Eight legged freaks

It's almost halloween, so how 'bout some scary biology curiosities? At least it's scary if you have arachnophobia, in other words if you're afraid of spiders (which I'm not...I'm only afraid of things that has no limbs and no face and dwell this earth a couple of centimetres under our feet...yep, I'm afraid of worms!).

Spiders are kind of cute. They have eight legs, nice eyes (and good vision to, actually), pretty colors and patterns and they may or may not have hair (which isn't hair as in "cuddly", but hair as in "I can sense the worlds movement through sensory systems you humans never could imagine").

Still, I can see why some of you are frightened whenever you come across an arachnid. They could bite you (which worms usually don't do, unless they're disgusting leeches!) with or without poison; they could move rapidly and unpredictable; they can climb up in any possible environment; you can come across them when you least expect it and they could be huuuge. And they can catch animals way bigger than themselves. They can even eat birds and sometimes, if we're lucky, there's a human with a camera to take some pictures so that we can be facinated that others than ourselves likes to eat some chicken now and then.


It's not really that common but it seems like they used to be munch frequently on feather delicacies during what one might refer to as "the golden age of mygalomorph spiders".

Sources:

http://en.wikipedia.org/wiki/Goliath_birdeater

http://www.blueplanetbiomes.org/goliath_bird_eating_spider.htm

Eye see you

I've never really considered that molluscs could percive the world in a highly sophisticated manner. Well, some actually do. And I should not really be that surprised, but since I'm a human I naturally assume that we are the measure of all things seen as life and that a "simple" little oceanic being would not have senses in the same class as our own...

Here's some close-up shots at a clam (Aequipecten irradians) with it's characteristic blueberry-like eyes. Have no time to dig up any dirt about these sensory organs but I trust that you're all familliar with the wonders of google.com!

Image sources:
http://www.augsburg.edu/biology/photoofmonth/scallop-eyes-close.jpg
http://www.eyedesignbook.com/ch3/fig3-05aBG.jpg
http://www.augsburg.edu/biology/photoofmonth/scallop-eyes-menacing-close.jpg

You fill up my senses

I'm taking an advanced course at the moment, named "Sensory ecology". It's not really my cup of tea, since I'm usually drawn to genes and molecular biology stuff but there are some highlights. Hot shot professors from all over the world have flewn over to Lund just to give us 50 PhD students (also from all over the world) a 2 h lecture about their topic. And we have ca 3 lectures per day in two weeks, which of course makes the speakers want to stand out from the other lecturers by telling us about behaviours and characteristics in nature that deviates from what we, as humans, would like to precieve as normal.

Image revised from http://www.nadeet.org/pics/newsletter/goldenMole.jpg

Today, one of the topics where the golden mole of Africa. This is a cute little guy, but it has such bad eye sight that evolution have allowed the skin to cover the eyes completely, which only allows it to distinguish light from dark. And it doesn't like it light, so as soon as the sun rises, the golden mole burrows itself deep down in the sand. Instead of relying on vision, these creatures dwell the Namibian desert during the night, searching for insects to eat. To be able to locate it's prey (that's only present on small grass humps in the sand, which in turn is only present here and there in the desert), they have an enormous malleus (that thing we have in our ears, banging at the ear drum when a sound wave causes it to vibrate) specialized for low frequency sounds. To detect the insects faaar away, the golden mole combine "head dipping" and "sand swimming", which allows it to detect things we wouldn't even hear if we had the insect in our ear canals. Marvelous!