People often say, including those with extensive knowledge in biology, that a ce

Question

People often say, including those with extensive knowledge in biology, that a certain species of animal will evolve in one way or another:

1.From changing environments.

2.Mutations.

3.Possibly even genetic engineering from human animals.

My question lies in the fact that, aside from the latter option, why haven't any differences in animals'(except humans) markup, morphology, intelligence, DNA, behavior, or any habits changed over thousands or (possibly millions) of years?

A cockroach has had the same behavior it has today more than 10 million years ago, and there's been no advancements in the species in the slightest bit.

It makes you question evolution, because why don't other animals (like cockroaches) have any changes over 10+ million years, yet humans, like me and you somewhat, have, in a relative period of time similar to the linked geological period above, evolved from spear tossing hominids into someone brilliant enough to even ponder this question.

If modern humans are the result of mutations in genes, how come no one species over the course of hundreds of millions of years has been fit enough, or advanced mentally like we have, or even in any slightest bit?

Explanation / Answer

"How come most animals never seem to evolve over millenia?"

The word "seem" in your question should not be disregarded. You seem to assume that cockroaches (or most animals as you say) did not change much the last tens or hundreds thousands of years. But what do you know about that? Have you actually reviewed many research that estimate the rate of evolution of different randomly chosen lineages in the past 500,000 years? I think you assume that other species evolved slower than humans rather than know it. And you will certainly put much more importance to the evolution of the gene FoxP2 (involved in language) than to a gene allowing cockroaches to have better sense of smell. This is a bias view of what is a rate of evolution. It would be much wiser to consider a rate of evolution as something like the number of newly arising mutations that succeeded to get fixed in the population. See Haldane's rate of evolution and the Darwin unit. Please don't make the mistake to think that being smart (or complex) is some kind of goal of evolution and those that are not smart (or complex) are "less evolved" or that they evolved more slowly.

You also seem to want to point on evolution of DNA and evolution of habits. I guess you might be appreciative of the evolution of human knowledge and culture. But this is obviously something that does not have to do with genetic evolution but is rather a matter of cognitive capacity. You cannot compare change of culture and traditions of insects and humans as insects have mostly no traditions.

Now, this is obviously true that different lineages evolve at different rates. Many things influence this rates such as the population size, the mutation rate, the generation time, the selection pressure (which itself might depends on social structure or the rate of environmental change for example). In these terms I would rather believe of Homo sapiens as a lineage that should have a rather slow evolutionary rate.

Homo sapiens is quite a recent species. And speciation is often linked with phenotypic divergence, with niche competition and niche complementarity and therefore with a high rate of evolution. In these terms I would believe that humans is a lineage with high evolutionary rate.

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