SCIENCE FYI: COULD A VIRGIN BIRTH EVER HAPPEN?IF YOU’RE A MAMMAL, NO. BUT IF YOU'RE NOT...
"Virgin birth, known to scientists as parthenogenesis, appears to be rather common in the animal kingdom. Many insects and other invertebrates are capable of switching between sexual and clonal reproduction. Among the vertebrates, virgin births have been documented in at least 80 taxonomic groups, including fish, amphibians, and reptiles.
But humans and our fellow mammals provide a notable exception. So far as anyone can say—and there are a few gaps in the data, notably the platypus—no mammalian species is capable of giving birth without a father. So what stands in the way? First, a mammal’s egg cell usually won’t divide until it receives a signal from the sperm. Second, most mammalian eggs have only half the number of chromosomes necessary for development. If there isn’t any sperm, the embryo will end up with only half the DNA it needs to survive. Both of those barriers could potentially be overcome in the lab or through random mutation, but there is a third obstacle that probably can’t be.
Under normal conditions, the DNA in both egg and sperm cells is altered such that some genes will be more active while others are suppressed. When the egg and sperm join to form an embryo, these imprints work in tandem, ensuring that all the necessary proteins are produced in the right amounts. If an egg cell starts reproducing on its own, without the sperm-cell imprint, the offspring won’t survive for very long."
DECEMBER 21, 2014 THE WINTER SOLSTICE
December Solstice: Shortest day of the year in the Northern Hemisphere
The December solstice is on either December 20, 21, 22 or 23. It is called Winter Solstice in the Northern Hemisphere, where it is the shortest day of the year. In the Southern Hemisphere, it is the Summer Solstice and the longest day of the year.
10 Things About December Solstice
The Sun Stands Still
The term solstice comes from the Latin word solstitium, meaning the Sun stands still. This is because on this day, the Sun reaches its southern-most (or northern-most during the June Solstice) position as seen from the Earth. It seems to stand still at the Tropic of Capricorn (and Tropic of Cancer during the June Solstice) and then reverses its direction.
It's the First Day of Astronomical Winter
In the Northern Hemisphere, astronomers and scientists use the December Solstice as the start of the winter season, which ends on the March Equinox. For meteorologists, on the other hand, winter began three weeks ago on December 1.