Charles Darwin’s complete Galapagos library posted online


This video says about itself:

11 November 2011

A classic example of evolution on Daphne Major Island in the Galapagos. Natural selection works on beak size variation of Darwin’s Finches.

From ars technica:

Darwin’s complete Galapagos library posted online

404 volumes kept on board the Beagle join the giant Darwin Online repository.

by Sam Machkovech – July 16 2014, 10:40pm +0200

Charles Darwin‘s massive ship library, including astounding drawings of species from far-off lands, meant he rarely had to come above-board while sailing on the Beagle in the 1830s.

Charles Darwin’s five-year journey to and from the Galapagos Islands ended in 1836. While that was over two decades before the publication of On the Origin of Species, he credited his time on board the Beagle as a formative experience for his theory of evolution. That extended trip wasn’t only spent studying local wildlife, especially during lengthy voyages at sea to and from home—Darwin also devoured a library of more than 400 volumes of text.

While many of those books were referenced in his later research, they were not preserved as a collection once the Beagle returned to England, leaving a gap in our understanding about the books and studies that kept Darwin’s mind occupied during such an historic era. Now, thanks to the painstaking efforts of a two-year Beagle project funded by the government of Singapore, that complete on-ship library has been transcribed and posted at Darwin Online, the world’s largest repository of Darwin-related texts and writings.

The library, which was stored in the same cabin as Darwin’s bed and desk during his journey, totaled out at 195,000 pages by the time researchers at the National University of Singapore assembled the full collection (and these weren’t exactly picture books, with only 5,000 corresponding illustrations). The complete list is quite astounding, made up of atlases, history books, geology studies, and even a giant supply of literature. Darwin also enjoyed a few books in French, Spanish, and German, along with a book in Latin about species and a Greek edition of the New Testament.

Historians and fans can read and perform text searches of the fully transcribed library. But if you’re pressed for time, we strongly encourage you to at least skim through the collection of gorgeous illustrations.

American tanagers’ colours and songs, new study


This video is called Colombia Tanagers [various species].

From Wildlife Extra:

Study dispels Darwin’s theory to prove birds can have it all

Despite popular belief birds can have a brilliant plumage, a virtuosic singing chirp and an intricate dance routine say scientists.

The author of a new study, Nick Mason, from the the Cornell Lab of Ornithology in New York state, challenged the long-held notion, first proposed by Charles Darwin, that for a bird species to excel in one area it must give up its edge in another.

For example, male northern cardinals are a dazzling scarlet, but sing a fairly simple whistle, whereas the dull brown House Wren sings one of the most complicated songs in nature.

Mason and his colleagues tested the theory by examining a very large family of songbirds from Central and South America, the tanagers.

This group consists of 371 species and included some of the most spectacularly colourful birds in the world such as the paradise tanager as well as the more drab birds, such the black-bellied seedeater. The group also includes both accomplished and weak songsters alike.

“If there were going to be any group of birds at all that would show this trade-off, the tanagers would be a very good candidate, because there’s all this variation in song and plumage complexity,” Mason said.

“But when we dived into it and did some rigorous statistics, it turns out that there is no overall trend. Tanagers can be drab and plain-sounding, or colourful and musical, or or anything in between.”

It’s still possible that trade-offs take place at the level of genus, Mason said, or that they influence species relatively fleetingly as evolutionary pressures appear and disappear.

But as a broad effect on an entire family of birds, a voice–plumage trade off doesn’t seem to exist. One possibility is that the resources needed to develop fancy plumage are different from the ones required for complex songs, freeing tanagers to invest in both forms of showiness simultaneously.

Darwin’s childhood garden now Wildlife Trust property


This video from England is called Visit Charles Darwin‘s Shrewsbury, the birthplace of evolution!

From Wildlife Extra:

Darwin’s garden purchased

January 2014: A wooden remnant of naturalist Charles Darwin’s childhood garden in Shrewsbury, Shropshire has been bought by Shropshire Wildlife Trust.

“No other part of Darwin’s childhood home is accessible to the public, so when we were offered the chance to buy this slip of woodland next to the river, we were thrilled at the opportunity to open up a cherished corner of his world,” said Colin Preston, Director of Shropshire Wildlife Trust.

While much of the land previously attached to The Mount, his birthplace, has disappeared under housing, other parts survived in private gardens, including the land the Trust has bought.

Through the wood, alongside an ice house once used by the Darwins, runs a path with views down to the River Severn. It was here 200 years ago, that the young Darwin was sent every day before breakfast to walk the path at the bottom of the garden. It was known as the Thinking Path and provided a regular time for thought and reflection. The habit became ingrained in Darwin’s daily routine and when he and his wife Emma bought Down House in Kent, they made their own Sandwalk through the grounds, carrying on the tradition of morning walks with their children.

The Trust intends to restore the Thinking Path, open up views and carry out essential boundary and safety work. The garden will be opened for group visits at various times throughout the year and schoolchildren will have the chance to walk in Darwin’s footsteps, inspiring them to enjoy and explore the natural world.

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Island lizards less scared of people


This video is called Marine iguanas of the Galapagos islandsBBC wildlife.

From Nature:

Islands make animals tamer

Lizard study supports Darwin‘s hunch that lack of predators leads to unwatchful behaviour.

Ed Yong

08 January 2014

When Charles Darwin visited the Galapagos Islands, he noted that many of its animal inhabitants were so unafraid of people that “a gun is here almost superfluous”. He swatted birds with his hat, pulled the tails of iguanas and sat on giant tortoises.

These antics fuelled his famous idea that animals become tame when they live on remote, predator-free islands. Now, William Cooper Jr of Indiana University–Purdue University in Fort Wayne has tested Darwin’s hypothesis on 66 species of lizards from around the world and found that island dwellers tended to be more docile than their continental relatives — the strongest evidence yet for this classic idea. The results are published this week in Proceedings of the Royal Society B1.

Several studies and unpublished reports have shown that particular species are more approachable on islands where there are fewer predators, or quicker to flee on islands that contain introduced hunters such as feral cats. But despite this largely anecdotal evidence for island tameness, “no one has ever established that it’s a general phenomenon in any group”, says Cooper. “We showed that for a large prey group — lizards — there really is a significant decline in wariness on islands.”

Taming of the few

Island tameness is an old idea, but there have been few tests of it,” says Dan Blumstein, a behavioural biologist at the University of California, Los Angeles. “This is a needed paper that convincingly shows some of the drivers of island tameness in lizards.”

Cooper and his colleagues scoured past studies and collated data on the distance at which lizards start to flee when approached by a researcher. They took a conservative approach, discarding studies in which researchers had pointed at the lizards, walked towards the animals faster or slower than a particular fixed speed, or studied populations that were habituated to humans.

Cooper and his team ended up with data for 66 species, from the Eurasian common lizard (Zootoca vivipara) to the Galapagos marine iguana (Amblyrhynchus cristatus). The results clearly showed that humans can get closer to island-dwelling lizards than to mainland ones, and that lizards become more approachable on islands that are farther from the mainland.

Island ecology is so important that it overrides any effect of evolutionary history, Cooper and his co-authors say. They also showed that even closely related lizard species have different escape behaviours depending on where they live, and that their evolutionary relationships were mostly irrelevant.

The results do not explain why island lizards are tamer than those on the mainland, although the relative lack of island predators is the most likely reason. Animals with skittish dispositions can needlessly abandon valuable resources, and natural selection would be expected to weed out such responses if predators are rare or absent.

Cooper wants to test this idea, but says that it is hard to get decent data on the numbers, densities and types of predators on different islands.

See also here. And here.

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Falkland Islands wolves mystery solved


Old Falkland wolf family tree

From Wildlife Extra:

Mystery solved – Where did Falkland Islands wolves come from?

Ancient DNA solves 320-year-old mystery

March 2013. University of Adelaide researchers have found the answer to one of natural history’s most intriguing puzzles – the origins of the now extinct Falkland Islands wolf and how it came to be the only land-based mammal on the isolated islands – 460km from the nearest land, Argentina.
Previous theories have suggested the wolf somehow rafted on ice or vegetation, crossed via a now-submerged land bridge or was even semi-domesticated and transported by early South American humans.

Darwin questions

The 320-year-old mystery was first recorded by early British explorers in 1690 and raised again by Charles Darwin following his encounter with the famously tame species on his Beagle voyage in 1834.

New stuffed specimen found in New Zealand

Researchers from the University’s Australian Centre for Ancient DNA (ACAD) extracted tiny pieces of tissue from the skull of a specimen collected personally by Darwin. They also used samples from a previously unknown specimen, which was recently re-discovered as a stuffed exhibit in the attic of Otago Museum in New Zealand.

16,000 years ago

The findings concluded that, unlike earlier theories, the Falkland Islands wolf (Dusicyon australis) only became isolated about 16,000 years ago around the peak of the last glacial period.

“Previous studies used ancient DNA from museum specimens to suggest that the Falkland Islands wolf diverged genetically from its closest living relative, the South American maned wolf (Chrysocyon brachyurus) around seven million years ago. As a result, they estimated that the wolf colonised the islands about 330,000 years ago by unknown means,” says Associate Professor Jeremy Austin, Deputy Director of ACAD and co-lead author with Dr Julien Soubrier.

“Critically, however, these early studies hadn’t included an extinct relative from the mainland, the fox-like Dusicyon avus. We extracted ancient DNA from six specimens of D. avus collected across Argentina and Chile, and made comparisons with a wide group of extinct and living species in the same family.”

ACAD’s analyses showed that D. avus was the closest relative of the Falkland Islands wolf and they separated only 16,000 years ago – but the question of how the island colonisation came about remained. The absence of other mammals argued against any land bridge connection to the mainland.

Eureka moment

“The Eureka moment was finding evidence of submarine terraces off the coast of Argentina,” says study leader Professor Alan Cooper. “They recorded the dramatically lowered sea levels during the Last Glacial Maximum (around 25-18,000 years ago).”

“At that time, there was a shallow and narrow (around 20km) strait between the islands and the mainland, allowing the Falkland Islands wolf to cross when the sea was frozen over, probably while pursuing marine prey like seals or penguins. Other small mammals like rats weren’t able to cross the ice.”

The study was published in Nature Communications.

Chinese dinosaur age bird discovery


This video is called The Fabulous Chinese Fossils— Chaoyang, Liaoning Province.

Sulcavis geeorum skull, photo credit: Stephanie Abramowicz

By Alan McStravick for redOrbit.com – Your Universe Online:

First Fossil Bird Discovered With Teeth For A Tough Diet

January 7, 2013

A trip to the Galapagos islands will bring you face to face with 14 closely related species of finch that Charles Darwin discovered on his adventure abroad in the 1830s. The finches he noted, still referenced in essentially every biology textbook, had beak sizes of varying lengths and sizes. This was true of both the ground- and tree-dwelling birds, and Darwin postulated that differing diets might have required the birds’ unique beaks for their specialized feeding tasks.

It was these birds, catalogued in 1835, that first helped Darwin to arrive at his theory of evolution. He was able to realize that each of the finch species had originally arisen from one ancestral form and that each of the successive forms – with their individual ecological niches and diets – were what he considered the most perfect examples of adaptive radiation, the process where one species undergoes several distinct changes to survive and thrive in a wider variety of habitats.

If Darwin had lived some 121-125 million years ago, he might have experienced the same sense of wonder at the site

rather: sight

of a Sulcavis geeorum, a species of early bird that existed in the Liaoning Province of what is now modern-day China. It was here that a new fossil discovery was made showing that these early ancestors of the dinosaurs

This should be “descendants of the dinosaurs”. Dinosaurs were ancestral to birds; not the other way round.

had evolved teeth adapted to their specialized diets.

In a report of the finding published in the latest issue of the Journal of Vertebrate Paleontology, researchers say they believe that S. geeorum existed on a so-called ‘durophagous diet’, one that included lots of prey with hard exoskeletons such as insects or crabs.

S. geeorum was an enantiornithine bird, a primitive group of early birds that were abundant in the Mesozoic era and carried over into the Cretacious.

Cretaceous

With the discovery of S. geeorum, researchers are enjoying their own Darwin-like moment as they see this discovery as representing a huge leap forward in the known diversity of tooth shape in early birds. This diversity of shape also leads them to believe that they may have stumbled upon an as yet unrecognized degree of ecological diversity.

According to the research team, S. geeorum is the first fossilized bird discovery that has ornamented tooth enamel. Looking back to the specific dinosaurs from which birds are believed to have evolved, researchers find that their tooth structure was specialized mainly for a carnivorous diet. The enanitiornithine family of birds have undergone the most minimal tooth reductions from their dinosaur cousins compared to any other extinct or extant groups of birds, and they also displayed a wide diversity of individual dental patterns.

In this newest enantiornithine discovery, researchers say that they have discovered a robust set of teeth that are marked with grooves on the inside surface. It is from these grooves, they hypothesize, that the teeth received their strength that allowed them to ingest harder food items.

“While other birds were losing their teeth, enantiornithines were evolving new morphologies and dental specializations. We still don’t understand why enantiornithines were so successful in the Cretaceous but then died out – maybe differences in diet played a part,” according to Jingmai O’Connor, lead author of the new study. One thing that is known is that until this discovery, no previous known bird species had preserved ridges, striations, serrated edges, or any other form of dental ornamentation.

“This study highlights again how uneven the diversity of birds was during the Cretaceous. There are many more enantiornithines than any other group of early birds, each one with its own anatomical specialization,” said the study’s co-author Luis Chiappe, from Natural History Museum of Los Angeles County.