Are Sperm Alive?

Dennis Goode goode at ZOOL.UMD.EDU
Fri Jan 3 17:15:56 EST 1997


Sid Lipkin wrote:
> 
> Always wondered this...Is human sperm classed as a living creature?
>   Is there a genus of animals that it belongs to?  Can sperm survive
>   outside the human body(in a lab setting)?
> 
>    What about anti-bodies?  are they Alive in the sense that we define life?
>      They have a purpose and act according to certain criteria?  is this life?
> 
>   Sorry if this is uneducated...just curious

Sid,

In addition to the other answers to your interesting questions, I might add that
human sperm are one of the stages in the life cycle of humans. Like other 
multicellular organisms, we evolved from a single-celled organism, 
but have kept the unicellular stages of our life cycle as the sperm 
and the egg.  Both of these are highly differentiated single cells, 
and as such are definitely alive, even tho sperm neither grow nor 
reproduce on their own, two of the defining properties of life.  
However they definitly show metabolism and response to stimili 
(chemotaxis toward  chemicals from the egg, and afertilization 
response upon contact with the egg). Basically Cell Biologists 
consider anything that is a cell to be alive, so sperm are alive but 
antibodies, proteins secreted from cells are not. 

But then we do have to distinguish between an egg or sperm and a human 
"being",  and of course there is a big debate about when that 
beingness comes into existence.

To extend your question, which came first, the egg or the sperm ?
The answer appears to be the sperm!
Evidence is accumulating that we (the animals) evolved from 
unicellular Choanoflagellates that look and swim very much like 
animal sperm.  We (the multicellular form) seem to be an addition on 
the the life cycle of these seemingly simple organisms.

-Keep asking questions; that's the best way to learn.

-Dennis
Dr. M. Dennis Goode                 Phone (301) 405-6917
Department of Zoology               Fax   (301) 314-9358
University of Maryland              e-mail goode at zool.umd.edu
College Park MD 20742
*************************************************************
"If the Lord Almighty had consulted me before embarking upon the 
creation, I should have recommended something simpler."
            -Alphonso X of Castile, 15th Century



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