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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Evolutionary reasons why you cannot tickle yourself but masturbate

There are obviously good reasons that explain why you cannot tickle yourself (see e.g. here). This got me thinking why it is possible to masturbate... Wouldn't it make more sense to not being able to ...
7
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93 views

What are parental antagonism & parental conflict?

I've been reading the chapter by Haig et al in The Genetics and Biology of Sexual Conflict. I think this chapter has them quite unclearly defined. Could anyone describe these two phenomenon more ...
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81 views

How to define “Quasifixation” in continuous approximation of finite population?

Background Many models including the famous very first models derived by Sir Ronald Fisher in his early career, assume infinite population size. In an infinite population, an allele can rise in ...
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595 views

Why would stablising selection ever happen?

If the aim of evolution is to allow an organism to better compete against rivals, why would stabilizing selection ever happen? If you're not selecting the most highly adapted competitors at either end ...
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537 views

Are there any multicellular forms of life which exist without consuming other forms of life in some manner?

The title is the question. If additional specificity is needed I will add clarification here. Are there any multicellular forms of life which exist without requiring the consumption (destruction) of ...
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3answers
341 views

Are there genes in humans from the common ancestor of all organisms?

How long ago can human genes be traced? Are there any genes that go back unchanged to the beginning of life on Earth? And if so, how many?
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957 views

Why did the urinary bladder evolve?

Sure it's convenient to decide when to urinate but not essential for survival or reproduction, as I understand. But just convenience is not a drive for evolution. Does the bladder serve any essential ...
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3k views

Why does so much variation exist within species?

My last phrasing of this question did not go down well, so I will try again. The genotype of species is not always the same. If you ask yourself why not all of these possible expressions except one ...
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474 views

What is the viability of Intelligent Design as a supplement to chemical abiogenesis and Darwinian Evolution?

First of all I am not endorsing Intelligent Design (Wikipedia link); I'm asking this because I (someone who does not have a background in biology, organic chemistry, or philosophy) got into a ...
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167 views

Can any species be bred selectively/engineered to become as diverse looking as dogs?

I've done some research and it appears that dogs are the most diverse looking single species of mammals. The questions that interest me is - are dogs special in respect to genes/gene activation ...
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1k views

How did giraffes develop their rete mirabile failsafe?

Giraffes, being one of the tallest mammals in the world, have a failsafe called rete mirabile to prevent them from dying from excessive blood pressure while lowering their head.[1] Due to their long ...
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623 views

Relationship Between Evolution and the Increase of Entropy of Earth

I was confronted by this question: Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellar eukaryotic organisms, A) has occurred in accordance with the laws ...
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847 views

How exactly are game theoretical evolutionary models described during implementation for computer simulations?

When a biologist or a layman tries to reason the evolutionary explanation for something, they would simply use English with some math thrown in (for a random example, pick any explanation out of "The ...
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68 views

Why are abiogenesis and evolution considered unrelated?

When a discussion about evolution comes across abiogenesis - the typical reaction is that they are unrelated (see the headline at http://www.factsnotfantasy.com/abiogenesis.php). It seems to be ...
6
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813 views

Why did humans lose their fur?

The little amount of body hair humans have don't seem to be of much use for keeping warm. Our Simian cousins on the other hand sport thick furs. At which point during the species evolution and why ...
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431 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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366 views

evolutionary reason behind sharing the same path for food and air?

What is the evolutionary reason behind sharing the same path for food and air? For example, we have a nose and lungs, yet they are linked by the pharynx, which is shared with the mouth and ...
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310 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 ...
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9k views

Why is dimethyltryptamine (DMT) being released during death?

I'm not very well informed about all the things related to biology and the current achievements of science in this field so if I'm wrong in anything I say, please let me know. Many times I've come ...
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411 views

Why are humans and almost every species on earth symmetrical?

I admit I'm not very learned on the subject of evolution, I just started researching it for myself about a week ago. One of the things that I don't understand is why humans and almost every other ...
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227 views

Is it possible to increase lifespan through controlled evolution?

A few years back when I was reading The Selfish Gene by Richard Dawkins, there's this short passage where he theorizes about a way to achieve an increased lifespan through controlled evolution. The ...
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922 views

How and why did mouth and nasal cavity evolve separate?

My initial objection is that nose filters air, mouth is for eating but is used for breathing also, plus they both are used to create sounds. What is the cause and reason in this case, why do we need ...
6
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2answers
162 views

Reasons why living fossils exist?

A living fossil is a living species (or clade) that appears to be similar to another species otherwise known only from fossils, typically with no close living relatives. A living fossil is ...
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165 views

Are there any known mutual symbiotic relationships that has more than two agents?

We are all familiar with the examples of symbiotic relationships in nature consisting of two agents, like lichen or the co-evolvement between certain birds and flowering plants. Do we know of any ...
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14k views

How do archaea relate to eukaryotes and bacteria?

I've read that they all share some genes, internal structure, and behaviour with each other, but with different degrees of overlap depending of what the function is. E.g., archaea have some eukaryotic ...
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228 views

Are we more attracted to people of the same ethnicity? [closed]

Are humans more attracted to people from their own ethnic groups? I ask this because most of the time people have relationships with people of their own ethnicity, and I wonder if it's purely social, ...
6
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380 views

Empirical evidence for species selection

Do we have any empirical evidence in favor of species (or lineage) selection? Do we know some cases that can only be explained (or seem to be only explained) by lineage selection? What are today the ...
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338 views

Computational/mathematical models for predicting phenotype from genotype

Karr, Sanghvi, et al. (2012) propose a whole-cell computational model for predicting phenotype from genotype in Mycoplasma genitalium. Their model simulates myriad cell processes such as DNA ...
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107 views

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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Why do most mammals have long snouts?

It seems like most mammals, e.g. dogs, have long snouts. My pet dog's snout would seem to me like an evolutionary disadvantage, since her canine teeth are way out at the end of her jaw, which acts as ...
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76 views

How are behaviors genetically coded in animals?

I am curious as to how complex behavior is passed down genetically? For example, how is the building of a web genetically coded in a spider? And how is the complex behavior of constricting prey coded ...
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167 views

Hamilton's inclusive fitness approach

The underlying intuition of Hamilton's model of inclusive fitness is that we should study social behaviors from the point of view of actors -- rather than the recipients. To build his model, Hamilton ...
6
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126 views

Effects of selection on effective population size

Background The effective population size ($N_e$) is a central concept of evolutionary biology and is influenced by several parameters. For example: sex ratio bias affects $N_e$ $\left(N_e = ...
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92 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 ...
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126 views

Hill-Roberston effects and effective population size

From this article, first page, middle of the second column: Even if harmful alleles do not become fixed, they can still reduce the efficacy of selection on neighbouring loci through a process ...
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78 views

Reformulation of Hamilton's rule

Who (and in which article) was the first to reformulate Hamilton's rule using the letters $B$ and $C$?. See below comments on this reformulation. Hamilton, in his 1964's article gave a mathematical ...
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221 views

Probability of Extinction under Genetic Drift

Here is the Wright-Fisher model of genetic drift: $$\frac{(2N)!}{k!(2N-k)!}p^kq^{2N-k} \Leftrightarrow \binom{2N}{k}p^kq^{2N-k}$$ where $\binom{2N}{k}$ is the binomial coefficient. This formula ...
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234 views

Is local equilibrium a reasonable assumption for evolutionary processes?

Whenever I look at discussions of fitness landscapes (in particular, Kauffman's NK model) the questions tend to resemble: The population is at a local equilibrium, but another equilibrium of ...
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155 views

The origin of molecular machines

DNA holds genetic information and holds the key to the evolution of living organisms. Transcription and translation mechanisms enable living cells to process information encoded in DNA. To that end, ...
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96 views

What is most ancestral: isogamy or anisogamy?

Sexual reproduction can be feasible with anisogamy (gametes of different sizes i.e. genders) or isogamy (gametes of same size i.e. mating types) or with undifferentiated gametes (i.e. true random ...
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82 views

Visualisation of phylogeography

I am working on phylogeography on one model species and I am a beginner. You can imagine one species that came on locality more than 5 mya (million years ago). It was a good environment, so the ...
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2k views

How would constantly growing nails have aided early human?

Nails grow rapidly and constantly, such that without constant artificial trimming they would reach lengths difficult to manage. How did this benefit early humans, say 200kya? Were they used like ...
6
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133 views

Why do women live longer than men?

According to Wikipedia and many other sources, women live substancially longer than men (over 5 years in the U.S.). Men can reproduce for much longer than women. So longer living men would have the ...
6
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1answer
158 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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84 views

Evolution of Chromosome Numbers

Some species have different numbers of chromosomes, as we all know. Throughout evolution, how was a species able to survive with an extra chromosome? How was this organism able to breed successfully ...
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226 views

What percentage of the (additive or not) genetic variance is explained by the 'n'- most important loci?

Standard models in population genetics look up at the evolution of few loci which impact fitness. The variance in fitness is determined by the genetic variance and the environmental variance (and the ...
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2answers
658 views

Why aren't we ambidextrous?

It seems so simple that if my brain can tell my right hand to do something, then it should be able to tell equally well to the left ? This seems like a pretty major evolutionary advantage. Why haven't ...
6
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1answer
126 views

Disproportion in cranial nerve innervation?

The cranial nerve innervation is highly disproportionate, as far as humans are concerned. I am not sure of the advantage of being innervated by cranial nerve versus being innervated by a normal ...
6
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1answer
162 views

Alternatives to fittest-win and Moran processes as simple mathematical models of selection

When modeling selective sweeps as a micro-building block in models of macroevolution (not to be confused with misuses of this in creationist arguments), I use the fittest-win model of selection as a ...
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173 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 ...