gogol

The emergence of the flowering plants is still something of a mystery. Darwin, in 1879, wrote his botanist friend Hooker that "the rapid development so far as we can judge of all the higher plants within recent geological time is an abominable mystery. I would like to see the whole problem solved." Seeds emerged as a further development of sporangia, for example, appearing within the cones of the conifers. Then seeds appeared within the flower. But where did the flowers come from? A possible candidate for the plesiomorph of flowering plants is a magnolia such as Magnolia soulangeana. As with all plesiomorphs, it shows a series of characters that are conservative and therefore representative of the ancestral condition, although a magnolia plant as a whole is not consistently a conservative plant. The actual ancestor of the flowering plant has not been found in the fossil record, and efforts are still being made to reconstruct it. In terms of the flower, which is the critical feature here, we see a structure still bearing parts highly suggestive of evolution from a twig.

A long fascinating story can be summarized by looking at some of the trends in floral evolution. This story tells us that flowers underwent an adaptive radiation and in some cases, reverted to pollination by wind, which probably occurred in the ancestral plants from which they somehow evolved. We say somehow because Darwin's "abominable mystery" is still with us. Statistical analyses, such as that by Kenneth Spome, of the University of Cambridge, England, can tellus that a plausible ancestor for the flowering plants is the curious group of plants known as the cycads. They are not conifers, but members of a group that seems to have had a parallel, but somewhat independent evolution. But that still begs the question of how they arose. That must be answered in selectionist terms. Something about the flowering plants gave them a survival advantage over other plants. A recent approach to this question is that of Philip Regal, of the University of Minnesota. He starts at an obvious point, i.e., the flower. This feature of these plants is obviously unique and neosernic, and it would not exist unless it had a selective advantage. Other angiosperm features can be found to one degree or another in other seed plants. These include broad leaves, substances that repel predators, and vessels instead of theA recent approach to this question is that of Philip Regal, of the University of Minnesota. He starts at an obvious point, i.e., the flower. This feature of these plants is obviously unique and neosernic, and it would not exist unless it had a selective advantage. Other angiosperm features can be found to one degree or another in other seed plants. These include broad leaves, substances that repel predators, and vessels instead of theregarding the evolution of the vascular plants. Quite clearly, Lignier is looking for aposemic changes connecting an aquatic green alga to a plant that is adaptive to the land.