What is a species? it is described as a group of organisms that can only reproduce with itself. correct? Evolution is a process that has been described as taking millions of years- the evolution of a macroorganism takes too long to be noticeably to human observers. HOWEVER... we can look at microorganisms, such as bacteria. They are evolving before our eyes. Natural selection occurs everyday in these organisms. Look at antibiotic resistant strains! Genes for antibiotic resistance can be transferred from one bacterium to another (a process called transduction). Once a bacterium has acquired the genes for antibiotic resistance, it is no longer susceptible to being killed off by said antibiotic, nor are its daughter cells. Ever heard of MRSA or VRSA staphylococcus? These strains have acquired serious resistance and are virtually untreatable by conventional antibiotics. This phenomenon is pretty much explained by OUR overuse of antibiotics (remember, back in the day, they prescribed penicillin for everything). After some horizontal gene transfer, and killing off of susceptible organisms, resistant strains have emerged ('evolved', if you will

) Natural selection/evolution before your eyes, homeboy.
It is observable to us in these organisms because of their extremely small generation times. You also see this in mice that are resistant to pesticides, in weeds that are resistant to herbicides, etc. etc.... For larger, k-selected species (that take forever to establish a new generation), evolutionary change takes way too long for us to notice. Now that we have written history, lets see in a few thousand years (if we are still around) what kind of changes our species has made, and what characteristics we will have acquired. It should be interesting!!!
edit: You must spread some Reputation around before giving it to David88vert again.
Thank you for intelligent debate.