Lines Blurred: Archaeopteryx Knocked From Perch of “First Bird”

December 14, 2011 at 3:57 am

Since its discovery in Germany in 1861, Archaeopteryx has been heralded as the “missing link” between birds and dinosaurs: the first bird. This conclusion was drawn because of the fossil’s bird-like features such as its feathers, wishbone, and three-fingered hands. However, recently, as more fossils are found with these same bird-like structures, Archaeopteryx’s position of “first bird” has been called in to question.

Professor Xu Xing, from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences in Beijing, who once researched Archaeopteryx in detail, now believes that his team’s newest discovery does indeed knock Archaeopteryx from its perch of “first bird.” His team has been studying a species very similar to Archaeopteryx named Xiaotingia.

Xiaotingia dates to 155 million years ago, the Jurassic period. By studying the two fossils, Xu has come to the conclusion that they are indeen feathered dinosaurs, not early birds. “There are many, many features that suggest that Xiaotingia and Archaeopteryx are a type of dinosaur called Deinonychosaurs rather than birds. For example, both have a large hole in front of the eye; this big hole is only seen in these species and is not present in any other birds,” said Xu. He also cited the fact that both Xiaotingia and Archaeopteryx both show “initial development” of a “highly extensible pedo-digit,” a characteristic of the Deinonychosaurs.

Professor Witmer from Ohio University, commented on Archaeopteryx’s downgrading, saying, “It changes a lot in terms of how we view early birds, and how early birds evolved. Every theory about the beginnings of birds – how they evolved flight, what their diet was like – were viewed through the lens of Archaeopteryx. So, if we don’t view birds through this we might have a different set of hypotheses.”

It’s a very hazy line between where dinosaurs end and where birds begin. Additionally, paleontology is more qualitative then quantitative so at the moment there seems no way to be sure of anything other than the fact that these two creatures walked the Earth at one point. Yet in this uncertainty is excitement. Anything could be discovered and rewrite the history of early birds, just like the discovery of Xiaotinga has. “Perhaps the time has come to finally accept that Archaeopteryx was just another small, feathered, bird-like theropod,” Professor Witmer said. But he added, “the reality is, that next fossil find could kick Archaeopteryx right back into birds. That’s the thing that’s really exciting about all of this.”

Sources:

http://www.independent.co.uk/news/world/asia/chinese-fossil-knocks-oldest-bird-off-perch-2327221.html

http://www.bbc.co.uk/news/science-environment-14307985

By Sam Charny | Posted in student post | Comments Off on Lines Blurred: Archaeopteryx Knocked From Perch of “First Bird”

The Wandering Albatross

December 13, 2011 at 12:31 am

The wandering albatross is known for it's ability to travel for many days over the open ocean. It can effortlessly glide for miles without flapping, and even drink salt water.

A wandering albatross in flight

Photo: Wikipedia Commons

The secret to their amazing flying abilities lies in their mastery of air currents. The wandering albatross uses both dynamic soaring and the principle of ridge lift to maintain flight over the open ocean without a need for flapping. Dynamic soaring is used when there are two planes of air moving at different velocities.

An animated explanation of dynamic soaring

Wikipedia Commons

By flying into the wind to gain altitude and then turning and flying with the wind to gain speed, and repeating the process the bird can actually increase its velocity and soar along at great speeds.

Ridge lift is another method of maintaining flight with little to no flapping by the bird. Ridge lift occurs when wind hits a wall of some soft, such as a cliff or ocean wave. the path of the air is diverted upwards creating a zone of lift for the birds to glide on.

Ridge lift diagam

Wikipedia Commons

With moving waves and shifting winds, it is possible for the birds to glide along with these currents for miles.

In addition to the ability to expertly use air currents to soar for miles, the wandering albatross has special tendons in it's wings that lock then in place when fully extended to conserve energy. this means that on a good day, the most physically demanding part of a journey for the albatross is taking off and landing. These attributes, coupled with a glide ratio around 20 : 1 make for a bird that can make some quite fantastic journeys.

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By szabo | Posted in student post | Tagged , , | Comments (4)

The Science of Smoke Rings

December 13, 2011 at 12:08 am

Though smoking may not be the best thing to your health, smokers have come up rather creative ways to exhale their smoke. For decades, smokers have been forming smoke rings as crowd pleasers or for own personal entertainment. Smokers, though capable of blowing these captivating rings, may not know the reason these rings form. It turns out that the rings are a product of fluid dynamics known as vortices.

Vortices, in their simplest definition, are spinning flows of air. Vortices have several properties:

  • The fluid pressure in vortices are lowest in the center and rises as the distance from the center increases. This is due to Bernoulli's principle. Bernoulli's principle states that "as the speed of a moving fluid increases, the pressure within the fluid decreases." (Mitchell Science). As the air in the vortex center moves the fastest, the vortex center will have the lowest pressure in comparison to its surroundings.
  • In every vortex, there is something known as a vortex line. A vortex line is at the core of every vortex and start or end at the boundaries in a fluid or will form closed loops. This creates the circular ring seen in smoke rings.
  • Vortices can interfere with each other, either constructively or not at all. That is, parallel vortices circulating in the same direction will merge to form a single vortex. Conversely, vortices may not combine if they are have opposite circulation, evident in airplane wingtip vortices where the two vortices spin in opposite directions but do not combine. This is due to a difference in air pressure among other reasons beyond the scope of this article.
  • Vortices also contain relatively large amounts of fluid energy

In a smoke ring, these principles explain why a smoke ring forms. The movement from the smokers mouth creates a disturbance in the surrounding air and as a result, creates a circular vortex.

But why do the rings travel through the air? In fact, though it seems like the ring is moving air forward, the surrounding air does not move.

As the website Science Hobbyist explains, "No air is moving on average. Think about it. If air was moving, then there would soon be less air at the right side of the diagram, and more air on the left side. But every time a dot moves forwards, some other dots are moving backwards. There is an overall circular flow, but air in general is not moving from right to left. If we put some smoke in the vortex, it appears that  something is moving form left to right. But smoke misleads us, since the smoke  doesn't show the backwards flow which cancels out the forward flow".

Vortex

Thus, in a smoke ring, the air is simply displaced around the ring while the air within the vortex simply circles within the ring. The smoke is carried along within this ring and creates the smoke ring seen.

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By Thomas Your | Posted in student post | Tagged | Comments (1)

A Hive of Robotic Bees

December 12, 2011 at 10:37 pm

In a previous post, Harvard's work toward developing a tiny robotic fly was discussed.  The idea proved interesting enough: small, insect-sized flying robots roughly 1.5 centimeters in length.  With enough revision, these robotic flies may even prove useful for more than just breaking new ground in small flight, such as aiding in rescue or gathering intelligence.  However, there were several problems.  To start, the robots were extremely unstable in their flight, and had to actually be tethered so they could follow a vertical course.  They were also energy-inefficient enough to require a cable connecting them to a power source.  Harvard is now in the second generation of this project- the robotic bee.  Their new ideas have also grabbed the attention of the National Science Foundation, and gained them a ten-million dollar grant in the process.

Since 2007, the launch of their first robot, the Harvard team has been busy.  A major aim of the new undertaking for a robotic bee consists of exploring the aerial maneuverability sought after in the original robot, using the first generation's design as a stepping-stone towards the new robotic bee.  They have also set their sights on possible practical uses outside of simple research.  Among those possible uses proposed by the Harvard team are robotic pollination of crops, traffic monitoring, military surveillance, and search and rescue.  The team will also aim to develop a high-power energy source compact enough to fit on the robot but efficient enough to power it, and to even develop a kind of "hive mentality."

Robotic Bee Design

Robotic Bee Design

Using what will essentially amount to a brain, the scientists aim to install sensors similar to the eyes and antennae of bees on the robot, allowing it to self-monitor its flight.  This will also allow it to keep track of its fellow robots and their actions, which will in turn allow for something of a hive mentality capable of communicating and making simple decisions as a group.  Essentially Harvard is aiming to set new standards in not only robotics and aerial locomotion, but also to provide new breakthroughs in the computing and programming of complex algorithms, low-energy cost computing, and high-energy power sources compact enough to fit on small machines.  Still in-progress, this project may change how scientists and engineers view complex flight.

Harvard's Robotic Fly

Harvard's Robotic Fly

Sources:

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By Andrew Chalifoux | Posted in Uncategorized | Comments Off on A Hive of Robotic Bees

The Saker Falcon

December 12, 2011 at 9:29 pm

The Saker Falcon is a very big falcon, one of the biggest with a wingspan of 105-129 cm and a length of 47-55cm. It is almost as large as the Gyrfalcon, and is a bird of prey which breeds from eastern Europe eastwards across Asia to Manchuria. There are several sub-species of Saker falcons; the steain Saker and the Altai Saker.

File:Falco cherrug Qatar.jpg

The Saker falcons have a wide range of colors, ranging from dark brown to grey to almost white. Saker falcons are known to lay 2-5 eggs, and in the winter they migrate south to Kazakhstan and the Middle East. Coming from the
United Arab Emirates i have seen many saker falcons as they are popularly used for falconry. The Altai Saker falcons are the favorite of Arab falconers as they are larger and are dark brown and gray. These birds of prey are pretty brave hunters sometimes attacking prey larger than themselves. Also it is known that the Saker falcons have no natural enemies other than human beings. Falconers prefer female falcons as they are more ferocious than the male ones.

( Warning some gruesome images) In this video Shaikh Hamdan Bin Zayed Al Nahyan of Abu Dhabi is shown with a group of friends going out to practice falconry in the desert of Abu Dhabi and you get a little taste of Arabian music.

The Saker falcons are now facing extinction, however, there are no accurate figures for the population of Saker Falcons, but it is believed that there are only 1000 pairs of birds left in Russia and 130 pairs in the rest of Europe. Due to their extremely large wingspan the Saker falcons are able to fly at very high speeds up to 200mph, this is one of the main reasons why the Sakers are popular in falconry. The have large eyes and a hooked beak which help them to find and eliminate their prey.

In the next video a man is shown training his magnificent Saker falcon, Herbert.

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By Saud Al Jawder | Posted in student post | Tagged , , , | Comments (1)