Thursday, July 29, 2010

The Jacana

well, I'll tell you what, I went to Les Grands Tetons avec my family and friend for vacation last week.

and i'll tell you what else, it was beyond beautiful.

[follow standard magic eye procedure and you'll see me. i'm on the right!]

i was really frustrated at first when we got there, because the birds were not iowa natives. i could not recognize hardly any of them! it was so annoying to see this guy:

and not have a clue as to who he was! i felt like such an ornithological fraud. don't worry, i didn't go into a state of depressed self re-evaluation wherein i decided to completely give up birding.

i just got a book for species ID!

turns out that black and white dude is a magpie. the bird on the front of the book is a male western tanager, which i saw flitting around camp more than once. his colors are so wild!

also at camp was a fellow birder! she works for hawkwatch,and it was great to hang around and geek out about birds with her. she had a sibley guide, which made me jealous. naturally, i had to get one so i didn't have to keep coveting hers! [and one about behavior. thanks mom and dad!]

my dad totally got mad at me for my instant gratification reflex. i blame society and say it's a symptom of not only me but my whole generation to want things RIGHT NOW. so gimme dat book!

i figure it is now up to me to:
a) wolf down the information in these books as fast as i can and then
b) relay it back in fun and easily digestible blog-o-form to you, the reader!

weird, it's kind of like when a mother bird regurgitates food into her young's gullets. happy analogy! but kinda gross!

while i was perusing these new books of mine for information about grouse mating rituals, i stumbled upon these guys:

jacanas! not grouse, but not bad! they're in a family known as jacanidae, and in the same order as killdeer [charadriformes].

the family is comprised of six species, all of which are characterized by what first caught my eye: the foot morphology.

jacanas, being shorebirds, have "amazingly long toes" adapted for smooth commute on top of floating vegetation.

holy phalanges, that thing can walk on lily pads!

my favorite, aesthetically speaking, is the comb crested jacana. also known as lilytrotters, comb crested jacanas are cool because they have those weird bright red combs on their foreheads; it's almost as if walking on water hyacinth wasn't impressive enough.

one might think: well, the comb must be for the males to attract the ladies. TyPiCaL~*

and one would be right! kind of!

BUT jacanas are an interesting set of birds: they are polyandrous.

as you may have guessed from the above stock photo, polyandrous implies "a lot of guys serving one girl." but i can break it down even further for you with my rudimentary understanding of greek! as i understand it, polygamy is multiple partners; polygyny multiple females to one male.

poly = many
gamy = any reproductively active bits
andry = male reproductively active bits
gyny = female reproductively active bits

polyandry, then, must be the opposite of polygyny!

with jacanas, the females mate with a male, lay the eggs, and leave the male to take care of the fertilized eggs. the female then mates with a different male and pulls the same stunt: she lays and leaves. no time for actually tending to the young--leave that to the male.

hey honey, can you take care of the nest? i'm going to be late tonight.

see yuhh

jacana females are, on average, much larger than the males, and seem to be the dominant [in the territorial sense] sex. according to the PBS online library, the reason behind the jacana's polyandry may be due to the high amount of egg predation the species of the jacanidae family has historically experienced. due to predatory conditions, if the females lay more eggs, the species has a higher survival rate. jacana females have evolved to become "egg laying machines"

and i mean, let's be honest, those eggs look SWEET. i would totally prey on those babies. [pun fully intended]

Tuesday, July 13, 2010


Warning: I want to address a theory on the evolution of feathers, but I have to reach Way-Back-In-The-Good-Days-Before-Even-Dad-Was-Born to do so. Don't worry, dinos rule!

Check it:

This is a Dromeosaur. It is a dinosaur from the clade [dur] Dromaeosauridae. Dromaeosauridae is a sister clade to Aves, and the way I understand the relationship between a dromeosaur and its bird contemporary is comparable to the relationships between chimpanzees and their human contemporaries.

[It's not a perfectly analogous fit, so don't quote me on that one.]

what I wanted to point out on this dromeosaur are the filamentous protofeathers. The dromeosaur's feathers:
a) were used for insulation
b) did not make dromeosaurs capable of flight
and c)are [were] derived from scales!

shall we investigate point (c)?

well, okay! heEeErE we go!

reptiles have scales, some of which are classified as scutes. we know almost certainly that dinosaurs had scutes from ample evidence in the fossil record:

uh okay that looks like an old rock.

reptiles like crocodiles and turtles have them, as well as really old fish like sturgeons. it's basically a bony plate that a lot of different organisms have, like

this weird catfish

dig the ridges! like ruffles, except not a delicious salty chip!

and turtles

what a ridiculous image--there is no way somebody could simultaneously hold the full time jobs of doctor AND mailman. gEt ReAl

so scutes are found in fish and reptiles, and i'll bet you have guessed by now that scutes are also found in birds! they're the bony gross part found on birds' feet.

the reason we can call all of these structures found on all of these different animals "scutes" is because they are chemically and structurally composed in the same way:

"The β-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheets, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the α-keratins of mammalian hair, horns and hoof"

[thanks for wording it for me, wikipedia!]

okokokokok so... what?!

essentially, the proteins that make up the keratinized structures we know as scales and scutes have the same structure as feathers and claws! the specific protein is known as beta-keratin.

oh baby do i love molecular structures.

the "beta" in beta-keratin is just referring to the way the molecules bond to form the 3-D structure of the protein. if it is a beta protein, the structure is sheet-like, and the sheets line up in opposite directions and then bond further to ultimately form a very strong material.

so: scutes [to a point] [[that could be a weak pun]] have the same molecular makeup as feathers.

but how do we get from a hardened bony structure such as a scute to a soft pretty feather that aids in flight?

i mean, scutes are not velly cute, you know?


no competish, thing with feathers is way cuter. i swear i'm not even biased!

to determine the relation between scutes and feathers, a guy named Alan Brush conducted a study in which an inhibitor virus was introduced to bird embryos that targeted scute development. when the birds hatched, they consistently had [some] feathers and/or filaments in place of where the scutes should have developed!

woah, so scutes are just hardened feathers? how exciting!

portrayal of the brush experiment. probably accurate!

chout and watch me work, i'm going to draw a conclusion:

over time, certain scales of reptiles [scutes] developed into the filamental protofeathers of early avian ancestors like dromeaosuars. initially they were used for warmth and protection, but these feathers started to serve for a means of locomotion, and hey! it worked out. avian feathers are derived from reptilian scales.

edit: an earlier version of this post incorrectly labelled an experiment as conducted by Alan Burns. Alan Brush conducted the experiment. Alan Burns was my simpsons-filled imagination running away with me. sorry!