Orchidaceae



is the family of the orchids, a diverse group of.

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.

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
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
The Star of Bethlehem Orchid of Madagascar,  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:

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"
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:

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.