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 can natural selection occur at species level whilst not occuring at the individual level?

The chapter by Douglas Futuyma in 'Evolution' (Losos et al 2013, Princeton) states that natural selection can occur at the species level. Futuyma states that if natural selection occurs at the species ...
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52 views

Interpretation of graph from evolutionary biology

I am studying evolutionary biology, and been presented with this graph: I am having some difficulties understand its meaning. For a start, why is time measured as a fraction of the population size? ...
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Why don't mammals have more than 4 limbs?

Arthropods have 6 or more limbs and arthropods with 6 limbs appear to move faster than arthropods with 8 limbs so I wonder whether this might have something to do with fast and efficient locomotion. ...
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51 views

Statistics on energy consumption breakdown per biological functions across organisms?

Are there any statistics available on how much energy organisms use for each biological functions (i.e. something similar to the line of "Bacteria spend X% of energy on information processing, Y% for ...
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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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97 views

Like other animals, why humans don't have species & breeds?

Like other animals, why don't humans have species & breeds ? Even my pet dog is one type of breed, but we (humans) lack breeds & species? What is the main reason?
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Why can we see so many different types of mushrooms if we assume that they arrived to Earth on a comet? [on hold]

Why can we see so many different types of mushrooms if we assume that they arrived to Earth on a comet? I mean they don't have to have bright colors to attract bees or birds for their reproduction. ...
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43 views

Is there an association between environmental and mutational robustness?

The robustness of a genotype is the ability of this genotype to resist (always produce the same phenotype) to various parameters such as mutations and environment. The ability of a genotype to resist ...
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Linkage disequilibrium with multiple alleles and loci

Linkage disequilibrium $\left(D\right)$ for two bi-allelic loci is defined as: $$D=X_{11}X_{22} - X_{12}X_{21}$$ where $X_{11},\ X_{12},\ X_{21},\ X_{22}$ are the frequencies of the haplotypes ...
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Is eating cooked food an evolved behavior or rather an intelligent one, passed down via culture?

I was just eating a rather rare steak when I started wondering whether eating foods cooked was something I would instinctively want to do if the practice hadn't been taught to me. So, is cooking food ...
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Are there specific features of birds that cats/small predators are attracted to?

I've recently heard a podcast, in which a professor describes one of the theories as to why we like abstract art. In his talk, he mentions an experiment with seagull chicks, in which the seagull ...
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3answers
177 views

Why are there no tree-like plants that grow in lakes?

Looking at aerial photos of boreal forests, with dense woods clear-cut by quiet lakes, I wondered why exactly are the woods so clear-cut at the edge of water? Why won't trees develop adaptations that ...
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Testing monophyly from per site log-likelihoods without optimising branch lengths

How can I obtain per site log-likelihoods for a topology against an alignment without optimising branch lengths? (which software can I use to do this) Per site log-likelihoods can be used for various ...
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Is natural absense of appendix result of the internal evolution? [on hold]

If we say that living organism is file of cells what absorbs nutrients, develops and responds to stimuli, we can say that any organ is a living organism - and if the organ has no function, it will not ...
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169 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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24 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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657 views

Why do plants fruit?

This is a two-part question: What is the point of fruit if not to be eaten? It’s is my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, ...
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0answers
92 views

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 ...
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721 views

What is the evidence that australopithecines were bipedal?

Before the discovery of Australopithecus afarensis in the 1970s, most anthropologists believed that an increase in brain capacity had preceded bipedal locomotion. However, this reconstruction of the ...
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181 views

Why does sex last so long?

I wonder why (especially human) sex lasts longer than just a few seconds? My thought is that the shorter it takes a man to ejaculate, the lesser is the risk that he gets interrupted by a rival or a ...
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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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1answer
50 views

How does rate of evolution/innovation scale with population size?

I understand that there will be many other factors that affect rate of evolution/innovation. However, other things being equal, how will the rate of evolution vary between two populations of different ...
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117 views

Do wolves bury food like dogs?

Many breeds of domestic dogs seem to like burying food, presumably in preparation for leaner times. Assuming that dogs evolved from animals similar to the modern wolves through a mix of natural and ...
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Which sex has higher variance of reproductive rate in modern societies - male or females?

Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
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1answer
27 views

Is genetic drift necessarily deleterious?

I read that genetic drift is random variation in the relative allele frequencies of a population. This question however seems to pin genetic drift down to increasing deleterious allele ...
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1answer
49 views

Comparative leg sizes

When I was a child, my father showed me the classic essay "On Being the Right Size", J. B. S. Haldane. It talks (among other things) about how large animals need stockier legs to support their ...
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Confusion regarding niches in evolution theory

This is the definition of a niche from Crash Course: An area of the environment that requires a special set of skills or traits to extract food and reproduce. Obviously, this version of the ...
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56 views

Why don't fish groom each other?

Fish are often plagued by external parasites, which are presumably difficult for them to remove. There are well known cases where large fish come to coral reefs and allow smaller fish to pick off ...
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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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41 views

Definitions of robustness and canalization

The concepts of robustness and canalization are fashionable today in the biology literature. However, I am not sure of their definitions and I am not sure either that all authors actually use the same ...
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110 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material (Big genome size)? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and ...
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1answer
35 views

Drake's Law. What is the genome-wide mutation rate and what are the estimates?

Drake's rule Drake's rule states that the genome-wide mutation rate is more or less constant across all species — from E.coli to the house sparrow. Data From what I think being Drake's original ...
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1answer
78 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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72 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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35 views

Why are the genomes of some trees so large?

For example, the current longest known genome belongs to a tree: http://motherboard.vice.com/read/the-largest-genome-ever-sequenced-belongs-to-a-tree I have heard that this could potentially be ...
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31 views

What is the most recent well-attested common ancestor of chimpanzees and humans?

Humans and chimpanzees are related and thus have a most recent common ancestor. Of course pinning down this precise point is essentially impossible, so I'm interested in close ancestors of this most ...
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499 views

How do I calculate the change in allele frequency in a haploid population under selection?

From this book For simplicity, let us consider a haploid organism and assume that the frequencies of alleles $A_1$ and $A_2$ are given by $x$ and $y=1-x$, respectively. We also assume that the ...
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97 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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Why is the strength of genetic drift inversely proportional to the population size?

I saw a concept on the Internet that says "the strength of genetic drift is inversely proportional to the population size". I don't know why they are inversely proportional? Can somebody explain? ...
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1answer
34 views

Does sociality evolved before or after the ability of motility?

According to book Life Ascending: The Ten Great Inventions o Evolution. (Lane, N.;2010), Motility has indeed transformed life on earth in ways that are not immediately apparent, from the ...
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Why are there no wheeled animals?

In physics, "almost everything is already discovered, and all that remains is to fill a few unimportant holes." (See Jolly.) Therefore, on Physics SE, people are veering off into different directions: ...
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716 views

Which came first: The Chicken or the Egg? [closed]

Has there been any serious scientific inquiries into answering this age old question?
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Why 22 amino acids instead of 64?

This question got me thinking about amino acids and the ambiguity in the genetic code. With 4 nucleotides in RNA and 3 per codon, there are 64 codons. However, these 64 codons only code for 22 ...
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2answers
253 views

Why haven't land animals evolved beyond urination?

It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is ...
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Which (naturally selected) evolutionary process led to the development of egg-laying?

I understand that eggs were around before chickens, and therefore this age-old question isn't properly framed. But the idea still stands, there was a first egg-laying organism which modern chickens ...
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1answer
44 views

What is the progressive evolutionary advantage that leads to flying?

As far as I understand, all life started as non-flying and flying came about by natural selection. What is the evolutionary advantageous "path" to flying? Or is there something else to explain this?
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501 views

If Evolution Is In Progress, Why Fight Extinction?

Natural selection is a central tenet of evolution. However, most biologists seem determined to prevent the extinction of the species that have been selected against. Why is this? Preservation of ...
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53 views

Poisonous plants, animals, mushrooms: is this always a kind of defense?

I wonder whether developing deadly toxins in the organism's body is always or usually a defensive strategy rather than a by-product.
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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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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 ...