Natural Selection?

Question

hey..
for a nat select question i got for an assessment i have to pick an example of natural selection.....
i was gonna use the peppered moth but my book isays it is well known but recently discredited
does that mean i shouldn't use it :S

Answer 1

Everything (in terms of life) you see around you is an example of natural selection! How on earth could the peppered moth be discredited?

Try viruses mutating to resist treatments. How about pests becoming resistant to insecticides? How about our problem with running out of effective antibiotics - this is why doctors will now usually prescribe carefully, rather than willy-nilly as they did years ago.?

Answer 2

A good example of natural selection, in an artificial environment, is the resistance of locusts to pesticides.

Each year, the locusts get harder to kill - larger doses of pesticide are required, eventually a new pesticide is developed and used, and the cycle begins again. This is because, when a pesticide is first used, it is highly effective, perhaps killing about 99.9% of all locusts. The 0.1% which survive will produce eggs for the next cycle. Some of the 0.1% survived because they did not get a dose of the poison, but many will survive because they are resistant, in various degrees, to the pesticide. This resistance may be passed on to the offspring. During the next cycle, the pesticide is sprayed again. This time, only 95% of locusts are killed, because of the higher level of resist locusts. These 5% go on to breed, and pass on the resistance, Next cycle, over 30% of locusts survive, so the pesticide strength is increased, and the survivors fall to less than 1% again. These are resistant to the higher dose of pesticide, and pass on this resistance to their offspring.

So, there is a cycle of increasing pesticide strength and increasing resistance. all due to natural selection, albeit in an artificially induced environment, ie pesticide.

Answer 3

You could use the emergence of antibiotic-resistance in bacteria, giving things like MRSA (Methicillin-Resistant Staphylococcus Aureus) and similar "superbugs":
http://en.wikipedia.org/wiki/MRSA

PS - the peppered moth wasn't discredited:
http://www.ncseweb.org/icons/icon6moths.html

Answer 4

how about the disappearance of excessive facial and body hairs of the prehistoric man to the modern man? "life finds a way" - from Jurassic Park film

Answer 5

I'm not sure why, but I smell a troll.