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Evolution, by definition, will never stop, so long as there is life. It is the way life works. It doesn't mean progress towards some arbitrary goal, such as int

Evolution, by definition, will never stop, so long as there is life. It is the way life works. It doesn't mean progress towards some arbitrary goal, such as intelligence or strength. It means fitness for the current environment. You might argue that the cockroach is one of the most successful products of evolution.

azakai 10y ago
Evolution in the sense that Darwin meant it - natural selection - does depend on some specific details of life. Namely, there must be variation in the species, the variation must be heritable, and there must be something that causes some of the species to produce more offspring. Without one of those, natural selection stops. In theory, life might exist without one of them - if we live forever and stop having children, or if we all have the same amount of children, or if we design our children's genes artificially, etc.
- svachalek 10y ago
  Who is "we"? All life on earth? Even "we" as humanity is a colony organism; we have more non-human cells in our bodies than human ones.
  - milkytron 10y ago
    Could you please elaborate on this part: > we have more non-human cells in our bodies than human ones. I'm not the most educated in biology, but I thought if a cell is created in our body by our body, it is a human cell. Is this wrong to think?
    - azakai 10y ago
      Depends what you mean by "created in our body by our body." Your body begins with a single human cell, then divides and grows. All those cells have your human DNA. But at some point bacterial cells also appear as part of your body, for example in your digestive tract, playing important roles you can't live without. Their source is not from your human cells, but they still form part of your body as a whole, in a sense.
    - taco_emoji 10y ago
      They're speaking of the multitudinous microorganisms which live in and on our bodies.
nogridbag 10y ago
The parent's question is pretty common and the answer given by scientists is always "Yes we're still evolving" but while it technically may be correct I think it gives people the wrong impression - like we could possibly grow a tail in 500-1000 years. I'm no expert by any means, but my understanding is that usually there needs to be some event that causes one species to diverge significantly. For example, if some percent of the population of some land dwelling animal becomes trapped on an island due to some geological activity, those that are better jumpers may be more fit for that new environment to survive like you stated (either to obtain food or avoid the common predators on that island). And thus over a period of hundreds or thousands of years in which they are separated on that island from the rest of their species, they will slowly evolve to be categorized as a new species. But I can't see humans evolving to become a vastly different looking species (which is the layman's definition of an "evolved" species) since we are now a global population and our physical abilities do not determine our fitness to survive unless there was some global killer such as climate change which significantly changes civilization as we know it (e.g. we go back to being hunter/gatherers).
- vidarh 10y ago
  It can be something relatively small. The trait for blond hair in Northern Europe dates back only ca. 11,000 years, and the benefit is unclear (it may be related to vitamin D). Keep in mind that it only needs to benefit survival a bit more than it hinders it. If it provides a big adantage, it will spread rapidly, but as long as it provides some advantage it stands a chance of surviving long enough to get a foothold and keep spreading. Even if it doesn't provide any advantage, as long as it doesn't have a negative effect it still has a shot at spreading if it just happens to occur in a population that's otherwise successful. > since we are now a global population and our physical abilities do not determine our fitness to survive Our fitness also involves our ability to select a mate and have offspring, not just physical survival. It could very well be that our ability to select a mate will over long enough time scales be affected by appearance and changing cultural factors.
  - Amezarak 10y ago
    As you allude later on, selection for environmental fitness is not the only form of selection. Blonde hair need not confer a survival advantage if at one point it conferred a reproductive advantage. That's sexual selection. In some cases, traits can be disadvantageous in terms of survival but immensely advantageous reproductively.

azakai 10y ago

Evolution in the sense that Darwin meant it - natural selection - does depend on some specific details of life. Namely, there must be variation in the species, the variation must be heritable, and there must be something that causes some of the species to produce more offspring. Without one of those, natural selection stops. In theory, life might exist without one of them - if we live forever and stop having children, or if we all have the same amount of children, or if we design our children's genes artificially, etc.

svachalek 10y ago
Who is "we"? All life on earth? Even "we" as humanity is a colony organism; we have more non-human cells in our bodies than human ones.
- milkytron 10y ago
  Could you please elaborate on this part: > we have more non-human cells in our bodies than human ones. I'm not the most educated in biology, but I thought if a cell is created in our body by our body, it is a human cell. Is this wrong to think?
  - azakai 10y ago
    Depends what you mean by "created in our body by our body." Your body begins with a single human cell, then divides and grows. All those cells have your human DNA. But at some point bacterial cells also appear as part of your body, for example in your digestive tract, playing important roles you can't live without. Their source is not from your human cells, but they still form part of your body as a whole, in a sense.
  - taco_emoji 10y ago
    They're speaking of the multitudinous microorganisms which live in and on our bodies.

nogridbag 10y ago

The parent's question is pretty common and the answer given by scientists is always "Yes we're still evolving" but while it technically may be correct I think it gives people the wrong impression - like we could possibly grow a tail in 500-1000 years. I'm no expert by any means, but my understanding is that usually there needs to be some event that causes one species to diverge significantly. For example, if some percent of the population of some land dwelling animal becomes trapped on an island due to some geological activity, those that are better jumpers may be more fit for that new environment to survive like you stated (either to obtain food or avoid the common predators on that island). And thus over a period of hundreds or thousands of years in which they are separated on that island from the rest of their species, they will slowly evolve to be categorized as a new species. But I can't see humans evolving to become a vastly different looking species (which is the layman's definition of an "evolved" species) since we are now a global population and our physical abilities do not determine our fitness to survive unless there was some global killer such as climate change which significantly changes civilization as we know it (e.g. we go back to being hunter/gatherers).

vidarh 10y ago
It can be something relatively small. The trait for blond hair in Northern Europe dates back only ca. 11,000 years, and the benefit is unclear (it may be related to vitamin D). Keep in mind that it only needs to benefit survival a bit more than it hinders it. If it provides a big adantage, it will spread rapidly, but as long as it provides some advantage it stands a chance of surviving long enough to get a foothold and keep spreading. Even if it doesn't provide any advantage, as long as it doesn't have a negative effect it still has a shot at spreading if it just happens to occur in a population that's otherwise successful. > since we are now a global population and our physical abilities do not determine our fitness to survive Our fitness also involves our ability to select a mate and have offspring, not just physical survival. It could very well be that our ability to select a mate will over long enough time scales be affected by appearance and changing cultural factors.
- Amezarak 10y ago
  As you allude later on, selection for environmental fitness is not the only form of selection. Blonde hair need not confer a survival advantage if at one point it conferred a reproductive advantage. That's sexual selection. In some cases, traits can be disadvantageous in terms of survival but immensely advantageous reproductively.