'Microraptors' Shed Light on Ancient Origin of Bird Flight
Indeed, the KU-China team's work provides such strong support for the trees-down model for the origin of avian flight that the alternative terrestrial (ground up) origin now may be abandoned.I still like the ground up theory a lot.
In Bats and Whales, Convergence in Echolocation Ability Runs Deep
The discovery represents an unprecedented example of adaptive sequence convergence between two highly divergent groups and suggests that such convergence at the sequence level might be more common than scientists had suspected.Value of Sexual Reproduction Versus Asexual Reproduction
The study looked at sexual, as well as asexual, varieties of a New Zealand freshwater snail (left), Potamopyrgus antipodarum, by sequencing mitochondrial genomes and found that the sexually reproducing snails had accumulated harmful DNA mutations at about half the rate of the asexual snails.[John M. Logsdon, blogging at Sex, Genes & Evolution is a co-author on this one.]
The above experiment shows what many people have been suspecting for a long time, namely that sex is great (!) because it helps remove deleterious mutations. That doesn't mean that cloning yourself once in a while isn't acceptable, as in sharks:
Study of Shark Virgin Birth Shows Offspring Can Survive Long Term
"Examination of highly variable sections of the genome prove that these young sharks had no father," Feldheim said. "These findings are remarkable because they tell us that some female sharks can produce litters of offspring without ever having mated with a male.Lastly, in non-evolution news, I used to say I'd give my right arm to be ambidextrous, but now I'm not so sure anymore:
Mixed-Handed Children More Likely to Have Mental Health, Language and Scholastic Problems
Around one in every 100 people is mixed-handed. The study looked at nearly 8,000 children, 87 of whom were mixed-handed, and found that mixed-handed 7 and 8-year old children were twice as likely as their right-handed peers to have difficulties with language and to perform poorly in school.The brain is the most curious thing, innit?
And that reminds me of a great entry in the Urban Dictionary: innit.
General positive exclamation meaning "yes, I agree!"
1. "Hey dere's some pigs in dat cop car over there innit?"
"Yo look at my new car innit!"
these words are used by individuals who use all three brain cells to create speech that in virtually incoherent.
Townie 1: Fuck, innit.
Townie 2: Innit
Etc.
These chav-bashers are cunts, innit?
Townie: An' ah was like at the club wit' ma mates innit
Smi: You go clubbing?
Townie: Yeah innit
Rabson: You're only 12!
Townie: Yeah innit don't ya mate?
Smi: No...
Townie: Oh ma God-a like! I can't believe ya don't go clubbin' innit!
A chav in a box - preferably a coffin.
(In a rather high-brow British accent, upon coming across a chav funeral) Hurrah, another of those bastards innit!
I'm not sure (and don't care) what a chav is, but the whole thing just cracks me up, innit
I'm not sure I understand why it has to be trees-down or ground-up. Why isn't it possible for different animals to have approached it from different directions?
ReplyDeletecicely
Cicely, I'm not 96 percent certain, but I think the idea is that while flight may have originated in different species, sometimes ground-up and other times trees-down, it most likely originated only once in the lineage that became birds.
ReplyDeleteIf this is true, then showing that one species (like these microraptors) evolved flight trees-down makes it more likely that the origin of avian flight is also trees-down, but by no means certain. This species was most likely not an ancestor of birds.