reproduction
dr. dolittle | June 19, 2017
Estradiol is the major estrogen in humans. Chemical structure by NEUROtiker (Own work) [Public domain], via Wikimedia Commons
I came across an article published in Physiological Reviews with a title so irresistible (Estrogens in Male Physiology), I just had to read it. While I knew that males have estrogen, this article impressed me with the numerous things estrogens are associated with, some of which were new to me and highlight how important estrogens are to male reproductive and non-reproductive physiology.
As early as the 1930's researchers discovered that stallions had high levels…
dr. dolittle | January 17, 2017 Photo of one of Leonie's hatchlings from Tourism and Events Queensland.
The story begins in 1999 when Leonie, a zebra shark (aka a leopard shark in Australia), was captured from the wild. In 2006 she was transferred to Reef HQ Aquarium in Queensland, Australia where she met her mate. By 2008, she had started laying eggs and the pair had multiple litters of offspring through sexual reproduction. After her mate was removed from the tank to prevent further breeding, she has shared the tank with one of her offspring, a female named Lolly who, since reaching sexual maturity herself, has never…
dr. dolittle | January 13, 2017 Image of an orca and her calf from Wikimedia Commons
Orcas are one of only three species of mammals that go through menopause, including humans of course. A new study published in Current Biology may have discovered why this happens in killer whales.
Examination of 43 years worth of data collected by the Center for Whale Research and Fisheries and Oceans Canada, revealed a remarkable finding about the costs of reproduction in orcas. Older mothers tend to spend more time taking care of the family, so to speak, by making sure her offspring know where or when to find food. While this…
dr. dolittle | September 16, 2016 Video of C. elegans from Wikipedia. https://upload.wikimedia.org/wikipedia/commons/b/be/CrawlingCelegans.gif
A new study conducted by researchers at Northwestern University examined the costs of reproduction in roundworms, otherwise known as C. elegans. They discovered that male roundworms can send two kinds of pheromones that prime females for reproduction. One type of pheromone they studied sparks the onset of puberty in young female worms while the other prolongs fertility in aging females. The problem is that these changes come at a cost as it shortens the lifespan of female…
pharyngula | August 2, 2016Perhaps we need to think more about human psychology. There's an interesting phenomenon that goes on all the time when people read about evolution: they shoehorn the observations into some functional purpose. There's just something so satisfying to our minds to be able to say "that thing exists for this particular reason", and we find it frustrating to say, "there is no reason for it, it's just chance and circumstance". It shouldn't be so, but our minds just try to fit everything into that particular mold.
Now watch: some people -- maybe even you -- are going to now try and develop an…
pharyngula | October 1, 2015Bill Nye talks about the realities of reproduction, and the right wing completely loses its shit.
It is not Nye at his most eloquent, but…he's actually right about everything important. Read this title for an example of the inanity of far right responses, titled WATCH: Bill Nye, Science Guy Makes An Idiot Of Himself On Reproduction. Nye is clearer and more correct than whoever wrote that, making it particularly amusing. It makes a lot of claims.
Not that this writer had all that great an affinity for Bill Nye anyway, but the video below has to be the most smug, snide, atheistic diatribe…
dr. dolittle | August 23, 2014A new study from researchers at the University of Sydney shows that golden orb-weaving spiders (Nephila plumipes) that live in the city are larger and produce more offspring as compared to country living.
When they say the spiders are big, they mean really big. The females can reach up to 20-25mm (males are only ~5mm).
Image from Spiders of Australiahttp://ednieuw.home.xs4all.nl/australian/nephila/Nephila.html
The researchers speculate that the urban heat island effect, which is attributed to a lack vegetation and hard surfaces, may lead to the increased body size as invertebrates in…
milhayser | April 6, 2014Perovskite solar cells can not only emit light, they can also emit up to 70% of absorbed sunlight as lasers.
Critical signaling molecules can be used to convert stem cells to neural progenitor cells, increasing the yield of healthy motor neurons and decreasing the time required to grow them.
Mexican blind cavefish are so close to their sighted kin that they are considered the same species, but they use pressure waves (from opening and closing their mouths) to navigate in the dark.
Electrostatic assembly allows luminescent elements (like Europium) to be embedded in nanodiamonds; these glowing…
pharyngula | March 11, 2014I was talking about sex and nothing but sex all last week in genetics, which is far less titillating than it sounds. My focus was entirely on operational genetics, that is, how autosomal inheritance vs inheritance of factors on sex chromosomes differ, and I only hinted at how sex is not inherited as a simple mendelian trait, as we're always tempted to assume, but is actually the product of a whole elaborate chain of epistatic interactions. I'm always tempted in this class to go full-blown rabid developmental geneticist on them and do nothing but talk about interactions between genes, but I…
dr. dolittle | May 17, 2013I was just digitally flipping through a new book called "Crime Against Nature", which describes various reproductive behaviors in the animal kingdom. It is written by an artist, Gwenn Seemel, not a scientist, so I cannot vouch for the scientific accuracy of the book as a whole. However, the illustrations are quite nice and the content is seemingly scandalous, which makes for an interesting read.
For example, did you know that male Dayak fruit bats can lactate to feed their young (True according to this article in Nature)?
Image from "Crime Against Nature", written and illustrated by Gwenn…
pharyngula | January 31, 2013Oh gob, the stupidity. The latest wave of anti-choice legislation is based on one trivial premise: it's got a heartbeat! You can't kill it if its heart is beating! So stupid bills have been flitting about in the Ohio, Mississippi, Wyoming, Arkansas, and North Dakota legislatures trying to redefine human life as beginning at the instant that a heartbeat can be detected. Here's Wyoming's story, for instance:
About two weeks ago, state Rep. Kendell Kroeker (R) introduced a measure to supersede the medical definition of viability. Current state law says abortions are prohibited after a fetus has…
pharyngula | January 25, 2013Have you ever noticed how the religious regard 'scientism' and 'reductionism' and demands for concrete evidence as barely a notch above obscenities? That is, until they need to reduce complex issues to simplistic claims and don the mantle of Science to support their beliefs. Then they become Holy Writ.
You can really see this behavior in the abortion debate, where suddenly anti-choicers decide that humanity is defined by a particular arrangement of alleles in the genome. Case closed, they say, Science has spoken! Unfortunately, they get the science wrong, and we know their commitment to the…
dr. dolittle | October 25, 2012
Image of Indonesia's Komodo dragons from Scientific American.
Dr. Tim Jessop from the University of Melbourne, Australia and colleagues spent eight years following 400 Komodo dragons (Varanus komodoensis) to learn more about their growth rate, lifespan as well as differences between populations on isolated Indonesian islands. Their most surprising finding was that female Komodo dragons only live an average of 32 years whereas males live for about 60 years. Females are additionally smaller (1.2 meters long, 22 kg body mass) than males (1.5 meters long, 70 kg body mass). The researchers…
denialism | August 22, 2012Everyone has heard about Akin's comments about "legitimate rape" and the push now coming from the GOP to get him out of the race. But is this really fair or ideal? The problem with removing Akin from the race over this is that his gaffe was not just one exposing his scientific ignorance, but because it was a Kinsley gaffe. That is, it's a gaffe because it unintentionally revealed the truth.
I'm not saying that his medieval medical hypothesis has any scientific validity, he is after all just parroting pro-life misinformation spread to attack scientific data about the frequency of pregnancy…
dr. dolittle | August 14, 2012
Studies of guppies show that bigger brains may mean "smarter" fish, but less offspring. Credit: Marrabbio2/Creative Commons
...at least for guppies. Dr. Alexander Kotrschal and colleagues at Uppsala University (Sweden) either shrank or grew the brains of guppies over multiple generations to create animals with up to 8-10% variations in brain size. To test for "smartness" they had the fish count by training the animals to look for food where a card with two or four symbols was shown. According to the researchers, the animals with larger brains tended to learn the task, whereas those with…
denialism | March 21, 2012In the continual spread of assaults on women's reproductive freedom in the wake of the 2010 tea party movement, another state, Idaho, is legislating women receive unnecessary and invasive medical procedures prior to obtaining abortion.
This is part of an unprecedented effort at the state level to restrict reproductive rights, and in 2011 a record number of these measures have passed.
And it won't stop here, as we've seen in Georgia, they are trying to pass a law to force women to carry all 20 week gestations to term, even if the fetus is dead. And if you think that's creepy, Georgia isn't…
denialism | March 13, 2012In a debate on the floor of the Georgia State house over a bill to force women to bring all pregnancies after 20 weeks to term, even in cases of dead or non-viable fetus, this Georgia representative reaches a new low. State Rep Terry England seems to be suggesting pigs and cows do it, why can't humans?
Rep. Terry England compares women to cows, pigs and chickens. from Bryan Long on Vimeo.
Aside from this genius on-the-farm reasoning of Mr England, the failures of reasoning and misrepresentations of scientific knowledge engaged in to pursue this legislation are many.
The legislation is…
sastyk | February 23, 2012Note: I wrote a slightly different piece under this title on ye olde blogge back in August, but given the emphasis on discussion of contraception going on, I thought it was worth reiterating and mulling over further.
When your specialty as a foster family is taking large sibling groups, you hear a lot of stuff you'd rather not. The typical comment involves forced sterilization, and it is hard sometimes not to have a little sympathy. Of the kids we've taken or been called about, we've had three groups of five and three of four, and almost all have involved very young mothers, sometimes with…
pharyngula | February 21, 2012This is Hazel Jones. She has two vaginas.
She has a condition called Uterus Didelphys. Variations of this condition aren't uncommon, occurring once in a few thousand births. The reproductive tract develops from paired tubes that fuse prenatally, and sometimes the fusion is incomplete, producing a range of arrangements illustrated below.
Would you believe a pornographer has asked Ms Jones to star in a movie? (Of course you would — that's exactly what you'd expect.) In this case, it's stupid as well as insulting and offensive. Women with these kinds of conditions often don't even know it…
pharyngula | February 14, 2012It truly does, and someone has caught us out and published a stunning exposé that reveals the horrible, awful behavior that our goddess, Nature, endorses. You must read "God Hates Checkered Whiptail Lizards!!!" and weep. This is but one page of a devastating revelation.
(Also on FtB)