Chinese biologists have made the first discovery of a plant that pollinates itself. Holcoglossum amesianum, a tree-dwelling orchid, works against gravity to place pollen from its male appendage (the anther) to the female cavity (stigma). Most flowers depend on natural forces (wind, gravity) or insects for pollination.
K.W. Liu et al. 2006. Pollination: Self-fertilization strategy in an orchid. Nature 441: 945-946.
Just got back from a trip to the Florida Keys; I hope to post something about that soon. In the mean time, heres a short essay I wrote for my class, where we have been discussing the evolution of sex and reproductive modes. I was examing a population of dandelions found in Europe. You might think them a dry subject, but they are really fascinating if you investigate a little.
The common dandelion (Taraxacum officinale) are found throughout western
and central Europe (Verduijn et al. 2004; Meirmans et al. 2003; Van Der
Hulst et al. 2000). Sexual reproducing diploid forms often coexist with
apomictic tripoloid, and in some rare cases tetraploid, lineages
(Verduijn et al. 2004; van Dijk 2003). While mixing occurs, apomictics
dominate the northern regions of Europe while sexual lineages dominate
central and southern latitudes. Several hypotheses have been proposed
for this distribution. One, apomictics perform more successfully when
there are limited biotic interactions; their reproductive mode gives
them an advantage. It is also thought that apomictics do better in
marginal, fluctuating environments. Sexual lineages perhaps do better
in the central and southern climes due to more complex ecosystems;
recombination allows them to keep up with the evolutionary arms race or
fill specialized niches (van Dijk 2003).
Early studies of T. officinale prompted many questions concerning the
evolution of the species reproductive modes. Despite the fact that
pollen plays no role in seed production for the apomictics, the plant
continues to produce pollen, nectar, and functionless yellow petals (van
Dijk 2003). Maynard-Smith (1978) came to the conclusion that this
hinted at a relatively recent origin for apomictic reproduction and that
evolutionary adaptation in asexuals is slow.
Since then, more progress has been made to understand the population
dynamics of the species. Hybridization can occur between sexual and
asexual populations. Haploid egg cells of sexual diploids can be
fertilized by diploid pollen of apomictic triploid/tetraploid lineages
(van Baarlen et al. 2000). Crossing between these apomictic clones and
sexual lineages will lead to genetic variation and thus provide adaptive
opportunities for changing environments (van Dijk 2003). Crossing also
results in the production of novel polyploid lineages (Merimans et al.
2003). It has even been suggested that the long term success of
apomixis largely depends on the plants ability to cross with sexual
relatives (van Dijk 2003).
Maynard-Smith, J. 1978. The Evolution of Sex. Cambridge University Press.
Meirmans, P.G., Vlot, E.C., Den Nijs, J.C.M, and S.B.J. Menken. 2003.
Spatial ecological and genetic structure of a mixed population of sexual
diploid and apomictic triploid dandelions. J. Evol. Biol. 16: 343-352.
van Baarlen, P., van Dijk, P.J., Hoekstra, R.F., and J.H. de Jong.
2000. Meiotic recombination in sexual diploid and apomictic triploid
dandelions (Taraxacum officinale L.). Genome 43: 827-835.
van der Hulst, R.G.M., Mes, T.H.M., den Nijs, J.C.M., and K. Bachmann.
2000. Amplified fragment length polymorphism (AFLP) markers reveal that
population structure of triploid dandelions (Taraxacum officinale)
exhibits both clonality and recombination. Molecular Ecology 9: 1-8.
van Dijk, P.J. 2003. Ecological and evolutionary opportunities of
apomixis: insights from Taraxacum and Chondrilla. Phil. Trans. R. Soc.
Lond. B 358: 1113-1121.
Verduijn, M.H., van Dijk, P.J., and J.M.M. van Damme. 2004. The role
of tetraploids in sexual-asexual cycle in dandelions (Taraxacum).
Heredity 93: 390-398.
Posted by Cameron at 1:25 PM
From BBC News:
Prime Minister Halldor Asgrimsson of Iceland has announced he is stepping down following his party's poor performance in local elections.A government leader taking responsibility? I wonder what that is like?
He said he would retain his seat in parliament, but would not hold a position in the cabinet.
"I take personal responsibility that the party lost," the prime minister said.
Analysts say Mr Asgrimsson had also been under pressure to resign amid rising interest rates and inflation.
Posted by Cameron at 9:11 PM
Kos points to a list that might better serve the protection of traditional marriage:
1. Raise the public's consciousnesas of the dignity and importance of women in our still deeply patriarchal society.
2. Provide every couple with a guarantee of health insurance that spares them the relational strains inflicted by devastating illness and an inability to pay for medical care.
3. Increase the minimum wage and offer tax breaks to the working poor so that spouses can see each other for more quality length of time, rather than briefly passing eachother on their way to two jobs.
4. Cover mental healthcare in medical insurance policies so that serious emotional difficulties can be prevented from tearing marriages apart.
5. Encourage family planning.
6. Set aside resources for dealing with domestic abuse. Well, at least, that's a start.
Posted by Cameron at 12:44 PM
My posting has been erratic over the last few weeks, mostly due to a crazy schedule. School is winding down, however, so I hope to have more time to look at some interesting things. In addition, my last grad course started today, Evolutionary Biology, so I plan on posting on some of the more interesting topics we cover.
I'll start with something basic: scientific theories, hypothesis, and laws. Most scientific misunderstandings stem from the publics lack of knowledge regarding some simple terminology. A theory in science is much different than the lay term. Peter Wilson provides a good explanation of these terms:
If you can keep these definitions in mind, you'll already be better prepared to interpret scientific information.
Scientific Law: This is a statement of fact meant to explain, in concise terms, an action or set of actions. It is generally accepted to be true and univseral, and can sometimes be expressed in terms of a single mathematical equation. Scientific laws are similar to mathematical postulates. They don’t really need any complex external proofs; they are accepted at face value based upon the fact that they have always been observed to be true.
Some scientific laws, or laws of nature, include the law of gravity, the law of thermodynamics, and Hook’s law of elasticity.
Hypothesis: This is an educated guess based upon observation. It is a rational explanation of a single event or phenomenon based upon what is observed, but which has not been proved. Most hypotheses can be supported or refuted by experimentation or continued observation.
Theory: A theory is more like a scientific law than a hypothesis. A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers. One scientist cannot create a theory; he can only create a hypothesis.
In general, both a scientific theory and a scientific law are accepted to be true by the scientific community as a whole. Both are used to make predictions of events. Both are used to advance technology.
The biggest difference between a law and a theory is that a theory is much more complex and dynamic. A law governs a single action, whereas a theory explains a whole series of related phenomena.
Some scientific theories include the theory of evolution, the theory of relativity, and the quantum theory. All of these theories are well documented and proved beyond reasonable doubt. Yet scientists continue to tinker with the component hypotheses of each theory in an attempt to make them more elegant and concise, or to make them more all-encompassing. Theories can be tweaked, but they are seldom, if ever, entirely replaced.
Posted by Cameron at 12:55 PM
Firedoglake had an interersting post on whether there really is a "war on terror." At the same time, former UN weapons inspector Hans Blix has released a report that says the US war on terror is making things worse and will lead to a new arms race. Worth mulling over.
Posted by Cameron at 12:55 PM
10 - You vigorously deny the existence of thousands of gods claimed by other religions, but feel outraged when someone denies the existence of yours.
9 - You feel insulted and "dehumanized" when scientists say that people evolved from other life forms, but you have no problem with the Biblical claim that we were created from dirt.
8 - You laugh at polytheists, but you have no problem believing in a Triune God.
7 - Your face turns purple when you hear of the "atrocities" attributed to Allah, but you don't even flinch when hearing about how God/Jehovah slaughtered all the babies of Egypt in "Exodus" and ordered the elimination of entire ethnic groups in "Joshua" including women, children, and trees!
6 - You laugh at Hindu beliefs that deify humans, and Greek claims about gods sleeping with women, but you have no problem believing that the Holy Spirit impregnated Mary, who then gave birth to a man-god who got killed, came back to life and then ascended into the sky.
5 - You are willing to spend your life looking for little loopholes in the scientifically established age of Earth (few billion years), but you find nothing wrong with believing dates recorded by Bronze Age tribesmen sitting in their tents and guessing that Earth is a few generations old.
4 - You believe that the entire population of this planet with the exception of those who share your beliefs -- though excluding those in all rival sects - will spend Eternity in an infinite Hell of Suffering. And yet consider your religion the most "tolerant" and "loving."
3 - While modern science, history, geology, biology, and physics have failed to convince you otherwise, some idiot rolling around on the floor speaking in "tongues" may be all the evidence you need to "prove" Christianity.
2 - You define 0.01% as a "high success rate" when it comes to answered prayers. You consider that to be evidence that prayer works. And you think that the remaining 99.99% FAILURE was simply the will of God.
1 - You actually know a lot less than many atheists and agnostics do about the Bible, Christianity, and church history - but still call yourself a Christian.
(Via Evil Bible)
Posted by Cameron at 8:39 PM