I remember my father running the statistics for any humans evolving from any thing mentioned. It was so obscure and miniscule it was an impossibility.
Aha, this is an example of the Texas Sharpshooter fallacy:
http://wiki.cotch.net/index.php/Texas_Sharpshooter_Fallacy
Let me give a simple example. Let's say a 32-year-old woman mother of 3 who works as an 8th grade teacher of mathematics and is married to 40-year-old civil engineer from Florida won the California lottery. Now, let's also say that the odds of winning the lottery is 1 in 18 million. It was extraordinarily unlikely that she would win the lottery; the odds of dying by being struck by lightning is only 1 in 30,000. But now let's say, what were the odds that the person who won the lottery would be not just a purchaser of a ticket (since the 1 in 18 million odds apply equally to all lottery ticket buyers), but would also be (1) a woman (as opposed to being a man), (2) a mother with (3) 3 children who (4) happens to work as a teacher of (5) mathematics (as opposed to some other subject) to (6) 8th graders (as opposed to some other grade level), who (7) happens to be married (as opposed to being divorced, widowed, or a single parent) to (8) a Floridian who (9) works as a civil engineer, and that (10) the winner would be 32 years old while her (11) husband is 40 years old? The odds that the lottery winner would end up fulfilling all these criteria would assuredly be impossibly infinitisimal. And yet she won the lottery. It wasn't impossible that she won the lottery, for there has to be a winner each time. Rather, those criteria played no role in selecting her as the winner. It wasn't as if the lottery balls seeked out a winner with those criteria. It could have been anyone, but it had to end up being someone who has their own unique combination of what could be regarded after the fact to be dozens or even hundreds or thousands of personal criteria. With this fallacy, you could basically claim that it is impossible for anything to happen to anyone.
Like chance phenomena such as the lottery, evolution is not driven towards a goal of producing a specific result in advance. It is guided towards some result by selective factors (and thus is not purely random), just as the lottery will result in a winner each time. But it is a mistake to calcaulate the odds "for humans evolving" (e.g. presuming the result) and then conclude that those are impossible odds for the event happening. To give another example, let's say a psychic is asked to guess exactly where you will be at 10:42:09am on September 22, 2007, e.g. exact geographical position in terms of millimeters and the exact position and stance of the body. Now, for a person to calculate that a year in advance would certainly be impossible odds (unless he or she kidnaps you or manipulates you to make it happen). But assuming that you are still alive and well in a year's time, it is 100% certain you will be somewhere at that moment in time. And wherever you end up being at 10:42:09am on that day, the odds would have been impossibly small that you would be there at that time.