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Amazon Molly Fish are All Female

Posted on April 24, 2008  Comments (2)

No sex for all-girl fish species

A fish species, which is all female, has survived for 70,000 years without reproducing sexually, experts believe.
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The species, found in Texas and Mexico, interacts with males of other species to trigger its reproduction process. The offspring are clones of their mother and do not inherit any of the male’s DNA. Typically, when creatures reproduce asexually, harmful changes creep into their genes over many generations.
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One theory is that the fish may occasionally be taking some of the DNA from the males that trigger reproduction, in order to refresh their gene pool.

Dr Laurence Loewe, of the university’s School of Biological Sciences, said: “What we have shown now is that this fish really has something special going on and that some special tricks exist to help this fish survive. “Maybe there is still occasional sex with strangers that keeps the species alive. Future research may give us some answers.”

He added that their findings could also help them understand more about how other creatures operate. “I think one of the interesting things is that we are learning more about how other species might use these tricks as well,” he said. “It might have a more general importance.”

Related: Female Sharks Can Reproduce Alone – Only Dad’s Genes – Bdelloid Rotifers Abandoned Sex 100 Million Years Ago – Sex and the Seahorse – more posts about fish

Really Old Coral – Over 2,000 Years Old

Posted on February 18, 2008  Comments (3)

photo of sea coral (leiopathes_glaberrima)

Worlds oldest animal aged to 4000 years

deep-sea gold corals (Geradia sp.) and black corals (Leiopathes glaberrima, pictured left) indicate these animals live between two and four millennia
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The new findings break all records previously claimed for marine invertebrates like the cold seep tubeworms (estimated 200 years old), quahog clams (estimated 400 years old), as well as the deep-sea wannabees Primnoa spp. and bamboo corals (45 – 300 years old). Given the new results, deep-sea animals can finally measure up to the longevity of the “Methuselah tree”, the Bristlecone Pine, estimated to be near 5000 years old.
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perhaps the most important thing to mention is that gold and black corals are colonial zoantharians. No single polyp is thought to be this old, just the skeletal axis.

How is Coral an animal?

Coral is an animal that belongs to the phylum cnidaria…
During the mating season coral polyp release eggs and sperm into the water (picture below) and when an egg and a sperm meet they form a larva known as a planula…
The baby coral looks like a little tiny jellyfish and it floats around in the water until it finds a hard place to attach to, usually a coral reef. Then it lands and starts to build itself a shell. It builds it by combining carbon dioxide (CO2) and calcium (Ca) in the water to make calcium carbonate (CaCO3) also known as limestone. This shell is shaped like a round vase and the coral polyp lives inside…

Related: South Pacific to Stop Bottom-trawling – Batfish Key to Keeping Reefs Clean – Bdelloid Rotifers Abandoned Sex 100 Million Years Ago

The Science of Kissing

Posted on February 11, 2008  Comments (1)

The Differences in Gender — Sealed With a Kiss

In people, kissing to express affection is almost universal. About 90 percent of human cultures do it. One traditional view is that kissing, known scientifically as osculation, evolved from women chewing food for their children and giving it to them mouth-to-mouth, Fisher said.

But, she said, “I’ve never believed that,” adding that similar behavior is found in many species. Birds tap beaks. Elephants shove their trunks in each other’s mouths. Primates called bonobos practice their own version of French kissing. Fisher believes kissing is all about choosing the right mate.

“There’s so much information exchanged when you kiss someone that I just thought it must play a vital role in mate choice, and this paper is elegantly showing that,” Fisher said. A disproportionate amount of the brain, she noted, is geared toward interpreting signals from the mouth.

The research paper – Sex Differences in Romantic Kissing Among College Students: An Evolutionary Perspective

Related: The Psychobiology of Romantic Kissing – Sexy Math – Summer Camp Psychology Experiment

Female Sharks Can Reproduce Alone

Posted on May 23, 2007  Comments (4)

Female Sharks Can Reproduce Alone, Researchers Find

A team of American and Irish researchers have discovered that some female sharks can reproduce without having sex, the first time that scientists have found the unusual capacity in such an ancient vertebrate species. The[y] report that sharks can reproduce asexually through the process known as parthenogenesis
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Though the three females had been caught before they reached sexual maturity and held in captivity for more than three years, researchers initially thought one had stored sperm from a male shark before fertilizing an egg. But the team — which included scientists at Nova Southeastern University in Florida, Queen’s University Belfast and the zoo — determined that the baby shark’s genetic makeup perfectly matched one of the females in the tank, with no sign of a male parent.

Mahmood Shivji — Nova Southeastern’s Guy Harvey Research Institute director and one of the paper’s authors — said that he and his colleagues determined that a byproduct formed when sharks produce eggs, known as a sister polar body, had fused with an unfertilized egg to produce the baby shark, whose DNA had only half as much genetic variability as the mother.

Related: Sex and the Seahorse – 50 New Species Found in Indonesia Reefs – Arctic Sharks – Bdelloid Rotifers Abandoned Sex 100 Million Years Ago

Bdelloid Rotifers Abandoned Sex 100 Million Years Ago

Posted on March 21, 2007  Comments (7)

Who Needs Sex (or Males) Anyway? by Liza Gross:

If you own a birdbath, chances are you’re hosting one of evolutionary biology’s most puzzling enigmas: bdelloid rotifers. These microscopic invertebrates—widely distributed in mosses, creeks, ponds, and other freshwater repositories—abandoned sex perhaps 100 million years ago, yet have apparently diverged into nearly 400 species. Bdelloids (the “b” is silent) reproduce through parthenogenesis, which generates offspring with essentially the same genome as their mother from unfertilized eggs.

Scientists stumped by 100m years of chastity

Bdelloid rotifers are egg laying microscopic invertebrates — widely distributed in mosses, streams and ponds — which have managed to diverge into nearly 400 species without a scintilla of sex… Now a new study, published today in the journal PLoS biology, has confirmed the worst fears of scientists: the rotifers do indeed present a major challenge to the assumption that sex is necessary for organisms to diversify into species.
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Rather than mixing up DNA, creatures like the bdelloid rotifers can evolve solely through the build-up of mutations that occur in the ‘cloning’ process when a new rotifer is born. The new study proves that these differences are not random and can help rotifers adapt to a different environment, such as the legs or chest of a water louse. Bdelloids can be found happily swimming around in a puddle in your garden, hot springs or in freezing ponds in the Antarctic.