Prehistoric Location, Location, Location

Human nature doesn’t change. Tour any archeological site and you will find necessities, desires and comforts of life common to all people. In particular this applies to the place we call home. A house buyer today views properties with a mental checklist of desired features and according to recent researchers, prehistoric cave-dwelling Britons did the same thousands of years ago.

A survey of over 400 caves in Northern England shows that people living in this area from 4,000 to 2,000 B.C. selected their homes based on five important features. Caves were favoured if they

*Were located at a higher altitude
*Had an east or west facing entrances
*Had large entrances
*Included deep passages
*Had a level area just outside of the entrance

Archaeologists discovered that the Peak District, a productive area for agriculture today, attracted more prehistoric cave users than the Yorkshire Dales. But caves were also used for more transitory purposes: sometimes caves were employed like roadside motels, where travellers would stop in for a few nights to rest before continuing their journeys

The benefits of this project include the discovery of many previously unexplored caves throughout Britain, a well-practiced methodology for surveying archeological sites, and an excellent compilation of data that will aid future researchers.

Blogroll Additions

Last week’s call for blogs has resulted in some great additions! Check out:

A California Nature Photographers Journal
Find out where, what, and how to photograph nature in California.

Interrogating Nature
A sensible and critical approach to all sorts of biology related topics.

Secret Sex Lives of Animals
A weekly column on the bizarre, wonderful, colourful and sometimes shocking world of animal mating habits.

The Domestic Minx
A deliciously dysfunctional diary about domestic living.

The Dragon's Tales
A great mix of science and current events from all over the globe.

Lonesome George isn’t alone anymore

Lonesome George, the giant Galapagos tortoise that has become a conservation icon may not be the last of his kind after all. George was thought to be the only survivor of a Geochelone abingdoni, a species of tortoise native to the Pinta isle.

But this week, Current Biology has reported a hybrid of the Pinta tortoise and another species discovered on Isabela isle. So the new tortoise, though not completely like George, is proof that hybrids are possible and the future of the George’s species doesn’t look as bleak anymore.

The new turtle is male so can not mate with George, who seems happy as a hermit. George has snubbed the many opportunities he has been given to mate with female tortoises of closely related species.

Researchers hope that a more thorough sampling of the 2,000 tortoises living on the island could reveal another of Georg’s species but are cautious as the project may be expensive and time-consuming.

It is thought that the collapse of the giant tortoise population on Pinta is due in large part to whaling activities in the Pacific during the 18th and 19th Centuries when sailors would take tortoises to store as food on their ships. They pefered the females, which were smaller and easier targets in lowland areas during the egg-laying season. By the middle of the 20th Century, only one giant tortoise was left on Pinta: George who is thought to have been born in the 1920s.

Why does a platypus lay eggs anyway?

Children are taught many ‘rules of thumb’ to help them identify animals, for example: mammals, are furry (or hairy), give birth to live young, make milk and take care of their children. So why does the furry platypus lay eggs? The discovery of this bizarre, egg-laying, duck-billed, web-footed mammal initially baffled naturalists, but now we understand them much better because we know much more about their special place in the tree of evolution.


All animals on Earth are related, even though these relationships aren’t always obvious. The reason these relationships are hard to figure out is that despite the diversity of animals we see, they represent a mere fraction of the life that has ever existed on this planet. In fact, one famous palaeontologist estimated that we know of less then 1% of the Earth’s diversity through time.

To understand the relationships between animals better, we have to look back in time, at the extinct ancestors of the animals alive today (animals living today are called ‘extant’).

This diagram (called a cladogram) shows how the five major groups of vertebrate animals are related:
-Fish gave rise to the first amphibians, which crawled on to land about 400 million years ago.
-Amphibians and reptiles share a common ancestor about 350 million years ago.
-Mammals and birds evolved from reptiles much later at different times during the Mesozoic Era.

Each of these major transitions was slow. It must be understood that a fish doesn’t become an amphibian overnight. There were many different species of animals that formed that transitory stages between these groups and possessed a unique set of characteristics, a sort of ‘mosaic’ between the two groups.

Now let’s look more closely at the evolution of mammals. Mammals evolved from mammal-like-reptiles, a very diverse groups of animals which are all (unfortunately) extinct. Through time three major groups of mammals evolved:
Prototherians - which lay eggs (eg. platypuses and echidnas)
Metatherians - which let young develop in pouches (marsupials such as kangaroos and koalas)
Eutherians – ‘modern mammals’ which give birth to well-developed offspring (this includes many familiar species such as rabbits, elephants, horses, and humans)

The platypus is a prototherian. This ancient group branched off of the mammal tree of life early on before the other two groups. There are many different prototherians in the fossil record but only platypuses and echidnas are still around. So the past there was a great diversity of egg-laying mammals, but sadly, all of those animals except for platypuses and echidnas) are now extinct.

If you are interested in this topic I recommend visiting Date A Clade, which has an excellent (and more comprehensive) cladogram with detailed information on when major groups of animals split away from each other.

Announcement: Blogroll Enrollment

Well I haven't been very diligent in keeping up my blogroll. If you would like a link to your site from Fish Feet, please leave a comment on this post with your blog’s name and URL and I will add your link to my blogroll (probably – no spam please). I appreciate links back also:)

Winner of Great Turtle Race Announced!

You may recall that a few weeks ago I posted about the Great Turtle Race, which tracks Leatherback Sea Turtles as they head back to their Galapagos feeding grounds. Spectators have been traveling their progress online and today the winner was announced: Billie. I hope the others do well, especially the slow starters, Sunda and Drexelina. Check out their journeys at http://www.greatturtlerace.com.

Earth-like planet discovered

Astronomers have found the most Earth-like planet to date and it may have running water

Statistics
Diameter: 1.5x Earth
Mass: 5x Earth
Orbit: 13 days
Temperature: 0 - 40°C
Distance from its sun: 14x closer than Earth
Distance from Earth:
20 light years

Astronomers have found the most Earth-like planet outside our Solar System to date, a world which could have water running on its surface.

The planet orbits Gliese 581, a faint star 20.5 light-years away in the constellation Libra. It is unclear if it is rocky, like our planet, or is covered in an ocean. But its temperature implies that water there could exist in liquid form and so it has raised the idea that it could also harbour life.

Already there is talk of aiming future space missions towards this planet. The first observational missions would put telescopes in place to seek any tell-tale light "signatures" that might be associated with biological processes such as changes in atmospheric gases and markers for chlorophyll, which is used by plants here on Earth to to photosynthesize.

Of the more than 200 planets outside of our solar system discovered so far, most are blazing hot Jupiter-like gas giants. The new Gliese 581 planet is in what scientists call the "Goldilocks Zone" where temperatures "are just right" for life to have a chance to exist.

Shark vs. Dinosaur

A recent find in Utah reveals a large prehistoric lake around 200 million years with an amazing fossil cache including an enormous, carnivorous dinosaur and several species of sharks. Anatomical features of the dinosaur suggest it specialized in eating fish, including sharks and huge bony fish, meals which palaeontologist James Kirkland describes as “like biting through chain mail [since] fish in the past were more armored than they are today."

The dinosaur, a relative of the crested dino Dilophosaurus, was about 20 feet long and so would have been a formidable adversary for its ferocious prey. The dinosaur’s slender, serrated teeth are quite unusual and only found in dinosaurs like Spinosaurus and Suchimimus.

Dilophosaurus was well adapted to being a fisherman. Its nasal openings retracted back from the end of its snout so that it could, like today's crocodiles and alligators, still breath when its mouth was underwater.

There are clear tracks and claw scrapes showing the dinosaur wading into the lake to catch its prey. "We have counted over 3,000 individual claw marks and toe scrapes that show incredibly detailed preservation," reveals palaeontologist Andrew Milner. "We can see details of cuticle on the tips of claws, skin impressions, scale scratch lines and where claw cuticle was overlapped by the fleshy toe pads at the end of the toes."

Happy Earth Day!

I’m sorry I’m a day behind! I hope that this weekend you were all able to enjoy some good weather and celebrate Earth Day 2007.

I’m not much for New Year’s resolutions but every year on Earth Day I try and make a change in my life that (however small) that will lower my impact on the environment. I have along ways to go towards a green lifestyle. Though I recycle and reuse my grocery bags I still do many, many other things that could be improved upon.

So for this year’s effort I will try to buy more local produce. I love exotic fruits and other foods and while I don’t plan on cutting these out of my diet entirely, I plan to have more seasonal meals and to try to appreciate the variety in which local foods can be prepared. Another advantage to buying locally is that it is often a cheaper option and you can buy directly from farmers and green grocers.

Here are 20 EASY ideas on how to contribute. All it takes is a little imagination and dedication. If you decide to make a change today, please leave a comment! Thank you, Sarda

Reduce, Reuse and Recycle
-Use plastic containers instead of cling wrap and aluminum foil
-Take your own bags to the grocery store
-Recycle where facilities exist
-Hold a garage sale
-Shop in used bookstores

Home, Office & Garden
-Turn the light off when you leave a room
-Use energy saving lightbulbs
-Use half as much washing powder
-But eco-friendly washing products (eg. Ecover)
-Purchase bleach free, recycled kitchen roll or use washable tea towels
-Use cloth napkins
-Put a ‘No Junk Mail’ sticker on your post box
-Buy organic
-Buy less meat, more fruits and vegetables
-Buy local
-Start a compost heap
-Use both sides of paper
-Bike, walk, carpool or use public transport to get to work.
-Pass read magazines to friends or give them to the doctor’s office

Holidays
-Personalize Christmas by being crafty and making new cards from old ones

Feathered Dinosaurs

A reader sent me this cartoon. Pollen has been found in high concentration with some Neanderthal bodies suggesting they buried their dead with flowers. But what about before flowering plants evolved?

Book Review: Lamb by Christopher Moore

A hilarious read, but only if you are not easily offended by religious blasphemy:) Lamb is a hilarious look at the life of Jesus through the eyes of his best friend Biff. It’s an easy read and one of Moore’s best books.

Synopsis: The birth of Jesus has been well chronicled, as have his glorious teachings, acts, and divine sacrifice after his thirtieth birthday. But no one knows about the early life of the Son of God, the missing years ? except Biff, the Messiah's best bud, who has been resurrected to tell the story in this divinely hilarious, yet heartfelt work reminiscent of Vonnegut and Douglas Adams' (Philadelphia Inquirer). Verily, the story Biff has to tell is a miraculous one, filled with remarkable journeys, magic, healings, kung fu, corpse reanimations, demons, and hot babes, Even the considerable wiles and devotion of the Saviour's pal may not be enough to divert Joshua from his tragic destiny.

Happy 100!

Well I have just posted my 100th post. Thanks to my regular readers and welcome to the new ones. I hope I am doing something right, I was recently awarded the Thinking Blogger Award by Oreneta, a Canadian sailor aground in Catalonia, Spain, thank you Oreneta! Now I will nominate five bloggers who make me think. I decided not to include science-related blogs which I have to admit are the majority of what I read, but rather consider five blogs which I make me think outside of my box.

The Domestic Minx has a deliciously dysfunctional diary about domestic living.

Ok, I said I wasn’t going to post a science blog, but this one is really good and completely out my realm of expertise. The (recently launched) All About Forensic Science blog explores anything and everything to do with forensic science.

Cucina Povera, which has a million great recipes for sustainable, organic living.

Wild in London is an excellent blog about the wildlife that can be found in one of the world’s largest cities.

and Clubbing Baby Seals... an interesting blog about the weird world around us and someone of the weirder products we can buy.

Tyrannosaurus Forelimbs Revisited

Earlier in the week, I posted some theories regarding the function of T. rex’s diminutive arms. I just thought I would add some recent research before I closed the topic:

Matt Smith (Museum of the Rockies) and Ken Carpenter (Denver Museum of Natural History) began examining the wrist, hand and finger bones of the T. rex forelimb and used wax to hold the bone joints together. This led them to figure out that the forelimb's two claws have an unusual feature: unlike the opposable human thumb and forefinger combo, which can grasp objects, the two dinosaur claws face away from each other like the barbs of a fishing hook.

What does this mean? Perhaps these claws embedded themselves into the prey’s flesh and immobilized it while T. rex used his jaws to finish the job. .

Matt Smith says, "People had been looking at [forelimb] function based on proportionate size. I don't think that's appropriate."

Sneezing in the Sun

After eight years and I am still learning new things my husband: we were walking down the street when the clouds parted, revealing a bright sun and he consequently sneezed! And now I realize that this phenomenon affects a significant number of other people I know. So in case you were ever wondering why looking at the sun on a bright day makes you sneeze here is the answer:

When a nerve cell is stimulated it passes on a chemical / electrical message to the next nerve cell in the chain. However, if it is a very strong message, this might also leak out and stimulate nearby nerve cells. So, when you look at the sun or a bright light, your eyes (and their nerves) suddenly have a lot of very strong information to pass to the brain. In addition to passing on their message, they also 'leak' a bit. Part of the path for the optic nerves (from your eyes) happens to be close to your sneeze reflex and so it can be triggered by accident.
-This text was originally contributed by David Hone on Ask a Biologist

Anecdotal evidence also seems to indicate that this unusual reflex has a genetic link, so may be common among members of the same family. This is confirmed by R. Eccles of the Common Cold and Nasal Research Group who says that this phenomenon (which he terms the ‘photic sneeze’) affects between 18-35% of the population. And that the photic sneeze is a well known hazard to fighter pilots when they turn towards the sun or are exposed to flares from anti-aircraft fire.

Shark Cartoons

Check out One Whale, home to 137 hilarious shark, whale and marine cartoons by Australian cartoonist Phil Watson.

Why do Great White Sharks always have a big bloody gape?

Something has been bothering me the last while. I can’t figure out why Great White Sharks are always depicted as having a big bloody gape? I have researched it a bit but have not come up with any good information. As it I see it though, there are three distinct possibilities:

1. The big bloody gape is a fallacy propagated by Hollywood
2. Blood is leftover from a kill
3. The blood is their own

There are few points to be noted about each possibility:

1. Purusing some stock photography (seen below) it seems that there a a mix of shark pictures, with and without bloody mouths. And of course, this may be subject to a photographer’s bias.

2. If the blood is indeed from a kill, why would it stain so long and not simply wash away? Also, it should be noted that Great Whites don't eat that often.

3. If the blood is their own, why doesn’t it attract other sharks?

If you have comments on this topic, please let me know, I would like to solve this mystery!

Scooped (or rather Bitten) again!

Once again, Brian Switek of Laelaps and Mike Ryan of Palaeoblog have beaten me to the punch on reporting on a recent publication that suggests the first tetrapods were able to bite their prey (rather then suck their food up).

Reference: Markey, M.J. and Marshall, C. R. 2007. Terrestrial-style feeding in a very early aquatic tetrapod is supported by evidence from experimental analysis of suture morphology Proceedings of the National Academy of Science. Early Edition on April 16 2007.

United States’ security measures extend to the moon

Since 9/11 a lot of people have been grumbling about the United States’ increased security measures, which have resulted in closer scrutiny of visitors to the US, more paperwork and long queues at the airport. Well this document, dated July 24, 1969, from the Apollo 11 mission goes to show that the United State’s strict customs policy is not new:

(Click on the image to enlarge)

The three signatures on the document belong to Neil Armstrong, Edwin (Buzz) Aldrin and Michael Collins. And their cargo (not surprisingly) was “moon rock & moon dust samples”. And their point of departure? “MOON”.

What were T. rex’s tiny little arms for anyway?

American palaeontologist Henry Osborn first described T. rex but initially expressed doubts that the diminutive arms he found belonged to this enormous animal. After investigating further and finding it to be true, he considered their purpose and advanced the first theory in 1906: that they were used as ‘graspers’ or stabilizers during copulation.

But this was only the start of a debate that still rages. In 1970 British palaeontologist Barney Newman suggested that the small arms braced the beast's body as it stood up.
Another, contrasting theory suggested that the small limbs are vestigials (degenerated organs that have lost their use).

To add to the confusion it seems that the muscular of the T. rex was very well defined and though the arms were disproportional to the animal's body, they were still very strong. So some people consider that the most useful function of the limbs was to be used as meat hooks while the animal fed. This theory is supported by the beautifully sharp claws on T. rex’s two fingers.

In contrast, Greg Erickson has recently commented on a biomechanical analyses of a new specimen. The aim of this study was to try and understand the physical capacities of T. rex's diminutive structures. Erickson has concluded that the elbow could not be extended beyond 90° and though the arms were very strong (they could lift about 180 kg or 400lbs) they had a very limited side-to-side and up-and-down motion.

It is also known that T. rex's arms were often broken (and mended) during its life, suggesting that the arms were poorly suited for their function that these animals could go without using their arms for extended periods of time.

I read an interesting theory a while back that suggested the arms were most useful in juveniles, as a counterbalance to the young dinsaurs fast quickly. The suggestion was made that the arms were proportionally longer in childhood compared to adulthood. However, as far as I know this theory did not gain popularity.

The truth is that no one knows the answer. Scientific inquiry into this issue has been going on for a century and it doesn’t seem likely that the mystery will be solved soon. If you have any other ideas, please let me know!

Oekologie #4

I have recently discovered blog carnivals (truth be told, my initiation to the blogosphere is recent as well). Blog carnivals and circuses are a great way to get to know your neighbours in the blogosphere and so I have requested to host Oekologie, one of the best travelling blog carnivals around. Oekologie reviews the best ecology and environmental science posts of the month from all across the blogosphere. My turn comes in September so is a way off, but I am looking forward to it! In the mean time check out the happening at the fourth edition of Oekologie, which inlcudes my article on Bears Who Hunt Belugas.