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 is genetic speciation defined?

What determines speciation at a molecular level? At what point does a scientist determine two lineages are different enough to be considered separate species? Does it have a margin of error?
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42 views

How do minute changes in an organism, as a result of evolution, get carried over to next generation

Theory of evolution states that random variations in organisms occur to better suit their surroundings. We take for example a bacteria's flagella. There's a bacteria who has a tube kind of structure ...
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328 views

Have we ever observed two drosophila lineages that evolved reproductive isolation in labs?

Background The standard definition of species refers to the concept of reproductive isolation. If two lineages are found to be reproductively isolated, then we consider these two lineages to belong ...
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2answers
3k views

Why do we assume that the first humans were dark-skinned?

According to the article Dark skin and blue eyes: How Europeans once looked: It is widely accepted that Man's oldest common forefather was dark skinned, and that people became more pale as they ...
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1answer
120 views
+300

Evolutionarily, why do male rats and horses lack nipples?

Developmentally male rats don't have nipples because (reddit) Testosterone release in the fetal male rat happens before the stage of mammogenesis where the teat is formed whereas other species ...
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1answer
34 views

What ways are there to determine how big genera are?

I want to look at genera as a whole, across the animal kingdom to determine the range of sizes of genera. I have examined species richness and genetic diversity (pairwise distance from sequence data ...
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1answer
378 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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5answers
7k views

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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40 views

How to seek for available genetic data relevant to ecology and evolution?

I had a quick look online. There seems to exist many different website of database archiving. Some data might be free of charge while some others might not be. I found things such as Dryad, TreeBase, ...
5
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234 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 ...
2
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1answer
75 views

What would be required to evolve an animal (non-human) brain to obtain human-level cognition? [on hold]

Could any animal subject to the right conditions evolve human-level intelligence? Suppose that an artificial intelligence (AI) decided to artificially evolve a population of octopus (don't ask why, ...
2
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1answer
40 views

Evolution and Phenotypes.

This may be better suited for the English language SE, but When discussing evolutionary changes in species is it proper to refer to their phenotypes? In this context: "Imagine if a cow did not ...
4
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1answer
56 views

How do bumblebees and hornets avoid the negative effects of inbreeding?

I just learned that all hornets and bumblebees except for the queen die at the end of the year and the queen starts a new nest in spring. But that means the next generation of queens have only ...
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1answer
53 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 ...
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2answers
49 views

Terminology for inefficacy of selection on recessive alleles

I am wondering is there some proper terminology which is used to say that deleterious recessive alleles might be able to hide, reducing the the efficacy of selection, in diploid organisms/chromosomes. ...
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2answers
45 views

Is there a name for the evolutionary loss of vestigial structures?

Consider a biological structure which no longer benefits an organism, such as the eyes of an organism whose population now lives in total darkness. I can think of three reasons why such a structure ...
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0answers
67 views

Epicanthic fold (eye)

What evolutionary advantage does the epicanthic (eye) fold provide? I know that the incidence of epicanthic folds is high in Central, East, and South East Asian populations, Mongolians, Inuit, etc. ...
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1answer
816 views

Term for trait that is advantageous to a population only as long as it is rare

I remember reading about a concept—in evolutionary biology or natural selection, I think—whereby a particular trait is advantageous to the population or species but only so long as that trait is only ...
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0answers
45 views

Can pandas hunt for meat?

Recently, I learned that pandas have a carnivore's digestive system but that it exists almost exclusively as a herbivore. If pandas hunted would they be able to find meat in their environment? Can't ...
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1answer
67 views

What is the point at which abiogenesis is complete and evolution begins? [closed]

Is the minimum criterion for life a single cell? It seems that self-replicating RNA is not enough, but I don't know. What would be the most basic cell that could fit this criterion and what cells ...
3
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1answer
74 views

Any evolutionary explanation for human blood groups?

What is the explanation of people having blood types from an evolutionary perspective?
3
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1answer
70 views

Why do cows (and other hooved animals) need a hierarchy?

Clearly numerous animals have a hierarchy - hereditary one. For example, I understand zebras have a pecking order, and must map this hierarchy from highest to first in line and lowest to last in line ...
3
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1answer
47 views

How did the endoplasmic reticulum come to be?

Organelles are sub-cellular compartments in cells. However prokaryotes don't use organelles to organise their intracellular space. Evolutionarily, there is evidence that mitochondria and ...
3
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2answers
380 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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3answers
64 views

how to find accurately the closest species to my plant species?

I'm working on some bioinformatic analysis of a non-model woody plant within the family with least information. So, I'm looking for a closest species to my plant. Any suggestion would be highly ...
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0answers
32 views

Evolution of Wheat

In the evolution of wheat, there are two instances of chromosomal doubling, when Emmer wheat Triticum turgidum was formed from Einkorn wheat, and when Triticum aestivum was formed from Emmer wheat. ...
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1answer
33 views

A non human adaptive behaviour with a spandrel

Is there any adaptive behaviour in non humans which, when it is functioning as it was selected to do, creates a spandrel behaviour? In evolutionary biology, a spandrel is a phenotypic ...
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0answers
57 views

Were we able to create vitamin B12 in past?

All herbivores produce vitamin B12 de novo. Gorillas, for example, are "vegans" so I suppose some human ancestor was also herbivore. Have we ever been B12 self-producers? If so, why have we lost that ...
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15 views

Analytical Methods for Estimating Probability of Fixation

The probability of fixation $P$ of an allele is an very important measure and there exists several solutions to estimate this probability. Each method has its own assumptions and it is often hard to ...
3
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1answer
46 views

How many traits can a multivariate breeders equation handle?

The multivariate breeders equation (MBE) by Lande predicts the change in a trait $\Delta \bar z$ (response) as $\Delta \bar z = G \beta$ where $G$ is a genetic variance-covariance matrix and ...
3
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1answer
55 views

The selective pressure of contraceptives

Does it seem probable that the existence of contraceptives (which has reduced human reproduction to below survival-level in many populations) will be a completely new selective pressure on human ...
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4answers
5k views

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. ...
7
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62 views

Expected time for a neutral allele to reach a frequency of $p_1$ when starting at frequency $p_0$

Kimura and Ohta (1968) showed that the expected time for a neutral allele to reach fixation (given that it will reach fixation) is $$\bar t(p_0)=-4N\left(\frac{1-p_0}{p_0}\right)\ln(1-p_0),$$ where ...
0
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1answer
54 views

Would it be more genetically efficient to have shorter lifespans?

If, for example, humans had an average lifespan of, say, 30 years, and we reached sexual maturity at age 10, then we could "evolve" more quickly and theoretically "weed-out" more genetic diseases ...
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2answers
63 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 ...
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1answer
41 views

Very introductory online source of information in evolutionary biology

We receive quite a lot of questions from layman in evolutionary biology in this site that are sometimes difficult to answer just because there is way too much to say. Why don't human keep evolving? is ...
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2answers
41 views

How to compute the regression of individual fitness on individual phenotype

Consider a population structured in groups of two individuals. Individuals' interactions follow an additive prisoner's dilemma: \begin{array}{c |c |c|} & C & D \\ \hline \text{Cooperate (} C ...
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1answer
131 views

Interlocus Contest Evolution means suicide?

I was reading Matt Ridley's "Genome" book. I am trying to understand the Interlocus Contest Evolution in his X-Y chapter. I do not understand why the X and Y chromosome would want to kill each other. ...
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1answer
61 views

History: Building a “Phylogenetic network” of famous evolutionary biologists [closed]

Seems like many of the famous evolutionary biologists are somehow related to each others. For example (and I might be mistaken), Ronald A. Fisher was mentored by a descendent of Charles Darwin. Joe ...
2
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1answer
57 views

Are there any examples of how to apply evolutionary models?

Apologies if this question it too open-ended; evolutionary biology is not my primary field. I have been reading a lot about the use of statistical mechanics in analyzing evolutionary dynamics. As an ...
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4answers
1k views

What is the difference between a circular and a cat's-eye pupil?

I've been to local zoo the other day and one lizard caught my attention: its pupils are circular, which, I thought, is not usual for reptiles. Turns out it is, but now I can't find any explanation on ...
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0answers
43 views

Does embryonic development mimic (partly at least) the evolution of organisms on earth?

What do we know about the forces/mechanisms which lead to this seemingly "fast forward" evolution stages of the embryo? What are the theories dealing with this idea?
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40 views

Basic Modelling in Quantitative Genetics

I am pretty bad in thinking quantitative genetics models. I am trying to get some basic understanding of modelling the evolution of a quantitative trait. I am therefore asking for help to analyze a ...
6
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2answers
672 views

Why is a slow worm not considered a snake?

Slow worms are considered lizards as opposed to snakes, both are reptiles. Now I get that there are traits that distinguish them (eye lids, ears ...). But snake species themselves vary already quite a ...
7
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2answers
489 views

Why does sexual selection evolve beautiful features?

First question here. I have a very raw understanding of sexual selection: Say a group of females of a certain species "likes" some feature of a certain groups of males; by "like" I mean some ...
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1answer
35 views

Evolution of dominance of alleles

Can someone tell me where can I find detailed text about mechanisms of evolution of dominance? Or, if it is possible, I would be grateful if someone will tell me about them here.
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1answer
44 views

Similarity between the human genome and archea genome in deep sea hydrothermal vents?

I'm trying to find some reference that shows what percentage of the human genome is similar to some organism from the domain Archea that lives near or on deep sea hydrothermal vents. Can someone ...
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3answers
1k views

How can homosexuality evolve despite natural selection?

I would imagine that the answer to this question would be population control, especially since even if one sibling is homosexual this does not necessarily mean that the other siblings will be too.
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Is homosexuality an adaptation in humans?

Homo sapiens have menopause - as some other mammals (e.g. some Cetacea) - a phenomenon where older females live for decades after the end of their own reproduction. Perhaps homosexuality, that looks ...
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Can we make a rough estimate of the number of generations since the origin of life?

According to what we've learnt : we can approximate the number of generations since the first human pretty much like us (depending what / who we talk about). we have an idea of the series of life ...