Reproducation

[worship4ever]

The subject of male and female is kinda kewl to me. Male and female have evolved thur time. The repoduction of male and female organs have, over time, formed into what we know and love today. Correct me please if im wrong, but sexual reproduction increases the diversity of a species. Yet, the mutations are random and individual. If a species were evolving to make male reproduction organs, this is still outside the relam of female reproduction organs. A species, over time, may be changing into a male, but thats still indepentant to a non-existant female. They work apart. There must be some cooridnation between the two. A male is making sperm, for what purpose, to fertalize the female egg obviously. Thats assuming that there was the SAME species evolving into a female. The sperm has a purpose, it only has one job. A male and female had to evolve together but apart from each.
The primary components of typical sperm are the nucleus, acrosome and flagellum. The nucleus contains the genetic information, the acrosome contains the enzyme that allows the sperm to enter the ovum, and the flagellum is the tail that the sperm uses to swim. All these components are necessary for the sperm to survive or operate. You cant have 2 out of 3, you must have all 3 funcational at one time. While this sperm is forming you must have a female.
Natural selection operates on the individual, but only species evolve. This leads me to believe that if an individual isnt "fit" to survive it'll die, but the species as a whole will evolve and benefit. A mutation is a random change in DNA on an individual. Survival of the fittest" demonstrates only how an organism has survived, not how it has evolved. For every beneficial mutation there will be hundreds of harmful ones so that the net effect, or result, over time will be that the harmful mutations always win and will ultimately cause the organism, or even species, to degenerate or die. Mutations can only alter and effect the existing structure of genes: they cannot create new genetic material or new genetic potential. I don't know that im explaining this well, hopefully you guys get a sense of what im talking about. The first sperm created (no one knows how) was created for a single purpose, and if the individuals are changing seperately how can the sperm do its job.

 

[Siliconaut]

w4e, you always assume (or at least transmit the impression) that sexual reproduction is something that evolved in "higher" lifeforms, when all we know shows that the concept started *much* earlier, in single-cell organisms. Furthermore, you are postulating that - since *our* method of copulation and impregnation is complex - it could not have evolved, when in fact the mechanisms simple organisms use are often just a simple exchange of DNA through cell membranes.

Since sexual reproduction has accompanied us since it was developed in eucaryotes, the whole complicated mechanisms we employ had hundreds of millions of years to develop - quite enough to eventually turn into the pleasureable apparatus we have come to enjoy so much.

Natural selection operates on the individual, but only species evolve. This leads me to believe that if an individual isnt "fit" to survive it'll die, but the species as a whole will evolve and benefit. A mutation is a random change in DNA on an individual. Survival of the fittest" demonstrates only how an organism has survived, not how it has evolved. For every beneficial mutation there will be hundreds of harmful ones so that the net effect, or result, over time will be that the harmful mutations always win and will ultimately cause the organism, or even species, to degenerate or die.

Since the truly harmful ones either die very quickly or at least suffer problems when trying to find a partner to reproduce (sexuality obviously adds another hurdle for "bad genes"), the net effect will be that the beneficial mutation will have better chances to thrive than others. The net effect will be beneficial for the species, since the better adapted genes will make an impact on the gene pool.

can only alter and effect the existing structure of genes: they cannot create new genetic material or new genetic potential.

Wrong, but often re-told by creationist resources. It's the old claim that new genetic information could not be induced by mutations (although I have yet to see a creationist who will exactly define what he means by "information", because whatever he says has probably been debunked already).

I point you to this ressource: http://biology-online.org/2/8_mutations.htm , but, really any biology book that adresses the different types of genetic mutations will do the same.

The first sperm created (no one knows how) was created for a single purpose, and if the individuals are changing seperately how can the sperm do its job.

Long, long, long before the first "sperm" was produced, sex had been going on. Sex is - when you get down to it - just an exchange of DNA. You don't need complicated vessels for it if you're just a cell.

 

[Jet Black]

I thought we had taught you about how evolution works.

 

[Siliconaut]

I guess teaching must be constantly re-evaluated from different angles...

 

[imagineer]

Re-evaluated? No, repeated... I don't think many creationists actually grasp the concept of evolution the first, second, third or fourth time around.

 

[Siliconaut]

@Imagineer: (re your nick: I liked that book - wasn't it by Robert Rankin?) Well, that's why I'm prepared to give fifth and sixth reprises...

 

[lucaspa]

There are so many misconceptions here that it is going to take several posts to cover them all.

The subject of male and female is kinda kewl to me. Male and female have evolved thur time. The repoduction of male and female organs have, over time, formed into what we know and love today. Correct me please if im wrong, but sexual reproduction increases the diversity of a species. Yet, the mutations are random and individual.

You did ask to be corrected.

Sexual reproduction increases the GENETIC DIVERSITY within a population. Genetic diversity can arise thru 1) mutation, 2) exchange of DNA sequences by plasmids, and 3) recombination. Asexually reproducting organisms have only the first 2. What you have in an asexually reproducing species is a community of genetically identical clones. Right? The cell divides, and the daughter is genetically identical to the parent. Each cell has n number of chromosomes. So, you have selection of CLONES. Some clones are eliminated, some survive.

However, in a sexually reproducing species, you have 2n number of chromosomes. One set of chromosomes from each parent. Now, many traits require more than one gene. If those genes are on different chromosomes, then you get unique combinations by sexual reproduction that you can't get by asexual reproduction. Thus, within the population, you have greater diversity since you don't have a population of clones but instead each individual is unique by it's recombination of chromosomes by sexual reproduction.

I'm assuming you understand what recombination is. If you don't understand, then ask.

If a species were evolving to make male reproduction organs, this is still outside the relam of female reproduction organs.

Not really. Because unless one gamete can make contact with the other gamete, fertilization can't occur. So here you have co-evolution.

Now, let's look at many fish. You have females making one gamete -- an ovum -- and ejecting that gamete out into water to deposit the eggs on the bottom of the ocean. So you have the ovary connected by a tube to the outside. A very primitive v-a-g-i-n-a (the word will be censored by the program, even tho we are using it technically and not lasciviously). The "male" fish is making sperm and also needs to eject them into the water to cover the eggs so fertilization an occur. Again you have a tube linking the testicles to the outside. However, there is really no projection that we would recognize as a p-e-n-i-s. So here you have definite "male" and "female" but without the organs you think are so "kewl". An intermediate step in the evolution of the reproductive organs you are so fascinated with.

Now, that method is very inefficient. Lots of sperm get lost. A more efficient means would be a projection that could be inserted into the female so that the sperm would be deposited inside next to the ova. So basically we have a female first and now the evolution of a male p-e-n-i-s following. IOW, looking at living species, you got your sequence wrong. It is not male first, then female. But female sexual organ first, THEN male. No wonder you had problems.

Stepwise that you think can't happen. But it can if you look at living species and give it a little thought.

 

[lucaspa]

The primary components of typical sperm are the nucleus, acrosome and flagellum. The nucleus contains the genetic information, the acrosome contains the enzyme that allows the sperm to enter the ovum, and the flagellum is the tail that the sperm uses to swim. All these components are necessary for the sperm to survive or operate. You cant have 2 out of 3, you must have all 3 funcational at one time. While this sperm is forming you must have a female.

You know, Worship4ever, I don't think you even bother reading my posts. If you had, you wouldn't be saying this. So, for the other members of the forum, this is the answer:

Only later in evolution, where you have two discrete genders making discrete gametes. In Dictyostelium you have an amoeba that engages in asexual reproduction part of the time and sexual reproduction part of the time. Thus, in this single celled species you don't have separate gametes. Instead, you have the production of the enzyme that allows cell fusion and the proteins to allow injection of genetic material into another cell. That's ONE out of the three.

In volvox, you have a species that has one type of somatic cell and the gametes. There is no distinguishable "male" and "female", so now you have the nucleus with the genetic information and the acrosome (in both cells) to allow one gamete to enter the other. But no flagellum. TWO out of the three.

So the next step is to add a flagella. From LIVING species we can see that we don't need all 3 for sexual reproduction. They CAN develop in steps.

Natural selection operates on the individual, but only species evolve. This leads me to believe that if an individual isnt "fit" to survive it'll die, but the species as a whole will evolve and benefit. A mutation is a random change in DNA on an individual. Survival of the fittest" demonstrates only how an organism has survived, not how it has evolved.

Remember, it is the POPULATION that evolves. What is more important is not the individuals who die, but the ones who live. Darwin looked on natural selection as a method of PRESERVATION of good designs. Those individuals lucky enough to have the genetic components that allow them to do better at competing for scarce resources will survive and reproduce -- PRESERVING those genes. In the course of generations, EVERY INDIVIDUAL in the population will be a descendent of that lucky individual and EVERY individual will have those genes. Thus, the genetic makeup of the POPULATION will have changed. And that's how the population evolves but the individual doesn't.

For every beneficial mutation there will be hundreds of harmful ones so that the net effect, or result, over time will be that the harmful mutations always win and will ultimately cause the organism, or even species, to degenerate or die.

You contradict yourself. Look at your quote above. What happens to the individuals unlucky enough to get the harmful mutations? You said it yourself: "This leads me to believe that if an individual isnt "fit" to survive it'll die" When the individual dies, the harmful mutation dies with it, and therefore is eliminated from the population. So only the "good" mutations will persist, and the population will not degenerate and die.

Now, as it turns out, only about 2.6 per 1,000 mutations is out and out harmful. That's a far cry from 'hundreds of harmful mutations for every beneficial one' that you said. Most mutations are neutral with respect to a given environment, staying in the population at low frequency until changes in the environment either make them "harmful" or "beneficial", depending on the environment.

Mutations can only alter and effect the existing structure of genes: they cannot create new genetic material or new genetic potential.

I'm afraid that's not true. Mutations in the broad definition are simply errors in copying the DNA. You are using the narrow definition of point subsitutions where one base is substitued for another.

But this is only a subset of mutations. Many mutations do indeed increase the amount of new genetic material (DNA). For instance, there are hundreds of known examples of DUPLICATION of genes. That is, making two copies of a gene instead of one. Also, part of a chromosome can be duplicated and attached to another chromosome. Even whole chromosomes (which, of course, are nothing but a long strand of DNA) can be duplicated. The visatch rat has 51 chromosomes instead of the normal 26 for rats. ALL the chromosomes except the sex chromosome has been duplicated. This rat species has a LOT of new genetic material and new genetic potential.

Obviously, the duplicated gene or chromosome can be altered without hurting the individual, because the original gene or chromosome is still there producing the original proteins. So here you have the new genetic potential needed to evolve new morphologies.

 

[Jet Black]

The visatch rat has 51 chromosomes instead of the normal 26 for rats.

could you tell me where I can get a bit more info on this. I tried google, but the only link it gave was to here... is the spelling ok?

 

[lucaspa]

could you tell me where I can get a bit more info on this. I tried google, but the only link it gave was to here... is the spelling ok?

9. Double dose of DNA. Science 285: 195, 2 July 1999.

 

[lucaspa]

Looks like Worship4ever has made an hit and run. Let's hope that, even if he doesn't acknowledge the refutation of his argument, that he doesn't repeat this particular argument from ignorance anywhere else. I'll be happy with that.