Human Evolution
Whatever your standpoint it is a beautiful thing so here. Children, please don't trash it.

'Men with wide jaws, flared cheeks and large eyebrows were considered as sexy in the eyes of our female ancestors as they are today. Studies of fossils of our primate ancestors by reasearchers at University College London (UCL) and University of Cambridge showed that ancient ladies (sic!) helped to shape evolution by choosing sexual partners with those facial traits.

"The evolution of facial appearance is central to understanding what makes men and women attractive to each other today," says palaeontologist Dr Eleanor Weston of UCL. "If you characterise masculinity by the simple ratio of dividing upper facial height by facial breadth, then attractive film stars do exhibit quite low ratios."

Unlike other facial features, this difference cannot simply be explained in terms of men growing larger than women. The researchers also found a similar development in the chimpanzee male face. " This does support our findings in that this facial difference occuring at puberty must have important evolutionary implication, " says Weston....'
BBC Focus magazine
http://tinyurl.com/2napsu

The grand topic of human evolution. Is there anything more beautiful than losing yourself in a debate on your own ancestry? No, or maybe it is the history of the xenathrans.

The story of human evolution can be approached from many different angles all equally interesting, although some of them are just plain repulsive.

Let's explore these approaches in this thread and let our minds wander (i was infected temporarily by Draqon).

Why not start with this article:
http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0020340

Genetic Analysis of Lice Supports Direct Contact between Modern and Archaic Humans

Parasite co-evolve with their hosts. By studying human parasites you can discover things about humans.

The researchers found two extant lineages of human lice that diverged 1.18 MYA ago. Which was suprising because we were supposed to have gone through a genetic bottleneck ca. 0.05–0.10 MYA ago.

There are tow main theories on origin of modern humans, Recent African Replacement and Multiregional Evolution.

The louse data supports a compromise between the two models, the Eswaran's Diffusion Wave model.
Eswaran's Diffusion Wave model proposes that a diffusion wave of modern H. sapiens left Africa (ca. 0.13 MYA) and replaced archaic humans through a process of introgression, natural selection, and gradual demic expansion.

The researchers cannot say with confidence whether the different human lineages of Homo sapiens and Homo erectus were fucking with each other because:
nonsexual, direct contact between hosts is sufficient for parasite transmission.

The researchers therefore suggest that maybe someone should look at pubic lice.

I start with evolution of facial features and spurious lowers it to pubes. I give up!
Hissy fit!

Why are us narrow-faced villians still around then?

The puberty reference is rather interesting though. Apparently we are the only primate that goes through puberty. And we are not sure why.

Puberty comes with a growth spurt, but that alone cannot explain it, because obviously a male Gorilla is larger than the male human which doesn't have puberty.

Some people suggest that it is the other way around. We limit our growth during the first years because it would be detrimental to be large and learning at the same time. If you stay small and cuddly while still making many mistakes and learning proper behaviour you have a greater chance of survival, or at least not rubbing someone the wrong way.

Maybe the answer is is facial structure?!

Humans have the most developed brains of all creatures. It takes many years to develop the brain. The body develops more slowly than the brain. Puberty is a way for the body to catch up with the brain?
OOps I think i may have expressed an opinion....but I'll call it conjecture.

It is true that there is a large growth of brain matter during puberty. And what happens afterwards is that connections are being pruned. And then we become 'resonsible' adults.

Regarding human evolution this is very interesting, because I have read some stuff that suggests that maybe we are the only human lineage with a puberty phase.

there are some studies (based on very little data of course) that other homo lines might not have known puberty. They did this by comparing bone growth to tooth growth, because tooth growth is more uniform, and bone growth can vary more (as the growth spurt during puberty).

But critics point out that there is a lot of variation within humans in this respect and since the datasets of other homo lineages is so limited we can't really make any conclusions, not even the one I posted in the previous paragraph.

As a 'resonsible' scientist can't you get some grant money to enlarge the datasets? I don't like science without conclusions.

it is not so easy to go and find a large collection of skeletons of homo erectus, or other human lineage even if you have the funds.

Enlarging the dataset is therefore dependent on luck.

Remember that there are still no fossils of the chimp ancestor!!!! (well, maybe there are, but not the last time I checked).

Oh well better carry on looking at genes then as therein lie all the answers.
Or maybe we are the chimp ancestor.

Or maybe we are the chimp ancestor.

Interesting that you say that. There are three options basically.

the ancestor of the chimps and humans looked human.

the ancestor of the chimps and humans looked like a chimp.

the ancestor of the chimps and humans looked like something inbetween a human and a chimp.

(and of course there are all the options in between for the continuous minded amongst us).

yet, we automatically think the ancestor must have been like a chimp.

And...was it?

Well what was the most recent common ancestor? Wasn't it more like a flying squirrel?

of chimp and humans?

no, that was something about 6 million years old.

It was humanoid then? A hobbit?

It was humanoid then? A hobbit?

It was most probably chimp-like, don't you think.
Here's an interesting article on it: http://www.theallineed.com/biology/06012903.htm

Probably chimp-like and the existence of bonobos and chimps give a clue.

Chimps and bonobos look remarkably similar. So similar in fact that not so long ago they were mixed in zoos because they thought they were just all chimps.

If the split between bonobos and chimps was very recently then we can't say if the ancestor between humans and chimps was chimp-like, or human-like.

It turns out that chimps and bonobos split from each other about 3 million years ago. (or something in that order) In 3 million years they hardly changed. It seems reasonable to assume they haven't changed that much before that.

The human lineage was 'radically' different 3 million years ago though. And therefore we can assume that the ancestor of chimps and humans was more chimp-like than human-like.

It takes many years to develop the brain. The body develops more slowly than the brain.But you're just talking about the physical brain. With a massive forebrain like ours, there is a lot more synaptic development--learning--remaining to be done after the physical development is complete, than with other species. Our bodies are more or less mature around 17 or 18, but the synapses for making good judgments and tempering emotional reactions, which are required for successful, independent adult behavior, aren't complete for another four or five years.Interesting that you say that. There are three options basically: 1. The ancestor of the chimps and humans looked human. 2. The ancestor of the chimps and humans looked like a chimp. 3. The ancestor of the chimps and humans looked like something inbetween a human and a chimp. Yet, we automatically think the ancestor must have been like a chimp.So look further. Next to one another, the closest relative to both humans and the two species of chimpanzees are the two species of gorillas. Which animal looks more like a gorilla, the human or the chimp?

The massive brain case; the fully opposable thumb; the spine, musculature and shorter arms for full-time bipedalism; the proliferation of facial muscles useful only for non-verbal communication; the loss of fur; the buoyancy that allows us to swim easily; the little webs between our fingers which, in conjunction with that buoyancy, almost make us wonder if we were once aquatic; the reorientation of the vagina and pelvis permitting face-to-face copulation... I'd say Homo is more different from the other hominoids ("great apes," which also include the orangutan) than they are from each other. If the common ancestor of Homo and Pan already looked like Homo, it would be extraordinary for Pan to devolve, back into an ancestral appearance common to all other hominoids.

I'd say Homo is more different from the other hominoids ("great apes," which also include the orangutan) than they are from each other.

Genetically, if I recall correctly, that is not true. Humans are closer to chimps, for example, than either is to gorillas.

I'd say Homo is more different from the other hominoids ("great apes," which also include the orangutan) than they are from each other.

You are quite right, and trees build on physical and behavioural characteristics show the human lineage sticking out with several magnitudes from the other apes.

Just go back to the top of the page and have a look at the study which highlights an evolutionary preference for wide jaws, flared cheeks and large eyebrows in men. The research team found similar patterns in chimpanzees.

sexual selection could also be the only decent explanation why we are the 'naked' ape. (obviously we are not really naked, even if we are)

Most recent ancestors to Homo sapien:

Neaderthal (anatomically modern Homo sapien): thick-limbed and short-bodied (typical to cold regions), found in French cave La Ferrassie; male 5 ft 5 in., 185 lbs; female 5 ft 1 in, 176 lbs.

Archaic Homo sapiens: based on fossils from Zambia; male 5 ft 9 in, 137 lbs; female 5 ft 2 in, 112 lbs.

Most recent ancestors to Homo sapien:

Neaderthal (anatomically modern Homo sapien): thick-limbed and short-bodied (typical to cold regions), found in French cave La Ferrassie; male 5 ft 5 in., 185 lbs; female 5 ft 1 in, 176 lbs.

Archaic Homo sapiens: based on fossils from Zambia; male 5 ft 9 in, 137 lbs; female 5 ft 2 in, 112 lbs.

The Neanderthals were not Homo sapiens sapiens ancestors.
Neanderthals are the subspecies Homo sapiens neanderthalensis.
Homo heidelbergensis is the common ancestor of both Homo sapiens neanderthalensis and Homo sapiens sapiens.

Read the post - it says the most recent ancestor for Homo sapien - not the most recent ancestor for Homo sapiens sapiens.

In addition, the time range of H. heidelbergensis and archaic H. sapiens overlap - suggesting co-existance.

Read the post - it says the most recent ancestor for Homo sapien - not the most recent ancestor for Homo sapiens sapiens.

In addition, the time range of H. heidelbergensis and archaic H. sapiens overlap - suggesting co-existance.

Ok my bad, most people just say Homo sapiens when they really mean Homo sapiens sapiens

Mutations are accidents in reproduction. The only place where such mutations can occur is in the production of the haploid cells (cells with a single set of chromosomes) in the sperm and egg, or in the joining of the two in conception. A reproduction accident anywhere else in the body will affect only the cell that suffers the accident. Such accidents will not be added into the gene pool and thus are not mutations. In such an accident, the sick cell is quickly replaced by a well one and the incident is over. Yet when such an accident occurs in the sperm or egg, it will appear in every cell in the offspring. This mutation then has a 50% chance of occurring in each grandchild. If the recipient of the mutation has several children, the odds are that the mutation will join the species gene pool by way of one or more of his children.

Natural selection then determines the fate of the mutation in the species gene pool. The test is not survivability or excellence. The test is in species population growth. If the mutation aids the growth of the species population then it is successful and will remain in the gene pool. If it does not, natural selection will remove it from the gene pool (through death and hardship).

Here are a few examples concerning man and evolution to help gain understanding of the way evolution works. The effects shown are not necessarily caused by genetics, but evolution treats all conditions as if they were. Note that natural selection acts as if all genes are involved in the success or failure of the individual. Each case that reduces the expected offspring is considered a vote against each gene in the genome. Each case that equals or exceeds the expected offspring is considered a vote for each gene in the genome. The mixing of genes in recombination allow individual allele selection over the long period of time.

Sexual selection is an important factor, because genetic drift can occur within a matter of generations as opposed to millions of years. More extreme selection methods could potentially be even more effective, and as abhorrent as something like the Holocaust was, such events were probably more common in human history than anyone would care to admit...

So sexual selection is a tame, easy to swallow explanation, but we cannot neglect genocide, or simply "killing all the hairy ones," which could virtually extinct a genetic variant in short time. Several million were killed in a matter of years during the late 1930's, early 1940's. Imagine a fictional civilization (Atlantis if you like) wherein hairy, dark-skinned individuals of short stature were rounded up and (for the sake of lighter reading) marched into the sea. A large segment of the phenotypic continuum wiped out in a matter of hours...

Then there's war, and biological factors such as invasive disease. It may take millions of years for a species of trees to creep across a continent and replace a less-adapted species, but suppose they are favored by Christians who carry them over by ship along with their co-evolved parasitic stowaways. Now you have a powerful invasive agent with a huge evolutionary advantage. This is in fact true of hundreds of species of insects, birds, plants, even some familiar agricultural crops.

Another interesting factor to consider is religion. Scientists don't like to include anthropological or philosophical components in their hypotheses, but religion is probably the single most powerful selection mechanism ever known, especially primordial religion where neighboring populations could be demonized and destroyed by mandate of the gods.

Just go back to the top of the page and have a look at the study which highlights an evolutionary preference for wide jaws, flared cheeks and large eyebrows in men. The research team found similar patterns in chimpanzees.

What about recent social developments where beautiful girls first marry those wide jawed people and then divorce them to marry money and education? And what about in India where natural selection favors the educated money maker? Perhaps the criteria is changing towards brain than brawn?

I saw a study that showed British women were more attracted to femenized male faces, while Jamaican women favored masculanized facial features.

The researches said it was proof that in populations where disease isn't an issue (such as the developed world), women will prefer men who can take care of babies, while in filthy places, like Jamaica, mating with a guy who's easily ravaged by worms is going to lead to weak offspring.

The main assumptions being that masculine facial features are indicative of increased testosterone levels, while feminine ones are indicative of lower ones, and that testosterone, in humans, is linked to immuno response and childrearing (in mice and birds, higher testosterone is positively and negatively linked, respectively).

I saw a study that showed British women were more attracted to femenized male faces, while Jamaican women favored masculanized facial features.

I think it is also true in USA too to certain extent. I used to teach yoga and meditation to college students and just talking to the ladies, I learned that some girls marry during high school to the square jaw types and then find out most of them end up as laborers - so they dump them and go after the other type nerds. Some go directly....with full aggressiveness and win.

it apears ladies first go for the strong genes to make baby's but then prefer a a more stable more society strong figure to help raise them.

Meaning first the wild years and then the mercedes

I believe that there have been many people who actually mixed bones of apes, and swapped them with the face of a human. It makes it appear that it was during when evolution was happening. Of course, I only heard of a couple of incidents where that has happened. It is very possible that evolution did happen. I dont believe it did, but whether or not you do, remember to research more than just what you believe in. I purposely put this at the end so that you would read what I have to say. I am only 14, so I am still trying to decide on what I believe about evolution.

I dont believe it did, but whether or not you do, remember to research more than just what you believe in.

And where is your research?

Hey, go easy on young Chuck Norris. He may grow up to kick your ass.

You don't have to dig up actual fossils (but it isn't all that hard, in some places, and there are diatoms etc). Research is possible via reading other's scientific work and discoveries (assuming you accept there is such a thing). In the outback of some places you can still find evidence of early human habitation; diatoms are from a bit further back.