October 27, 2010

Do Bacteria Age?

Biologists call the aging process senescence because they simply cannot go on living without inventing new words that sound far more complicated and science-y than the ones they are replacing.

When I think about aging (or senescence, if you think that sounds better, because you're a snob), I usually consider organisms that go through different developmental stages because it's easy to see the aging process:

But bacteria don't go through these stages. They aren't born as baby bacteria that grow into adult bacteria.
While multicellular creatures grow by adding more cells, bacteria are single-celled creatures, so they don't grow. A bacterial cell is and always will be just one bacterial cell (but that doesn't stop bacteria from multiplying and producing millions more of themselves). Bacteria also don't have babies like animals do: to reproduce they split in half and form two daughter cells.

Since they don't go through the developmental stages we usually associate with aging, is there any evidence that they actually grow old?

The answer is, "Um, kinda."

Aging is basically the accumulation of cell damage. As years go by, all of our cells acquire damage (some faster than others). Signs of such cell damage include wrinkles, grey hair, crankiness, and/or feebleness.

Bacterial cells accumulate damage too, but they have a way around this (which is really no fair). When an old, damage-laden bacterium splits in two, it doesn't spread the damage equally. It turns out that bacteria are able to transmit most or all cell damage to just one daughter, making a nearly perfect daughter cell and a rejected step-child one.

This is a great way to prolong the life of the bacterial colony: concentrate all the negatives into one area, like Texas.

I hope the Beverly Hills crowd doesn't catch wind of this. They might try to clone themselves a damage-catcher to harbor all of their signs of aging. I mean, ick. Plastic surgery is bad enough as it is.

October 21, 2010

The Pre-Cambrian Era: It Was Boring

The Pre-Cambrian era is the time between the formation of earth and the beginnings of complex life in the cambrian era.  Things were much simpler back then.  You know how you look back on your childhood, and think, man, things were so much easier back then? That's what the Pre-Cambrian era is for the Earth. She misses the good ol' days, before all of us horribly complicated everything.

The Pre-Cambrian era accounts for 85% of the history of earth, which is too bad for the Earth because it was, to put it lightly, really boring. I'd say it was like 3.9 billion years of crickets chirping,

but there were no crickets.

I'd also like to say it was like a vast expanse of nothingness with but a lone tumbleweed blowing by, but alas, there were no tumbleweeds either. It was consumingly, completely, and downright super-ridiculously boring. (Kind of like my day at work today, but don't tell my boss I said that. I need to pay my bills and get acupuncture treatments.)

The first cell appeared around 3.8 billion years ago. He was really lonely. Think of the time you felt most alone in the world and multiply that by a jillion, and you won't even come close to how alone the first cell was. 

Lucky for him, and us, he did make more cells, though. So it all worked out okay.

These first cells in the Pre-Cambrian era weren't floating around saying, "Like, ohmygod, it's totally the Pre-Cambrian era. Cool beans, yo." They didn't say anything about the Pre-Cambrian era at all.

No. Even if the first cells were self-aware, they wouldn't know it was the Pre-Cambrian era. We just call it that from our viewpoint now--the same way that Aristotle wasn't all like "Hey, it's 350BC, bitches." He didn't know that. (He also may or may not have worded it that way.) He knew nearly everything else there was to know at the time, but not what year it was by our current year-counting standards.

Pfffft, Aristotle. Figure it out.

Instead of discussing what geologic era the cells were in, they busied themselves by multiplying and figuring out how to do photosynthesis.  The first cells figured it out around 3 billion years ago, and they got BUSY.  They churned out so much oxygen, that it completely changed the climate of the planet and set up favorable conditions for the evolution of some upcoming oxygen-breathing fellas in the Paleozoic era, starting with the Cambrian explosion.

I'll talk about explosions next week, and until then, I'll leave you with this:

October 14, 2010

I Love You, Mitochondria

I think that lately I've been taking my mitochondria for granted, so I decided to do a post about how sweet and helpful they are.

A mitochondrion (-on being singular, and -a being plural. So much lately about strange singular/plural pairings. I apologize...)

Yeesh, that wasn't even a sentence. Take 2:

A mitochondrion (still with me?) is the organelle we have that provides our cells with energy. You know how you feel hyper and stupid when you eat too much sugar? Or is that just me?

The mitochondria are the ones that turn that sugar into the energy that makes you run around in circles.

They look like a bean on the outside.

But if you cut it open and look on the inside,

there are lots of folds and creases.

This shape allows the mitochondria to set up a chain of reactions that turn energy from sugar into energy the cell can use to do all the stuff they do--like move around or make proteins or help you read this blog. Whatever.

Mitochondria are especially cool because they aren't really yours.  They have their own DNA, they multiply on their own schedule, and they follow their own rules.

It is thought that they were once independent, stand-alone living things that squished inside another cell and took on their role as the energy producer.  This explains why they look a lot like bacteria and have their own DNA.  This whole idea is called the Endosymbiont Theory. (I just heard a voice in my head say "you're an endosymbiont theory." I think I need counseling.)

You get your mitochondria from your mother only: egg cells have mitochondria, but sperm do not. Remember, the egg cell is humongous compared to the sperm, so you get most of your cellular accessories from your mom.  The sperm just contribute DNA. They can't bring much else on their marathon journey because, after all, it's a race, and winner takes all--no point weighing oneself down with unnecessaries.  Mom's egg cell has to do the heavy lifting when it comes to providing baby's first cell with what it needs. So technically, you get more DNA from your mother if you count your mitochondrial DNA, which you should.

This fact makes maternity tests very easy, because the mitochondrial DNA of a mother and child are the same (save a few mutations, since those just happen). But maternity tests aren't as common as paternity tests: usually a woman is pretty sure if a kid is hers... since... well, you know.  However, they are very helpful if you are studying ancestries... or identifying bodies.

So to recap:
1. Mitochondrion in singular, mitochondria is plural (are plural?).
2. Mitochondria provide your cells with energy.
3. They are not yours. You can't tell them what to do.
4. You get them from you mom.

I hope they don't ever realized that they have become our prisoners and must work forever as our slaves, tirelessly storing energy for our cells. If they ever rise up and revolt against us, we're screwed.

October 08, 2010

The Giant Pacific Octopus

This is a Giant Pacific Octopus. It was well named by a certain Captain Obvious, for it is indeed all of the following: giant, pacific, and octopus.

If I had to pick a favorite animal (because a 2nd grader demanded so, for instance), it would probably be the Giant Pacific Octopus. But to be fair, all octopuses* are awesome. These animals are crafty, sneaky, curious, and awesome. To illustrate this, I offer your the following anecdotes and random facts:
*It is indeed octopuses, and not octopi.  Latin words ending in "us" are made plural with "i," but octopus ends with "pus" from the Greek word for "foot."  With no Latin directly involved, you don't make it plural with any fancy "i" at the end. It's just octopuses. Consider yourself knowledge-bombed.
1. Octopuses, like all intelligent animals, can get bored, which can lead to destructive behaviors, so many aquariums supply their resident octopuses with toys. The octopus at the Aquarium of the Pacific in Long Beach, CA has a Mr. Potato Head in his tank. I'm not kidding. I saw it.

2. Octopuses can tell their human handlers apart, and they often have favorites... and not-so-favorites. If an octopus doesn't like you, you might get squirted with water when you walk by his tank. So watch out.

3. Octopuses eat just about everything they can find in the ocean, which is probably why they are so smart. They have to improvise all the time to get food.

4. Giant Pacific Octopuses are solitary animals and only live for 2 years. How strange to be so smart and complicated, but live alone and sleep under rocks for just 2 years.

5. Giant Pacific Octopuses have been known to curiously "inspect" scuba divers' equipment, which usually consists of tugging on various parts of the scuba get-up. I read a report of a diver who almost had his mask pulled off by an octopus. In the octopus's defense, I don't think he realized that his curiosity could literally kill the cat, or human, in this case.

After writing this, I did a quick google search for "scuba cat" and found the highlight of my day:

6. Lastly, I present to you a story from my friend Sharin about the octopus in her UCSD Zoology class.

It would appear that the octopus swooshed herself across the room to rid the other tank of its inhabitants and then fwooshed herself back to her own tank.

I have heard reports of octopuses in aquariums breaking into other exhibits in the night, gorging themselves on rare fish, and retreating to their own tanks before detection, but before this, I hadn't heard of an octopus leaving water to do this.

Several questions:
1. How did she even notice the tank across the room full of fish?
    1a. What if it had just been a TV playing an endless loop of Finding Nemo? What would she have done then?

2. Wasn't she worried about dying on the munchy-induced journey?
    2a. Was the zoology department putting her on a diet or something? Why so desperate for food?

3. Did she return to her own tank, despite the risk of being out of water a second time, to avoid immediate blame?
    3a. Has she done this before?

October 01, 2010

Dam Impressive

The dam. An amazing feat of engineering. A testament to mankind's triumph over the flow of water.

I have mixed feelings about dams (dam feelings?). They can be used to create hydroelectricity, they are the source of endless dam jokes, and they're just generally impressive looking.  But it's also a big disruption for natural habitats.

If only dams proved to be suitable habitat for some sort of daredevil, cliff-hanging, Sylvester Stallone-esque animal. If only there was photographic evidence that some animal could just walk across a dam's nearly vertical face like it was a natural feature of the landscape. Maybe then I could cast aside my dam doubts and just be ensconced in a blanket of dam appreciation for ever more.

Thank you, ibex. Thank you.

**photos courtesy of my younger bro (not little, for he is indeed much bigger), Mattman.