One theory about the rise of intelligence in humans specifically is a sexual selection effect, where mates were preferred over others who were able to exhibit some as yet undetermined intelligent action. Art has been proposed to be a mechanism, or perhaps an bility to make better tools. Sexual selection is a funny thing and produces outlandish, counter-intuitive adaptations. It could be that humans represent a line of apes who were consistantly selected for intelligence by this method, though it's almost certainly not that simple.

But like Brent said, intelligence comes at a metabolic cost. In humans it's not just brain size and length of maturation that are problems, but earlier births and increased post natal parental investment also place significant limitations on breeding. The same can be said of any organism, especially ones where the young are essentially left to fend for themselves and who therefore have greater benefit from "hard wired" behaviours rather then intelligently discovered behaviours.

I can't say for sure about paper wasps, but with hymenoptera in general with the destruction of the nest most if not all of the workers will die. If the queen survives, she might establish a new nest elswhere.

In so far as the pollinating, paper wasps probably won't contribute much as they are primarily predatory, though do feed on nector occasionally. There are quite a few other invertebrates which perform pollination services, like beetles and moths, even if you don't see them.

Secondary sexual charateristics like antlers are somtimes found on both sexes, though often in a reduced form. Think about nipples on males. The female antlers are usually very small and not actually useful for much.

The wikipedia page on deer was enlightening.

I'm not sure, but my gut feeling is no. The acetate buffer I use is at pH 4.8, which I don't think is low enough to cause any actual damage to the DNA, on purely pH grounds. Having said that, at sufficient concetration the acetate might start doing nasty things directly to the DNA by electrophilic attack. Any chemists out there able to expand on that?

(posted in Evolution)

The uncatagorical "No" is spot on. Coming from the other direction, there are many complex things that aren't alive or aware. Think of a crystal, or a star.

I can't add much more then the posts above, but I can say that I agree. Evolution is a unifying theory of biology; you could say THE unifying thoery. The theoretical framework provided by evolution is absolutely essential for understanding and investigating virtually all aspect of biology.


Nucleic acids emerged as the dominant medium for heredity probably because it was one of the first, but also because they performed best under all of the conditions tested: it's chemically very stable, has convenient hydrogen bond sites that enable replication and perhaps most importantly, it can be built very easily from the abundant materials available. I have no doubt that given different conditions, say lower temperature or different dominant solvent (ie something other then water), another set of molecules could fill the same role.

If you wanted to look for life, limting to looking for specific terrestrial chemicals seems a little short-sighted.

(posted in Mammals)

I've been trying to encourage my cat to catch the mice around my compost bin, but he occasionally brings down a bird as well. I've never had any luck with the bells on his collar, he just learns how to walk silently! I'm told you need at least two bells to be effective.

Cats are indeed ambush predators; remember those Nature Docos with lions stalking the zebra? Leopards are so ambush-oriented that when a spotted by a troupe of monkeys, the whole lot of them will come and watch, never letting it get close enough to make a kill, until it goes away again.

I've seen my cat leap out of a tree above my lawn into the middle of a flock of sparrows. Must have been 2 metres, but he got one. I rescued it:)

(posted in Evolution)

That depends on your definition of conciousness. If you mean simply awareness, all life is aware to a greater or lesser degree, it's one of the definitions of life.

I suspect you mean human-style self-awareness and it's tough to draw a line. There isn't really a concensus as to what to even look for. What we can see is evidence of human-like self-awareness in some apes and dolphins, and problem-solving intelligence in birds, monkeys and other mammals.

Mu guess woul be that one MUST include the non-coding regions in any such calculation. The regulation of genes is at least as important as the gene products themselve in developing one organism over another and the non-coding regions are where the regulation elements are found.

I'm not sure, but I think that apart from the chromosomal fusion in humans reducing the number of chromosomes, most of the sequence changes between chimps and humans are in the non-coding regions. Development of an adult organism requires synchronised regulation across the genome, which is where I would bet the critical factor lies for successful growth of a hypothetical hybrid, assuming that all the other barriers are passed or circumvented.

Horses and donkeys must have similar enough regulation networks to produce an adult animal, but obviously chromosome number differences prevent gamete production.

That is a very big question. Determining the function of a protein is not a trivial matter, as the full spectrum of possibilities precludes meaningful screening. Generally the first step is to look at homologous proteins based on sequence and their annotation. Sometimes this provides good clues, sometimes te 3D structure does better.

Assuming that you were able to prove a particular biochemical activity, it's another matter entirely, and an order of magnitude more difficult, to determine biological function.

You could argue that some pathogens promote their spread by causing physical reactions, like vomiting. Look at the life-cycle of the typhoid organism, which causes massive diarrhea containing millions of infectious cells. The rabies virus causes increased saliva production and agression which increases transmission.

Some common pathogens produce immune system toxins. Strains of Staphylococcus and Streptococcus are known to produce toxic protiens which induce wild, undirected immune responses, simlar to anaphilactic shock, called toxic shock syndrome. Other strains produce related proteins which have a similar action, but less acute. This family is called superantigens. The theory goes that if the invading bug can distract the immune system from it's proper job, it can do better.

The pathogens which cause gangrene isolate the infected tissues from general circulation by killing surrounding blood vessels.

Other pathogens completely change the behaviour of their host. Look up some baculovirus literature, and check out the co-opted virus used by parasitic wasps.

http://sciencefictionbiology.blogspot.c … avior.html … r-dna.html … anguage/nl

Hi guys,

We have a selection of antibodies in our bodies that are generated just as Adam described, about 100,000,000 of them. When you get an infection, most of those randomly generated antibodies won't bind at all, while some will bind poorly. While you are fighting off the infection, the cells producing the poorly binding antibodies will go through another round of randomisation, producing a second generation of antibodies which bind much better. This process is called "affinity maturation" and generates "memory" of the infection, enabling you to fight the same infection much better if you happen to catch it again.

The wikipedia article on antibody recombination is a little technical, but there are some cool pictures:)

This is a very active area of research and realistically not a great deal is known for certain. We can only speculate on conditions thought to prevail on early earth and any inferences on the origin of nucleic acid genomes are based on those speculations. My favourite hypothesis is the RNA world, where RNA formed both the genome and the catalytic agent, called an aptamer or Ribozyme. It is thought that DNA came along later.