Over the course of the past week, we have been talking about the 'Characteristics of Life' in class. We are trying to figure out what all organisms (living things) share in common, and then classify this evidence as "characteristics of life." This is a surprisingly complex process.
One of the preconceptions members of our class held was that organisms have brains. After some debate, we recognize that organisms such as plants and fungi don't have what could be classified as a brain. We agreed then that having a brain is not a characteristic of life.
BUT CHECK THIS OUT!
The structure of the brain and how it came to be is very interesting. A research team has recently identified a brain-like structure inside a marine ragworm, a creature which hasn't evolved in hundreds of millions years! Apparently this neurological control center might be responsible for the organism's olfactory senses (sense of smell).
The ragworms brain-like structure, known as a mushroom body (because it looks like a mushroom), reveals a similar gene-expression as that of more complex animal brains, such as the brain of the human.
The importance of this research suggests that there is a common ancestral brain, that humans share in common with worms, insects, and other invertebrates. For more information visit http://www.nytimes.com/2010/09/07/science/07obbrain.html?ref=biology_and_biochemistry
QUESTION:
What 'characteristic of life' would be supported by the brain-like structure in a marine ragworm? In other words, how would a the ragworm benefit from a brain-like structure that allows for olfactory senses?
Since humans have 40% of the same genes as a bannana, that doesn't come as a big suprise. The brain-structure probably helps the ragworm make better responses to the environment or support breathing (like the autonomous part of human brains). But the structure could also do nothing at all, like whale-fingerbones.
ReplyDeletePS.: Ragworms for sale!
http://www.onlinebaitsuk.co.uk/live-baits-ragworm-c-21_53.html?osCsid=dvrb2o6mc1msulfb5d0qdidgc4
Correction here, what I meant was the "autonomic nervous system". And what sort of commenting tool is this? I get to type in a monowidth font?
ReplyDeleteGood idea about the response to environment. Also interesting is how you go further to suggest an autonomic response, involving 'gas exchange'. How does gas exchange generally happen in ragworms?
ReplyDeleteI think they use there things called "parapodia" to respirate, and they use those for locomotion too.* They are paired appendages on each segment of the ragworm. However another source staes that gas exchange occurs over the whole of the ragworm's body**, although particularly on the parapodia. This is concluded because there are more blood vessels there than usual. Some species even have gills.
ReplyDelete* http://www.bumblebee.org/invertebrates/ANNELIDA.htm
** http://www.earthlife.net/inverts/polychaeta.html