Posts Tagged ‘Death’

When is a strawberry dead?

June 25, 2013

An interesting discussion yesterday on BBC Radio

What Is Death?

Series 8 Episode 1 of 6 Monday 24 June 2013

“What Is Death?”

In the first of a new series of the award winning science/comedy series, Brian Cox and Robin Ince are joined on stage by comedian Katy Brand, biochemist Nick Lane and forensic anthropologist Sue Black to discuss why death is such an inevitable feature of a living planet. As well as revisiting such weighty scientific issues, such as when can a strawberry, be truly declared to be dead, they’ll also explore the scientific process of death, its evolutionary purpose and whether it is scientifically possibly to avoid it all together.

The death of a strawberry had apparently been discussed on an earlier program last year:

Brian Cox Strawberry

A fascinating discussion regarding when a cell can be truly considered “dead” though I couldn’t quite agree that death was necessary to evolution. Only birth is of course. It would be pretty crowded without death but life – or death – after procreation no longer has any part to play in the passing on of genes to the next generation or on evolution. With immortality there would, of course, be no need for procreation or for any future generations. But if immortal beings did beget other immortal beings then an Infinite Universe would come in very handy. However, the fertility rate needed for replenishment of the mortal members of a species is unconnected to the longevity of the individuals and I cannot see that death, per se, has any impact on evolution.

As far as the life and death of a strawberry are concerned it seemed to me that the question was essentially meaningless. You could as well ask if your finger could be alive when it no longer was connected to your body. A finger -like a strawberry is never truly alive unless connected to the body that it is a part of and the question of life or death when it is separated from its host body is moot.

Self-replicating fingers – or strawberries – would make John Wyndham’s Triffids seem benign.

Reproduction after death: Guppies do it, humans can – but should they?

June 13, 2013

Guppies use stored sperm while humans can use stored sperm. Using the sperm of someone long dead is certainly possible to “create” a new human. The ethical question – if there is one – is the responsibility (whose?) to the child so produced. And this could be even more important if it is also true that the age of the sperm producer at the time of sperm production has an impact on the health of the child. And is there a responsibility to the deceased sperm donor? By agreeing to the storage of sperm does not the donor implicitly consent to the use of that sperm even after his demise unless he explicitly forbids it?

Photo shows guppies.

Guppies are small freshwater fish PHOTO CREDIT: PIERSON HILL.

UCRtoday:

Performing experiments in a river in Trinidad, a team of evolutionary biologists has found that male guppies continue to reproduce for at least ten months after they die, living on as stored sperm in females, who have much longer lifespans (two years) than males (three-four months).

“Populations that are too small can go extinct because close relatives end up breeding with each other and offspring suffer from inbreeding,” said David Reznick, a professor of biology at the University of California, Riverside and the principal investigator of the research project.  “If there are stored sperm, then the real population size is bigger than the number of animals you see.  Also, stored sperm can increase genetic variation in other ways.”

Scientific American:

Is it ethical to use a dead man’s sperm to father a child? Experts are calling for a consensus on policies surrounding this question, which currently vary widely across the country.

It has been possible for a few decades to obtain a man’s sperm after his death and use it to fertilize an egg. Today, requests for postmortem sperm retrieval (PMSR) are growing, yet the United States has no guidelines governing the retrieval of sperm from deceased men, said Dr. Larry Lipshultz, a urologist at Baylor College of Medicine in Texas.

In the absence of government regulations, medical institutions should come up with their own rules so they can handle the time-sensitive and ethically questionable procedures, Lipshultz argued in an editorial published June 5 in the journal Fertility and Sterility. 

Requests for PMSR can come from the wife or parents of a young man who suddenly died in an accident before having a chance to leave a child, and requests can also come from living, terminally ill men who wish to preserve sperm to be used after death.

But the institutions trying to draft a protocol for these situations face a number of ethical concerns. For example, has the deceased consented to have his sperm used for reproduction after he’s gone? Could just anybody request to obtain his sperm? Is it in the best interest of the child to be brought into the world without having a father? …… 

…. PMSR is currently illegal in France, Germany, Sweden and other countries, even with written consent from the deceased. In the United Kingdom, it can be done if there is written consent, and in Israel, the sperm can be retrieved, but then a judge has to decide whether it can be used.


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