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January 29, 2013

Twenty-five Questions Not Solved by Conventional Evolutionary Theory




1. In all Bilaterian species individ­ual specimens are very similar to one another; they all have the same complex vital organs arranged in a virtually uniform manner. Some species of nema­todes and rotifers even exhibit eutely: each specimen consists of the identical number of cells arranged in precisely the same pattern. Such strict unifor­mity of entire phenotypes is not found in other multi­cel­ls (plants, Porifera and cnid­arians). In those phyla, plasticity reigns. How could the same mecha­nism, natural selection, possibly explain the emergence of both strict pheno­typic uniformity and wide­spread pheno­typic plasticity?

2. In cell colonies (plants, cnidarians, and Porifera) the most complex and highly organized tissues are those directly involved in sexual reproduc­tion. Natural selection ex­plains sex-organ complexity: if those organs had not functioned with exquisite precision the lineages would have perished. But Bilaterian complexity is different. In those animals vital organs located throughout the body perform func­tions not di­rectly involved in sexual repro­duction. How can the identical mechanism -- natural selection -- logically ac­count both for the existence of complex vital organs in ani­mals and their absence in cell colonies?

3. Among cnidarians, large organisms are found in sunny habitats; in the genus Cyanea some jellyfish grow to two meters in diameter. All jellyfish are comparatively simple organ­isms. However, among the later­ally symmetrical animals the combination of large size and exposure to sunny habi­tat is found only in the most transformed lineages, the terrestrial vertebrates. These animals are extremely complex. There seem to be no large, relatively simple animals (as simple, say, as annelids) living in sunny habitats. Why not?
 
4. Based on the fossil record the earliest Bilaterians all avoid­ed exposure to sunlight. Somatic cells were not directly exposed until about 400 mil­lion years after those ani­mals first appeared, and then only in lineages that produced animals with adaptive immune systems. In fact, most extant Bilaterians avoid expo­sing unprotected cells that divide. On the other hand, plants, Porif­era and most cnida­ria­ns do not avoid sun­light; many spend all their days bask­ing in it. What is the evolu­tion­ari­ly plausible expla­nation for this fundamental differ­ence in the life histo­ries and observed characteristics of the two groups of multicells?

5. Jellyfish fossils found in 2007 in Utah are estimated to be more than 500 million years old. According to University of Kansas investigators the ancient jellyfish were phenotypically very similar to present day jellyfish. It seems that, compared to Bilaterians, there has been little organismic transforma­tion in the cnidarians (and in the Porifera). What is the mechanistic expla­nation for such (what some might call) unpunct­uat­ed equilibrium? 

6. The theoretical problem of senescence, contrary to the opinion of some, has not been solved. Most plants, unlike all Bilaterians, do not exhibit programmed aging. An exception is found in certain bamboo species where all the individual plants live for a fixed number of years before they flower and reproduce. Then all the individual plants die. This is true aging -- the pro­grammed cessa­tion of mitosis following a fixed time period.

But programmed death dependent on cues from the environment which is exhibited by most plants (think of annual plants dying in the fall) is not aging; bring the geraniums inside before frost and they will survive to spring. Perhaps some annual plants do not survive indoors but with few exceptions plants do not undergo the temporal-sensitive slowdown in cell renewal that is the hallmark of aging in Bilaterians. Studies of Porifera and cnidarians indicate that they too do not age. 

All Bilaterians age and investigators have actually identified (in some species) genes "for" senescence.

How could the identical mechanism -- classic Darwinian selection -- possibly account for both the presence of such a fundamental character in all the Bilaterians and its absence in virtually all other multi­cells?