by chasingdaylightphotogra phy
Annual Leonids meteor shower provides sky show
[Via BBC News | Science/Nature | World Edition]
The annual Leonids meteor shower is set to reach its peak.
[More]
It seems that every year when this shower is up it is raining here. So I have yet to see them. Same with the Perseids.
Not too surprisingly, the Western part of Washington State is just not the best for watching the heavens. Your chances are not great but when it happens, the sky is really amazing.
by orcmid
Not A Good Start
[Via Eschaton]
That’s not supposed to happen.
[More]
No one was on board but until there is a good reason for this, it sure makes traveling on the train line a little scary.
from Wikipedia
Starvation ‘wiped out’ giant deer
[Via BBC News | Science/Nature | World Edition]
The giant deer, also known as the giant Irish deer or Irish elk, is one of the largest deer species that ever lived.
Yet why this giant animal, which had massive antlers spanning 3.6m, suddenly went extinct some 10,600 years ago has remained a mystery.
Now a study of its teeth is producing tantalising answers, suggesting the deer couldn’t cope with climate change.
[More]
The Irish Elk holds a special place in history because its discovery led some of the very first discussions about whether extinctions could even occur. The accepted wisdom was that species did not go extinct, that every animal created by God that survived the Flood was still around.
It was Cuvier’s work in the early 1800s that definitively proved that the Irish Elk and other megafauna had no living members; that they, were in fact, extinct.
The huge antlers these animals possessed became a just-so story in early evolutionary thought. In the 1800s some analogs of physics were applied to evolution. Species evolved along a trajectory. They became extinct when their trajectory made them unsuited for the environment.
So, the ‘reason’ Irish Elk became extinct was because big antlers were selected for. Eventually their antlers got too big and they got stuck in the trees. Later work indicated that this was not likely at all but it made a good story with a nice moral to it.
Steven Gould showed the much more likely explanation for the large size of the antlers — they are actually exactly the size one would expect for such a large animal. As an example of allometry Gould showed that as different species of deer grow larger, their antlers increase in size in a linear relationship. So the Irish Elk had such large antlers because it was a large animal.
Often, natural selection will drive a species towards larger size. In particular, sexual selection sees large size as a demonstration of the healthy nature of the animal, a measure of its reproductive prowess. And the large antlers then become an even more prominent display of reproductive strength and the overall health of the animal. Essentially, only an animal in very good health would be so large.
So why did they die off? It looks like the same way most animals become extinct. Their environment changed and the benefits of large size were turned against them as it became harder to find sufficient food to support such a large animal.
At least that is what this latest research would seem to indicate. If a species is unable to adapt to a changing environment that provides less food, it will see its population decrease.
A species survives because it is well adapted to its environmental niche. Change the environment and the species has to change, if it is to survive.
If the environment selects for smaller animals because there is not enough food for larger ones but sexual selection still drives for bigger ones, then the species is in for a rough time. It looks like the Irish Elk was not able to solve the conflicting needs of these two selective pressures.
SpreadingScience
Sustainable Path Foundation Idea Club
