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Human evolution: when male and female fully developed into separate and distinct ...?

by jackson6612
Tags: developed, distinct, evolution, female, fully, human, male, separate
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jackson6612
#1
Jun13-10, 12:03 PM
P: 348
I'm finding it hard to describe what I mean, but here it goes. According to the evolution theory monkeys, apes among others, and humans have a common ancestor - their hereditary line of ascent leads to a common forefather(s). As evolution predicts, let's say, male nipples is a proof that human species is a product of evolution. Where did that male and female beings got separated - became fully developed into separate and distinct entities? What I'm trying to say is: there would be times when, perhaps, male being also had nipples which somewhat looked more like female mammary glands which would simply mean male hadn't become a full male yet, on the other side, maybe female vestigial organ looked more of a male sex organ. Also, before they fully developed how did they reproduce? Were they able to reproduce before the sex organs fully developed? What about all those enzymes, chemicals - without the proper chemicals sexual reproduction is impossible, at least that's what I can possibly think?

It's possible I'm thinking along the wrong lines. I'm not a biology student neither am I very knowledgeable about the evolutionary theory. So, please, try to keep your reply as simple as possible so that I and many others like me can understand what you say and appreciate your effort to the fullest. Thank you.
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arildno
#2
Jun13-10, 12:13 PM
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Were they able to reproduce before the sex organs fully developed?
Definitely. Otherwise, we wouldn't be here. Thus, whatever sex organs they had were fully functional then, whatever degree of similarity they might have with our own.

As for when sexual distinction arose, I'd hazard for an extremely early age in mammalian history, long before there were any apes, let alone humans, around.

I'll leave to others more qualified than me to answer some of your other questions
AlexB2010
#3
Jun13-10, 12:15 PM
P: 39
The sex differentiation of animals go far beyond you imagine on evolutionary line. Apes still have full sexual differentiation from their ancestral. Fishes already have full sexual separation.
If you study molecular evolution you will see that some proteins are very well the same in their folded forms from bacteria to humans.

nismaratwork
#4
Jun13-10, 12:21 PM
P: 2,284
Human evolution: when male and female fully developed into separate and distinct ...?

Probably the best place to learn about this is through the study of amphibians which can and do change their gender according to environment. It is not the beginning of the story, but it's a good place to start.
Proton Soup
#5
Jun13-10, 12:47 PM
P: 1,070
aren't sea squirts the earliest chordates? it seems they were initially hermaphroditic.

http://marinebiology.suite101.com/ar...plex_sex_lives

http://sci-s03.bacs.uq.edu.au/biol/b...er08/crean.pdf
nismaratwork
#6
Jun13-10, 01:10 PM
P: 2,284
Quote Quote by Proton Soup View Post
aren't sea squirts the earliest chordates? it seems they were initially hermaphroditic.

http://marinebiology.suite101.com/ar...plex_sex_lives

http://sci-s03.bacs.uq.edu.au/biol/b...er08/crean.pdf
That sounds about right to me. Ugly little things aren't they? :p
Proton Soup
#7
Jun13-10, 01:14 PM
P: 1,070
Quote Quote by nismaratwork View Post
That sounds about right to me. Ugly little things aren't they? :p
i was always excited to find them on a piece of live rock in my old aquarium
nismaratwork
#8
Jun13-10, 01:31 PM
P: 2,284
Quote Quote by Proton Soup View Post
i was always excited to find them on a piece of live rock in my old aquarium
You had sea squirts in your aquarium? That's... actually pretty cool. Beats the hell out of brine shrimp in a bag!
Proton Soup
#9
Jun13-10, 01:36 PM
P: 1,070
Quote Quote by nismaratwork View Post
You had sea squirts in your aquarium? That's... actually pretty cool. Beats the hell out of brine shrimp in a bag!
i had those once, too. Sea Monkeys!
jackson6612
#10
Jun13-10, 01:58 PM
P: 348
Quote Quote by AlexB2010 View Post
The sex differentiation of animals go far beyond you imagine on evolutionary line. Apes still have full sexual differentiation from their ancestral. Fishes already have full sexual separation.
If you study molecular evolution you will see that some proteins are very well the same in their folded forms from bacteria to humans.
re: The sex differentiation of animals go far beyond you imagine on evolutionary line

I'm sorry for this off-topic question. I'm also an English learner, so it'd be nice if you could help with the language so that I can get the point.

I would have written: The sex differentiation of animals go far beyond you can imagine on the evolutionary line.Or, rather better: The sex differentiation of animals happened far long ago on the evolutionary line. Does my way match what you had in my mind?

re: Apes still have full sexual differentiation from their ancestral. Fishes already have full sexual separation

Here, by apes , you mean monkeys, gorillas, etc? Yes, I have no doubt about it - there are a lot of male and female monkeys around! But I don't think this is what you exactly meant. You used two different words, 'sexual differentiation' and 'sexual separation', to refer to what appears the same feature to me. Did you do that on purpose, or, just for the sake of variety?

Thank you for all the help.
russ_watters
#11
Jun13-10, 01:59 PM
Mentor
P: 22,301
Not a biologist either, but I wonder if the OP's question isn't looking in the wrong direction: things like nipples and sex organs need not be completely separate sexual "parts". Thinking as someone who'se done a little computer programming, it strikes me that the genetic code could be simplified by making related functions or having certain parts of a program activated in different ways. Hence, you could differentiate male and female before nipples and breasts even evolve at all.

Just speculating though - I'm curious to know from a biologist how that actually works.
russ_watters
#12
Jun13-10, 02:00 PM
Mentor
P: 22,301
Quote Quote by jackson6612 View Post
re: The sex differentiation of animals go far beyond you imagine on evolutionary line

I'm sorry for this off-topic question. I'm also an English learner, so it'd be nice if you could help with the language so that I can get the point.

I would have written: The sex differentiation of animals go far beyond you can imagine on the evolutionary line.Or, rather better: The sex differentiation of animals happened far long ago on the evolutionary line. Does my way match what you had in my mind?
Yours is better.
jackson6612
#13
Jun13-10, 02:01 PM
P: 348
Quote Quote by nismaratwork View Post
Probably the best place to learn about this is through the study of amphibians which can and do change their gender according to environment. It is not the beginning of the story, but it's a good place to start.
Can you give me an example, please?
AlexB2010
#14
Jun13-10, 02:40 PM
P: 39
Quote Quote by jackson6612 View Post
re: The sex differentiation of animals go far beyond you imagine on evolutionary line

I'm sorry for this off-topic question. I'm also an English learner, so it'd be nice if you could help with the language so that I can get the point.

I would have written: The sex differentiation of animals go far beyond you can imagine on the evolutionary line.Or, rather better: The sex differentiation of animals happened far long ago on the evolutionary line. Does my way match what you had in my mind?

re: Apes still have full sexual differentiation from their ancestral. Fishes already have full sexual separation

Here, by apes , you mean monkeys, gorillas, etc? Yes, I have no doubt about it - there are a lot of male and female monkeys around! But I don't think this is what you exactly meant. You used two different words, 'sexual differentiation' and 'sexual separation', to refer to what appears the same feature to me. Did you do that on purpose, or, just for the sake of variety?

Thank you for all the help.
Unfortunately, I am Brazilian and English isnít my native tongue, I am just struggling to be understood and trying to improve my English like you. Maybe a native speaker can correct me too.
AlexB2010
#15
Jun13-10, 02:50 PM
P: 39
Quote Quote by russ_watters View Post
Not a biologist either, but I wonder if the OP's question isn't looking in the wrong direction: things like nipples and sex organs need not be completely separate sexual "parts". Thinking as someone who'se done a little computer programming, it strikes me that the genetic code could be simplified by making related functions or having certain parts of a program activated in different ways. Hence, you could differentiate male and female before nipples and breasts even evolve at all.

Just speculating though - I'm curious to know from a biologist how that actually works.
Sex has a stronger selection factor than just sexual mechanics. The generation of genetic diversity is the reason sex separated individuals are so successful. Sex mechanics, or how individuals exchange genetic material is a know cause of speciation.
nismaratwork
#16
Jun14-10, 01:00 AM
P: 2,284
Quote Quote by jackson6612 View Post
Can you give me an example, please?
Of course, I'm sorry I should have done that in my original post. Here is one very odd example, where the frog in question has some funky chromosomes.

http://www.genetics.org/cgi/content/full/164/2/613

Here is a less rigorous, but broader bit to read: http://www.thefreelibrary.com/Jumpin...+he.-a08784789

Jumping gender: Frogs change from she to he

Shrimp do it, orchids do it, even some tropical fish do it. Now biologists find that frogs do it, too--switch their sex, that is. A West German research team reports that females of two related frog species can become males without hormonal or surgical intervention. So complete is the transformation -- observed so far only in the laboratory -- that the newly male frogs breed successfully with members of their former sex.

Ulmar Grafe and Eduard Linsenmair detected the gender-bending while studying African reed frogs, Hyperolius viridiflavus ommatostictus, at the University of Wurzburg. The two were analyzing male life histories when a female began fighting with one of the males. "We were really excited, because that shouldn't happen -- females don't fight," says Grafe. In the days that followed, several females adopted the masculine mating stance, extending their forelegs forelegs

see forelimb.

--------------------------------------------------------------------------------

inherited thick forelegs
juvenile hyperostosis (inherited thick forelegs) of pigs. and emitting a low-pitched whistle.

During the next few months, seven adult females -- including six previously observed to lay eggs -- developed functioning testicular testicular /tes∑tic∑u∑lar/ (tes-tikīu-lar) pertaining to a testis.
--------------------------------------------------------------------------------

tes∑tic∑u∑lar
adj.
Of or relating to a testicle or testis.


--------------------------------------------------------------------------------

testicular

pertaining to the testis. nodulesNodules
A small mass of tissue in the form of a protuberance or a knot that is solid and can be detected by touch.

Mentioned in: Leprosy
..... Click the link for more information. and aggressive behavior typical of male frogs, the researchers report in the current issue of COPEIA, released in January. Four of the seven "secondary males" copulated with females, fertilizing up to 70 percent of the eggs and generating normal offspring, the investigators say. Grafe and Linsenmair found that two females of a related species also changed sex in the laboratory terrariums.
and from the gov:

http://newton.dep.anl.gov/askasci/bio99/bio99128.htm

Question: Why can frogs (some species) change sex?
Mike A Smola

Answer:
This is a complex subject. Several studies have exposed some of
the answers to this question, but a definitive answer is yet to be
made.

It all boils down to the level of which genes are activated.
Studies have shown that the sex chromosomes are not necessarily the
determining factor. The traditional display of a female is when
an individual has two X chromosomes present. When one of these
genes is a Y, it is a male. This tends to be the case for most
organisms that sport individuals that are different sexes.
However, the Y chromosomes has been almost always a male determining
chromosome, but with molecular biology and genetic engineering
techniques, a male can be made from a XX combination and females
have developed from XY combinations. These are extremely rare, but
they have given insight to the fact that there are other factors
beside X and Y chromosomes that determine sex, probably a gene
found in both chromosomes.

As far as frogs are concerned (and other organisms that display this
Phenomenon), apparently there are chemical triggers that respond to the
number of members in a population that will activate the gene(s)
that will allow for the disintegration of one set of sex organs and
the development of the other. This is an advantage to a species
whereby they have evolved the ability to assure their reproductive
success.
Steven D Sample
Some fish do this to an astonishing degree, where there are all females, save for one male. If the male dies, another female undergoes major morphological changes and rapidly grows, and becomes male!
pgardn
#17
Jun14-10, 09:06 PM
P: 621
It is also possible for different sexes to arise independently in different types of organisms. There are clearly male and female plants in some species. There are lizards that are essentially all female... So having differentiation of sexes can be thought of just like any other trait that might help, or sometimes not, in the continuing evolutionary success of a certain population of organisms. There are some protist species with about 13 different sexes I believe.
nismaratwork
#18
Jun14-10, 09:32 PM
P: 2,284
Quote Quote by pgardn View Post
It is also possible for different sexes to arise independently in different types of organisms. There are clearly male and female plants in some species. There are lizards that are essentially all female... So having differentiation of sexes can be thought of just like any other trait that might help, or sometimes not, in the continuing evolutionary success of a certain population of organisms. There are some protist species with about 13 different sexes I believe.
13 sexes, that must be one fun orgy, but the cleanup! Yuck. :)


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