Why you get carsick when reading

Do you get carsick when you try to read in the car? It’s very annoying for someone who really likes to bury their nose in a book. There’s this time in the car going somewhere—maybe a couple of hours. Why waste that time just staring out the window, when you could be reading? But once you start reading, your stomach tells you, in no uncertain terms, that you’re going to be sick soon.


Well, it has to do with how your body interprets mixed messages. Your vestibular system in the ears is constantly telling your brain that you’re moving. At the same time, your eyes are looking at a book that isn’t moving. These mixed messages tell your brain that something’s wrong. And the only thing that leads to this kind of mixed messages—at least the only thing for many millions of years of evolution—is that you’ve been poisoned. The body’s reaction to thinking that it has swallowed something really nasty is to un-swallow it. You know, throwing up.

This doesn’t affect everyone to the same degree, which is just individual variation. Maybe you have genes that don’t get as upset about this. That’s good if you like reading in the car. But it doesn’t bode well if you inadvertently swallow some poison.

New pre-human transitional fossils found in South Africa

Two years ago, in September 2013, cavers went deep into the Rising Star cave in South Africa. They found fossils of a previously undiscovered ancestor of humans. The new species, Homo naledi, fits into a fossil gap between the Australopithecine, and Homo erectus. The followup expedition found more bone fossils than at any other pre-human site in Africa. They found bones from at least 15 individuals.

Many of the features fell between what you would expect for Australopithecus and Homo: teeth, pelvis, hands, etc. The skulls looked like Homo, but the brain case was a little of half the size of H. erectus’s.

It is difficult to determine how old the fossils are. They weren’t found embedded in rock, which would allow radiometric dating, and are too old for carbon dating. If H. naledi is very old, it could predate Lucy; if young, it would be contemporary with H. erectus. But most likely is that it would fit in just as the Australopithecines and Homo branched, around 2,000,000 years ago.

You can read more at National Geographic, The Atlantic, and the Washington Post.

NOVA Evolution Lab

What could you possibly have in common with a mushroom, or a dinosaur, or even a bacterium? More than you might think. In this Lab, you’ll puzzle out the evolutionary relationships linking together a spectacular array of species. Explore the tree of life and get a front row seat to what some have called the greatest show on Earth. That show is evolution.

Nova has made a cool game where you can explore how different species are related to each other. It’s over at NOVA Evolution Lab. It’s a cool game where you drag different species to create a phylogenetic tree. You also have to identify what characteristics cause the different branches of the tree.

Why do we have allergies?

Allergies are really annoying, and sometimes deadly. They are caused by our immune system overreacting to a stimulus and causing the allergy symptoms, sometimes even death. So, how is this an evolutionary advantage? Why hasn’t natural selection removed this?

A good article at Gizmodo explains how a Russian researcher, Ruslan Medzhitov, has studied allergies and the immune response.

Allergies make a lot more sense in terms of evolution when seen as a home-alarm system, argues Medzhitov. Toxic chemicals, whether from venomous animals or plants, have long threatened human health. Allergies would have protected our ancestors by flushing out these chemicals. And the discomfort our ancestors felt when exposed to these allergens might have led them to move to safer parts of their environment.

It looks like the allergic response isn’t triggered by the presence of an allergen, but when that allergen starts harming the body–destroying cells. Essentially, allergies are your body’s way of trying to remove the allergen. Coughing, itching, sneezing, and tears are all ways that bodies try to get things out of the body. More research needs to be done on this.

Sitting on Cullen’s lab bench is a plastic box that houses a pair of mice. There are dozens more of these boxes in the basement of their building. Some of the mice are ordinary, but others are not: using genetic engineering techniques, Medzhitov’s team has removed the animals’ ability to make IgE. They can’t get allergies.

Medzhitov and Cullen will be observing these allergy-free mice for the next couple of years. The animals may be spared the misery of hay fever caused by the ragweed pollen that will inevitably drift into their box on currents of air. But Medzhitov predicts they will be worse off for it. Unable to fight the pollen and other allergens, they will let these toxic molecules pass into their bodies, where they will damage organs and tissues.

This would show that allergies are helpful to the body and there would be selective pressure for allergies as an adaptation.

Hope for fighting antibiotic resistant bacteria

One of the things that really scares doctors is antibiotic resistant bacteria. There is a version of tuberculosis that is immune from all of the drugs we normally would use; if you get it, doctors can’t do anything to fight it. This happens because some bacteria are naturally more resistant than others. Over time, these manage to survive better because they aren’t killed by antibiotics as quickly. This is evolution by natural selection. About 2/3 of bacteria form biofilms. Researchers have found a peptide that can destroy biofilms or stop them from forming. This can kill the bacteria. Hopefully this will give us a good class of drugs that can kill the normally antibiotic resistant bacteria. Videos:

  1. https://www.youtube.com/watch?v=a-apdGwBPz4
  2. https://www.youtube.com/watch?v=r_B2dURVl2I

How are we different from Neanderthals?

Our genome (all of our genes) is a fraction of a percent different from our evolutionary cousins, the Neanderthals. Our genomes are 99.84% similar. So what made us so different?

For one, consider how much really needs to be the same. All of the work that cells do needs to be there. How to make the endoplasmic reticulum and other organelles is the same. Heck, our genome and a banana’s are about 50% the same. And the Neanderthals need to have the same body plan, bones, heart, liver, teeth, etc. The genes for building these things are going to be virtually identical–I expect them to be 100% the same.

But it’s how these genes are turned on and off that’s interesting. Most of our DNA isn’t in genes. We used to call it junk DNA. Now we’ve learned that there are things in the DNA that turn genes on and off. And when you turn a gene on can greatly affect the structure of the organs involved. Darwin’s Galapagos finches had different beaks depending on what kind of food they ate. But the genes for the beaks were the same. So how did they have different beaks? The genes were turned on at different stages of development while in the egg. If you turn the gene on sooner, you get a larger, stronger beak, good for cracking nuts open. Turn it on later, and you get a narrow, pointy beak, good for picking insects out of plants.

So, the genes for us and Neanderthals are mostly identical. It’s the switches that turn these genes on and off that’s different.

Bill Nye and Ken Ham on Evolution

On Feb 4th Bill Nye had a debate with Ken Ham at the Creation Museum on the question “Is creation a viable model of origins in today’s modern, scientific era?”. Ken Ham is a creationist, and was on the side of religious creation. Unsurprisingly, Bill Nye was on the evolution side.

First of all, this is a bad debate. It doesn’t matter who “won” the debate, because evolution isn’t something that can be decided by arguing. As Neil deGrass Tyson likes to say:

The good thing about science is that it’s true whether or not you believe in it.

Also, what’s the point in a debate if one of the people involved states that there is nothing you can possibly say to change his mind? That’s what Ken Ham said, while Bill Nye said he would need evidence.

But someone asked creationists for questions, and another person answered these questions on YouTube. He does so in a non threatening manner and it’s very nice. He’s a chemistry student, and it shows in his understanding of the fossil record, especially around Lucy, and on genetic mutations, but then those aren’t his areas of expertise. There are many more examples than just Lucy, and there are mutations that cause duplication of genes. But I recommend watching the video.

Interbreeding among different hominid groups

Just because there were different kinds of ancient humans doesn’t mean they were separate from each other. The Neanderthals (Homo neanderthalensis) coexisted with Homo sapiens for a long time. But there was interbreeding among the different species. A recent article in Nature talks about genetic analysis of different groups of proto-humans, showing that these groups interbred with each other. In fact, much of the diversity in our variations came about due to the interbreeding of H. sapiens to H. neanderthalensis and H. Denisovan. Depending on where you’re from, up to about 4% of your genome can come from one of these other species.

However, there is some controversy about these results. David Reich has better quality genome sequences that should be analyzed in light of this work.