The evolution of orchids

Nov 19, 2009 by Lin Edwards weblog
Angraecum sesquipedale ('Comet Orchid').

(PhysOrg.com) -- Charles Darwin and many other scientists have long been puzzled by the evolution of orchids, the largest and most diverse family of flowering plants on Earth. Now genetic sequencing is giving scientists insights into how these plants could evolve so quickly.

There are over 25,000 species of orchids, but few fossilized specimens have been found. A specimen preserved in amber alongside a bee was discovered in 2007 and dated to 100 million years ago, which means orchids were present at the same time as dinosaurs.

Orchids are pollinated by a greater variety of than any other family of plants. Petals of the fly orchid found in Britain resemble a female bee so strongly that males attempt to mate with the petal, pollinating the plant as they do so. An amazing orchid studied by Darwin, the Catasetum, actually fires "arrows" covered with pollen at insects brushing past the flower.

Another orchid studied by Darwin was the comet orchid of Madagasca, which had an elongated nectar tube. Darwin predicted its pollinator would be a moth with a tongue the same length as the tube. It was not until the BBC's The Private Life of Plants in the 1990s that the moth was found.

Even stranger is the fact that Madagascan comet orchids also exist on Reunion Island, some 480 km (300 miles) away, but the moth is not present on the island. Instead, these orchids are pollinated by the white-eye, a nocturnal bird. A closely related orchid was found by student Claire Micheneau of the Royal Botanic Gardens in Kew, London, to be the first example of a flower being pollinated by a cricket.

Researchers at Kew Gardens are trying to unravel the mystery of why and how orchids became so diverse. They have discovered that the plants have fused female and male parts, and they also have a special petal that is governed by different genes to those controlling the remaining petals. This genetic difference enables it to evolve differently to the remainder of the flower, producing structures such as the petal resembling the female bee.

The rapid evolution of so many species of orchids and other flowering plants may also lie in the fact that exhibit allopolyploidy or genetic redundancy, in which there is more than one gene to do a particular job. Professor Chase, the new Keeper at Jodrell Laboratory in Kew, explains that allopolyploidy means a gene can mutate and the duplicate will still be able to do the job. If the mutation is useful, the plant can evolve into a new species faster than other organisms could.

Professor Chase and his team have been studying the genetics of plants since the 1980s, spending the first 10 years gathering samples of the same gene in a collection of 500 different species, and analyzing the differences and similarities. Later on, as genetic sequencing techniques became easier, scientists were able to study a range of genes in plants, rather than just one.

Professor Chase's work on allopolyploids is concentrating on wild tobacco (Nicotiana) native to North and South America, and marsh and spotted (Dactylorhiza) many of which are native to the UK.

© 2009 PhysOrg.com

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mattytheory
Nov 19, 2009
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mabarker
1 / 5 (5) Nov 20, 2009
Is Mattyth being sarcasic? Regardless, it looks as though orchids have always been orchids - just as the creation model predicts. Orchids found in the Cretaceous - that's where we find other weird, *prehistoric plants* such as the oak, willow, magnolia, maple & palm. The floral big bang is as much of a mystery/embarrassment to the darwinists as the Cambrian b.b. (*Relationships among the 5 groups of extant seed plants [e.g., conifers & angiosperms] remain uncertain* - American J. of Botany, 2002). When darwinists try to paint an unscientific macroevolutionary scenario they encounter a brick wall. Just ask James A. Doyle of UC Davis. He said, for example, morphology indicates that the flowering plants and Gnetales are *related*, but detailed scenarios depend on uncertain relationships of fossils. As always, the molecular data deepens the darwinian mystery because it refuses to cooperate with the fossil evidence. Quoting mattytheorie - it truly must be the work of The Creator.
mattytheory
Nov 20, 2009
This comment has been removed by a moderator.
Ethelred
5 / 5 (2) Nov 23, 2009
Is Mattyth being sarcasic?
Is Mabarker being obtuse? It looks like orchids evolved a lot SINCE they evolved, like all flowers, from leafs
Regardless, it looks as though orchids have always been orchids - just as the creation model predicts.
No. Not predicts since it predicts that orchids have only been around for LESS than 10,000 years. Just a tad less than 100 million.
such as the oak, willow, magnolia, maple & palm.
All different then today and of course lots of extinct animals and plants. Long extinct. And of course a few mammals that are MUCH different than any existing today.[]qThe floral big bang is as much of a mystery/embarrassment to the darwinists Utter rubbish. Flowers are modified leaves. Early evolution in any new niche goes quickly.

Continued

Ethelred
Ethelred
5 / 5 (2) Nov 23, 2009
When darwinists try to paint an unscientific macroevolutionary scenario they encounter a brick wall.
Beyond obfuscation and entering the realm of pure fabrication. Macroevolution is seen often. Even today we can see species that fit even Mabarker's Brick Wall thinking. Want to talk about Flying Squirrels? Actually talk and not make one hit and run post and then pretend that I didn't blow out of the water.
*related*, but detailed scenarios depend on uncertain relationships of fossils
As yet Ma pretends that uncertainty about SOME things makes all the evidence against Creationism go away.

It doesn't.
As always, the molecular data deepens the darwinian mystery because it refuses to cooperate with the fossil evidence.
As always Mabarker makes up crap to avoid the truth.

Want to talk about early hominids and the genetic predictions?

Continued

Ethelred
Ethelred
5 / 5 (1) Nov 23, 2009
Or even Lucy, that ONE Creationist called an ape and another called a human. Clear evidence that she was transitional between the two.

Still don't want to show ANY evidence to support YOUR position I see. You can only point out what everyone in science already knows. We don't know everything.
it truly must be the work of The Creator.
A creator that perfectly created bad backs, poor eyesight, a panda with a makeshift thumb, hideous parasites, a coccyx made out of a tail bone, birds using wings for balance instead of flight, even people that use their brains to deny reality. A perfect brilliant creator. Not a sign of makeshift evolution ever. Or was that practically everywhere. Over billions of years.

Go on. Run away Mabarker. Just like always.

Show me a Creationist trying to prove the world is young and the Bible is correct. Which, if Creationists weren't lying about being scientists, they would be doing. Instead they stumble around trying to obfuscate reality.

Ethelred