Saturday, 24 September 2016

Sexual Selection: how the female mind works

I spent a lovely afternoon at Gwydir Castle in North Wales last weekend.  Gracing the beautiful gardens were a number of peacocks and peahens.
Peacocks (the males) are well known for displaying their magnificent long tail feathers in a fan.  The brown feathers have shimmering tips of blue and green and a pattern that resembles an eye.  It is not difficult to see why a peahen would be impressed by that tail.



In evolutionary biology terms, the dimorphism of the peacock/peahen is because of a form of sexual selection.  Sexual selection is when the female gets to select her mate and the father of her offspring.  Obviously she will choose the one that is the most fit; big, strong, healthy, so that he can pass these genes on to her offspring and make them successful.
How does the elaborate peacock tail indicate his fitness as a father?  The theory is rather bizarre.  Peacocks are native to the rainforest, and to be honest a very long brightly coloured tail could be considered a hindrance; it makes you very conspicuous to predators, and it really hampers your movement through dense vegetation. 
And that is just it! Any individual who survives in spite of this handicap must have good genes, and therefore will make a good father!

Saturday, 10 September 2016

It's raining Slugs....


Arion rufus

Not many people like Slugs! Ugly, and slimy, and resembling doggy doo! But like all organisms, they have their role in the ecosystem, and somebody has to do the dirty work; the decomposition.  Slugs are omnivores, consuming a large variety of organisms.  Their exceptional suite of digestive enzymes is testament to this: not just amylase and invert awe, to digest starch and sugar respectively, but also proteases (protein), chitinases (the material of insect exoskeletons), and xylemases and ligninases to digest the woody stems of plants.

The other interesting thing about slugs that everybody knows is that they are hermaphrodite.  But did you know how intricate and beautiful the reproductive organs of a slug or snail are?  Best thing I ever dissected at university, and so I think we must introduce this to Dissection Club. Watch this space...