Orchidaceae

Figure from Darwin's Fertilisation of Orchids, showing the Coryanthus speciosa flower's structures

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Orchidaceae is the family of the orchids, a diverse group of flowering plants.

Orchids are among the original "complex contrivances" in biology that astounded naturalists. Their pollination mechanisms often involve Rube Goldberg-like complexity. As such, they are often used as examples of irreducible complexity (IC) by creationists. However, even Charles Darwin was well aware of orchid complexity and of the IC argument. The first book Darwin published after the On the Origin of Species (1859) was On the various contrivances by which British and foreign orchids are fertilised by insects(1862), also called Fertilization of Orchids.

Evolution

When?

Ramírez et al. (2007) hypothesized orchids must have evolved at least 15-20 million years ago, during the Miocene, based on the finding of amber containing an extinct species of stingless bee, Proplebeia dominicana, that was carrying pollen of a previously unknown orchid taxon.

Genetic sequencing indicates orchids may have arisen 76 to 84 million years ago, during the late Cretaceous.

And according to Chase et al. (2001), the biogeography and phylogenetic patterns of Orchidaceae show it may be up to ca. 100 million years old.

Contrivances

An Ophrys.

An Ophrys cf. serotina with a Eucera clypeata bee.

Many orchids produce pheromones to attract their insect prey partners, but several have evolved further, specialized features.

Lure

Most species of the genus Ophrys ("eyebrow") imitate the female form of their specific pollinator, usually a bee, or a wasp, sometimes a large fly, or a beetle. This visual lure is enhanced by the production of pheromones which mimic the female sex pheromones of that insect.

"Bucket"

The labella of Paphiopedilum species are modified into pouches. Flies or bees are lured into the pouch due to the bright colors of the flowers, try to land, fall into a fluid-filled bucket, and in the process of climbing out of the pouch, the hapless pollinator gets the flower's pollinium (pollen packet) glued to its abdomen (or elsewhere).

This "contrivance" is the most commonly cited as evidence for IC, since it's a multistep process.

"Catapults"

The bizarre Catasetum orchids produce either male or female flowers, depending on the individual. Male flowers have special triggers that literally flick away the pollinators they lure in the process of applying their pollinia. Darwin, himself, observed this spectacular process in C. saccatum, and was ridiculed by Thomas Huxley as a result due to the event's alleged preposterousness.

Length

Angraecum sesquipedale

The Star of Bethlehem Orchid of Madagascar, Angraecum sesquipedale, often called Darwin's orchid, has an 18-inch long nectar-spur emanating from its labellum. Knowing that sphinx moths (Sphingidae family) pollinate all of its relatives, Darwin predicted that there was a sphinx moth with an 18-inch long tongue that pollinates it. He wrote:

[I]n Madagascar there must be moths with probosces capable of extension to a length of between ten and eleven inches [25.4–27.9 centimeters].

Xanthopan morganii praedicta

While a candidate moth, the Madagascan sphinx moth Xanthopan morganii, had been catalogued from the Congo region of Africa in the 1830s, the Congo is a bit far from Madagascar and Darwin had no knowledge of it. In 1903, 20 after Darwin's death, a subspecies Xanthopan morganii praedicta (named praedicta in honor of Alfred Russel Wallace's prediction), which has an 20 centimeter-long tongue, was discovered, though said subspecies was ultimately determined to be identical to the mainland species. Paradoxically, this particular sphinx moth has never been observed feeding on the orchid in the wild. In 1992, observations were made of the moth feeding on the flower and transferring pollen from plant to plant with both videos and stills. This was observed in the wild and confirmed further with studies in captivity.

"Perfume"

Euglossine bees visiting the orchid Coryanthes speciosa

Male neotropical orchid bees (tribe Euglossini) collect specific aromatic chemicals (including methyl salicylate, eugenol, cineole, benzyl acetate, methyl benzoate, methyl cinnamate and skatole) from various orchid flowers in their special collection organs. The male bees derive no nutrition from these orchids, but instead use these collected scents to attract female orchid bees for mating. This collection of specific volatile chemicals is believed to be unique in the animal kingdom. One species of orchid bee, Eufriesia purpurata, was observed to actively collect large amounts of DDT from treated house walls in Brazil without suffering ill-effect.

On knowledge of this argument

Michael Ghiselin writes:

Darwin's next book, published in 1862, was entitled On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects, and on the Good Effects of Intercrossing. This was a deliberate attack on the argument from design, and indeed on the notion of purpose in the world in general. Even the title was ironic, for Paley had said that there can be no contrivance without a contriver. Darwin managed to achieve two major goals. He showed how complex and remarkably effective adaptations could in fact be built up by small steps through natural selection. And he turned the argument from design on its head: Nature produces what we might call contraptions rather than contrivances. In other words, natural selection predicts both adaptation and maladaptation. The latter makes no sense as a deduction from the creative action of an omniscient and omnipotent being. Carried to its logical conclusion, the argument from design gives rise to the argument from incompetent design, hence to an argument for atheism.

The Harvard botanist Asa Gray was one of Darwin's ablest supporters, but the book on orchids was a bit much for Gray's religious sensibilities. He devised a theory that John Dewey later called design on the installment plan: God works by natural selection but includes a dose of providence by guiding variation along definite lines. Darwin replied that a deity who did that would have to foresee everything in evolutionary history, leading to a very heterodox theology.

All this ought to be common knowledge, but it is not. Special creation — the watchmaker's work — was decisively refuted over a century ago, and evolution soon became as well-established as the circulation of the blood. But people keep reinventing the same old arguments, sometimes with minor variations. Richard Dawkins is no exception. He never mentions Darwin's book on orchids.

Orchids ... A Witness to the Creator

Geoff Chapman published said article in Answers in Genesis' Journal of Creation in 1996. It asserts that several aspects of certain Orchidaceae are evidence of irreducible complexity. It was wrong then and wronger now.

There is no evidence whatsoever that flowering plants evolved.

The article starts out with a grand statement that it never gets around to proving.

Charles Darwin himself once commented: 'Nothing is more extraordinary in the history of the vegetable kingdom, as it seems to me, than the apparently very sudden and abrupt development of the higher plants.'

What a lovely "quote" you have there.

The orchid family is one of the largest plant families, with about 30,000 species. Orchids come in many shapes and sizes, the best known probably being the insect–mimicking species. Many of these mimics have very ingenious ways of attracting pollinating insects, appealing to the senses of both sight and smell.

All of this is true, yet fails to prove creationism.

Can evolution explain the origin of these mechanisms?

Can it?

Contrivances

Darwin was fascinated by orchids; in his Origin of Species he mentioned the 'inexhaustible number of contrivances' by which orchids ensure their pollination, pointing out that these would have entailed changes in every part of the flower.

What a lovely "quote" you have there.

However, Darwin did not attempt to explain how natural selection could gradually produce flowers that resemble insects so perfectly that the insects themselves are fooled. He merely described these structures as 'the sum of many inherited changes', which is not an explanation, merely an opinion.

It's unfortunate that Chapman didn't notice that Darwin's entire Fertilization of Orchids covered the subject over a century prior.

Modern–day evolutionists have no convincing explanation, either, simply claiming that flowers and insects have evolved simultaneously to be complementary to each other.

It's unfortunate that Chapman also didn't notice any of the evolutionary literature on orchid evolution. It's important to note that, even though we have limited knowledge about orchids, this doesn't mean that God did it.

The late Gordon Rattray Taylor was an evolutionist, who, nonetheless, posed many difficult questions about the theory. Concerning orchids, he wrote: 'Many of the variations in the form of orchids can have little or no selective value; or, at least, one variant is not more advantageous than another.' He also wrote: 'The Lady's Slipper Orchid has an immensely complicated system of fertilization—and is on the verge of extinction.'

What lovely "quotes" you have there.

Intricate Design

The intricate design of many orchids belies the idea that they slowly evolved. Since the whole purpose of their sophisticated machinery is to ensure the continuation of the species through pollination, and since without pollination the species would become extinct, it follows that every part of this apparatus needed to be in place and working right from the start. If an orchid needed to look like a bee or other insect in order to attract a pollinator, then until it bore a significant resemblance the insect would not be interested.

Chapman argues that whatever mechanism an orchid grew must have worked the very first time, or else it would have died out. However, as Mark Isaak notes: Of course the mimicry did NOT have to work the first time. Many orchids attract pollinators by scent. If one of these had a variant which additionally attracted just a small number of pollinators by it [sic] appearance, that variant would survive more, and so would in time dominate that species of orchid. In future generations, variants which looked more and more like the female wasp (or whatever appearance was favored by selection) would likewise come to predominate. Before too long, you would see convincing wasp-mimic orchids. If this scenario is true, we should expect to see "transitional forms" of mimics which look somewhat like what they mimic but are not convincing. In fact, nature is rife with them.

Amazing Mechanism

One of the most amazing members of the orchid family is the Bucket Orchid, which comes in two species, Coryanthes speciosa and Stanhopea grandiflora. These orchids have an intricate mechanism by which bees are attracted, trapped, and then released. Bucket orchids are pollinated by the males of two species of bee—Euglossa meriana and Euglossa cordata—which themselves are specially designed for the task. Attracted in the first instance by the smell of nectar emanating from the orchid, the bee gathers from the surface of the flower a liquid which will make him attractive to female bees. These bees have collecting organs on their modified forelegs which pass the odour to pockets in the hind legs, from which it can be released to attract females for mating. The surface of the orchid is slimy, which causes the bee to slip and fall into the 'bucket' that contains a pool of liquid dripping from a gland above. The only way the bee can escape is through a tunnel, and there is a convenient step leading from the pool of liquid to the tunnel entrance. As the bee is about to escape from the tunnel, the walls of the tunnel contract, gripping the bee. The plant's mechanism then glues two pollen sacs to the bee's back, and after allowing time for the glue to dry, releases it. If the bee then flies to another bucket orchid, the same process will take place, except that this time, when the bee attempts to leave the tunnel, a hook in the roof of the tunnel removes the pollen sacs, and the fertilization process is completed!

Correct Sequence

The bucket orchid's mechanism involves at least five separate functions, which must work in the correct sequence—attracting the bee, causing it to fall into the bucket, the provision of the gland to keep the bucket 'topped up' with liquid, provision of a tunnel exit, and the devices for attachment and removal of the pollen sacs. If any part of the mechanism were missing, or incomplete, the plant could not be fertilized. The origin of the bucket orchid's wonderful and ingenious machinery is surely fatal to the theory of gradual evolution.

These flowers must have been created and designed to operate this way from the very beginning, and bear abundant witness to the design and power of God, the Creator.

Stephen Gould writes: Orchids manufacture their intricate devices from the common components of ordinary flowers, parts usually fitted for very different functions. If God had designed a beautiful machine to reflect his wisdom and power, surely he would not have used a collection of parts generally fashioned for other purposes. Orchids were not made by an ideal engineer; they are jury-rigged from a limited set of available components. Thus, they must have evolved from ordinary flowers. One example, as noted by Mark Isaak, is that on "orchids that provide a platform for pollinating insects to land on, the stem of the flower has a half twist to move the platform to the lower side of the flower."

Designed pollinators

1: Bees become attracted to the flower of the Coryanthes orchid. 2: The bee slips and falls into the ‘bucket’. 3: Because of the angle and slipperiness of the interior walls, the bee is forced to exit through the narrow ‘escape tunnel’, conveniently aided by a step and hairs suitably placed near the surface. As it does so, pollen sacs are glued to its back by the plant. The bee then visits another flower, and after the process is repeated again, the flower has a mechanism for removing the pollen from its back this time, completing fertilization.

This nicely describes the process of the bucket orchid's fertilization without explaining why it proves creationism true.

Further reading

Eucera taurica on a Ophrys xtardans. The yellow stalk on the bee's head is a pollinium that the orchid attached.

• Pijl, Leendert van der, an Dodson, Calaway H. (1966). Orchid flowers: their pollination and evolution. Coral Gables, Fla.: Published jointly by the Fairchild Tropical Garden and the University of Miami Press. pp. 1-214.
• Benzing, David H. (1987). "Major Patterns and Processes in Orchid Evolution: A Critical Synthesis." Orchid Biology: Reviews and Perspectives, Volume IV. Edited by Arditti, Joseph. Ithaca, N.Y.: Comstock Pub. Associates. pp. 33-77.
• Arditti, Joseph (1992). Fundamentals of orchid biology. New York : Wiley. pp. 103-134.
• Dawkins, Richard. River Out Of Eden. Phoenix, 1995. Ch 3 discusses the Orchid as an example of IC.

External links

• See the Wikipedia article on Orchidaceae.
• A video of a bee trying to mate with an orchid and getting pollinated as a result
• A lesson plan discussing Gould's famous essay on the Panda's Thumb, which also included an extensive discussion of orchid contrivances and Darwin's orchid book
• Orchid Hacks by Carl Zimmer. Zimmer describes orchids that mimic female wasps (to attract male wasps for pollination, of course, and a recent research paper in the Journal of Evolutionary Biology that figured out just how the orchid does it).
• The Panda's Thumb blogs Orchids
• Orchid Discussion Forum on orchid cultivation, pollination, flasking, and care
• Orchid Pollination by Michael Sones. October 2000. Popular summary of some of the diverse methods that orchids use to achieve cross-pollination.
• Greg Pryor discusses orchid pollination and the movie "Adaptation," a (sort-of) adaptation of the book "The Orchid Thief," which itself is based on orchids and orchid lovers, and the science of orchids.
• Pollinator attraction and mechanisms of chemical communication in sexually deceptive orchids
• Chemical Mimicry in Pollination