Changes in the heritable attributes of populations of organisms over time. Major mechanisms include drift, natural selection, mutation, and gene flow (migration).

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How does Natural Selection shape Genetic Variation?

Background Importance of the additive genetic variance As stated here, the fundamental theorem of Natural Selection (NS) by Fisher says: The rate of increase in the mean fitness of any organism ...
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1answer
91 views

What does “Mutational Variance” mean?

Background The concept of mutational variance can be found in many articles including this one for example. The mutational variance of a trait number $i$ can be found in the M-matrix in position ...
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2answers
166 views

Did Darwin ever reach the conclusion that selection will remove variation?

According to simple models of selection the genetic variance in a population should be reduced by selection. (Fisher's fundamental theorem states that the rate at which a population can evolve is ...
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2answers
125 views

Is greed an evolved trait?

Thanks for looking. I am not a biologist, but I am fascinated by evolution. I was watching the news this morning and, as so often is the case, there was a news story about a corrupt politician who ...
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1answer
183 views

Why has our nose evolved with the nostrils facing down?

For most animals, the whole bottom of their face sticks out and they have a snout with a mouth and nose at the end. But humans have a flat face and just a nose that sticks out. We used to have the ...
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7answers
2k views

Is there a biological mechanism for evolution encoded into our DNA?

Throughout high school, I remember learning about Darwin's theory of evolution as if it were near-fact. But something always seemed wrong about the ideas presented. Survival of the fittest Random ...
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1answer
35 views

Is there any evidence that soft tissue can be preserved for 65m+ years and if not what hypotheses exist to explain it?

I read an article on howstuffworks.com and they mentioned how we have found soft tissue in dinosaurs. According to the article even Mummies and Mammoths have no soft tissue left. Is there any evidence ...
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0answers
31 views

Evolution of sexually concordant genetic variation on the X-chromosome

It was theorised in 1984 that sexually antagonistic genetic (SA) variation should more easily evolve on the X-chromosome. This is partly because female beneficial/male deleterious mutations face less ...
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1answer
45 views

What prevents this blue lobster from becoming dominant?

Like everyone else in the world I saw the blue crustacean from becoming dominant? I would think the blue camo would be an evolution advantage.
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1answer
86 views

Main mechanism of the evolution of sexual dimorphism

Sexual dimorphism is very common and (normally) requires the evolution of sex-specific genetic variation/regulation so the genetic correlation between the sexes can be <1. Is there consensus as to ...
9
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1answer
131 views

When did CRISPR/Cas9 evolve and what is the likelihood that a superior system for live cell genome editing has already evolved on earth since then?

I've read that CRISPR/Cas9 is currently being implemented and tested for its ability to edit genomes in live cells, and that it is supplanting other genome editing tools in labs, such as TALENs and ...
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1answer
107 views

What are the atmospheric requirements for large dinosaurs?

What are the atmospheric requirements for large dinosaurs? and are the atmospheric constituents for supporting large dinosaurs any different from the atmosphere today?
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1answer
41 views

What can myelination tell you about the evolution of sensory receptors?

I am reading Avi Chaudhuri's Fundamentals of Sensory Perception and wondering if the information given about the somatosensory system could tell us anything about the way it evolved. It seems (at ...
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1answer
89 views

Does the fossil record disprove Evolution? [closed]

It is said by people opposed to Evolution, that the fossil record contradicts and disproves it. They say all the animals suddenly appeared, exploded everywhere, were fully formed, had no transitions, ...
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1answer
78 views

Why are recombination rates increasing in mammals?

I have recently become fascinated with an awesome topic in biology and evolution that I feel is rarely covered in biology courses. That is, rates of meiotic recombination, or the the amount that an ...
5
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3answers
134 views

What is the point of having evolved two nostrils?

How would having two nostrils be advantageous to your sense of smell or your ability to breath? I already hypothesized that either one of the nostrils could act as a back up for when another gets ...
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2answers
52 views

Periodic Muscular Growth in Humans

If a healthy human is at a certain muscle state and then experiences muscular atrophy solely due to disuse/lack of exercise, is it easier to gain that muscle back than if the human had never reached ...
5
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1answer
267 views

Evolution of umbilical cord and reason of its elongation

To answer a question myself, recently I've read that Years and years ago, a long umbilical cord enabled a woman to grasp her baby after birth and run away from predators" Update: $Question:$ ...
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1answer
120 views

If evolution is a gradual and continuous process, how can we say humans came about 200k years ago? What is so special about that point in time?

It just seems arbitrary to me to say "ok, now THIS is officially a human" when you could look at its parents and find no noticeable differences. At no point in the line of my ancestral history is ...
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1answer
81 views

What's the purpose of colorful mushrooms' caps?

What's the purpose for many mushrooms to have colorful caps? Is not it is in their interest to hide as well as possible? Or there are mushrooms that propagate by being eaten, like fruits? Why not all ...
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2answers
92 views

Convergent evolution of fruits

Many fruits are not homologous, originating from different parts of a plant. Yet they all have similar properties: Ripe fruits all have yellow to dark red color They all have a lot of water and ...
3
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2answers
104 views

Human Evolution in Modern Times

I understand that evolution occurred to form the current hominids from a common ancestor millions of years ago. As evolutionary processes take a long time, is there proof of evolution occurring with ...
7
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1answer
426 views

Why Did 6 Great Ape Species Survive But Only 1 Hominid Species?

My dad asked this question when I explained some circumstances surrounding Homo sapiens survival against all odds. We know there is only one hominid species left in the world, Homo sapiens. We also ...
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4answers
317 views

Extinction of species

I barely know anything about biology and realize that this might be a stupid question, but I'll ask anyway! I know that species "transform" into other species through the process of evolution. Many ...
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3answers
103 views

Is there an evolutionary purpose to armpit perspiration?

Given that most Americans seem to do fine using anti-perspirant, it got me wondering: is there an evolutionary purpose to underarm perspiration? I can't imagine it acts to attract the opposite sex. ...
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2answers
76 views

Questions about the Evolution Theory [closed]

I'm trying to understand more about evolution theory. (I am coming from a mathematical background) What i understand till now is that the "improvement" of the dna is a purely random development and ...
2
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2answers
57 views

Conservation Genetics - Book recommendations

Can you please give me some advice for a book in (evolutionary) conservation genetics that offers an in-depth review of the mathematical formulations used in this field. I read the book Evolutionary ...
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3answers
380 views

What exactly does adaptive mean?

This is a quote from Dey et al 2014: Hatching asynchrony is thought to be adaptive because... What exactly does adaptive mean here? Does it mean hatching asynchrony has fitness benefits? Or does ...
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0answers
61 views

How to track and describe the evolution of a gene?

So I have a project student (undergraduate) who has been assigned a project to study the evolution of a gene (and possibly related genes) through species. I am not an evolutionary biologist, and hence ...
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1answer
29 views

Periods of Heavy Speciation

I have a set of microRNA ages with corresponding labels suggesting which clade they first emerged from. For instance, for hsa-mir-1, let's say, it would have an age of Eutheria. I have several peaks ...
7
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1answer
74 views

Why do Mangoes have a single large seed, and not multiple small ones?

I was just thinking about this, wouldn't it make more sense for a mango to have multiple seeds, as it would allow more seed propagation?
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1answer
31 views

Does documentation exist that shows the evolutionary connection between common horses and the okapi?

I'm trying to put together some documentation on the relation between the common (modern) horse and the okapi. I've found a tree that shows that connection but it has no references. I'm hoping that ...
5
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1answer
74 views

Gender and age-specific mutation rate in plants

Background General concept According to Cochran and Harpending (2013), mothers transmits on average a number $x$ of new mutations to their offspring. This number $x$ is independent of the age of the ...
3
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1answer
55 views

Horizontal gene transfer versus convergent evolution

There are several often noted examples of convergent evolution (eyes, bat/bird wing evolution etc.) How do we rule out horizontal gene transfer in these cases?
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3answers
100 views

How did the horned lizard evolve?

It's a lizard that has the ability to burst blood vessels in it's eyes and shoot blood as self defense. How can this behavior be explained evolutionary? Wouldn't it mean that there had to be some ...
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5answers
2k views

Why are there species instead of a continuum of various animals?

As I understand it, various animal traits have to evolve gradually, but what happens to the species that are "neither here nor there"? To put it differently, if a species evolved from another, it did ...
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3answers
217 views

Where are the evolutionary “inbetweeners”? [closed]

The problem I've always had with evolution is the actual lack of variation between animals. More specifically, the lack of observable gradual change between species. Take for example the hammerhead ...
5
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1answer
110 views

Lost Ability to Regenerate Body Parts during the Transition from Amphibians to Mammals

Why have higher-order animals lost the ability to regenerate body parts during evolution? Wouldn't it be better for survival? What is the evolutionary theory behind it?
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Intuitive explanation for Kin- and Group- selection

It is known from theoretician in the field of kin selection that kin selection (inclusive fitness theory) and group selection are actually two sides of the same coin. In other words, these two ...
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501 views

Which phylum appeared most recently

I'm aware that our earliest records of many major animal and plant phyla come from the Cambrian or Precambrian periods, and I'm also vaguely aware of some of the objections raised with general concept ...
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1answer
87 views

What is the outcome of a human population starting with only 2 individuals? [closed]

Starting with a human population N = 2, is there any way the genetic variability seen today could have come about? I don't know that much about meiosis, but isn't there a very limited number of ...
2
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1answer
39 views

How did the Chromosome #2 Fusion propagate?

There is strong evidence that chromosome 2 in humans is a fusion of two chromosomes of a common ancestor of chimps and humans as explained at wikipedia here Was it necessary for the common ancestor ...
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1answer
68 views

Do species which have a closer common ancestor to humans tend to be more intelligent?

Q: Do species which have a closer common ancestor to humans tend to be more intelligent? Our closest living relative, the chimpanzee, seems to be regarded as intelligent: Chimpanzees make ...
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0answers
44 views

Odds of Fusion of Chromosome #2

There is strong evidence that chromosome 2 in humans is a fusion of two chimp chromosomes (i.e. common ancestor of chimps and humans) as explained at wikipedia here The question is what are the odds ...
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1answer
172 views

Soft and Hard selection

Seems to me that these two sources (M. Whitlock, B. Wallace) use different definitions of soft and hard selection. M. Whitlock: Soft selection occurs when the relative fitness of an individual is ...
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1answer
585 views

Why are men stronger than women?

What are the evolutionary explanations for why women are weaker than men (on average), and is this difference adaptive? See figure one here. I suppose that something puts pressure on men to be ...
4
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1answer
107 views

Are there any cases of observed extreme speciation [closed]

Is there an observed (direct not indirect) speciation on record showing a species shift within the span of history of recorded science?
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3answers
145 views

Theoretically, is domestication of (virtually) any animal possible?

Looking at ones that manage well alongside us human animals, such as dogs and cats, we see that this is possible for evolved, distant animals to have heritable, preferable traits around people. ...
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1answer
77 views

Has any creature ever devolved to be cold blooded? [closed]

Is this even possible? Because I have a non-scientific gut feeling that it is irreversible. Whales and dolphins are evolved from land mammals, and they've remained warm blooded while it doesn't give ...
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0answers
73 views

Can human change its morphology or anatomy due to ecological changes?

According to Charles Darwin, as the surrounding environment changes, so changes the anatomy or morphology of a specific organism. But nowadays, humans have become very advanced in the technology and ...