Feeding the Birds Feeds Their Evolution

http://www.loughallenbasin.com/birds.html

Humans undeniably make a huge impact on the world. We are shaping the Earth's climate, its habitats and ultimately their inhabitants.

But did you ever think something as simple as throwing some crumbs to our feathered friends are driving their evolution? Probably not. Some birds have become so dependent on humans for food that is has changed their migratory pattern and their wing shapes.

Over 3.5 years, scientists in Germany studied the migratory patterns of birds called blackcaps. The birds has split into two groups with significant different routes. One set of birds migrated from Central Europe to southwestern Spain, the other to northwestern UK.

The newer pattern to the UK is shorter than to Spain. As a result, these lazier birds have rounder wings that give better maneuverability, but makes them ill-equiped for flying long distances. Their bills are also more narrow than their Spanish-destined counterparts who eat large fruit.

Surprisingly, these birds are raised in the same forest side by side but do not interbreed. The split into two distinct populations occurred in less than 30 generations.

"Humans Still Evolving as Our Brains Shrink "

There has been debate on whether or not humans are still evolving. The short answer, is yes we are, stupid.

Some changes are:

• The human brain is shrinking. Using skull measurements, it shows that the brain has been getting smaller in the last 5,000 years--about 150 cubic cm, or "roughly 10%." This is true regardless of the population measured. Researchers theorize this is because of societal differences such as a movement away from the hunter-gatherer lifestyle and more specialization use of our brains. Basically, maybe we don't need all those extra brain space.
• Humans have evolved some defenses against malaria. Malaria is caused by a parasite that is spread by mosquitoes, enters the bloodstream and infects red blood cells. One defense is sickle cell anemia, which deforms the cells and prevents parasitic infection. Interestingly, an Indian-Pakistani version has also evolved.
• A lot of people are lactose intolerant, but lactose tolerance only evolved about 7,500 yrs ago in Europe so that we could take advantage of non-human milk. Also, some genes have shown to allow resistance to type II diabetes.
• More analysis has shown that there has been many changes in our genome in the last 40,000 yrs. This may have be in response to our change in diet that used to be based on hunter-gatherers.

"Male Sabertoothed Cats Were Pussycats Compared to Macho Lions"

We remember sabertoothed tigers as being badass. I mean they had to be, they had awesome fangs and it had a Power Ranger!

However, science might be telling us that TV lied to us. Analysis of fossils of sabertoothed tigers and American lion may suggest that the tiger wasn't as aggressive as we thought.

As discussed in an earlier post, sexual dimorphism is common in many species. In the case of the prehistoric American lion, males were much bigger than females. However, tigers appeared to be the same size regardless of sex. Since neither cat exists today, how did scientists figure this out?

Fossils. And teeth. Although, you can easily sort fossils into groups based on size you have to consider that the animal grows over time. A bone from a young male could be the same size as an older females. Instead, researchers x-rayed the lower teeth and jaw of American lions and sabertooths. As the cats grow, their hollow teeth become filled with dentin, giving an estimated age.

By plotting tooth cavity diameter and jaw length for both species, it was obvious that the size fell into two groups, regardless of age. There was clear evidence for sexual dimorphism--that the bigger teeth were male and the smaller ones were female. However, the tigers sizes were only based on age--that "males were indistinguishable from their mates."

What does that mean?

Well, there needs to be a evolutionary reason for having bigger males. Bigger males can compete and battle better than smaller ones for resources and females. So if the American lion had big males, then they were more aggressive in competition. Scientists theorized that the lions had 1-2 male-dominated groups of females. The sabertooth tiger, instead shows no real difference in size, suggesting that the males and females existed more equally with no reason for aggression.

Duke University (2009, November 5). Male Sabertoothed Cats Were Pussycats Compared To Macho Lions. ScienceDaily. Retrieved November 5, 2009, from http://www.sciencedaily.com/releases/2009/11/091105121050.htm

Why Didn't I Evolve Sooner!?-Blame the Bacteria

Sometime after an event slightly elevating atmospheric oxygen and the already present simple life forms scattered about on Earth...nothing happened. For a billion years.

WTF happened?

Researches now theorize that bacteria utilizing sulfur is to blame. It is theorized that the oceans back then were mostly sulfur, not oxygen allowing these microbes to thrive. Sulfur-oxidizing bacteria do not produce oxygen, which kept the Earth stuck at simple life forms for a while.

However, something must have shifted in order to jump start evolution such as iron being introduced into the oceans by continental shift. About 600 million years later, multicellular lifeforms showed up and eventually evolved to.....Starbucks drinking, twittering, facebook using humans.

Snake with Foot Found in China

At the risk of this being photoshopped, I decided to post it for it's wtf-ness rating alone.

From the UK Telegraph:

Dean Qiongxiu, 66, said she discovered the reptile clinging to the wall of her bedroom with its talons in the middle of the night.

"I woke up and heard a strange scratching sound. I turned on the light and saw this monster working its way along the wall using his claw," said Mrs Duan of Suining, southwest China.

Mrs Duan said she was so scared she grabbed a shoe and beat the snake to death before preserving its body in a bottle of alcohol.

The snake – 16 inches long and the thickness of a little finger – is now being studied at the Life Sciences Department at China's West Normal University in Nanchang.

Snake expert Long Shuai said: "It is truly shocking but we won't know the cause until we've conducted an autopsy."

A more common mutation among snakes is the growth of a second head, which occurs in a similar way to the formation of Siamese twins in humans.

Such animals are often caught and preserved as lucky tokens but have very little chance of surviving in the wild anyway, especially as the heads have a tendency to attack each other.

10 Worst Evolutionary Designs

Taken directly from Wired Magazine.

Illustration: Roman Klonek

1 Sea mammal blowhole. Any animal that spends appreciable time in the ocean should be able to extract oxygen from water via gills. Enlarging the lungs and moving a nostril to the back of the head is a poor work-around.

2 Hyena clitoris. When engorged, this "pseudopenis," which doubles as the birth canal, becomes so hard it can crush babies to death during exit.

3 Kangaroo teat. In order to nurse, the just-born joey, a frail and squishy jellybean, must clamber up Mom's torso and into her pouch for a nipple.

4 Giraffe birth canal. Mama giraffes stand up while giving birth, so baby's entry into the world is a 5-foot drop. Wheeee! Crack.

5 Goliath bird-eating spider exoskeleton. This giant spider can climb trees to hunt very mobile prey. Yet it has a shell so fragile it practically explodes when it falls? Well, at least it can produce silk to make a sail. Oh, wait — it can't!

6 Shark-fetus teeth. A few shark species have live births (instead of laying eggs). The Jaws juniors grow teeth in the womb. The first sibling or two to mature sometimes eat their siblings in utero. Mmm ... siblings.

7 Human stomach. People can digest a lot — except for cellulose, the primary component of plant matter. Why don't we have commensal bacteria in our guts to do it? They're busy helping termites.

8 Slug genitalia. Some hermaphroditic species breed by wrapping their sex organs around each other. If one of said members gets stuck, the slug simply chews it off. What. The. Hell?

9 Quadrupeds. Let's say you're a four-footed animal. Now let's say you get a wound on your back, or an itch, or a bug wandering up there. Tough luck, kid. You probably can't do much about it. Hope there's a low branch around.

10 Narwhal tusk. The unicorn-like protuberance on a male narwhal's head is actually a tooth that erupts through the front of the jaw and keeps on growing, up to 9 feet. Narwhal: "Doc, I have a toothache." Dentist: "Indeed."