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Evolution of reproduction: Mobility of cells

Discussion of everything related to the Theory of Evolution.

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Evolution of reproduction: Mobility of cells

Postby Engel08 » Mon Jun 25, 2007 7:33 am

I understand that much has been said about the process of reproduction as a whole. As an act in evolutionary discussion. But what I'm curious about is the importance of the jump between birds and bees to human dna and reproduction.
Let me explain. Pollen is mobile but the plants do not send each other the pollen directly. Instead they have bees carry it.
My idea on this is that somehow nature evlved so that two beings of the same species could interact more directly.
I believe I would get a clearer image of this if I were to let's day...Research the evolution of asexual vs sexual reproduction. But would this scientist be able to explain to me what the benifits were and what the steps were towards a internal reproductive strategy. Because if you think about it there is a definitive stepping stone relation to styles of reproduction to evolutionary progress.
A fish may have to lay both the eggs and the males have to sprinkle their sperm on the unfertilized eggs in a atmosphere that is normally not even sclose to calm. What is the evolutionary step to this point? Because in a way it is a higher form of the way flowers reproduce. But the visual and physical difference between the species is huge. To thepoint it's in a different catogory.

Maybe some book reccomendations can be made? Good ones.
I would like to research the evolutionary steps in the "how's of reproduction. Focusing on mobility and transference of reproductive products. I can resaerch physical changes as well. But those have been covered already. By some brilliant mnds.

I apologize for my choppy wording. Normally I'm quite fluent but on this topic I'm afraid I never got past physical science. I was barred from learning higher science in high school due to academic reasons but it sdoesn't stop a persons mind from the curiosity nor from research.
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Postby MrMistery » Mon Jun 25, 2007 8:51 am

I don't quite understand your question. There aren't many resemblances between fish and angiosperm reproduction, except maybe that both of them carry out sexual reproduction.
However, reproduction in both animals and plants evolved to be as independent from water as possible. Let me explain.
Let's take animals first. Animals that live in water carry out external fertilization mainly. think of fish. The reason why they do so is that the environment permits this. water is more or less stable, and fertilization can occur there. so there was no need to evolve specialised structures for this purpose. Also, since larvae can exit the egg and start feeding very soon, the eggs do not need to carry any excess nutrients. These two combined allow fish to produce immense amounts of offspring. A female fish can lay many thousants of eggs at once.
Frogs then took a shy step towards land. they can live on land, but they still need to reproduce in water. they lay eggs in water where males fertilise them. however, frogs have resolved the problem of sperm finding eggs, since the female only lays eggs when the male is there to fertilise them.
Reptiles developed the amniotic egg and internal fertilisation. there reproduction was truly water-independent. Since fertilization takes place inside the body of the female it does not require water(take note that external fertilization cannot occur on land - the eggs would dry up and sperm could not move). Also, the egg has an amnion, so there is no need for a water-dwelling larva. The organism develops entirely in that egg, the amnion being sorta like a fragment of the ancient ocean where the eggs of fish used to develop.
A similar process has occured with plants. However, i have no time to explain that now. maybe later or tomorrow.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
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Postby JDavidE » Tue Jun 26, 2007 12:53 am

MrMistery wrote:A similar process has occured with plants. However, i have no time to explain that now. maybe later or tomorrow.


In particular, that strange half-way step in the reproductive cycle of Bryophyta.

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Postby Heronumber0 » Sat Jul 07, 2007 6:46 pm

Reptiles developed the amniotic egg and internal fertilisation. there reproduction was truly water-independent. Since fertilization takes place inside the body of the female it does not require water(take note that external fertilization cannot occur on land - the eggs would dry up and sperm could not move). Also, the egg has an amnion, so there is no need for a water-dwelling larva. The organism develops entirely in that egg, the amnion being sorta like a fragment of the ancient ocean where the eggs of fish used to develop.
A similar process has occured with plants. However, i have no time to explain that now. maybe later or tomorrow.


Strange old world isn't it? How and why is the sperm adapted with enzymes in the acrosome and with various glandular fluids for a location which it has never visited befoe? I'd love to find out the answer.
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Postby kotoreru » Sun Jul 08, 2007 8:53 pm

In the words of the Borg-Queen from a Trekkie film: "You imply disparity where there is none".

(Geek alert!)
"What are humans if they don't learn at University? Animals, yes."

^^One of my ex-girlfriends said that. I stress the ex part.
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Postby mith » Sun Jul 08, 2007 11:14 pm

lol.wow
Living one day at a time;
Enjoying one moment at a time;
Accepting hardships as the pathway to peace;
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Postby kotoreru » Mon Jul 09, 2007 2:02 pm

I thought you might like that ;)
"What are humans if they don't learn at University? Animals, yes."

^^One of my ex-girlfriends said that. I stress the ex part.
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