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Author Topic:   Natural selection? By means of suicide
Delshad
Inactive Member


Message 1 of 7 (18343)
09-26-2002 8:21 AM


Read the following carefully and with an open mind.

There are some creatures that defy all logic behind some well known theories.
Heres some examples: A bee found fossilized in a tree 120 million years ago is just like any normal type of bee found today.
The long time needed to adjust some unecessary functions is there.
Then how come that a bee still dies after it has stung an enemy, shouldnt a minor adjustment had taken place during that long time thus enabling it to reproduce more frequently.
Or there is a fish, Im sorry but ive forgot the name but youll maybe recognise it anyway, that for the last 10-20 million years has crawled on its belly and its small fins up from the water it lives in for a journey out in the swamps , thus in most cases enabling its death, (it has no structure that even resembles a leg and it has no lungs), shouldnt natural selection making it easy for this poor fish.
In these cases and many more its seems like natural selection is taking a vacation.
If not, then please reply(Im quite curious myself).


Replies to this message:
 Message 2 by John, posted 09-26-2002 9:50 AM Delshad has not yet responded
 Message 3 by Andya Primanda, posted 09-27-2002 4:47 AM Delshad has not yet responded
 Message 4 by Quetzal, posted 09-27-2002 10:22 AM Delshad has not yet responded

  
John
Inactive Member


Message 2 of 7 (18347)
09-26-2002 9:50 AM
Reply to: Message 1 by Delshad
09-26-2002 8:21 AM


quote:
Originally posted by Delshad:
[B]Heres some examples: A bee found fossilized in a tree 120 million years ago is just like any normal type of bee found today.{/b][/quote]

Point me to something concerning this bee.

{quoteThen how come that a bee still dies after it has stung an enemy, shouldnt a minor adjustment had taken place during that long time thus enabling it to reproduce more frequently.]


Bees, except for the queen and a few males during mating season, are all sterile. They would not have reproduced anyway. Unless enough of them die to effect the survival of the queen, the reproductive fitness of the hive is uneffected.

quote:
Or there is a fish, Im sorry but ive forgot the name but youll maybe recognise it anyway, that for the last 10-20 million years has crawled on its belly and its small fins up from the water it lives in for a journey out in the swamps , thus in most cases enabling its death, (it has no structure that even resembles a leg and it has no lungs), shouldnt natural selection making it easy for this poor fish.

There are several varieties of 'walking' fish. You need to be specific if you want a decent answer.

------------------
www.hells-handmaiden.com


This message is a reply to:
 Message 1 by Delshad, posted 09-26-2002 8:21 AM Delshad has not yet responded

  
Andya Primanda
Inactive Member


Message 3 of 7 (18404)
09-27-2002 4:47 AM
Reply to: Message 1 by Delshad
09-26-2002 8:21 AM


quote:
Originally posted by Delshad:
Or there is a fish, Im sorry but ive forgot the name but youll maybe recognise it anyway, that for the last 10-20 million years has crawled on its belly and its small fins up from the water it lives in for a journey out in the swamps , thus in most cases enabling its death, (it has no structure that even resembles a leg and it has no lungs), shouldnt natural selection making it easy for this poor fish.
In these cases and many more its seems like natural selection is taking a vacation.
If not, then please reply(Im quite curious myself).

http://goodnightstories.com/wildlife/fish/card5.htm
The walking fish... Periopthalmus, the mudskipper, has no lungs and its fin does not resemble a leg. However it leads a ahappy life in the tropical mangrove forests, looking for food in the muddy beaches. Periopthalmus can breathe air as long as its gills are wet.


This message is a reply to:
 Message 1 by Delshad, posted 09-26-2002 8:21 AM Delshad has not yet responded

  
Quetzal
Member (Idle past 4044 days)
Posts: 3228
Joined: 01-09-2002


Message 4 of 7 (18413)
09-27-2002 10:22 AM
Reply to: Message 1 by Delshad
09-26-2002 8:21 AM


quote:
Originally posted by Delshad:
Read the following carefully and with an open mind.

There are some creatures that defy all logic behind some well known theories.
Heres some examples: A bee found fossilized in a tree 120 million years ago is just like any normal type of bee found today.
The long time needed to adjust some unecessary functions is there.
Then how come that a bee still dies after it has stung an enemy, shouldnt a minor adjustment had taken place during that long time thus enabling it to reproduce more frequently.


You're a bit off. The oldest known true "bee" is Trigona prisca from about 95 million years ago. It was stingless. You're approximately right in that T. prisca closely resembles other Trigona spp. However, there are a huge number of lineages that have branched out of the Apoidae lineage that includes T. prisca. There are even a lot of bees living today that are stingless (c.f. the Meliponinae suborder).

Only a relative handful of Apoidae species die when they sting. Why has this unfortunate "suicidal" tendancy persisted? John provided the main explanation - there is no selective pressure to eliminate it because all of the bees with stingers are non-reproductive females. They are basically dead-end clones of each other. Any mutation or variation within a given worker simply dies out when she does. Nothing for natural selection to operate on. In addition, the bees DON'T die when they sting their primary enemy: other bees and insect predators.

As to your "suicidal fish", without more info than you have provided, I'm afraid I can't comment. Please provide at least the common name of the species you're talking about. Andya mentioned one. There are others (a lot of the Gobiidae can live for shorter or longer periods out of water, for instance).


This message is a reply to:
 Message 1 by Delshad, posted 09-26-2002 8:21 AM Delshad has not yet responded

  
lpetrich
Inactive Member


Message 5 of 7 (29585)
01-19-2003 4:38 PM


Among bees, it's mostly honeybees whose workers are kamikaze stingers.

And honeybees may have an additional impetus toward evolving this feature: their large hives (~10,000 individuals, with lots of honey and poilen and grubs in their honeycombs). This makes their hives a much more attractive target than those of many other social bees, making it necessary to administer extra-potent stings to their hives' predators. Furthermore, the large population of workers means that individual workers are more expendable than they would be in a small hive.

By comparison, for a small hive, workers surviving the stings they administer is a reasonable tradeoff for inflicting less potent stings -- and such stings would be OK for the relatively small predators that their hives attract. Thus, small-hive bees (and wasps) have smooth stingers.

Furthermore, queen honeybees have to survive the stings they administer in order to reproduce; they continue to have smooth stingers.

There is even some evidence of venom optimization; worker-bee venom is twice as lethal to mice as queen-bee venom. Queens only sting rival queens, while workers sting hive predators, which are often vertebrates.


  
lpetrich
Inactive Member


Message 6 of 7 (29587)
01-19-2003 4:49 PM


When they emerge from their hive cells, queen honeybees try to sting all the other queens that they find -- even those still in their hive cells. This is difficult to explain in "good of the species" fashion, but it is a straightforward consequence of the "selfish gene" concept -- a queen who stings all her rivals gets an entire hive for herself.
  
Bald ape
Inactive Member


Message 7 of 7 (30232)
01-26-2003 12:47 AM


You must understand that evolution is not a contious thought process it runs more by chance than anything else. For an animal to develope lungs which are very comlex things, there needs to be a process of random genetic mutations. If an animal does not undergo the aproriate mutations and have them supported by natural selection it cannot evolve lungs. A fish cannot simply go "I'd really like a set of lungs" and then presto get a set!

This kind of argument fits the evolution model very well so is more of an "evolution is right" statement than enything else!

One (or more) group of aquatic animals did develope lungs, and here we are thanks to some lucky genetics!

Bald ape


  
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