Thu, 19 Jul 2007 01:07:13 GMT

How Do Unrelated Animals Evolve Similar Traits?

All of us, who have seen a Tasmanian devil and also a wolf, would support the fact that both more or less look the same but, how many of us have ever paused to find out why is it so, even when both are not related at all?

Perhaps none, and am sure this question will leave many pondering. But, you dont need to brainstorm much as our palaeontologists now have the explanation for it.

This is the magic of biomechanics. This evidence of convergence is revealed by the evolutionary theory its

Australian researchers have recently concluded on the fact that similar diets have led to the evolution of similar snout shapes in a range of similar looking, but unrelated animals.

Explaining the new study, Dr Stephen Wroe of the University of New South Wales said,

Animals that had long skinny snouts tend to eat plants or small prey. Those with short broad snouts tended to be true carnivores and eat large prey.

The convergent evolution occurs when unrelated animals independently evolve similar traits when made to adapt to similar environmental problems, like the carnivorous’ need to eat raw meat.

It is found that shorter snouts are more common in true carnivores that ate large prey and animals with long, narrow snouts tend to eat plants or smaller prey.

Thus, this interesting and vital link between diet and snout shape is an important building block of the theory of evolution.

Image Posted by: Irani      Read more     Source

July 12, 2007, 8:06 PM CT

Fragmented Structure of Seafloor

A number of earthquakes in the deep ocean are much smaller in magnitude than expected. Geophysicists from the Woods Hole Oceanographic Institution (WHOI) have found new evidence that the fragmented structure of seafloor faults, along with previously unrecognized volcanic activity, may be dampening the effects of these quakes.

Examining data from 19 locations in the Atlantic, Pacific, and Indian oceans, scientists led by graduate student Patricia Gregg have observed that "transform" faults are not developing or behaving as theories of plate tectonics say they should. Rather than stretching as long, continuous fault lines across the seafloor, the faults are often segmented and show signs of recent or ongoing volcanism. Both phenomena appear to prevent earthquakes from spreading across the seafloor, thus reducing their magnitude and impact.

Gregg, a doctoral candidate in the MIT/WHOI Joint Program in Oceanography and Oceanographic Engineering, conducted the study with seismologist Jian Lin and geophysicists Mark Behn and Laurent Montesi, all from the WHOI Department of Geology and Geophysics. Their findings were reported in the July 12 issue of the journal Nature.

Oceanic transform faults cut across the mid-ocean ridge system, the 40,000-mile-long mountainous seam in Earth's crust that marks the edges of the planet's tectonic plates. Along some plate boundaries, such as the Mid-Atlantic Ridge, new crust is formed. In other regions, such as the western Pacific, old crust is driven back down into the Earth......... Posted by: Tyler      Read more         Source

Tue, 10 Jul 2007 04:24:35 GMT

Just a roadside weed

I need more “weeds” like this one. Actually, I need any weeds like this one. This is, based on my wholly inadequate botany skills, Verbena stricta, sometimes called wooly verbena or hoary vervain.

I haven’t seen this plant in Roundrock itself, but we passed a nice grouping of these beside the ridgetop road on our hike in and out of Roundrock last weekend.

What’s not to like about this flower? I really enjoy the subtle colored flowers more (though the bright splashes are welcome too). This plant is a Missouri native, and it is supposed to be common. The fact that I haven’t seen it (yet) in my own woods and fields is probably due to my poor observation skills rather than the lack of the plant. The roots of this drought-resistant beauty are said to plunge as much as twelve feet into the ground!

Note the far hilltop in the background. Libby and I were on that hilltop (or nearly to the top) when we were trying to find a way around the rushing torrents that blocked our hike into Roundrock. I babbled endlessly about that adventure here. Thus you can get a sense of how far afield we had hiked to avoid (futiley) getting our feet wet that day.

Missouri calendar:

• Birds and mammals feast on wild fruits.
• Earth farthest from sun (aphelion, about 94 million miles).

Posted by: Roundrockjournal      Read more     Source

Tue, 03 Jul 2007 19:11:42 GMT

Animal Behavior

Any ideas on what is going on here?

Or here?

I suspect we don't know nearly as much about large mammal behavior as we think we know.
First photo:

HUMPBACK WHALE AND DOLPHIN
Kauai, Hawaii, USA
Lori Mazzuca
Kailua Kona, Hawaii, USA

Second photo: Daily Mail: Striking aerial image of an unusually large herd moving through Chad toward the Tinga. Posted by: Dennehy      Read more     Source

Tue, 03 Jul 2007 11:48:18 GMT

Butterflies: A Vital Natural Indicator of an Ecosystems State

A butterfly with its colorful and bright wings, while romanticizing nature in its own rights, welcomes spring in the process bidding the long sticky summer goodbye.

Fluttering energetically over the lawn, these butterflies can do a lot besides adding color to mood and nature it can well indicate in what state a particular ecosystem is!

The healthier the ecosystem, more you will find them in their flamboyant selves. Yes, butterflies are particularly sensitive to climate change be it pollution or habitat loss.

Dedicating in the study of butterflies, moths and their habitats, Dr Martin Warren, chief executive of Butterfly Conservation, the UK charity explains,

Butterflies have annual lifecycles, they make the transformation from egg to caterpillar to chrysalis to adult every year. Their populations can build up or decline very quickly, which makes them far more responsive than plants or birds.

They are also sensitive to their thriving conditions. They need the right conditions every year for breeding, — once failed, there is no second chance, unlike birds in general.

Call the insects habitat specialists?

The climate-sensitive insects rely on one very specific set of conditions. The specialist species as they are addressed to be, are struggling for survival when the opportunistic generalists are boomingly spreading north.

While on one hand, the specialists are indicating the change in the regions climate, the generalists indicates the change by chasing their loving warmer weather.

So, a butterfly can act as a natural indicator of a particular regions climate as well as at far-lands where the insects are found to chase their ways in. Hence, nature seems to be itself equipped with its “mood-swing indicators”.

Image Posted by: Irani      Read more     Source

Tue, 03 Jul 2007 09:15:54 GMT

Passiflora miniata

Thanks again to Earl B. of the eastern USA for contributing an image to BPotD, this time from a recent vacation to Costa Rica (I'm envious!).

For decades, if not centuries, this species in the photograph has been known in cultivation as Passiflora coccinea. However, what is pictured here is not the same species as was described by Aublet in 1775. The true Passiflora coccinea (or scarlet passionflower) is quite different from the plant in the photograph; for example, it has two series of corona filaments with the outer series being white or pale pink, large floral bracts and upright pear-shaped fruits that are golden-brown in colour. The Passiflora coccinea of cultivation has three series of corona filaments, the outer series being purple in colour and the two inner series being white (as shown in today's image), small floral bracts (also illustrated today) and large, subspherical, pendulous (and variegated!) fruits.

After learning that this isn't Passiflora coccinea, the logical question that follows is: “What is it?” Hard to believe, perhaps, for a plant that has been cultivated in tropical areas around the world, but it didn't have a published scientific name until 2006, when John Vanderplank set the record straight about Passiflora coccinea and Passiflora miniata in an article in the (subscription-only, sorry) Curtis's Botanical Magazine (Vanderplank, J. 2006. 562. Passiflora miniata. Passifloraceae. Curtis's Botanical Magazine. 23 (3):223-230).

Since the name Passiflora coccinea has been used for so long for this species in cultivation, it is important to establish a link between Passiflora miniata and the wrongly applied name. Botanists will do this by writing Passiflora miniata Vanderpl. (syn. Passiflora coccinea hort.), with the “hort.” meaning “of horticulture”.

The Germplasm Resources Information Network contains the correct information (and species distribution) for Passiflora miniata. On most other sites (and search engines), you'll have to mentally substitute Passiflora miniata when you see Passiflora coccinea, e.g., on the Kemper Center for Home Gardening entry on red granadilla. Posted by: Daniel Mosquin      Read more     Source

Tue, 26 Jun 2007 02:06:32 GMT

Hola

Photo by John Wertz

I'm an evolutionary biologist. I study the evolutionary ecology of bacteriophages (viruses that infect bacteria, see inset). No, we aren't really evil as the title of this blog suggests. We just think that biological phenomena is best explained by evolutionary theory, and if evolutionary theory contradicts long cherished beliefs formulated in ancient societies, so be it. Personally I think there is much wisdom in the ancient beliefs, but we can't expect all these beliefs to be correct, or even relevant, today. The only constant is change, and we, as a species, must continually adapt. Science is the only belief system that truly adapts to changing circumstances.

I'm going to post thoughts about things that excite me. These may naturally be as random and idiosyncratic as my interests at present, but generally speaking, I'm interested in evolutionary biology, molecular biology, genetics, ecology and parasites, particularly bacteriophages. Once a week I will post on a Citation Classic i.e. science papers that, for me, best epitomize the aesthetics of science. Contrary to common belief, science is an art, and some art is more beautiful than others. These papers mainly will fall among my major interests. Posted by: Dennehy      Read more     Source

Mon, 25 Jun 2007 12:53:21 GMT

Fierce Chickens....

So it turns out that our docile barnyard friends, the chickens, have quite a fearsome ancestor: T-rex. Asara et al. used mass spec to determine the amino acid sequence of collagen extracted from 68-year-old Tyrannosaurus rex bone. The determined sequence closely resembled that obtained from chickens. Of course most popular current hypothesis for the origin of birds is that they are the descendants of dinosaurs, but most of the evidence comes from anatomical structure. This is the first evidence to come from actual molecular data. Actually the most surprising thing about this study is that collagen survived 68 million years.

It doesn't quite mean the onset of Jurassic Park quite yet, but as my friend Thad said, "Barbecued or fried T-Rex sounds good!!" Posted by: Dennehy      Read more     Source

Thu, 24 May 2007 00:53:07 GMT

Early Arrival of Butterflies in Britain Reveals Climate Changes Impact

If you are mature-watcher and loves watching butterflies, you no longer have to wait for the right time for the various colorful species of butterflies to arrive in a nearby garden. Thanks to the global warming’s effect on environment.

Britain, with its this April having recorded the highest temperatures ever, is witnastounding manifestation of the natural world to the lash of global warming its at least 11 species of butterfly are making their earliest recorded appearances this spring.

59 butterfly species have been recorded to reside and migrate regularly marking Britains spring, but astoundingly, 37 of them have already appeared. And of these, all — except the orange tip — have emerged earlier, compared to what they used to a decade ago, the wildlife charity Butterfly Conservation says.

To add to the surprise, 11 of them are found to have broken all records for early emergence, with some by scarcely-believable margins!

Britain’s wildlife seems to be visibly having the burn of climate change to the shock and surprise of even the scientists, who have been watching the effects of warming temperatures on living organisms for several years, not to mention the laymen.
Image Posted by: Irani      Read more     Source

May 9, 2007, 11:11 PM CT

Genome Sequencing Of The First Marsupial

Since the launch of the Human Genome Project, which released a first draft of the entire sequence of human DNA in 2001, a number of scientists have dedicated themselves to creating a library of comprehensive, species-specific genetic sequence "maps" available for study. Researchers at LSU recently took part in a multi-institutional effort spearheaded by the Broad Institute of MIT and Harvard University to sequence the complete genome of the gray, short-tailed opossum, Monodelphis domestica.

As the first marsupial, a mammal equipped with a special "pouch," to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. The results would be reported in the journal Nature on Thursday, May 10.

Marsupials diverged from a common ancestor with placental mammals, a group including humans, approximately 180 million years ago. Marsupials and placental mammals are more closely correlation to one another than to any other vertebrate model species, such as birds, amphibians or fish, yet marsupials are also genetically distinct from all current mammalian biomedical research models. This makes the marsupial an integral part of evolutionary and biomedical studies.

Kangaroos of Australia and the North American opossum, which is abundant in Louisiana, typically come to mind when one thinks of marsupials. However, Monodelphis domestica, a South American opossum, was chosen for genome sequencing because it is the predominant laboratory-bred research marsupial in the world and therefore represents an important model organism for comparative genomics. Studies in this species will help to identify genome features common to all mammals and will also help to pinpoint specific differences between placental and non-placental mammals......... Posted by: Ashley      Read more         Source