Questions tagged [evolution]

Changes in the heritable attributes of populations of organisms over time. The mechanisms of evolution are mutation, migration, drift, and selection.

230 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
9
votes
0answers
229 views

Do ring species exist?

In trying to understand evolution better, I have been looking at examples of speciation, and have thus come across the topic of ring species. I have tried to find concrete examples of how these work, ...
9
votes
1answer
366 views

What percentage of the genetic variance is explained by the 'n'- most important loci?

Introduction 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 ...
8
votes
0answers
99 views

Where does Darwin state his “principle of multiple utility”?

I have never heard of Darwin's 'principle of multiple utility', but several papers refer to it. For example, from Darwin at the molecular scale: selection and variance in electron tunnelling proteins ...
5
votes
0answers
116 views

How frequent are selective sweeps?

Introduction Selective sweep is the most famous genetic signature of selection. We know of a number of classical examples of selective sweeps, some of them in humans. See the classical example of the ...
5
votes
0answers
133 views

Evolutionary explanation of the bicuspid on the left and tricuspid on the right

The left heart handles more pressure and logically it would make sens to have a valve with three leafs on the left (If I had got to choose, I'd have put three on both sides). Other than being more ...
5
votes
0answers
150 views

Escaping resource limitations during tumor evolution

In their discussion of the importance of r- and K-selection on tumors, Aktipis et al. (2013; figure 3) provide the following illustration of a hypothetical cancer growth curve: In it, you can see ...
5
votes
0answers
56 views

Games with non-uniform interaction rates

Background: Many models in evolutionary game theory assume uniform interaction rates. For instance, consider the $2\times 2$ game: \begin{array}{l c c} & A & B \\ A & a & b \\ ...
5
votes
0answers
99 views

Why do naked mole rats live in colonies with a queen?

What was the evolutionary advantage in having queens? Is it because the ones that had queen like tendencies in the new environment had kids that cooperated better giving higher chance of survival of ...
5
votes
0answers
181 views

How does the population fitness change after a change in mutation rate?

The mean population fitness as given by mutation load theory depends only on the genome-wide mutation rate ($U$). My question is: How many generations is needed to reach a new mutation load ...
5
votes
0answers
172 views

At what rate do chromosomal rearrangements occur?

How often do chromosomal rearrangements occur? I am interested about these kind of chromosomal rearrangements that are passed on to the descendants, i.e. germ line chromosomal rearrangements. The ...
4
votes
0answers
56 views

Inheritance percentiles

I am aware that the average DNA contribution from each grandparent is 25%, while the possible range is 0%-50%. I found a source citing 18%-32% as the "normal" range but this was undefined. I assume ...
4
votes
0answers
49 views

Who invented dN/dS?

I am writing a paper, and I want to refer to the original paper that coined the term dN/dS (or Ka/Ks for that matter). I have found early works on dN and dS (like Miyata and Yasunaga 1980), but cannot ...
4
votes
0answers
50 views

Evolution of scratching

Is scratching (aka the scratching reflex) thought to be inherited from a single vertebrate ancestor or is it something that evolved several times e.g. in birds, mammals etc., i.e. is it a case of ...
4
votes
0answers
203 views

Were Neandertals as Hairy as We Are?

What I mean to say regards facial and androgenic hairs. There are many theories as to why some people have both kinds of hairs, while others have one or the same and others still have neither. The ...
4
votes
0answers
1k views

Mutation-Selection-Drift Equilibrium

mutation-selection-drift equilibrium is one of the most important concept of population genetics. I could easily find the calculations for mutation-secltion equilibrium and for mutation-drift ...
4
votes
1answer
518 views

How did the nucleus of eukaryotic cells evolve?

What is/are the most popular theory/theories on how the nucleus evolved? I know mitochondria came from alpha-proteobacteria, chloroplasts from cyanobacteria and that eukaryotes evolved directly from ...
3
votes
0answers
45 views

Were there any terrestrial species in the ancestry of all crustaceans?

To the exception of woodlice, Crustaceans live in aquatic (marine or freshwater) environments. Crustaceans are arthropods which is an immensely diverse taxon. Many arthropods live in terrestrial ...
3
votes
0answers
212 views

How old is the action of sneezing?

Is there an estimate for when the ability of sneezing evolved? A little bit of research, and some critical review of my memories tell me that: Many, if not maybe all mammals sneeze. Some reptiles ...
3
votes
0answers
54 views

Is there recent info about the hypothetical ancient two-codon genetic code?

Here is the latest I have found. link This is the basic idea: Evolution does not look ahead and make plans. It would not create a system of mRNA with giant ribosomes to create proteins, until ...
3
votes
0answers
126 views

Mammalian scales

Many small mammals have scaly skin on their tails and sometimes limbs. The examples can be found among rodents (rats, degu, scaly-tailed squirrels), insectivores (shrews, desmans), oppossums, musky ...
3
votes
0answers
67 views

Why are animal mitochondrial genomes so conserved and small in comparison to those of plants?

Background Levings and Brown (1989): Higher plant mitochondrial genomes are much larger and more complex than those of other organisms. They vary in size from about 200 kb in Brassica species ...
3
votes
0answers
54 views

First infection of malaria

As I know Plasmodium falciperum survive in either a host animal, human or mosquitoes. But how does malaria come to infect either of them initially? I am interested in knowing evolution of malaria. ...
3
votes
0answers
148 views

For which taxonomic levels are xylotomical, embryological, and palynological evidence each most useful in determining species relationships?

From the 2010 USABO Semi: In plant systematics, three lines of evidence may be useful in determining relationships; xylotomical (wood anatomy), embryological and palynological. Match these ...
3
votes
0answers
66 views

Why might the chirality of gastopods be dominantly dextral?

This wikipedia page on gastropods provides a definition of chirality, and briefly describes the genetic mechanisms behind why a shell is wound left (sinistral) or right (dextral) handed. It also ...
3
votes
0answers
179 views

Why does a broad-leaved evergreen (Mahonia aquifolium) has red leaves?

To my knowledge, oregon grape (Mahonia aquifolium) is purportedly an evergreen shrub? Deciduous broadleaf plants lose their leaves in autumn usually and before that as the leaves die they oxidize and ...
3
votes
0answers
244 views

Derivation of discrete replicator dynamics

Related: Discrete vs Continuous Replicator Dynamics I am trying to perform a derivation of the discrete time replicator dynamics, but I am unable to get through Cressman's derivation in "Evolutionary ...
3
votes
0answers
110 views

What is the effective population size of a simple two deme metapopulation?

I am confused as to how to compute the effective population size $N_e$ of a theoretical structured population. Let's consider here a simple case study. Imagine a 2-deme metapopulation. Each deme is ...
3
votes
0answers
253 views

Population size and genetic drift - What are the evidences?

Wright-Fisher model From the Wright-Fisher model of genetic drift, the random sampling of allele from one generation to the next is taken from a binomial distribution with parameters $2N$ and $p$, ...
3
votes
0answers
110 views

Is $F_{ST}$ a probability and a correlation coefficient?

$F_{ST}$ is one of the most famous and most important statistics of all of evolutionary biology. Yet, many people misunderstand it or misuse the classical results from the literature on $F_{ST}$ (...
3
votes
0answers
177 views

What form of reproduction did the first land animals use?

What form of reproduction did the first animals on land use*? Were they hermaphrodites, or did they have male and female sexes? [Is there a proper term for sexual separation in a species?] Were any ...
3
votes
0answers
171 views

Why does bacillus thuringiensis produce bt toxin?

Background : B.thuringiensis produces an inactive crystalline toxin during sporulation which when ingested by an insect, gets activated and causes pore formation in gut , subsequently leading to death ...
3
votes
0answers
175 views

How to understand relatedness in an infinite island model?

My understanding is that the relatedness coefficient in kin selection models measures positive assortment. That is, altruism is more likely to evolve if altruists tend to interact with other altruists....
3
votes
0answers
158 views

What are the common methods to estimate additive genetic variance?

Additive genetic variance can be estimated in a number of ways, and is a key concept in evolutionary biology and quantitative genetics. What are the typical methods (experimental designs) used to ...
3
votes
0answers
106 views

Understanding the meaning of $s$ and $t$ in a population genetics equation

Sewall Wright in this article (1937) at the end of page 313 gives the equation: $$\Delta q = (s+tq)q(1-q) \space\space\space\space\space\space\space\space\space(1)$$ This equation is an ...
3
votes
0answers
649 views

Does the Jungian notion of collective unconsciousness have any legitimacy in the light of modern neurobiology and epigenetics?

Carl Jung has long ago proposed a rather controversial notion of collective unconsciousness [1, 2, 3], a form of the unconscious (that part of the mind containing memories and impulses of which ...
3
votes
0answers
28 views

Evolutionary motivation behind number of neurons in DCMMP

I'm studying neuro-anatomy right now and I was surprised to learn that there are only three neurons along the Dorsal Column Medial Lemniscal Pathway (DMLP) which relays mechanical sensations from the ...
3
votes
0answers
91 views

$F_{ST}$ and the genetic variance in metapopulations

From this video (21'15''), the speaker gives the following formulae in order to calculate the between and among populations genetic variance from the $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ $$V_{...
3
votes
0answers
157 views

Inbreeding Coefficient and Coefficient of Relationship

Wikipedia gives the following formula to calculate a "path of coefficient of relationship" between an ancestor $A$ and an offspring $O$: $$\rho_{AO} = 2^{-n} \left( \frac{1+f_A}{1+f_O} \right)^{1/2} =...
2
votes
0answers
72 views

Evolution of the unique mating system of the scorpion Androctonus australis

Sperm transfer in the scorpion Androctonus australis involves a sclerotized spermatophore, which is formed in the paraxial organs of the male reproductive system. The right paraxial organ produces the ...
2
votes
0answers
39 views

Has anyone confirmed Darwin's theory that nectar began as something “injurious” to sap?

In "Origin of Species", Darwin says (I have added bold for emphasis): Certain plants excrete sweet juice, apparently for the sake of eliminating something injurious from the sap: this is effected,...
2
votes
0answers
63 views

What are haplotype blocks and what is the effect of hybridization on these?

In this PDF, there is a quick definition of haplotype blocks. A haplotype block is a set of closely linked alleles/markers on a chromosome that, over evolutionary time, tend to be inherited ...
2
votes
0answers
24 views

Is evolution of gametangia in land plants and charophyceae convergent?

Is the presence of gametangia in both land plants and charophyceae a result of convergent evolution or are they of the same origin (and have been lost in other types of algea)?
2
votes
0answers
43 views

How would inserting a nonfunctional protein impact fitness of an organism?

Producing proteins costs energy, and producing longer proteins costs more energy than shorter proteins. Producing proteins which have no function, would therefore presumably negatively impact the ...
2
votes
0answers
53 views

What function will survive evolution?

I wrote the following phrase in my scientific text: X is ubiquitous in life of Y. On some occasions X might be detrimental, resulting, for example, in so so phenomena. But is it plausible that a ...
2
votes
0answers
87 views

What is the closest relative to odd-toed ungulate?

I have seen about 3 variation of phylogenetic tree about odd-toed ungulate and I don't know which one is really updated or outdated or which one have more backed up theory First is odd-toed ungulate ...
2
votes
0answers
36 views

Are cloned spieces significantly more vulnereble to deseases than sexually reproducing species?

I would like to be able to compare the risk for species to go extinct implied by their reproduction mechanism in the very short term. Imagine we choose some species A that can reproduce both sexually ...
2
votes
0answers
89 views

What is the evolutionary or biological origin of apathy and indifference. Is it uniquely a human thing?

I believe that social apathy is one of the main reasons why changes cannot easily be brought about in contemporary society due to the general lack of interest of the public, and this has ties with ...
2
votes
0answers
171 views

Difference in multicellularity between prokaryotic and eukaryotic organisms

As most prokaryotic organisms are single-celled, and in eukaryotic organisms this is the reverse, is there some evolutionary advantage that led to these features evolving? Or is it purely the fact ...
2
votes
0answers
93 views

Is there any evolutionary significance of downward facing nostrils in human beings?

The nostrils in apes and monkeys are almost at the front, but in humans nostrils (external nares) face downwards. Also a lot of non-primate mammals like goats have nostrils at the front. Is it the ...
2
votes
2answers
181 views

Is the suicide of a moribund individual to be considered group selection?

When a moribund individual commits suicide (e.g., Refardt, Bergmiller & Kummerli, 2013; http://rspb.royalsocietypublishing.org/content/royprsb/280/1759/20123035.full.pdf), is this to be considered ...