Is there ? <a href=" http://www.kosovalindore.com/2011/08/13/tv-presheva-lajmet-e-dates-13-gusht-2011-lorenc-luka-ka-shprehur-vullnetin-e-mire-dhe-gadishmerine-per-bashkepunimin-e-ndersjelle-ne-mes-te-komunave-shkoder-presheve-ne-sh-f-9-maji-ne-leran/shkolla-fillore/ ">using viagra safe</a> Five hundred thirty million years ago, the number and diversity of life forms on Earth mushroomed. This so-called Cambrian explosion kept Charles Darwin, the father of evolution, awake at night, as he worried that his theory of natural selection couldn’t explain the sudden proliferation of species. Now, researchers have combined evidence from the fossil record with clues in the genes of living species to estimate the speed of that evolutionary explosion. Their finding—that the rate of change was high, but still plausible—may put Darwin’s fears to rest.