Generations of Eastern European housewives doing battle against bedbugs spread bean leaves around the floor of an infested room at night. In the morning, the leaves would be covered with bedbugs that had somehow been trapped there. The leaves, and the pests, were collected and burned — by the pound, in extreme infestations.
IntelligentDesign/RandomDrift
curriculum vitae Oxalis research teaching cars photography Europe 2010 Brasil 2011 Mediterranean 2012
Andy Gardner; andyggardner@gmail.com, aggardner@wisc.edu; husband / evolutionary biologist / teacher / espresso-obsessive / car nut / etc.
Andy Gardner; andyggardner@gmail.com, aggardner@wisc.edu; husband / evolutionary biologist / teacher / espresso-obsessive / car nut / etc.
Even on the evolutionary time scale of tens of millions of years there is such a thing as being in the right shape at the right time. An anatomical difference in the ability to seize the moment, according to a study led by Brown University biologists, explains why more species in one broad group, or clade, of grasses evolved a more efficient means of photosynthesis than species in another clade.
Their findings appear this week in the Proceedings of the National Academy of Sciences.
“Evolution of Oxygen” —New Theories of Key Event 2.3 Billion Years Ago.
The Great Oxidation Event occured around 2.3 billion years ago, when it was no longer possible for newly created oxygen to be captured in chemical compounds. Instead, it started to accumulate as oxygen in the oceans and in the atmosphere. Before this event, in the Earth’s early atmosphere, there were only traces of free oxygen. All life was based exclusively on anaerobic processes - chemical reactions that did not require oxygen. With the emergence of cyanobacteria that oxidized water with the help of light and produced oxygen as a by-product, the conditions for life on Earth gradually began to transform.
New research by scientists at the University of Bristol and Boston University suggests that the evolution of multicellularity coincided with increased diversification of cyanobacteria and the Great Oxidation Event. Cyanobacteria are among the most diverse prokaryotic phyla, with morphotypes ranging from unicellular to multicellular filamentous forms, including those able to irreversibly differentiate in form and function. It has been suggested that cyanobacteria raised oxygen levels in the atmosphere around 2.45–2.32 billion years ago during the Great Oxidation Event and dramatically changing life on the planet. However, little is known about the possible interplay between the origin of multicellularity, diversification of cyanobacteria, and the rise of atmospheric oxygen.
The team tested whether the evolution of multicellularity overlapped with the Great Oxidation, and whether multicellularity is associated with significant shifts in diversification rates in cyanobacteria. Our results indicate an origin of cyanobacteria before the rise of atmospheric oxygen. The evolution of multicellular forms coincided with the onset of the Great Oxidation Event and an increase in diversification rates, suggesting that multicellularity could have played a key role in triggering cyanobacterial evolution.
From the NYTimes:
Hooks on the bean leaf exploit thinner areas in the bedbug’s exoskeleton to trap it, scientists have discovered. The more the bug struggles to raise its legs to free itself, the more stuck it gets.
By FELICITY BARRINGER Published: April 9, 2013
Now a group of American scientists is studying this bedbug-leaf interaction, with an eye to replicating nature’s Roach Motel.
A study to be published Wednesday in The Journal of the Royal Society Interface details the scientists’ quest, including their discovery of how the bugs get hooked on the leaves, how the scientists have tried to recreate these hooks synthetically and how their artificial hooks have proved to be less successful than the biological ones.
At first glance, the whole notion seems far-fetched, said Catherine Loudon, a biologist at the University of California, Irvine, who specializes in bedbug locomotion.
“If someone had suggested to me that impaling insects with little tiny hooks would be a valid form of pest control, I wouldn’t have given it credence,” she said in an interview. “You can think of lots of reasons why it wouldn’t work. That’s why it’s so amazing.”
But even though there is no indication that the bean leaves and the bedbugs evolved to work together, the leaves are fiendishly clever in exploiting the insects’ anatomy. Like the armor covering knights in medieval times, the bedbug’s exoskeleton has thinner areas where its legs flex and its tiny claws protrude — like the spot where a greave, or piece of leg armor, ends.
“The areas where they appear to be pierceable,” Dr. Loudon said, “are not the legs themselves. It’s where they bend, where it’s thin. That’s where they get pierced.”
This folk remedy from the Balkans was never entirely forgotten. A German entomologist wrote about it in 1927, a scientist at the United States Department of Agriculture mentioned it in a paper in 1943, and it can be found in Web searches about bedbugs and bean plants.
But the commercial availability of pesticides like DDT in the 1940s temporarily halted the legions of biting bugs. As their pesticide-resistant descendants began to multiply from Manhattan to Moscow, though, changing everything from leases to liability laws, the hunt for a solution was on.
The first task was to determine exactly how the hooks — the technical name is trichomes — worked. The process was viewed through an electron microscope, Dr. Loudon said. “The foot comes down onto the surface, but as it’s lifting up, it’s catching on these hooks,” she said. “The point is pointing down. So all of their legs get impaled.”
“And as soon as one leg gets caught,” she added, “they are rapidly moving legs around and try to get away on the surface. That’s when they get multiply impaled.”
Dr. Loudon and her co-authors — Megan W. Szyndler and Robert M. Corn from Irvine and Kenneth F. Haynes and Michael F. Potter of the University of Kentucky — then set out to mimic the mechanism.
Using a casting process similar to one a sculptor might choose, the scientists replicated, with polymers from different epoxies, the geometry of the trichomes, the sharp point on their tips and their flexibility and strength. Sometimes the tips of the hooks broke off during the molding process, resulting in a hybrid of biological and fabricated materials.
On the natural leaves, bugs were snagged, on average, after six steps, or locomotory cycles. (In one cycle, each of the insect’s six legs moves once.) Once stuck, they tried to free themselves, but they usually ended up just flailing in place around the impaled limb.
The bugs, however, were largely unimpeded by the synthetic surfaces. According to the study, it took them, on average, a Hitchcockian 39 steps to be momentarily snagged, but their armor was never pierced, and they usually moved on.
The scientists, though, think they know what needs to be done. “Future development of surfaces for bedbug entrapment must incorporate mechanical characteristics of whole trichomes,” they concluded in their paper.
And they are far from giving up. As they wrote in the study, “With bedbug populations skyrocketing throughout the world and resistance to pesticides widespread, bio-inspired microfabrication techniques have the potential to harness the bedbug-entrapping power of natural leaf surfaces.”
Or as Dr. Loudon said, “It would be our greatest hope that ultimately this could develop into something that could help with this horrible problem.” Already, she said, she and her colleagues have a patent on the technology pending. It has, she said, been optioned by a commercial company.
The green algae Acetabularia is a remarkable tool for studying cell biology because, although complex in shape and giant in size, it is a single-celled organism. Acetabularia were used in an experiment by Joachim Hämmerling to show that the nucleus determines a cell’s development and characteristics.
Image by Dr. John Huisman, Western Australian Herbarium.
The Dragon Blood Trees (Dracaena cinnabar) are palm-like plants found in the Socotran archipelago, 150mi east of the Horn of Africa. This small island chain has more than 700 endemic species, half of which are plants! Learn more about Socotra and it’s Galapagos-like biodiversity here.
(via theherbarium)
12 Parasites That Control the Lives of Their Hosts →
#parasite
#biology
#entomology
#science
#teaching
#professional
From io9:
Many parasites are satisfied with just living off of their hosts, while others decide their hosts must die. But there are also some parasites who can change their hosts’ behavior or physiology in ways fit only for science fiction. Here are 12 parasites who manipulate their hosts in incredible ways.
I saw this in central Mexico while collecting Oxalis in early July!
Pinguicula moranensis
… is a perennial rosette-forming insectivorous herb native to Mexico and Guatemala. A species of butterwort, it forms summer rosettes of flat, succulent leaves up to 10 cm (4 in) long, which are covered in mucilaginous (sticky) glands that attract, trap, and digest arthropod prey. Nutrients derived from the prey are used to supplement the nutrient-poor substrate that the plant grows in. In the winter the plant forms a non-carnivorous rosette of small, fleshy leaves that conserves energy while food and moisture supplies are low. Single pink, purple, or violet flowers appear twice a year on upright stalks up to 25 cm long…
(read more: Wikipedia)
(photos: T/CR/B - Noah Elhardt; CL - winter stage, by Kristian Peters)
(via botanicalperversion)
UW-Madison Darwin Day promotional materials.
The Oldest Trees on the Planet
Trees are some of the longest-lived organisms on the planet. At least 50 trees have been around for more than a millenium, but there may be countless other ancient trees that haven’t been discovered yet.
Trees can live such a long time for several reasons. One secret to their longevity is their compartmentalized vascular system, which allows parts of the tree to die while other portions thrive. Many create defensive compounds to fight off deadly bacteria or parasites.
And some of the oldest trees on earth, the great bristlecone pines, don’t seem to age like we do. At 3,000-plus years, these trees continue to grow just as vigorously as their 100-year-old counterparts. Unlike animals, these pines don’t rack up genetic mutations in their cells as the years go by.
Some trees defy time by sending out clones, or genetically identical shoots, so that one trunk’s demise doesn’t spell the end for the organism. The giant colonies can have thousands of individual trunks, but share the same network of roots.
This gallery contains images of some of the oldest, most venerable and impressive trees on earth.
Pando
While Pando isn’t technically the oldest individual tree, this clonal colony of Quaking Aspen in Utah is truly ancient. The 105-acre colony is made of genetically identical trees, called stems, connected by a single root system. The “trembling giant” got its start at least 80,000 years ago, when all of our human ancestors were still living in Africa. But some estimate the woodland could be as old as 1 million years, which would mean Pando predates the earliest Homo sapiens by 800,000 years. At 6,615 tons, Pando is also the heaviest living organism on earth.The photo above of the Pando colony was taken by Rachel Sussman, as part of The Oldest Living Things In The World project.
Image: “Clonal Quaking Aspens #0906-4318 (80,000 years old, Fish Lake, UT)” / Rachel Sussman
Methuselah
The world’s oldest individual tree lives 10,000 feet above sea level in the Inyo National Forest, California. A staggering 4,765 years old, this primeval tree was already a century old when the first pyramid was built in Egypt. The tree is hidden among other millennia-old Great Basin bristlecone pines in a grove called the Forest of Ancients. To protect the tree from vandalism, the forest service keeps its exact location secret, but this one looks like it could be Methuselah.
Image: cwsteeds/flickr.Zoroastrian Sarv (Sarv-e-Abarkooh)
This giant cypress lives in Abarkooh, Iran. The evergreen took root between 4,000 and 4,500 years ago, around the time that Stonehenge was being completed. It may be the oldest living thing in Asia, and is a national monument in Iran. The Zorastrian Sarv stands about 82 feet high and has a girth of 37.8 feet.
Copyright Image: Leo Kerner/flickr.Llangernyw Yew
This common yew in Llangernyw, Wales, sprouted during Britain’s Bronze Age, and is between 3,000 and 4,000 years old. Yew trees can live so long because new shoots from the trunk fuse with it. When the main trunk dies, these offshoots keep going. Branches can also take root in the rotting trunk, or reach down into the soil near the base.
Image: Wikimedia CommonsAlerce Tree
The majestic evergreen tree was discovered in 1993 in a grove in the Andes Mountains of south-central Chile. Using tree rings, scientists showed the giant is 3,620 years old. Though these Patagonian cypresses can reach 150 feet tall, they gain only a millimeter in girth each year, and can take a thousand years to be full-grown. The Zoroastrian Sarv and the Llangernyw yew are thought to be older, but the Alerce is the second oldest tree to have its exact age calculated.
Image:andreaugarte/flickrThe Senator
This giant bald cypress lives in the semi-tropical Big Tree Park, Florida, among palm trees. The Senator is the biggest tree by volume east of the Mississippi River. The 125-foot-tall behemoth is about 3,500 years old. The cypress germinated around the same time as the Polynesians first settled Fiji.
Image: rogue_poet/flickrJōmon Sugi
This cryptomeria tree’s 83-foot height and 53-foot girth makes it the largest conifer in Japan. The tree grows in a misty, old-growth forest on the north face of the tallest mountain on Yakushima island in Japan. Tree rings indicate the venerable cryptomeria is at least 2,000 years old, though some estimate it could be as old as 7,000 years.
Image: mattb_tv/flickrOld Tjikko
This ancient, 16-foot tall Norway spruce lives in the scrubby Fulufjället Mountains in Sweden. At 9,550 years, Old Tjikko is the oldest single-stemmed clonal tree, and took root not long after the glaciers receded from Scandinavia after the last ice age. To figure out the hardy spruce’s age, scientists carbon-dated its roots. For thousands of years, the forbidding tundra-climate kept Old Tjikko in shrub form. But as weather warmed over the last century, the shrub has grown into a full-fledged tree. The spruce’s discoverer, geologist Leif Kullman, named the tree after his dead dog.
Image: Copyright Leif Kullman.
(via science-junkie)
Why trees can’t grow taller than 100 metres
TYPICALLY, the taller the tree, the smaller its leaves. The mathematical explanation for this phenomenon, it turns out, also sets a limit on how tall trees can grow.
Kaare Jensen of Harvard University and Maciej Zwieniecki of the University of California, Davis, compared 1925 tree species, with leaves ranging from a few millimetres to over 1 metre long, and found that leaf size varied most in relatively short trees.
Jensen thinks the explanation lies in the plant’s circulatory system. Sugars produced in leaves diffuse through a network of tube-shaped cells called the phloem. Sugars accelerate as they move, so the bigger the leaves the faster they reach the rest of the plant. But the phloem in stems, branches and the trunk acts as a bottleneck. There comes a point when it becomes a waste of energy for leaves to grow any bigger. Tall trees hit this limit when their leaves are still small, because sugars have to move through so much trunk to get to the roots, creating a bigger bottleneck.
Jensen’s equations describing the relationship show that as trees get taller, unusually large or small leaves both cease to be viable (Physical Review Letters, doi.org/j6n). The range of leaf sizes narrows and at around 100 m tall, the upper limit matches the lower limit. Above that, it seems, trees can’t build a viable leaf. Which could explain why California’s tallest redwoods max out at 115.6 m.
Source: New Scientist.
Images: 1 - 2 - 3 - 4.
The picture is a very useful link to bibliodyssey’s plant anatomy charts.
Cork, from Dodel-Port Atlas (1878 - 1883)
(via historiantinanatural)
![scientificillustration:
Welwitschia mirabilis Hook.f. Curtis’s Botanical Magazine, vol. 89 [ser. 3, vol. 19]: t. 5368 (1863) [W.H. Fitch]
http://www.nhm.ac.uk/nature-online/species-of-the-day/biodiversity/economic-impact/welwitschia-mirabilis/index.html
http://www.kew.org/plants-fungi/Welwitschia-mirabilis.htm](http://25.media.tumblr.com/5bf8e3f9ee58c59a92f3d3059faac436/tumblr_mfu81bIPRE1qgzqeto1_250.jpg)
