that strong, ...
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  • 4,710
10 votes
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Why do many people seem to prefer unhealthy compared to healthy foods?

It's a very simple answer. "Unhealthy" foods, for example potato chips, sugary drinks, and other fatty, cheesy or sugary edible items, have only been around a few hundred (at most) years. In ...
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10 votes

Is hunting animals, crafting and attacking/defending from enemies intellectually equivalent to learning quantum physics?

Addressing some assumptions/presumptions apparently present in the question (this might be too long for a comment): First, natural selection has not stopped. The sexual selection might be more active ...
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