|Feature Article - March 2010|
|by Do-While Jones|
We continue to explore the problem that sexual reproduction poses for evolutionists, especially when it comes to flowers.
Last month we started looking at some of the problems that evolutionists have trying to explain the origin of sexual reproduction, but ran out of space before we could get to flowers.
The origin and rapid diversification of flowering plants has puzzled evolutionary biologists, dating back to Charles Darwin. 1
So, let’s continue from where we left off.
We ended last month’s essay addressing the issue of why asexual creatures would lose the ability to reproduce without a partner and become strictly sexual creatures.
Some evolutionists postulate that the first sexual creatures must have had the option to reproduce sexually or asexually. Then, at some point in their evolutionary history, sexual creatures lost the ability to reproduce asexually. What’s the advantage in that? Last month we saw that the best explanation the evolutionists could come up with was,
If sex started out as an optional way to reproduce, then a new question emerges: How did sex later become mandatory in many species, including our own? Hadany suspects that the answer has to do with sexiness—that is, with the preference sexually reproducing organisms often have to mate with some individuals over others. 2
No matter how enjoyable sex may be, it doesn’t really explain the advantage of losing the less exciting ability to reproduce without a partner if the need arises. Furthermore, the argument really doesn’t work for plants which, as far as we know, derive no pleasure from sex.
In a previous newsletter, we told you about a two-minute winning video by Stephen Anderson about evolution titled 120 Seconds. 3 In it, Anderson claimed that there are, “literally millions of separate facts from fields as diverse as paleontology, embryology, comparative anatomy, and genetics that support the theory.” That’s the propaganda that is taught in American public schools.
But if you read the peer-reviewed scientific literature, you find that simply isn’t true. Data from different scientific fields often don’t suggest the same evolutionary history. This is especially true when it comes to paleontology versus genetics. Species that appear to be closely related based on the physical appearance of their fossils often are declared not to be closely related by geneticists.
Before DNA analysis, paleontologists told one story about the origin of flowering plants. Now the geneticists are telling us a contradictory one.
Studies of fossil flowers showed that bisexual and unisexual flowers both occurred in the earliest fossil flower floras, so it was still possible that plants with unisexual flowers consisting of a single stamen or a single carpel (resembling extant Ceratophyllum or Hedyosmum) might reflect the ancestral angiosperm condition. Other analyses supported the directly opposite view: the overall organization of the bisexual angiosperm flower (flat structures surrounding male organs surrounding central female organs) had been inherited directly from gymnosperm ancestors. 4
Molecular phylogenetic analyses of seed plants now indicate that living gymnosperms are monophyletic, with Gnetales related to conifers, although this remains controversial. Palaeobotanists are increasingly willing to consider extant gymnosperm monophyly, but with varying levels of surprise and disquiet over the implications. In the two most recent morphological analyses, placing Gnetales with conifers made trees one step longer or forcing extant gymnosperm monophyly cost four additional steps, showing that the signal against extant gymnosperm monophyly is not especially strong. 5
These two quotes come from a geneticist, so he naturally takes the position that his interpretation of the DNA is right, and the paleontologists’ interpretations of the fossils are wrong.
When the fossils and DNA do agree, it is because the evolutionists have looked hard for ways to make them agree.
The 'anthophyte theory', the dominant concept of the 1980s and 1990s, has been eclipsed; Gnetales, previously thought to be closest to the angiosperms, are related instead to other extant gymnosperms, probably most closely to conifers. Finally, new theories of flower origins have been proposed based on gene function, duplication and loss, as well as on morphology. Further studies of genetic mechanisms that control reproductive development in seed plants provide a most promising avenue for further research, including tests of these recent theories. Identification of fossils with morphologies that convincingly place them close to angiosperms could still revolutionize understanding of angiosperm origins. 6
Let’s try to explain this in plain English. Before DNA analysis became common, there was a presumed evolutionary relationship between the various kinds of flowers and trees based on the paleontologists’ interpretations of fossil imprints of leaves and fossilized pollen. These interpretations were based on “morphology” (that is, their shapes). But when geneticists started studying the DNA of trees and flowers, they found that the DNA of “closely related” plants didn’t confirm the conclusions they reached using the old fossil data. Arguments ensued, and the geneticists won (at least, according to geneticists) causing paleontologists to suffer “surprise and disquiet over the implications.” But the geneticist says, the problem will be solved if the paleontologists can find some new fossils that agree with the geneticists’ new theory (or if the paleontologists can figure out a diplomatic way to reinterpret the fossil plants they have already discovered).
The reason why the genetic argument trumps the fossil argument is the radical difference in the complexity of plant reproduction at the genetic level. We will demonstrate how complex and confusing the genetic argument is by quoting a few paragraphs. We don’t really expect you to understand the argument. We merely want to impress upon you that it is a complex argument involving the number of cells and nuclei that isn’t completely understood, even by the experts. Don’t worry; there won’t be a test on this!
Until quite recently, Amborella and members of the Nymphaeales and Austrobaileyales were generally thought to exhibit a standard seven-celled, eight-nucleate Polygonum-type female gametophyte. However, earlier reports of Polygonum-type female gametophytes in Nymphaeales and Austrobaileyales have now been shown to be erroneous, as is also clearly the case for Amborella. Ironically, it is now evident that none of the most ancient lineages of flowering plants produces a seven-celled, eight-nucleate female gametophyte, a stark reminder that much remains to be discovered or correctly circumscribed for the earliest angiosperms. The mature female gametophytes of members of the Nymphaeales and Austrobaileyales contain four cells and four nuclei at maturity: a haploid uninucleate central cell, an egg cell and two synergids. The mature female gametophyte of Amborella contains eight cells and nine nuclei at maturity. 7
The issue of whether the eight-celled, nine-nucleate female gametophyte of Amborella represents an autapomorphy of the Amborella clade or is a plesiomorphic characteristic for all angiosperms cannot be resolved at this time. However, two (among several) evolutionary developmental explanations are particularly intriguing. One possibility is that the Amborella-type female gametophyte is peramorphic and derived from a late developmental modification of a standard Polygonum-type female gametophyte. As such, this would suggest that the Polygonum-type might be plesiomorphic for angiosperms, even though a seven-celled, eight-nucleate female gametophyte is not present in any of the most ancient extant lineages of flowering plants. According to this hypothesis, a terminal addition (a single cell division to create the egg and an additional synergid) to the ontogenetic sequence of the Polygonum-type would have led to the creation of the novel Amborella-type female gametophyte. Within the precepts of this hypothesis, the four-nucleate and four-celled female gametophytes of Nymphaeales and Austrobaileyales would be viewed as derived (and not plesiomorphic) within angiosperms, a conclusion at odds with that recently articulated by Williams and Friedman and Friedman and Williams.
Alternatively, the unique four-celled egg apparatus in Amborella could represent a critical link between angiosperms and gymnosperms. An important difference between female gametogenesis in gymnosperms and angiosperms relates to the fact that gymnosperms never directly form an egg cell; rather they form a mother cell ('central cell' sensu gymnosperms) within an archegonium that later divides to yield a ventral canal cell (or nucleus, if no cytokinesis occurs) and an egg cell. In all flowering plants, with the exception of Amborella, egg cells are always directly produced at the time of cellularization of the syncytial female gametophyte. One way to account for the four-celled egg apparatus in Amborella is that the mother cell that divides to give rise to the egg cell and third synergid is the homologue of the egg mother cell (central cell sensu gymnosperms) within the archegonium of a non-flowering seed plant. In this interpretation, the third synergid cell can be viewed as homologous to the ventral canal cell of a gymnosperm archegonium. Ultimately, if it can be shown that Amborella contains vestiges of the basic archegonium of non-flowering plants, this discovery will certainly rise to the standard of a 'missing link'. 8
We apologize for that long, boring quote; but the devils (evolutionists) made us do it! We can claim that the geneticists and paleontologists come to opposing opinions about the origin and relationships between flowering and non-flowering plants, but if we did nothing more than that, you would have to take our word for it. Ideally, you would read the peer-reviewed scientific literature and discover that for yourselves. But, since many people don’t have access to that literature, we have to give you samples so that you can read for yourselves what scientists really say to each other.
Flowering plants, or angiosperms, are thought to have originated in an environment where rapid reproduction was advantageous. Virtually all of their most defining features, including the flower, closed carpel, highly reduced male and female gametophytes, double fertilization, sexually formed polyploid endosperm, and an exceptionally short pollination-to-fertilization interval (progamic phase), are thought to have evolved under selection for a faster reproductive cycle. 9
Is rapid reproduction advantageous? You could argue that either way. Rapid reproduction is advantageous because it produces more offspring quicker. Clearly that’s a survival advantage—except when it isn’t. If a creature has too many offspring too soon, the parents won’t be able to take care of them, and all will die. How do you know which argument is correct? It’s simple. In all those creatures which have rapid reproduction, it is an evolutionary advantage. In all those creatures which have slow reproduction (elephants, etc.), it is an evolutionary advantage. Rapid reproduction rates and slow reproduction rates are both evidence that natural selection works!
Rapid reproduction is necessary for rapid evolution. That is, the more generations there are in a given period of time, the more opportunities there are for change. Evolutionists emphasize rapid reproduction because the earliest flowers are so different from each other. Let’s call it the Carnation Explosion—maybe the term will catch on.
Recent advances in angiosperm phylogeny reconstruction, palaeobotany and comparative organismic biology have provided the impetus for a major re-evaluation of the earliest phases of the diversification of flowering plants. We now know that within the first fifteen million years of angiosperm history, three major lineages of flowering plants—monocotyledons, eumagnoliids and eudicotyledons—were established, and that within this window of time, tremendous variation in vegetative and floral characteristics evolved. Here I report on a novel type of embryo sac (angiosperm female gametophyte or haploid egg-producing structure) in Amborella trichopoda, the sole member of the most ancient extant angiosperm lineage. This is the first new pattern of embryo sac structure to be discovered among angiosperms in well over half a century. This discovery also supports the emerging view that the earliest phases of angiosperm evolution were characterized by an extensive degree of developmental experimentation and structural lability, and may provide evidence of a critical link to the gymnospermous ancestors of flowering plants. 10
In other words, the fossils and genetics both agree that the “earliest flowers” are radically different. Therefore, there must have been a tremendous burst of evolution right at the start for so many different kinds of flowers to have come into being so quickly. There must have been a Carnation Explosion similar to the Cambrian Explosion (which supposedly caused so many diverse life forms to appear suddenly in the Cambrian rocks).
Another problem that plants have, when it comes to sex, is their lack of mobility. It’s hard to find a mate when you are rooted in one place. Remember, the primary advantage of sexual reproduction is that it allows the combination of genes from different individuals to produce variations which are better suited for survival in the current environment. Plants need to exchange pollen with other plants to achieve that benefit.
Some plants can self-pollinate, but what’s the advantage in that? Why break your own sex cells in half and separate them, just to put them back together again? Even those plants that self-pollinate have to find some way to move the pollen from the stamen to the ovule.
There are two methods of moving pollen—wind and insects. Wind just blows. It just blows the pollen anywhere and everywhere. It is very inefficient. But, since bees need flowers to survive, flowers presumably evolved before bees evolved, wind must have been the original pollinating method. Inefficient as it is, it must have been efficient enough, if plants truly evolved before insects evolved to pollinate them. If wind pollination was good enough, there wasn’t any need to evolve ways to attract insects.
Here’s where things get dicey for the evolutionists. They insist that evolution has no goal or purpose. It all happens by chance. Therefore, it is simply very good luck that flowers and insects coevolved in a way that helped each other. Clearly, flowers don’t make any conscious decisions to attract insects to help them propagate. Even if they could make a conscious decision to attract insects, flowers could not simply wish hard enough to make it happen.
So, evolutionists have to believe that it was simply by chance that flowers attract bees exactly the same way as women attract men (with food and fantasy); and sometimes they don’t deliver the goods.
Although most insect-pollinated plants pay their pollinators in energy-rich nectar, about a third of orchids offer no rewards. Roughly 10,000 species deceive their pollinators by mimicking plants that do provide nectar. And, unique among plants, another 400, including the early spider orchid, mimic females and promise their pollinators sex. 11
Hundreds of orchid species lure their pollinators with the promise of sex, only to send them away unfulfilled. 12
It was purely by luck that some flowers produce nectar, which is of no direct benefit to the flower itself, but is indirectly beneficial because the nectar attracts insects, which happened to evolve the sense of smell to detect the nectar, and happened to evolve the instinct to eat things that smell like that. Furthermore, insects also evolved sexual urges triggered by sight or smell, and some flowers happened to evolve in such a way that they looked (or smelled) like they were in heat (even though they weren’t). If that wasn’t lucky enough, some flowers evolved, purely by chance, to look or smell like flowers that produce nectar and some insects turned out to be stupid enough to fall for them.
It doesn’t make sense; but evolutionists are highly skilled at inventing fanciful stories to make the absurd seem plausible. Here’s how one evolutionist explains it.
At first glance, dishonesty seems to be a bad policy for orchids. Non-rewarding flowers have low pollination rates, and produce only half as much fruit as rewarding flowers. Add nectar to a non-rewarding plant and pollination rates shoot up. If reproductive success was measured by seed production alone, then deceptive orchids would have lost the evolutionary race long ago.
But deception may be worthwhile because it prevents inbreeding and so boosts the quality, rather than quantity, of seeds. Deceived pollinators are more likely to go off in a huff after realizing they've been tricked: they'll take their package of pollen and fly to a more distant patch of flowers, reducing the chance of landing on a close relative of the original plant. "To be deceptive means that the orchids have less sex, but the sex is better because it's not with a close relative," says Salvatore Cozzolino, an evolutionary biologist at the University of Naples in Italy. 13
Stop laughing. The story gets better!
And what of the insects in this web of deception? Both orchid and insect enter into the encounter in the hope of better sex — but only the flower comes away with it. This apparent inequality is such that Charles Darwin refused to believe that pollinators would waste their efforts on orchids that offer no reward. He expected the insects to figure out the ruse and save energy by avoiding the flowers and forcing the orchid into extinction.
But evolutionary biologists now know that young insects gain more by enthusiastic but indiscriminate mating than they would by being more choosy. Females are often in short supply and there is intense competition among males to find a mate — so it is better for males to try and fail than not to try at all. "The males aren't too picky," Peakall says, "Their strategy is 'Hey, I will go for anything that looks like a female because I can't afford not to'." 14
The origin of sex in general, and in flowers in particular, just doesn’t make sense from an evolutionary point of view. It never has, and never will, because sex didn’t originate by mutation and natural selection. But as long as evolutionists believe that it did, they will continue to waste valuable scientific resources trying to find an explanation that doesn’t exist.
Nearly 130 years after Darwin proclaimed the origin and early evolution of flowering plants an "abominable mystery" (Charles Darwin's letter to Joseph Dalton Hooker, 23 July 1879), reconstructing the biological features of the first angiosperms and linking them to non-flowering seed plant ancestors continue to challenge evolutionary biologists. Because flowering plants are distinguished from all other plants by diverse aspects of their reproductive biology, the importance of understanding the embryological features of early angiosperm lineages cannot be overstated. For more than a century, the presence of a highly reduced female gametophyte, within which a process of double fertilization initiates an embryo and a sexually formed embryo-nourishing tissue called endosperm, has been viewed as one of a suite of key characters integrally associated with the 'success' of angiosperms. Nevertheless, the origin and early evolutionary diversification of the angiosperm female gametophyte has remained enigmatic. 15
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Williams, PNAS, August 12, 2008, “Novelties of the flowering plant pollen tube underlie diversification of a key life history stage”, pp. 11259-63
2 Zimmer, Science, 5 June 2009, “Origins: On the Origin of Sexual Reproduction”, pp. 1254 - 1256
3 Disclosure, January 2010, “Evolution Video Finalists”, http://scienceagainstevolution.org/v14i4f.htm#120
4 Frohlich & Chase, Nature, 20 December 2007, “After a dozen years of progress the origin of angiosperms is still a great mystery”, pp. 1184-1189
7 Friedman, Nature,18 May 2006, “Embryological evidence for developmental lability during early angiosperm evolution”, pp. 337-340
9 Williams, PNAS, August 12, 2008, “Novelties of the flowering plant pollen tube underlie diversification of a key life history stage”, pp. 11259-63
10 Friedman, Nature,18 May 2006, “Embryological evidence for developmental lability during early angiosperm evolution”, pp. 337-340
11 Ledford, Nature, 22 February 2007, “Plant biology: The flower of seduction”, pp. 816-7
15 Friedman, Nature,18 May 2006, “Embryological evidence for developmental lability during early angiosperm evolution”, pp. 337-340