|MadSci Network: Anatomy|
You were confused with good reason - this is what would be called an "ill- posed question." "The most complex" doesn't really mean anything unless you focus it down quite a bit, so I will try and answer this on several levels. If you mean at a genetic level, the answer is clearly no. The genome of an organism consists of the complete DNA sequence, including coding and non-coding genes. Of the number of animals for which is there is good genome data (about 3800 so far), the smallest known genome is about 39 million base pairs (Mb) in Trichoplax adhaerens, a placozoan. Placozoans are very tiny organisms whith only about 20-30 cells. On the other hand, the largest genome is not in an elephant or a whale or a human, but rather in Protopterus aethiopicus, the marbled lungfish (about 130,340 Mb). Mice and humans come in at quite a modest 3000 Mb. A good place to look at this information can be found here: http://www.genomesize.com/summary.htm or here http://www.web-books.com/MoBio/Free/Ch3H.htm If the question meant complexity in terms of physiology, the answer is definitely no. Humans are bipedal primates, adapted for complex manual manipulation and flexible mental and time-binding capacities in a terrestrial environment. While we adapt well to most environments on earth, this is largely because of our cognitive and manipulative abilities, not physiological complexities. You could easily argue that newts, who can adapt their basic physiology to living underwater as well as on land, or cichlid fish that can change their sex when gender differentials become a problem, are more complex. We share most of our basic biological systems with just about every other vertebrate on the planet - each species "tweaks their setup" to be only as complex as they need to be to cope with and take advantage of environmental niches. The only manner in which humans might be considered to be the most "complex" organisms on the planet is in mental cognition and neocortical complexity, and even here it's contentious. Humans do not have the biggest brains on the planet - our brains are about 1.4 kg (3.08 pounds). That honor goes to the Sperm Whale (physter catadon) at 7.8 kg (17 lbs 3 oz). However, whale brains have less neocortex and seem to be laid out on a simpler, less densely interconnected plan. So it's not just size, it's also brain/body ratios, number of layers of cells, number of interneuronal synapses, organization, and a very large host of other factors. Humans do not always come out on top with these types of comparisons (in several elephants and orcas come out way ahead). A good basic web site on this is here: http://serendip.brynmawr.edu/bb/kinser/Home1.html An excellent site comparing mammalian brain neuroanatomy can be found here: http://brainmuseum.org/ Humans also are not the only (or sometimes even the best) problem solvers. Chimps and dolphins use tools, dogs and primates have been shown to be able to lie (a very cognitively complex function, meaning they understand truth and how to manipulate it to get what they want) and african gray parrots show a remarkable ability at language use. All in all, to answer this question you are going to have to reask it in different ways (which is always a valid method of response). Just point out that complexity is a relative and often meaningless term if you don't also ask "complexity of what?" Hope this helps.
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