Bio 103, Week 5, Diversity an Evolution

Although this whole new concepts on evolution are still battling in myhead, like many have mentioned, I can't imagine this world without humans.I can't agree with the idea that something else will come out, or evolvefrom us. It's easier for me to see the changes and adaptations in animalswith their environment and as mentioned in class the idea that there areinternal changes in species create environmental changes, which then causenew changes in the new species seems logical. Still, I can only apply thatto animals, like Darwin's finches. The whole idea of humans going extinctis not something that will convince me just because of what's happened inthe past with old species - even if it's 99% of them..., if that was thecase, then prokaryotic cells would not exist any more - since that's whatit all started with and created new cells. I can however think ofdifferent ways in which humans have adapted to different things, likelifestyles, different eras, etc. The idea of a physical change is notsomething that I take, even when argued that our brain has evolved,because I see that due to more discoveries leading to more intelligentobservations of things rather than smarter brains...

Friday's discussion was definitely overwhelming! I for one can't imagine a world where humans are not the dominant form of life. Of course, I won't necessarily have to face this issue in my lifetime, however it surely gives you something to thing about. On the other hand, theres that statistic that 99% of all organisms in the fossil record are now extinct. I'm still grappling with the idea that humans could one day be a minority, but it is STILL entirely possible that we could just become extinct. As a matter of fact, it's not just possible, it's likely when considering history and its patterns.

In a way, this statistic contradicts what we agreed to about evolution. We decided that "better" cannot really be used when comparing existing organims because just like we have been successful enough to thrive on Earth, so have bacteria and prokaryotes that exist today. For humans to become extinct like the majority of the fossil record's other organisms, something BETTER would have to come along that would prevent us from thriving. I hate to be arrogant, but can anyone think of anything better than us? Not smarter, not more efficient, not bigger, but better?

I thought that Friday’s discussion on evolution was very interesting. I have always found evolution to be a process that was very visible in animals but not much in humans. When the question of, how have humans evolved over the past 60,000 years was asked, it made me think. The class came up with answers like our skin color has changes and we have gotten taller. Then the question of what will happen to humans in the future was asked. This was very interesting because many people said we may be extinct. What would the world be like if there were no humans? What would replace us?

Like a few have already suggested, the idea of evolution is a very complex story but at the same time a good story.  It is interesting to think that simple organisms have evolved into more complex organisms.  The concept itself is fascinating because it is hard to grasp the idea that we are all different because we are a product of a system that produces with variation but at the same time it makes a great deal of sense!  Also, the idea that humans are only a step in the process of evolution and not the final result is scary but understandable because as history has proven, there are many organisms that have come into existence and then gone extinct.  It is all fascinating but rather mind-boggling at the same time!

i like the notion that evolution is a consequence of history 'cause that puts a time dimension to the change which doesn't simply equivocate "change" as necessarily being advancement, which is why there are still the simple living organisms like bacteria and complex living organisms like humans.

but what i don't get is how from simple living organisms...other more complex living organisms came about. are we all essentially related in a sense then?

In the book I am reading for this class, The red Queen, Sex and The Evolution of Human Nature, the author, Matt Ridley helps us understand the idea that asexual reproduction is more vunerable to losing its ability to contribute its specific genes when bad mutations are also apart of the organism.

First, we must understand Herman Muller's the "Muller ratchet", which can be explained like this:

There are ten water fleas in a tank, only one of which is entirely free of mutations; the others all ahve one or several minor defects. On average only five of the water fleas in each generation manage to breed before they are eaten by a fish. The defect-free flea has a one-in-two chance of not breeding. So does the flea with the most defects, of course, but there is a difference: Once the defect-free flea is dead, the only way for it to be re-created is for another mutation to correct the mutation in a flea with a defect- a very unlikely posibility. The one with two defect can be re-created easily by a single mutation in a water flea with one defect anywhere among its genes. In other words, the random loss of certain lines of descent will mean that the average number of defects gradually increases. Just as a ratchet turns easily one way but cannot turn back, so genetic defects inevitably accumulate. the only way to prevent the ratchet from turning is for the perfect flea to have sex and pass its defect-free genes to other fleas before it dies.

Muller's ratchet applies if you use a photocopier to make a copy of acopy of a copy of a document. With each successive copy the quality deteriorates. Only if you gaurd the unblemished original can you regenerate a clean copy. But suppose the original is stored with the copies in a file and more copies are made when there is only one left in the file. You are just as likely to send out the original as to send out a copy. Once the original is lost, the best copy you canmake is less good than it was before. But you can always make a worse copy just by copying the worst copy you have.

( Ridely, Matt 48)

just a thought:

if change over time accounts for clustered diversity and reproduction with variation accounts for individual variation, does random movement (of atoms) account for anything? i mean, after all, everything around us, including us, is made up of atoms.