Sex, Football, Dinosaurs & Apes

LiveScience is one of my favorite publications. They have a lot of really interesting articles. Here are some links and excerpts from stories that caught my eye.

Fourth and Goal: NFL Coaches Make Lousy Decisions

"It's fourth-and-goal in the first quarter of an important National Football League game. The fans rally for the coach to go for it, but they know he probably won't. As usual, the kicker trots out.

Obviously the conservative coach knows something the fans don't. He's analyzed the numbers and is making a sound judgment.

Right?

Actually, the decision is consistently botched, according to a new study by David Romer of the University of California, Berkeley."

The Biggest Carnivore: Dinosaur History Rewritten

"The Age of Dinosaurs ended millions of years ago but paleontologists are still attempting to get a handle on the immense diversity and diverse immensity of these creatures.

Take the report last month that Spinosaurus is now officially the biggest carnivorous dinosaur known to science. This two-legged beast actually strode onto the fossil scene in 1915 when a specimen was described by German paleontologist Ernst Stromer. He figured this theropod (defined as a two-legged carnivore) was bigger than Tyrannosaurus rex, but the original Spinosaurus bones were destroyed by Allied bombs in 1944. So the T. rex reigned as the king size, carnivorous land beast for decades.

Then along came Giganotosaurus 11 years ago.

Now Cristiano Dal Sasso of the Civil Natural History Museum in Milan says Giganotosaurus has been dethroned based on estimates from a new Spinosaurus skull.

So just how do all these carnivores match up?"

So just how do all these carnivores match up?

Tyrannosaurus rex
Length: 40-50 feet
Weight: 6 tons
Fear factor: teeth up to 13 inches long
Lived: 65 million years ago Where: North America

Giganotosaurus
Length: 47 feet
Weight: 8 tons
Fear factor: 8-inch-long serrated teeth
Lived: 95 million years ago
Where: Argentina

Spinosaurus
Length: 55 feet
Weight: 8 tons
Fear factor: long, crocodile-like jaws
Lived: 100 million years ago Where: Argentina, Morocco, Tunisia, Algeria scale)

Why We Have Sex: It's Cleansing

Scientists have long wondered why organisms bother with sexual reproduction. It makes a whole lot more sense to just have a bunch of females that can clone themselves, which is how asexual reproduction works.

Turns out sex might have evolved as a way to concentrate lots of harmful mutations into individual organisms so they could be easily weeded out by natural selection, a new computer model suggests.

The classic explanation for the onset of whoopee, about 1 billion years ago, is that it provides a way for organisms to swap and shuffle genes and to create offspring with new gene combinations that might survive if the environment suddenly changes.

But some scientists think this isn't enough of a justification to outweigh the many costs of getting together to make little ones. Just ask any single person—sexual organisms have to spend valuable time and resources finding and attracting mates.

If all organisms were like starfishes and cacti, which just drop pieces of themselves when they want to multiply, reproduction would be a whole lot simpler. There would be no need for elaborate peacock feathers or bird songs; stags wouldn't need antlers; elephant bulls wouldn't have to produce stinky cologne and guys probably wouldn't spend so much money on dates.

Natural cleansing

The new work could help test a hypothesis first proposed nearly 20 years ago, stating that sex evolved as a way to purge harmful mutations from a population. According to this view, the random shuffling of genes through sex will sometimes have the effect of concentrating many harmful mutations into single individuals.

These individuals will be less healthy than their peers, and therefore more likely to be weeded out by natural selection, the thinking goes.

This hypothesis, called the "mutational deterministic hypothesis," is controversial though, because it assumes that single mutations by themselves are only slightly harmful, while a combination of many mutations together is much more damaging. Scientists call this phenomenon "negative epistasis."

Case Closed: Apes Got Culture

"They may not take in the opera or sip fine wines, but the verdict is in: apes are cultured.

Fifty years of research on gorillas, chimps and orangutans has shown they use tools, communicate, and sometimes shake their hands just because it’s cool.

Ecologist Kinji Imanishi first introduced the concept of culture in a non-human species in 1952. He suggested that Japanese macaque populations develop behavioral differences as a result of social, rather than genetic, variation.

Since then, scientists have claimed that a wide range of species exhibit signs of culture, including rodents, birds, fish, marine mammals, and non-human primates. Of all the species studied to date, only humans exceed the level of cultural variation shown by chimps.