Freethought & Rationalism Archive

Dr.GH · 07-27-2003, 11:23 PM

Who did the first human have sex with?

Well, if the first human was like all the rest, s/he first had sex with themselves.

TeHe

caravelair · 07-28-2003, 02:11 PM

Quote:

the closest human ancestor probably looked about like your average creationist.

he he he he.

lpetrich · 07-28-2003, 02:29 PM

Actually, in a sense, the vagina came first -- a duct without a projection. External fertilizers essentially have vaginas for both sexes of gamete. Penises and penis-like organs were later inventions for assisting in internal fertilization -- and were invented several times. Even seed plants have a sort of penis -- a pollen grain stuck onto a pistil sprouts a long, thin tube for reaching the ovules.

Coragyps · 07-28-2003, 03:35 PM

Quote:

"Half a penis" is a low-quality penis,

Watch it there, bud! It was higher-quality fifteen years ago!

"Half a penis" is what we eutherian mammals have anyway - marsupials and monotremes, as well as at least some lizards (and snakes? Are you out there, Doov?) have a double-barrelled arrangement, and the monotremes, if I'm reading my reference right, have theirs internally in their cloaca anyway.

Supercaliber · 07-28-2003, 04:58 PM

Quote:

Originally posted by Doubting Didymus
What do yer say, supercaliber? Need more? Clearer? Specifics?

I must say, the replys to my thread have been enlightening indeed..Thankyou..

But because I find the sciences enthralling and somewhat comprehensible doesn't mean my Xtian boss will also..As a matter of fact, most Xtians won't either..I now have the burden of explaining this to him..

Has anybody spent any time in a room full of them recently?..They won't recite the word "dirt" much less find some..Fundies DO NOT show a good grasp of the sciences nor, even worst, any interest..If they did, they wouldn't be fundies..Of course, there is the exception..

I am not knocking the intelligence of religous fundamentalists..I am knocking their ignorance..

I will keep reading and try to present a meaning to the "Birth of the Family Jewels pt1"

BTW, since the anus came before both sex organs, is it possible anal sex came 1st?!!..

I think I just lost my job..

tronvillain · 07-28-2003, 05:23 PM

Happy Wonderer:

Quote:

The vagina. Virtually everything important to reproduction is part of the human female's anatomy. With enough technology, the last female human could probably clonally reproduce. Ain't gonna happen if the last human is male. (This is a crude way of making a point said much more accurately by previous posters.)

Well, that clonal reproduction would only be successful in the long term if that technology prevented or corrected the mutational meltdown that eliminating sexual reproduction would eventually result in.

As for the evolution of the penis, how difficult is it to imagine a smooth progression from "pressing two holes together" to "insterting a tube connected to one hole into another hole? Any swelling that increases the efficiency of the connection will be a benefit: a one-percent penis would be an improvement over no penis, and so on.

lpetrich · 07-28-2003, 06:21 PM

Supercaliber:
(fundies...)
Has anybody spent any time in a room full of them recently?..They won't recite the word "dirt" much less find some..

???

I will keep reading and try to present a meaning to the "Birth of the Family Jewels pt1"

BTW, since the anus came before both sex organs, is it possible anal sex came 1st?!!..

I think that it was gonads before anus, and anus before internal fertilization. To see why, consider comparative anatomy and reconstructed early animal evolution.

The most primitive sort of (multicelled) animal is sea sponges (Porifera), which have little differentiation of their cells. In fact, their cells look much like choanoflagellates (collar flagellates -- one-celled), suggesting that sponges originated as colonies of these protozoans. And gene-sequence comparisons reveal that the closest relatives of the animal kingdom are indeed the choanoflagellates.

They catch their food by sending the surrounding water through them and catching whatever they find floating in it. And they do not have well-defined gonads, parts of them produce eggs and sperm, without those parts being outwardly very distinct.

Getting a bit fancier, we find the Cnidaria, which include the likes of sea anemones and jellyfish. They have a blind gut, with a two-way mouth; when they finish digesting their prey, they spit it out.

Their cells are more specialized than those of sponges; they have muscle and nerve cells, though not a well-defined brain. They also have well-defined gonads, which eject eggs and sperm into the surrounding water (external fertilization).

These examples indicate "vagina" before anus.

A one-way digestive system, including an anus, is a very common feature of bilaterians, bilaterally-symmetric animals. And though many bilaterians live on the land, those that do are in groups that are nested in groups of aquatic ones:

Land vertebrates in fish
Pillbugs in aquatic isopods
Land crabs in aquatic crabs
Land snails and slugs in aquatic gastropods

(their are some cases of aquatic animals like cetaceans, but they do not affect this discussion)

So one concludes that the ancestral bilaterian had been aquatic.

Similarly, one finds that external fertilization is widespread among aquatic bilaterians, and one concludes that the ancestral bilaterian had practiced it also.

Internal fertilization was invented several times, however, usually as a result of living on land; this is apparent from the details of the organs involved.

Thus, anus before internal fertilization.

And no anal-sex phase!

Happy Wonderer · 07-28-2003, 07:16 PM

Quote:

Originally posted by tronvillain
Happy Wonderer:

Well, that clonal reproduction would only be successful in the long term if that technology prevented or corrected the mutational meltdown that eliminating sexual reproduction would eventually result in.

Hi Tronvillian:

Hmm, could a female give birth to a male by varying hormones in the uterus? (I think the answer might be that the offspring would physically be a male but would still lack a Y chromosone, and there is nowhere any access to the Father's Y for the female. If males gave birth, it seems like you could clonally produce both males and females.)

Note that my hypothetical female has access to two different sets of information in each chromosone, so she would only be twice as bad off as if there were a single male around. The bottleneck would probably eventually, er, screw the species eventually in either case if accidental death didn't get it first. ("Damn, Joey just fell off a cliff -- there goes 1/5 of the population!")

Anyway, the point that I was trying to get at in a roundabout way didn't have as much to do with this catastrophic hypothetical as it was to indicate that males play a very small part in reproduction. This point alone should be enough to annoy some fundamentalists (of various religions.)

Your point about the penis seems exactly right to me. There are an incredible variety of mechanisms that exist in nature that look nothing at all like human penises.

hw

Coragyps · 07-28-2003, 07:39 PM

Speaking of varieties of mechanisms....how about a clownfish (Amphiprion percula):

Quote:

In Madang Lagoon, Papua New Guinea, groups of A. percula inhabit sea anemones, which protect them from predators (Fig. 1). Each group is composed of a breeding pair and between zero and four non-breeders. Within each group, there is a size-based dominance hierarchy: the female is largest (rank 1), the male is second largest (rank 2), and the non-breeders get progressively smaller as the hierarchy is descended (ranks 3�6). If the female of a group dies, the male changes sex and becomes the breeding female, while the largest non-breeder becomes the breeding male.

P. Buston, Nature, 424, 145-146 (10 July 2003) (footnotes omitted)

I'll bet their family reunions are strange, and downright baffling to creationists. Yeah, "male and female he created them" but that's not supposed to be the same one on different days!

tronvillain · 07-28-2003, 08:02 PM

No, it is totally impossible for a female to give birth to a male by varying hormones in the uterus. You cannot be genetically female and physically male, though you can be genetically male and physically female: female is the default for mammals. So, if males could give birth, they could give birth to both males and females, but females could only ever give birth to females.

Now, your point that "males play a very small part in reproduction" but what that tells us is that sexual reproduction must have a huge payoff to compensate for the fifty percent decrease in reproductive efficiency. It seems likely that the payoff is that it permits additional complexity by preventing the mutational meltdown that would otherwise occur with an increase in genome size. It isn't just that two parents start off with twice as much information as one parent, it is that sexual reproduction can actually filter out deleterious alleles via recombination, while clonal reproduction cannot.

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07-27-2003, 11:23 PM	#11
Dr.GH Veteran Member Join Date: Jul 2001 Location: Dana Point, Ca, USA Posts: 2,115	Who did the first human have sex with? Well, if the first human was like all the rest, s/he first had sex with themselves. TeHe

07-28-2003, 02:29 PM	#13
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	Actually, in a sense, the vagina came first -- a duct without a projection. External fertilizers essentially have vaginas for both sexes of gamete. Penises and penis-like organs were later inventions for assisting in internal fertilization -- and were invented several times. Even seed plants have a sort of penis -- a pollen grain stuck onto a pistil sprouts a long, thin tube for reaching the ovules.

07-28-2003, 06:21 PM	#17
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	Supercaliber: (fundies...) Has anybody spent any time in a room full of them recently?..They won't recite the word "dirt" much less find some.. ??? I will keep reading and try to present a meaning to the "Birth of the Family Jewels pt1" BTW, since the anus came before both sex organs, is it possible anal sex came 1st?!!.. I think that it was gonads before anus, and anus before internal fertilization. To see why, consider comparative anatomy and reconstructed early animal evolution. The most primitive sort of (multicelled) animal is sea sponges (Porifera), which have little differentiation of their cells. In fact, their cells look much like choanoflagellates (collar flagellates -- one-celled), suggesting that sponges originated as colonies of these protozoans. And gene-sequence comparisons reveal that the closest relatives of the animal kingdom are indeed the choanoflagellates. They catch their food by sending the surrounding water through them and catching whatever they find floating in it. And they do not have well-defined gonads, parts of them produce eggs and sperm, without those parts being outwardly very distinct. Getting a bit fancier, we find the Cnidaria, which include the likes of sea anemones and jellyfish. They have a blind gut, with a two-way mouth; when they finish digesting their prey, they spit it out. Their cells are more specialized than those of sponges; they have muscle and nerve cells, though not a well-defined brain. They also have well-defined gonads, which eject eggs and sperm into the surrounding water (external fertilization). These examples indicate "vagina" before anus. A one-way digestive system, including an anus, is a very common feature of bilaterians, bilaterally-symmetric animals. And though many bilaterians live on the land, those that do are in groups that are nested in groups of aquatic ones: Land vertebrates in fish Pillbugs in aquatic isopods Land crabs in aquatic crabs Land snails and slugs in aquatic gastropods (their are some cases of aquatic animals like cetaceans, but they do not affect this discussion) So one concludes that the ancestral bilaterian had been aquatic. Similarly, one finds that external fertilization is widespread among aquatic bilaterians, and one concludes that the ancestral bilaterian had practiced it also. Internal fertilization was invented several times, however, usually as a result of living on land; this is apparent from the details of the organs involved. Thus, anus before internal fertilization. And no anal-sex phase!

07-28-2003, 08:02 PM	#20
tronvillain Veteran Member Join Date: Oct 2000 Location: Alberta, Canada Posts: 5,658	No, it is totally impossible for a female to give birth to a male by varying hormones in the uterus. You cannot be genetically female and physically male, though you can be genetically male and physically female: female is the default for mammals. So, if males could give birth, they could give birth to both males and females, but females could only ever give birth to females. Now, your point that "males play a very small part in reproduction" but what that tells us is that sexual reproduction must have a huge payoff to compensate for the fifty percent decrease in reproductive efficiency. It seems likely that the payoff is that it permits additional complexity by preventing the mutational meltdown that would otherwise occur with an increase in genome size. It isn't just that two parents start off with twice as much information as one parent, it is that sexual reproduction can actually filter out deleterious alleles via recombination, while clonal reproduction cannot.

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