How did blindness evolve?

Blindness has evolved repeatedly across taxa in caves, creating nearly a thousand cave-dwelling species and many more sub-populations [1–4]. Thus, genetic drift has been proposed to accelerate the evolution of blindness due to mutation pressure [8–10].

Is evolution fixed in one direction?

Evolution is random but directed toward better adaptation. The direction of “better adaptation” is different for different species in different environments. There is no overall direction for evolution.

Can mutations be nonrandom?

Thus, although mutations are generally assumed to occur independently of their fitness effect, it is conceivable that local mutation rates themselves might evolve, resulting in genomes whose mutations occur non-randomly: more frequently where they are more often advantageous and less frequently where they are most …

Why did the cave fish evolved without eyesight?

The fact that cave fishes don’t use their eyes has no effect on their genes. Instead, cave fishes are blind because something happened to the genes that control the development of their eyes. This change is passed on from parent to offspring. That explains why a blind fish would have blind offspring.

How did blind cave fish evolve?

Evolution in cave A. mexicanus results in LOSS of sight (regressive evolution). Selective “pressures” directly force change in the species to occur. The lack of light forced the ancestral fish to lose their eyesight.

Why evolution is not progressive?

Evolution has nothing to do with progress. Because the evolution of a species is constrained by its history, there will be features that are themselves non-adaptive, but come about as side-effects of more important adaptive changes.

Is evolution progressive in nature?

These advertisements reflect the popular view of evolution as a progressive force that drives an inexorable improvement. But in reality, evolution is based largely on natural selection, a handy term for the interaction between the environment, mutation and superabundance.

Is evolution blind or random?

Evolution is often said to be “blind,” because there’s no outside force guiding natural selection. But changes in genetic material that occur at the molecular level are not entirely random, a new study suggests.

Why is evolution not random?

Evolution Is Not Random (At Least, Not Totally) But changes in genetic material that occur at the molecular level are not entirely random, a new study suggests. These mutations are guided by both the physical properties of the genetic code and the need to preserve the critical function of proteins, the researchers said.

Is the theory of evolution simple and plausible?

When presented in its true form, the theory of evolution is not only simple and plausible, but the only explanation of biological diversity that is scientific and consistent with the facts. Unfortunately, creationists work through the political process, not the scientific one.

What is evolutionary developmental biology (evo-devo)?

One extension, known as evolutionary developmental biology and informally called “evo-devo,” emphasises how changes between generations (evolution) acts on patterns of change within individual organisms ( development ).