ZThemes
oosik:

sarvavyapakata:

The Goddess Dhumavati(From a Mahavidya series)Mandi, 1725-5018.5 x 12.5 cm.Private Collection

I don’t claim to know the Hindu pantheon that well, but this looks more like Shitala who is the goddess of sores, ghouls, pustules, and disease for northern India, Nepal, Bangladesh, and Pakistan. Her mount is a donkey, whereas the mount for Dhumavati is a crow. 
Shitala does have variants within the Hindu religion which can include Parvarti or Mariamman. These versions are often worshiped or revered in southern India, Malaysia, and Indonesia. She is often referred to as “Mother” (ma) and is associated with the spring. So here you have Mother Mari riding a donkey bringing about a season of change who is said to be full of mercy, grace, and kindness, yet is celebrated by the lowest castes.

oosik:

sarvavyapakata:

The Goddess Dhumavati
(From a Mahavidya series)
Mandi, 1725-50
18.5 x 12.5 cm.
Private Collection

I don’t claim to know the Hindu pantheon that well, but this looks more like Shitala who is the goddess of sores, ghouls, pustules, and disease for northern India, Nepal, Bangladesh, and Pakistan. Her mount is a donkey, whereas the mount for Dhumavati is a crow. 

Shitala does have variants within the Hindu religion which can include Parvarti or Mariamman. These versions are often worshiped or revered in southern India, Malaysia, and Indonesia. She is often referred to as “Mother” (ma) and is associated with the spring. So here you have Mother Mari riding a donkey bringing about a season of change who is said to be full of mercy, grace, and kindness, yet is celebrated by the lowest castes.

biomorphosis:

Colugos are little-known, forest-dwelling animals that have huge gliding membranes, similar to flying squirrels. This enables them to make spectacular leaps from tree to tree.
Baby colugos are born tiny and helpless, and are carried on the mother’s belly for six months until they are developed enough to strike out on their own. 

biomorphosis:

Colugos are little-known, forest-dwelling animals that have huge gliding membranes, similar to flying squirrels. This enables them to make spectacular leaps from tree to tree.

Baby colugos are born tiny and helpless, and are carried on the mother’s belly for six months until they are developed enough to strike out on their own. 

steelandcotton:

Qing Period Arrowhead

Date: ca. 18th–19th century
Culture: probably Tibetan or Chinese
Medium: Iron, reed, sinew, bark
Dimensions: L. overall 9 in. (22.9 cm); L. of head 4w in. (10.2 cm)
Classification: Archery Equipment-Arrowheads
Credit Line: Purchase, Arthur Ochs Sulzberger Gift, 2011
Accession Number: 2011.502.9

Source: http://www.metmuseum.org/collection/the-collection-online/search/35805?rpp=30&pg=1&ft=chinese+arrowheads&pos=3

steelandcotton:

Qing Period Arrowhead

Date: ca. 18th–19th century
Culture: probably Tibetan or Chinese
Medium: Iron, reed, sinew, bark
Dimensions: L. overall 9 in. (22.9 cm); L. of head 4w in. (10.2 cm)
Classification: Archery Equipment-Arrowheads
Credit Line: Purchase, Arthur Ochs Sulzberger Gift, 2011
Accession Number: 2011.502.9

thejunglenook:

whatthefauna:

Common marmosets have extra long tongues. These little primates eat sap and gum off trees, and their long tongues are useful in getting between gaps in the bark. Females also flirt by flicking their tongues at males to show they are ovulating.

Image credit: (T) Helen Cherry, (B) bio-morphosis

This is also how mum tells dad(s) to come pick up the kids so she can forage in peace. 

astronomy-to-zoology:

Rosy Maple Moth (Dryocampa rubicunda)

…a beautiful species of Royal Moth (Ceratocampinae) which occurs in Eastern North America. Like other Saturniid moths adult rosy maple moths lack mouthparts and live short lives dedicated solely to breeding. In the north they typically fly from May-August (with one brood) and in the south they fly from April-September (2-3 broods). Rosy maple moth caterpillars are typically known as Green-striped Mapleworms and are commonly seen feeding on maples (Acer spp.), sycamore (Platanus spp.), beech (Fagus spp.) and oaks (Quercus spp.) 

Classification

Animalia-Arthropoda-Insecta-Lepidoptera-Bombycoidea-Saturniidae-Ceratocampinae-Dryocampa-D. rubicunda

Images: Mike Boone and PiccoloNamek  

ancientart:

Her gods and men call Aphrodite, and Aphrogeneia (the foam-born) because she grew amid the foam.” -Hesiod, Theogony 176.

A few depictions of Aphrodite, the Greek goddess of love and beauty, in ancient Greek pottery.

Aphrodite and Adonis (detail). Attic red-figure squat lekythos, Aison, ca. 410 BC. Courtesy of the Louvre, MNB 2109. Photo by Marie-Lan Nguyen.

Aphrodite on a swan (detail). Tondo from an Attic white-ground red-figured kylix. From tomb F43 in Kameiros (Rhodes). Pistoxenos Painter, circa 460 BC. Courtesy of the British MuseumGR 1869.10-7.77. Photo by Marie-Lan Nguyen.

Vessel with Leda and the Swan (detail). Attributed to the Painter of Louvre MNB 1148, Greek, Apulia, South Italy, about 330 B.C. Courtesy of the Getty Villa, 86.AE.680. Photo by Dave & Margie Hill.

archaicwonder:

Temple of Apollo, Acropolis of Rhodes
The Temple of Apollo is located on the acropolis hill of ancient Rhodes. It is of Doric style and dates from the Hellenistic period. (3rd–2nd century BC). The site consists of the Temple of Apollo (aka Athena Polias and Zeus Polieus), a stadium and a small theater.

archaicwonder:

Temple of Apollo, Acropolis of Rhodes

The Temple of Apollo is located on the acropolis hill of ancient Rhodes. It is of Doric style and dates from the Hellenistic period. (3rd–2nd century BC). The site consists of the Temple of Apollo (aka Athena Polias and Zeus Polieus), a stadium and a small theater.

sciencesoup:

The Origin of Genetic Variation

Mutations in the nucleotide sequences are the original source of genetic variation, causing different versions of alleles to exist. Once we have these differences, alleles can then be reshuffled, like a pack of cards, in order to produce the variation that makes each individual organism have its own unique combination of characteristics.

In sexually-reproducing organisms, most variation arises from processes that happen during meiosis and fertilisation.

Independent Assortment of Chromosomes:

  • When homologous pairs (with one maternal and one paternal chromosomes) line up at the metaphase plate in meiosis I, their orientation is random—there’s a 50% chance that the daughter cell will be given the maternal or the paternal chromosome of any given homologous pair.
  • In addition, each homologous pair orients itself independent of whatever any other chromosome is doing, i.e. independent assortment.
  • The daughter cells are therefore just one of many possible combinations of maternal and paternal chromosomes. Because humans have 23 chromosomes, the number of possible combinations is 2^23, or about 8.4 million.

image

(Image Source)

Crossing Over:

  • Also known as recombination
  • Each individual gamete does not have only one paternal or one maternal chromosome. Rather, it actually ends up with a mix of them. This is due to recombinant chromosomes.

image

  • As we saw in our discussion of meiosis, in prophase I homologous pairs join up along their lengths, precisely aligning with corresponding alleles next to each other. Then, they essentially swap out alleles, exchanging them along their lengths—like swapping arms.
  • The further away alleles are from each other, the more likely they’ll be swapped. Alleles that are located close to each other are therefore more likely to be inherited together.
  • What results is a pair of homologous chromosomes that have been randomly mixed up.
  • This is incredibly important, because mutations are happening all the time. They can actually destroy the function of genes, so if no crossing over ever occurred to increase diversity, mutations would just accumulate and eventually all genes would be destroyed. Instead, crossing over helps non-mutated chromosomes to reform.

image

Random Fertilisation:

  • Basically, a sperm cell randomly chooses an egg cell. Because each one is already one of 8.4 million combinations, the random fusion of sperm and egg produces a zygote of 70 trillion possible combinations (2^23 x 2^23).

Body images sourced from Wikimedia Commons

Further resources: Genetic variation video

sciencesoup:

Mendel’s Gene Ideas

In the 19th century, a European monk called Gregor Mendel performed experiments in the garden of his abbey that would forever change the course of biology. Until that point, farmers and agriculturalists had been attempting to grow hybrids of plants with mixed success, because they didn’t really know what laws dictated how genetic information is passed on. Though Mendel had never looked through a microscope and had no idea what the actual process of DNA replication and meiosis was, he still was able to determine four fundamental rules of genetics through the power of his well-designed experiments.

Mendel’s experimental subjects were peas (Pisum sativum). Not very exciting, but perfect for what he wanted: they had short generation times, a large number of offspring, can both self-pollinate or pollinate with others, and they were available in lots of varieties. Their physical characteristics like colour and shape were also very obvious, allowing him to visually track the changes through the generations. Remember that the expression of a gene is called a character, like pea colour, and the expression of an allele is called a trait, like green or yellow pea colour.

Mendel selected pure-bred pea plants with particular traits and cross-bred them in order to see what phenotypes they expressed in different generations. Using carefully planned experiments, he figured out patterns of inheritance.

In a typical experiment, Mendel would take two very different pure-bred plants and cross them together. For example, he crossed a pure-bred yellow pea plant with a pure-bred green pea plant. This mating is called hybridisation. Note: we call the first generation the P generation (for parent), the second generation the F1 generation, and the third generation the F2 generation, usually given by self-pollination.

In completing this yellow and green pea cross, Mendel found this relationship:

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(Image Source)

In the F1 generation, all plants produced yellow peas. Even though the parents were green and yellow, the F1 generation didn’t mix the colours to be greeny-yellow—they were just yellow.

Then, when Mendel crossed the F1 gen with the F1 gen (through self-pollination), he found that only three quarters of the plants had yellow peas, and one quarter mysteriously were green. This 3:1 ratio is recurring—remember it.

This happened every single time Mendel crosses plants in this way. He realised that this regularity must be the key to some underlying mechanism of inheritance.

image

(Image Source)

If crossing two different genes plants could blend the genes, then we’d expect the F1 generation to be a greeny-yellow colour. However, this isn’t the case. So what happened to the green in the F1 generation? Obviously it hasn’t disappeared completely, because it crops up again in F2. Mendel reasoned that it was hidden from view, and termed the yellow colour as a dominant trait and the green colour as a recessive trait. We now know that there are dominant alleles and recessive alleles, and only one is expressed in the phenotype.

In order to come up with the law of segregation, Mendel noted four related concepts.

  1. Offspring have different physical characteristics because genes have different “versions”, called alleles. These account for variation.
  2. For each gene, an offspring inherits one allele from each parent.
  3. If two alleles at a locus are different, then the dominant allele will determine what the organism looks like. The recessive allele will have no observable effect.
  4. The two alleles for a gene of one parent separate when gametes are formed. They end up in different gametes, so the egg or sperm only get one of the two alleles present in the somatic cells of the organism. For example, if the gene has a dominant and a recessive allele—this separation means that 50% of gametes will end up with the dominant allele, and 50% will end up with the recessive one. This is called the Law of Segregation.