
Originally Posted by
brownprose
That's a very good question pien and is also the most common question that arise from the example.l
Germs/bacteria are commonly unicellular and their DNA are much exposed to mutagens. And they, in fact, "speciate" in a form of new strains. There is also solid evidence that bacteria can evolve into a new specie read this:
Bacteria make major evolutionary shift in the lab - life - 09 June 2008 - New Scientist
Unlike in unicellular organisms (as bacteria), multicellular organisms like animals and humans evolve at a slower rate simply because their DNA is buried under each cell's nucleus. But that's just one part of it pien as far as humans or higher organisms are concerned. As I have said evolution takes several other processes aside from exposure to mutagens. Adaptation Genetic drift > Gene flow > Mutation > Natural selection > Speciation. If you want to know more about their systematics I will explain it as simply as I can

kung ang human beings keeps on evolving, wala paman lagi ta mu evolve into something else hangtod karon nga millions of years naman unta ang niagi since pag emerge sa modern human. millions of years naman unta ang nilabay nganong hangtod karon human raman gihapon wala man mu evolve into another specie?
siguro lagi sa field of microbiology, pwede ma apply ang evolution PERO DILI SA TANANG LIVING ORGANISM. kay naay mga living organisms nga wala pa gihapon mu evolve hangtod karon millions of years naman unta ang nilabay.
Living Fossils
Since 1822 thousands of previously unknown animals have been found, many of which are known as "living fossils" - animals that once known only by its fossilized bones and presumed to have been extinct for millions of years and used as "proof" of evolution. But then, to the embarrassment of scientists, these animals were later found to be alive in remote parts of the world.
Charles Darwin, himself, coined this term. In the Origin of Species he called lungfish and other species whose form remained unchanged since its inception "anomalous forms" that "may almost be called living fossils."
Living fossils are living proof of the accuracy with which plants and animals reproduce themselves and the fact that many are not changing at all.
The Okapi was once thought to have been extinct until they were found still living. These animals were once used as evidence that the horse had evolved.
Living Coelacanths
The Australian and African lungfish are . . . living fossils. They all look "primitive" and have lobed fins. Obviously lungfish can't be our ancestors because they have remain unchanged, again for 400 million years [ET*]. Another animal, the horseshoe crab, would be a great candidate for our ancestor. It looks "primitive" and leaves the ocean to spawn on dry land. However, it, too, is a living fossil, appearing about 425 million years ago [ET*] in the Silurian period, and remaining unchanged.
Similarly, gars, sturgeons, bowfins, and paddlefish all look "primitive" but are living fossils. Yet they are doing nicely in today's environment.
IN 1994. in Wollemi National Park (in the Blue Mountains) the New South Wales National Parks and Wildlife Services found a pine tree once thought to be extinct. They are close relations to plants only found in the so called "Jurassic and Cretaceous" periods. (65-200 million years ago [ET*]). There are very few of these trees left in an isolated area.
The following aquatic animals alive today are also examples of creatures that have not evolved since their fossil ancestors:- lobsters, crayfish and rays (fossils found in Jurassic rock), lampshells, mussels oysters, thumb nail shells (fossils found in Carboniferous rock), sharks (fossilized teeth found in Devonian rock), mackerel, perch, herring, jelly fish, fogs, the nautilus etc.
Of the 12,000 fossilized insects the majority are similar to living types of insect found today.
The fossils of bees, ants, cicadas, beetles, termites or cockroaches, and other insects are always practically identical with (though often larger than) their modern descendants. The same applies to the arachnids and myriapods.
Other famous living fossils include the tuatara (supposedly extinct since the Cretaceous Period until found still living in New Zealand), the Lepidocaris crustacean (only found as fossils in Devonian rocks), the lingula brachiopod ("extinct" since the Ordovician), and even the trilobite (chief index fossil of the even more ancient Cambrian Period).
If all of these species have not evolved in 50 million [ET*], 100 million [ET*] or even 200 million [ET*] years, then why should we believe that they (or anything) have evolved? Some changes due to speciation have occurred, but not the large scale changes that evolution supposes.
The list goes on; example after example of no change from one type of animal to another in the fossil record. Darwin tried to cover over this embarrassment by saying the fossil record is incomplete, but it wasn't then and it's not now. What we know about living fossils, then and now, is a representative sample of the fossil record.
Living Fossils