Showing posts with label science. Show all posts
Showing posts with label science. Show all posts

Monday, September 29, 2014

Meet the Kardashian family of the fossil world

Hallucigenia, my bestie.
Remember this weird little dude, Hallucigenia, who lived about 500 million years ago?

He's so freaky that scientists can't place him in a family tree with any other animals -- they don't even know which end is his head and which is his rear. Oh, Hallucigenia, you oddball, orphaned critter with a mysterious butt, I love you truly.

But wait. What's this I hear? Some scientists have just discovered its family tree! Turns out Hallucigenia has two living relatives, who also happen to be among the most lovable and preposterous creatures on our planet. Hallucigenia is related to:

1. Velvet worms
In some species, the male puts some sperm
onto the female's back, then the sperm
melts her skin to get inside her body.
Ouch, tough break for the ladies.
OK, get this. Turns out Hallucigenia's legs each ended in a kind of foot with two opposing claws. These claws later evolved to form the mouth of today's velvet worms.
Yes, that said mouth. Velvet worms' jaws are "no more than legs modified for chewing," according to the scientists
Think how weird this is. The shape of the Hallucigenia claw turned out to be pretty handy for chewing, so after a few hundred million years -- voila! -- there's the foot, right in somebody's mouth, chewing. Just goes to show you that evolution is willing to make use of any tool for any job. (But don't try feeding your foot a sandwich. It probably won't work.)
2. Water bears
Way kooler than any Kardashian.
If you don't know about water bears, hang on to your hat. These tiny eight-legged dudes can survive basically anything. No really, anything. Temperatures from nearly absolute zero to above boiling. Enough direct radiation to kill a person. They can dehydrate and go dormant for ten years, and then come back to life, all fine and ready to party. Best of all, they have survived the vacuum of space. All true; look it up and fall in love.
As a longtime fan of both Hallucigenia and water bears, I am so happy to find out they are cousins. How did I miss the family resemblance?
This excellent family tree also includes several fan favorites in the extinct category, such as Anomalocaris and Opabinia. Check your Giant Evolution Timelines for those little guys.

Like the Kardashians, everyone in this family tree is bizarre, attention-getting, and related in confusing ways. They are physically repulsive and riveting at the same time. I can't look away. When's the family reunion? 

Smith MR, Ortega-Hernández J. Hallucigenia's onychophoran-like claws and the case for Tactopoda. Nature. 2014 Aug 17. doi: 10.1038/nature13576. [Epub ahead of print] PubMed PMID: 25132546.

Thursday, June 26, 2014

In which we get a nibble from National Geographic Kids

Friends, something went down in New Paltz, New York last weekend. Something small, nerdy, and delightful. It was:


I learned many, many delicious things there, but most importantly, I met one Ms. Shelby Alinsky, Children's Book Editor at National Geographic Kids. Take a good look at Shelby, my Rockstar #1.

Shelby (left) and I weren't actually
standing in a lovely meadow.
But we look nice there, right?
I had arranged for a one-on-one consultation with Shelby, and I confess to some nerves. National Geographic Kids is one of the publishers I have daydreamed about for years, and now I was meeting an actual, living, Homo Sapien editor who might just hate the Timeline. Oh, jeez, how's my hair?

Rarely have my fears been so thoroughly dismissed by reality. Shelby is lovely. Within a few minutes was on the floor with me, checking out the Timeline and asking great questions. We got to chatting, and ended up taking about 45 minutes instead of the planned 15.

Best of all, she expressed interest! She took a Timeline and Ancient Creature Cards to "discuss with the team." By the end of the weekend she was saying things like, "I could see a great future for this." Oh, Shelby, how I love thee.

I know, I know, I know. I shouldn't get my hopes up and all that. Whatever. They're up already.

David (left) and I weren't really flying
through space close to the Rosette Nebula.
But he's a big ol' space geek, so I put us there.
Also, there was a Rockstar #2, one David Aguilar, Director of Science Information at the Harvard Observatory, and author of many great books for kids about space. Check out this recent one, which also deals with evolution in really funny, unexpected ways.

David and I also had a one-on-one consultation, in which he was kind and supportive. By the end of the weekend we were like old friends. Well, old friends who just met. And who don't really know each other. Listen, I got his card, what do you want?

So there you have it: hope.

Saturday, January 18, 2014

Found! The cute, fuzzy ancestor of bears, wolverines and your kitty (To read with the kids)

Did you know that your kittycat and the wild hyenas of Africa evolved from the same animal? Kids, meet Dormaalocyon Latouri, or Dorma for short.

Dorma was a small, 2-pound, squirrelish, tree-loving mammal living about 55 million years ago in what is now Europe. Scientists have discovered a new bunch of fossilized teeth from Dorma and figured out that she is the ancestor of lots of animals alive today, including our excellent kitty, Mr. Opposite, and your excellent kitty, if you have one.


What does it mean to be Mr. Opposite's ancestor, you ask? Well, take a look at Mr. Opposite's Family Tree #1 (which contains females only to keep it simple.) You can see that Mr. Opposite and his sister share one mom kitty. He and his cousins don't have the same mother of course, but they do share one grandma kitty with Mr. Opposite. If we include his second cousins too, you can see that all twelve cousins share one great grandma kitty. Let's call her Norma. (Hi, Norma!)


Norma lived maybe ten years ago, long enough ago for her to have her two babies, for those babies to grow up and have their babies, and for them grow up and have more babies, including Mr. Opposite, who is alive today. Because she is the shared great-grandma, Norma is the ancestor of Mr. Opposite and all his cousins.

Family trees can go back waaaaay longer than ten years. They can go back so far that they show the evolution of one kind of animal into another. Check out Mr. Opposite's Family Tree #2, which goes back 55 million years, to Dorma's time.

You can see from this tree that Dorma is the shared ancestor not only of Mr. Opposite, but also of all his distant cousins alive today: coyotes, eared seals, wolverines, skunks, red pandas, bears, raccoons, mongoose, hyenas, civets, and African civets!

Even though Dorma went extinct a long, long time ago, she left us all these fuzzy mammalian carnivores, one of whom is in my lap purring as I write this.

Thanks, Dorma, you're the greatest.

Saturday, October 12, 2013

Hey kids! Birds are evolving right before our eyes!

First, meet the cliff swallow. These sweet little birds use mud to build bubble-shaped nests that hang from walls and ceilings. They also eat bugs that they catch flying in mid-air. The little bugs try their best to dodge being eaten, but the birds are able to turn and dive in tight patterns to catch them. Cliff swallows' wings are triangular, short, and pointy, which are good for close maneuvering like that.
Cliff swallows: 
Anti-gravity housekeeping at its very cutest.

But here's the thing. Cliff swallows love to nest near highways. This brings them close to lots of speeding cars, and
-- BAM! -- 
plenty of cliff swallows become roadkill. (Brief pause here to be sad about that. Poor birdies!)

So over thousands of years, these birds evolved wings to be able to maneuver in the air and catch bugs. But then highways were built, and suddenly huge hunks of metal were zooming through the neighborhood way faster than bugs. The birds had a new way to die (BAM!) or if you think of it another way, a new way to survive (dodge that huge speeding metal thingy!)

Birds with shorter wings can dodge and turn more quickly. Birds who can turn more quickly can better dodge the cars. The birds who can better dodge the cars have a better chance of surviving. Hmmm, it's starting to look like some evolution might happen...

Meanwhile, meet Charles and Mary Brown. They study cliff swallows at a research station in Nebraska that is chock full of the birds. Charles and Mary always pick up roadkill. Here's what they say in one paper:
"As we traveled daily in the course of our research,
we stopped for each road-killed cliff swallow. We made the same effort
 to search for road kills and drove the same roads each year."
How many years did they do this, you ask? Thirty.

Charles and Mary. Ah, biology love.
Yes, you read that right. Thirty years. Think about that. A woman and her husband, driving the same roads for thirty years, picking up roadkill. For science. Was it romantic? Did the car smell bad? I don't know, but I love these people.

Anyway, while they picked up the dead swallows, they were also studying the living ones. So now they have thirty years of information on both the birds that got killed by cars and the birds that didn't. And they noticed that fewer and fewer birds were getting killed by cars. Could it be that the birds were evolving the ability to dodge the cars?

Yup. After thirty years and many generations, the cliff swallows' wings got shorter on average. As the longer-winged birds got killed off more often, the shorter-winged ones were left to produce the next generation. And on it went, so that fewer and fewer birds had longer wings, so fewer and fewer were killed.

This is a perfect example of how natural selection works:

  1. There's a change in the environment. (That's the cars zooming through like they own the place.)
  2. Some animals have an advantage in surviving in the new environment. (Shorter wings.)
  3. The animals who don't have the advantage (longer wings) die more often.
  4. The animals that survive longer have more kids than the ones that die. (Well, duh.)
  5. The animals born to the survivors have that same advantage. (More baby birds have shorter wings like their parents.)
  6. After several generations, more of the animals have that advantage. (Thirty years later, everybody's wings are shorter.)

So there you have it, kids. Proof that when two biologists fall in love, they will do nerdy and excellent things together for a long time.

Oh, and also that evolution is happening around us all the time.