Episode 17: Sickles and Hammers and Bears. OH MY!
In the news this week: the Indiana Star newspaper has some bad news for its christian readership, Oregon proves once again that it is totally awesome and Mississippi proves again that it is a sucking, black hole of iniquity. You will also totally not be shocked by the news that George Bush is STILL a retard and that religion makes crazy people even crazier. But, on the bright side, it looks like the Atheist Bus Campaign has taken over the UK entirely and we can soon look forward to a very pertinent ruling from the ASA on a hot-button topic we’re all interested in (and no, it’s not sex. Pervert.)
And for the second part of our discussion about crazed mass murderers, we turn to the red team and take a look at Stalin, Mao, Pol Pot, et al. Did atheism cause them to kill millions of people? Does atheism make anyone do anything? I am pretty sure it’s the reason that I have so many unpaid parking tickets. Will that fly in court, do you think?
Stream this episode!
Just wanted to point out that the reason that you look different from your parents is not because of mutations. Rather, it is because of the random segregation of chromosome, combined with random recombination within those chromosomes, both of which occurs during the creation of sperm and eggs. Neither are considered to be mutations, since no DNA-level changes occur (other than reshuffling), though it can result in mutations, for instance via a phenomena known as gene-conversion, whereby one allele (variant of a gene) is converted to the another. Secondly, a “scientific law” needs not be universal. See for instance the Mendelian laws of inheritance as one counter-example. In fact, laws tend to operate within very specific parameters, though many are considered to be universal. Also, the origin of DNA is still very much uncertain, though various hypotheses have been put forward (RNA-world being one of them). It is not even clear if RNA was the first medium of genetic information, with some facts speaking against that being the case, such as the low stability of RNA molecules, and others speaking for it, such as the catalytic properties of some RNA molecules.
Other than those points (which stood out because I happen to study biology), I just want to praise your podcast as being very enjoyable. Keep up the good work. Cheers!
Hey, thanks for pointing that out, It was my understanding that part of the reason sexual reproduction has been such a survival advantage is that chromosome segregation is an imperfect process and thus has an effect of not only preserving possible mutations from both parents but introducing new ones as well.
I will admit that this may not be why you “look different” it’s an exaggeration to drive home a point without genetic drift and mutation populations would be much more similar in appearance.
As to scientific laws, I do stand corrected (on multiple accounts), what makes a “law” in science seems more objective than I can handle.
Lastly, to the RNA/DNA question, there’s a lot of interesting research going on, and abiogenesis is still a relatively young field, in earlier shows I think i tried to be more clear of the uncertainties surrounding this work, apologies if I was sounding too certain. Work in this field is fascinating and we seem to see breakthroughs every month or so, an exciting time to be sure.
Thanks for sharing your corrections, while I spend a lot of time reading on a wide range of fields it’s always nice to have an expert in a single field come down and tell me what’s up. I also dig your handle.
Hey Eli.
Chromosome segregation is (obviously) not perfect, but failures (esp. among multi-cellular organisms) tend to result either in cell-death, a failure to complete the developmental process, or a reduced fitness (think Down’s syndrome, caused for instance by an extra copy of chromosome 21). Survivors tend to be infertile, or have reduced fertility.
There are exceptions, natural and induced chromosome doubling in plants being the most obvious example, something which can in fact result in more (agriculturally) useful plants. But plants are as far as I know the main exception. Thus, segregation tends to be a lesser source of mutations, while recombination can in fact induce a number of mutations, including inversions, duplications, translocations and deletions. Other are caused by the replication-machinery of the cell, etc.
You are partially right that mutations (inc. genetic drift) are the reasons why different populations look different, but not entirely. Keep in mind that even without these, you could still have radically different populations arising from the same stock, simply on account of changes in gene frequencies facillitated through segregation and recombination, via (natural) selection. And it would be a lot faster than only mutations and drift, which is probably the main advantage to sexual reproduction.
Ultimately mutations are what allow populations to continue to diverge indefintly (excluding HGT), but in the vast majority of cases these have only a very tiny effect on the appearance, relative to that caused by random recombination and segregation, when we compare child with parent in sexual organisms.
But don’t take what I say as “gospel truth”. I just study biology (at the bachelor level in fact, hope to finish it by summer) so I’m hardly an expert. I just have strong opinions. But thanks for the compliments. :)
Cheers.