Questions tagged [human-evolution]

The study of evolution with a particular focus on questions about the evolution of modern humans.

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9
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1answer
1k views

Why do we blink instead of winking each eye independently?

Question Why do we blink both eyes at the same time rather than winking each eye as needed? Why would winking independently be better? The benefit would be a minor improvement whereby a person ...
3
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0answers
99 views

What niche was humanity theorized to fill before we possesd weapons and coordination to hunt & kill large prey?

I'm really interested in evolution, and for a err 'hobbyist' I think I understand a good bit of evolution and adaptation and the role it has played in many species. However, I feel I'm rather ...
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1answer
5k views

Why are the genomes of Humans 99.5% the same?

Human's DNA sequence is said to be roughly 99.5% equal. As far as I understand, this means that if I walked up to you and compared our DNA, the sequence of base pairs would be 99.5% the same. My ...
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1answer
5k views

Why are human immune systems comparatively weaker than other animal immune systems? [closed]

Humans get sick on such a regular basis and animals will hardly ever get sick. Animals are typically exposed to the same pathogens as humans, yet a dog won't have a cold or the flu twice a year, with ...
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1answer
2k views

Are there different species of modern day humans? [duplicate]

I've been watching nature shows on Netflix (Wildest series) and different animals of the same "family" are actually different species. e.g. Asian elephants vs African elephants. Asian elephants are ...
4
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1answer
804 views

Do the claims in this paper have any degree of validity?

The paper The waiting time problem in a model hominin population talks about a problem of waiting time, etc. Is the methodology of this numerical simulation, and the conclusion right or is it wrong? ...
3
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3answers
145 views

What is the human species divergence time

How far back along the evolutionary tree do we have to go to find divergence to a completely different species to Hom. sapiens? I don't count Neanderthals because it seems that part of our genome ...
36
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7answers
12k views

Is evolution a fact? [closed]

Richard Dawkins in one of his videos says that Evolution is a fact and not just a theory. He goes on to say that man and chimpanzees both evolve from apes. Is this correct (Is evolution a fact and ...
0
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1answer
560 views

Neanderthal and modern human population sizes

Are there any estimates of both the modern human and Neanderthal population sizes over the last, say, 100 k years? Since "purebread" Neanderthals are extinct, their population has to hit zero; that ...
81
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5answers
25k views

How could humans have interbred with Neanderthals if we're a different species?

To be clear, I'm not doubting that homo sapiens and homo neanderthalensis did interbreed: of that much I'm convinced. Within the past few years I've seen an upcropping of pop-sci articles discussing ...
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3answers
436 views

Did we evolve from monkeys?

Since I was young, I always understood that evolution taught that we descended from monkeys (or apes, not too sure a distinction was ever made). However, someone recently told me that this isn't ...
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2answers
283 views

How quantitative is the theory of evolution right now? [closed]

We developed complex structures like eyes and brain, whose mechanisms rely on specific species of molecules and relevant chemical reactions. But we did not develop an enhanced night vision, the ...
5
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3answers
523 views

Why are there so many different humans yet chimpanzees are just chimpanzees?

There are two species belonging to the Pan genus (Pan troglodytes and Pan paniscus). That's just two. I mean, humans have changed radically since we split from chimpanzees, we have Australopithecus ...
1
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1answer
220 views

What factors cause males to be more common than females in humans, from an evolutionary perspective? [duplicate]

Fisher's principle states that there should be a 1:1 ratio between males and females born on average for a population. However, if you look at birth statistics your find that boys are slightly more ...
1
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2answers
178 views

Junk DNA and “random” mutations [closed]

I'm somewhat irritated by "mutation" generally being described as a fully random factor in evolution: pure randomness does not seem like something that can survive in a long evolutionary process. And ...
2
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1answer
122 views

How did people's liking of ceremonies evolve? [closed]

Habitual group activities are prevalent across many animal species, particularly in mammals, especially in primates. However, I do not see any evolutionary benefit of this. 'Ceremonies' take time, ...
5
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1answer
532 views

What was the evolutionary reason for cross lateralization of the brain?

In the human brain the right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body. What led to this development? Why doesn't the left side of the ...
33
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2answers
5k views

How do we know the human species arose in Africa?

I have heard (from multiple sources) that the current scientific opinion is that the human species arose in Africa. What are the reasons for this opinion? If possible, simple and non-technical ...
7
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1answer
122 views

How does chromosome fusion get fixed in the population?

It's well known that one of human chromosomes is the result of fusion between two chromosomes in a primate ancestor. If we put anthropocentrism aside, it becomes clear that fusion events happened a ...
0
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0answers
93 views

Why do human have continuously-growing hair on their head? [duplicate]

Why do hair continuously grow on human heads, while the same doesn't happen on other parts of the human body? Where there are hair, they only usually grow to a fixed length; but they seem to have no ...
7
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2answers
1k views

Why cannot there be multiple sources for same species origins?

We often associate Africa as the geographical location of the origin of humans. Why cannot there exist multiple geographic locations of origin (given same environmental conditions)? The same ...
3
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2answers
690 views

Why don't we keep evolving until we are super-human? [duplicate]

Humans (homo sapiens) have been on the earth for thousands of generations, and we have kept evolving throughout that time. Why don't we just keep evolving so that, let's say, we live for an average of ...
9
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1answer
4k views

Why some parts of the human body have immune privilege?

Why have the eye and CNS have immune privilege? Why does the body not develop tolerance against their tissue and instead risk their damage in case an accidental immune cell infiltration? Wiki: ......
4
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1answer
380 views

Current Trend in Evolution of Human Intelligence

Up front, I am specifically not interested in philosophical or ethical considerations re Eugenics and related concepts. In an effort to receive a concise answer I'll post a narrowly defined question ...
9
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2answers
9k views

Why do people feel pleasure when using roller coasters / centrifuges?

The feeling when using an amusement park unit is usually a pleasure. Why is it not a pain instead? Are there advantages, from an evolutionary point of view, in loving this potentially dangerous ...
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3answers
371 views

Why don't half of us have situs inversus?

I don't see any possible evolutionary disadvantage in situs inversus(the condition where major organs are mirrored from their normal positions) when people with situs inversus can have a normal ...
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2answers
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Why did humans evolved the scratch reflex?

I've been wondering about this for some time, and I can't come to an answer... Everybody keeps telling me that scratching one's own skin is bad. It damages the epidermis, creates the hazard of ...
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1answer
515 views

How far can we go in engineering our own evolution? [closed]

After recently seeing Christopher Nolan's Interstellar and reading Kip Thorne's The Science of Interstellar, I've seriously been reflecting on the challenges mankind faces in becoming space pioneers, ...
3
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1answer
2k views

Largest direct ancestor of humans

Going back the genealogical lineage from present humans to the beginning of life, what was the biggest - in terms of body size or mass - animal in this sequence? More generally, what would a time vs. ...
2
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1answer
402 views

Which came first in hominid evolution: language or bipedalism? [closed]

I suspect both language-use and upright-posture have anatomical consequences. So does the fossil record show which came first? NOTE: To the folks who marked this question "homework": This is ...
4
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1answer
336 views

A colony of humans are sent to an alien world, at what point would the descendants evolve to be genetically incompatible with Earth humans? [closed]

I recently heard about the evolution of the London Underground mosquitoes, and how they have changed genetically enough that they almost can no longer reproduce with above ground mosquitos. Since this ...
3
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1answer
609 views

Fecundity per woman in early humans

The average fecundity per woman varies a lot from country to country. I call average fecundity per woman the average number of born children per woman. In Homo sapiens, what was the average fecundity ...
4
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1answer
522 views

Miscarriage in early humans

Today, about 10 to 20 percent of known pregnancy end in miscarriage. Pregnancy is a biological process that has been very well studied by medicine. As a result, modern medicine helps a lot to prevent ...
7
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1answer
660 views

When did our ancestors switch to a menstrual cycle instead of the estrous cycle?

The Wikipedia page on the Estrous cycle says: Humans have menstrual cycles instead of estrous cycles. They shed their endometrium instead of reabsorbing it. Unlike animals with estrous cycles, ...
2
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1answer
5k views

Speciation of humans? [duplicate]

Since we homo sapiens (and all other species) are continuously evolving, are humans undergoing speciation based on our environment? OR has there been any difference across people that could say ...
9
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2answers
322 views

How was the resemblance between apes and humans explained in pre-Darwinian biology?

Humans and apes have somewhat obvious similarities, these must have been apparent to natural philosophers before the possibility of a common ancestry was first proposed in the mid-1800's. These ...
23
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1answer
7k views

Why do we have five fingers?

Humans (and other humanoid mammals) have five fingers in each hand. Curious to know, why five? Wouldn't more fingers be more useful? Is there any evidence that it used to be different and natural ...
5
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3answers
416 views

Is there evolution in humans since the first homo sapiens sapiens

Has the human species changed since first defined as homo sapiens sapiens? I'm asking this question partly because I'm wondering how we might evolve next.