Similar Exo-Solar System



7th grade did 2 point discrimination lab


The 7th grade is currently studying skin. Today we did a lab on 2 point discrimination. This is the poking lab. Students paired up and bent paperclips so the ends were close together. They then tried seeing if the “pokee” could tell the different between a touch when the tips were 1 mm apart at various body locations (finger, back of hand, back of neck, earlobe, etc.). They tried this with increasing distances until they could tell the difference between 1 tip and 2 tips. Some locations on the body can detect tips that are very close together, others don’t have as many touch sensors and the tips need to be further apart.

Your brain is busy processing things you are never aware of

In an interesting experiment at the University of Arizona, researchers have found that your brain does a lot of processing of visual information, and sees things that your conscious self doesn’t “see”.

faces vase

When looking at the famous image of a vase that has faces on either side, your bring is doing processing of the negative images in white. They hooked subjects up to an EEG, the researches looked at the brainwaves of the subjects when they were exposed to images of black middle figures (silhouettes) with negative white space on either side, similar to the faces and vase picture. There is an N400 spike when looking at images where there is something in the negative white. That means that 400 ms after the image is shown, the brain shows a negative voltage spike. But it only does this when there is something in the negative white. There is no N400 spike if it’s just a center black object and the sides don’t mean anything.

So the brain is processing the white shapes, but not necessarily passing that on to the consciousness. There are things that your brain senses, but you don’t perceive.

Mutualism with a darker side

You should know what symbiosis is. One species helping another and vice versa. But that’s not quite it. Only one of the two species needs to be helped for it to be symbiosis. There are 3 main types:

  1. Mutualism: This is where both help the other. One species helps the other, and the other helps back in return. Many people think of this as symbiosis, but it’s really only one of the forms.
  2. Commensalism: This is where one species is helped, the other doesn’t benefit, nor is it harmed. A bird building a nest in a tree; the bird is helped, the tree isn’t helped nor harmed.
  3. Parasitism: One species is helped, the other is hurt. A tick sucking blood from a mouse. Yes, this is symbiosis.

One of the really cool examples of mutualism is the acacia tree, and the ants that live in them and protect them. The tree provides a place to live and food (nectar). The ants provide protection by attacking anything that comes near, from elephants to weeds.

But researchers have recently discovered that there is a dark twist to this mutualistic relationship. The acacia tree actually enslaves the ants. Once an ant eats the nectar, it can’t get sugar from any source other than an acacia tree.

The nectar contains sucrose, a sugar. To digest the sugar, ants use the enzyme invertase to break sucrose into simpler sugars. But the acacia ants don’t make invertase properly, and can’t digest sucrose. It turns out that the acacia nectar includes invertase in it. Kind of partially digested. So the ants can eat the nectar and digest it.

But why can’t the adult ants make invertase? As larvae they can. So where does it all go wrong for the ants?

The nectar contains another enzyme that blocks invertase production. Once an ant eats the nectar, they can’t produce invertase anymore. And to be able to digest sucrose, they need to get it. From now on, they need to eat nectar that is laced with invertase: the nectar from the acacia tree.

The first time a new adult ant eats the nectar, it essentially becomes a slave. It has to protect the acacia tree, because the tree is the only source of food it can eat.

This may be Australia’s hottest year in history

According to The Guardian, Australia is on track for 2013 being its hottest year in recorded history. The past 12 months have been warmer than those months in any previous year. Almost 2 months to go, and their summer is looking pretty hot.

So far in 2013:

  • Warmest summer
  • Warmest January and September
  • Warmest 12 month period
  • 15 months in a row of above average temperature

Migration patterns of animals have changed due climate change.

And, just like her in the US, their politicians are also head-in-the-sand saying that climate change isn’t real. It’s sad. Really sad.

At least it’s not dinosaurs …

Not a dinosaur, or any other species of animalia. But scientists have taken prehistoric seeds and grew them, using in vitro technology, to adult plants. The seeds were from before the last ice age, around 31,800 years ago.  The plants grew to maturity, and need to be cross-fertilized to reproduce.

This is the new most ancient, multicellular, viable, living organism. The previous record-holder was from a 2000 year old seed from Masada.

This reminds me of Norway’s Seed Vault in Svalbard.