Why The Evolution Accelerates In Certain Periods? The Human Ability To Speak Is Theorized Happened Quickly?

Question

Why The Evolution Accelerates In Certain Periods? The Human Ability To Speak Is Theorized Happened Quickly?

Answer 1

I suppose that's because there were some events which caused strong need of learning some new skills e.g. if the weather is cold,the people need fire and etc.

Answer 2

Evolution is in part a random process and there is no reason to expect its speed to be constant. There can be a few reasons its rate appears to change:

We may be looking from a biased point of view. Evolution doesn't value complexity or sophistication, it values the ability to procreate. At times, existing lifeforms may be very well adapted to their environment, and the the best strategy may well be not to change. At other times, the best adaptations may be ones that, to us, appear slight.

Speech, for example, is an adaptation that has massive consequences. But it may, evolutionarily, be nearly invisible if you only see the last change. The steps that made speech possible don't seem very interesting, but then suddenly there's speech, and that seems like such a huge change.

Long periods may lay the groundwork for small changes that have huge effects. But those small changes could not have had those huge effects without that long period of gradual change. (An extreme form of this, where genetic changes accumulate with no apparent changes, is called 'evolutionary capacitance, which is controversial. But the more mild form, where physical changes accumulate is not.)

The rate of evolution, and the distinction between the apparent rate (how quickly we can tell that things have changed from the fossil record) and their actual rate of change (how quickly their genes change) are still active areas of research.

Answer 3

it can be speed up by their needs or essentials in life or by picking their mate. on the past our ancestors pick the smartest as a mate. so we evolved to be smart because smart + smart= genius.

Answer 4

Depends on the amount of selective pressure that is being applied, and how beneficial the prevailing trait is to the survival of the species.

Answer 5

Evolution is normally a gradual process, but when drastic changes occur in the environment, a species may face such drastic changes with their own.

An example would be during the industrial revolution, when smog was all over in, say, London.  Populations of moths in the immediate area were affected, as the dark moths were able to hide more easily in the soot-covered environment.  Over time, the populations became heavy on dark moths, as the light colored ones were more easily picked off by predators.

Over time, such drastic changes may cut off certain populations from others of their species...  and as time takes its course, new species may arise.  In the case of "Darwin's Finches," I believe that a number of different species of finches were discovered on different islands, all with a common relative.  In this case, they were geographically separated.  (Perhaps storms isolated these populations?)

Actually, in a pretty recent news article, it was stated that ancestral humans may have risked extinction at one point.  (Right before the stone age, I think?)  I wish I could find it again.

Hope this helped a bit :)

Answer 6

If, for some reason or another, lots of niches are vacant, relatively rapid bouts of evolution can allow those opportunities to be seized.  Lots of niches were open during the Cambrian 'explosion', for example, and again for placental mammals following the extinction(s) at the end of the Cretaceous; when the last non-birdy dinos seem to have gone into extinction.  Within only 300,000 years, placentals are known to have radiated riotously.

Usually, large numbers of niches aren't vacant.