Category Archives: Friends of Miles

Jellies: Milos Radakovich

Jellyfish, or sea jellies, have traditionally been considered simple and primitive.
When you gaze at one in an aquarium
tank, it’s not hard to see why. Like its relatives, the sea anemones and corals,
jellyfish looks like a no-frills animal.

The ancestors of jellies go back to a time before animals evolved
what we call bilateral symmetry – mirrored right and left sides –
or cephalization – the centralization of a brain and sensors, often
on a neck, and away from the main body. As a result, jellies,
anemones and corals have no head and no brain, no front or
back, no left or right; and while they have no legs, they often
have lots of arms, arranged in a circle around a central mouth.

While not the best arrangement for bounding across open fields
or swinging from the treetops, jelly architecture has been wildly
successful in the word’s oceans for nearly 600 million years. Now
that’s endurance.

That’s not to say that jellies haven’t changed in all that time. In
fact, jellies are one of the most diverse groups on the planet.
Some are nearly microscopic, while others can be the size of a
laundry basket, trailing thirty feet of stinging tentacles. Many are
transparent, some are luminous, while others, like the sea wasp
of Australia, are some of the deadliest animals in the sea.

Mostly marine, but also in fresh water,
jellies occupy 99.9% of the available living
space on Earth, from tropical lakes
and shallow lagoons to the deepest
ocean basins. If nothing else, these simple,
gelatinous organisms are some of
the most interesting animals on Earth.

Milos Radakovich

Naked Mole-Rats: Milos Radakovic

Naked mole-rats. It’s hardto pin down which part of
the name is more disturbing;
the fact that they are rats, that they live underground,
or that they do so while completely naked.

They live in underground colonies of up to 300 individuals, with
one breeding female, similar to a queen bee. They rarely come
out and are nearly blind.

The part that is really fascinating is that they can live for 30
years. Like a pink burrito with legs, naked mole-rats live many
times the lifespan of their hairy above-ground relatives.

In the body, oxygen splits into single atoms, causing damage to
cells, proteins and genetic material. Antioxidants produced by
the body help to neutralize this free-radical attack.

Since mole-rats live several times longer than other rodents their
size, we would expect them to exhibit either lower oxidative
stress or a greater ability to defend against the attack by free
radicals, perhaps by employing more antioxidants.

In fact, mole-rats exhibit more oxidative damage, including more
DNA and protein damage in the kidney and liver. Plus, they had
lower levels of oxidative neutralizers. Yet somehow they live on.

Researchers claim this animal may one day provide clues to how
we can significantly extend life, but they are quick to point out
that the wisdom of doing so is perhaps an even bigger question.

In any case, further research is needed to figure out exactly how
the mole-rats live with the damage caused by oxidative stress.
Maybe the secret is in being naked… Eeeeeeeeeeeeeek!

Milos Radakovich

Ear Wax: Milos Radakovich

Do you have dry, flaky earwax or the
gooey, stinky type? The answer is
partly in your heritage. A new study
reveals that the gene responsible for
the drier type originated in an ancient
Northeastern Asian population.

Today, 80-95 percent of East Asians have dry earwax, while 97-
98 percent of Africans and Europeans have the moist variety.

Populations in Southern Asia, the Pacific Islands, Central Asia,
Asia Minor, Native North Americans and Inuit of Asian ancestry,
fall in the middle with dry wax ranging from 30 to 50 percent.

Researchers identified a gene that alters the shape of a cell
membrane channel that controls the flow of molecules that directly
affect earwax type. They found that many East Asians have
a mutation in this gene that prevents cerumen, the molecule
that makes earwax moist, from entering the mix.

Scientists think that the mutation was very common in Northeast
Eurasia and, following a population increase, expanded over the
rest of the continent. Today the gene’s distribution is highest in
North China and Korea.

While there are many hypotheses about the usefulness of earwax,
moist or dry, in truth we have no compelling explanations.
Some speculate that it might play a role in the production of
pheromones, while others have even more exotic suggestions.

Earwax type is a possible adaptation to heat,
cold, humidity, dryness, day, night, sexual attraction
or revulsion, and possibly political orientation.
All we can say for sure is: don’t stick
anything in your ears, especially cotton swabs.

Photo: Wikimedia

Milos Radakovich

Flying Reptiles: Milos Radakovich

Paleontologists have recently uncovered
the remains of two new
flying reptile species that shared
the skies with early birds 120 million
years ago in what is now China.

The two species belong to a family of flying reptiles known as
pterosaurs. Both were discovered in Liaoning, a NE province of
China famous for yielding fossils of bird-like dinosaurs.

Both had wingspans of about 8-feet and belonged to groups previously
found only in Europe. Pterosaurs were distant relatives of
dinosaurs and ruled the skies for millions of years before birds.
The members of their order ranged from sparrow-sized Pterodactyls
to Quetzalcoatlus, the largest flying creature of all time
with a wingspan of nearly 40-feet (12 m).

Some pterosaurs flew by flapping their wings like modern birds.
Others used their thin wings of stretched skin to ride the wind
like modern hang gliders. Many pterosaurs were covered in hair
similar to that of mammals.

Overall, 15 species of pterosaurs have been discovered in Liaoning.
The discovery of many more bird-like species in the region
suggests that early birds were more diverse and outnumbered
the pterosaurs. The distribution of the fossils also implies that
the birds and pterosaurs inhabited different environments.

Evidence also suggests that in coastal areas pterosaurs predominate
and birds were exceedingly rare, while in the interior, despite
the presence of pterosaurs, birds were more successful.

The hills of Liaoning are famous for their bounty of feathered
dinosaur fossils – evidence that birds evolved from theropod dinosaurs
– relatives of T. rex, Velopciraptor, Deininychus.

Pterosaur (Google Images)

 

Milos Radakovich

Figs: Milos Radakovich

Figs are one of the oldest of domesticated
crops, widely popular
in ancient Persia, Arabia, and all
around the Mediterranean.

Often thought of as fruit, the fig
is actually an infolded flower –
like a bud that matures without ever opening. As you can imagine,
pollinating such a flower requires creativity.

Most flowering plants have co-evolved with birds, mammals, and
insects, used to carry pollen and distribute seeds. Fig pollen is
transferred from flower to flower by an insect called a fig wasp,
barely an eighth of an inch long. There are a thousand species of
fig, and nearly as many fig wasps.

The wasps overwinter as larvae inside the winter crop of figs. In
April, the larvae change into adults. Inside the fig, males emerge
and promptly impregnate the still-cocooned females. Soon after,
the wingless male bores an exit tunnel for the female and dies.
The winged, gravid female emerges and leaves the fig.

The female flies to a spring-flowering fig and enters through the
end opening, called the ostiole. She deposits eggs inside the fig,
while also delivering pollen, and then dies.

While some figs can develop without the benefit of fertilizing
wasps, Smyrna figs are considered to be the most desirable because
of their tender skin, and the oil in the fertilized seeds delivers
extra flavor.

Speaking of extra flavor, the skeletons of female wasps plus
some dead larvae of the next generation are often found in
Smyrna figs. They say the “crunch” of the Smyrna fig is mostly
from the seeds… Eeeeeeeeeeeeeeeeew!

Milos Radakovitch

 

House Sparrow: Dr J Murray Speirs

House Sparrows

This cosmopolitan species was introduced from Europe to Brooklyn, N.Y., in 1850 and into Ontario in about 1870. It spread rapidly and was considered a pest by the end of the century. It was much more abundant in the days of horse-drawn transportation than it is now, living on waste grain and droppings, but it is still one of the most abundant species near human habitations, becoming increasingly rare in Northern Ontario where it is found mainly near settlements and farms and absent from large, unsettled areas. Although usually considered nonmigratory I have witnessed flocks taking off over Lake Erie from Point Pelee. Nests are usually built in cavities under the eaves of houses or other buildings, or in bird boxes designed for other species but some build big  globe-shaped nests about the size of a football in trees, more fitting for a member of the Ploceidae (the weaver finches).

House Sparrow (male) photo: wikimedia

Males with their gray crowns, chestnut napes, white cheeks and black bibs (reduced to the chin in winter) are easily identified, and their dingy mates by association with them.

House Sparrow (female) photo: wikimedia

Males are sometimes confused with the rare Harris’ Sparrow because both have black bibs (but the Harris also has a black crown).