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

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Variance in reproductive success and effective population size

Background The effective population size $Ne$ is the size of the Wright-Fisher population that experience the same amount of drift than the population under consideration. The higher the variance in ...
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1answer
8k views

Why does a coconut have exactly three holes

A theory says: As coconut is a sibling of palm, somehow long time ago, three palms were in a same husk. Based on evolution theory, it's how the coconut was born in the world with three holes. ...
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180 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 = \frac{...
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3answers
230 views

Why does all life use the same macromolecules in their genetic code?

There is no biochemical constraint of any sort, so why doesn't some other code work? Why is it specifically RNA/DNA?
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4answers
182 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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138 views

Which primates can swim underwater?

I saw a documentary awhile back and they were profiling a certain species of monkey which regularly swims underwater. I can't recall which species it was but they said it was rare for primates to do ...
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174 views

What are the evidence that all life today descended from a common ancestor (LUCA), and which organisms (if any) challenge the concept?

If I understand correctly, the concept of the LUCA (last universal common ancestor) is based on the hypothesis that archaea and bacteria share common ancestry. In the realm of mathematics, the same ...
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4answers
583 views

Is our genome decaying (see “Genetic Entropy”), and, if so, is this evidence for our genome being “young”?

In the book Genetic Entropy & the Mystery of the Genome the author says that the genome cannot be old because the genome is "decaying". Decay is a very subjective term, but in this case he means ...
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2answers
40 views

What makes tones sufficiently useful that it would lead to the evolution of tonal processing?

I will define a "tone" as  a steady periodic sound. As an example, I consider a sinusoidal wave to be a tone. By "tonal processing", I mean ratio relationships between the notes. For instance, if I ...
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Why would a single celled organism evolve to be multi-celled?

I read a story this week on Richard Lenski who has been 'evolving' E. coli for more than 50,000 generations now. One comment I read was from someone who doesn't accept Evolution who pointed out that ...
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How does evolution produce complex organs

I've been wondering lately how evolution manages to produce complex organs. It is pretty obvious to me how evolution would select some minor traits like size, resistnce to illness or climate. There is ...
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39 views

Seeing through the rain

This question leads me to wonder about seeing in and through rain. From visual point of view, rain is light-bending droplets moving downwards, unformly in steady rain, less uniformly if there's ...
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162 views

Evolution of a Population

Scientists observe a newly established population of sexually reproducing plants growing on the shore of a small island. An observable trait of the plant has two possible phenotypes. It is determined ...
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1answer
406 views

Hardy-Weinberg Equilibrium Question

I have four questions concerning H-W Equilibrium: (i) In a population of mice, the presence of black spots is the result of a homozygous recessive condition. If the frequency of the allele for this ...
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4answers
6k views

Why is polyploidy lethal for some organisms while for others is not?

Polyploidy is the multiplication of number of chromosomal sets from 2n to 3n (triploidy), 4n (tetraploidy) and so on. It is quite common in plants, for example many crops like wheat or Brassica forms. ...
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2answers
89 views

Junk DNA and “random” mutations [closed]

I'm somewhat irritated by "mutation" generally being described as a fully random factor in evolution: pure randomness does not seem like something that can survive in a long evolutionary process. And ...
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1answer
332 views

Parasitism and mimicry

I was reading this article which states this: Classical Batesian mimicry, in which an undefended mimic evolves to look like a toxic model, is a parasitic relationship in which the mimic gains ...
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0answers
18 views

Why is 2 sexes in an organism so common? [duplicate]

Sorry if this is a super simple question, but why do a lot of species have only 2 sexes? Some species just have 1 sex, but I've never heard of an organism having 3 sexes, for example. 3 sexes seems ...
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0answers
49 views

How octopus develops its imitation skill?

I've watched one documentary about a Mimic octopus which they can imitate another animals in several form e.g. a Lion fish, a Sea snake, a Flatfish, etc. My question is how these octopuses can have ...
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2answers
214 views

Is it possible there were multiple origins of life? And, if so, why did the one which became the common ancestor between all organisms prevail?

I have learned that all currently-living organisms come from a common ancestor, which I theoretically understand. However, my professor in a class mentioned that there is a chance that there were ...
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0answers
68 views

How did the double circulatory system evolve from the single circulatory system

I already learned how the mammal circulatory system (double circulatory system) evolved from the reptilian circulatory system. How did natural selection evolve the reptilian circulatory system and the ...
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0answers
56 views

Why do we turn darker in the sun? [duplicate]

I tried the all powerful google to answer this question - but I am not getting the answer I seek. I know we turn darker because the skin produces melanin. The question remains - why darker? I am a ...
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3answers
144 views

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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3answers
183 views

Why didn't humans evolve to reproduce identical twins all the time?

According to the selfish gene theory, it seems like because identical twins sometimes get produced, a mutation to a gene that says, "if you have an identical twin, be fully altruistic towards them" ...
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1answer
450 views

why didn't natives of south america evolve darker skin?

I understand that darker skin tone is caused by melanin which helps to protect against the extra UV radiation that comes from more direct sunlight. It evolved in Africa before we migrated away from ...
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0answers
48 views

How did the tendency to perform death rituals evolve?

Both elephants and humans perform rituals when deaths occur. However, I do not see any evolutionary benefit of this. The rituals take time, which apparently could be better spent hunting, foraging, ...
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1answer
562 views

Why do genetic drift generates negative linkage disequilibrium?

The very first sentence of the abstract of this article is: "In finite populations subject to selection, genetic drift generates negative linkage disequilibrium, on average, even if selection acts ...
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1answer
76 views

How did people's liking of ceremonies evolve? [closed]

Habitual group activities are prevalent across many animal species, particularly in mammals, especially in primates. However, I do not see any evolutionary benefit of this. 'Ceremonies' take time, ...
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1answer
75 views

History: Do evolutionary and ecological processes occur at the same timescales?

Classically, it was thought that evolutionary processes occurred at a much slower pace than demographic/ecological processes. Nobody, ever thought about incorporating both processes into the same ...
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2answers
128 views

Within and Between Allelic Class Diversity

I am reading Charlesworth et al. 1997. They talk about diversity within and between allelic classes. Nucleotide diversities ($π$) at each neutral site were estimated from the mean of $2 \sum z_t (...
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1answer
70 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 $\beta$...
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1answer
87 views

Extinction of species with extant descendants

From what I've seen, species such as Homo heidelbergensis which have extant descendants are classified as extinct, which makes sense as far as it goes. However, given that species exhibit a continuum ...
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1answer
76 views

Is it “easier” for researchers to detect evolutionary ancestry than distance in the evolutionary tree?

I'm a researcher in another field who has wandered into a problem with applications to biology. I hope to sell my results by making the following statement: Given two species X and Y, it is "...
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1answer
115 views

What was the evolutionary reason for cross lateralization of the brain?

In the human brain the right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body. What led to this development? Why doesn't the left side of the ...
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1answer
2k views

Why is the pituitary gland located in the brain?

Why is the pituitary gland located in the brain in humans, instead of elsewhere in the body? Why would this be an evolutionary beneficial adaptation?
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1answer
102 views

What are the units of Phylogenetic Independent Contrasts (PICs)

PICs are a popular phylogenetic comparative method and I was wondering what units the actual contrasts are in. I want to say they are unitless but I am not entirely sure.
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0answers
27 views

Why does our body exhibit bilateral symmetry? [duplicate]

Externally, we (humans) look symmetrical. However, internal organs don't show the same patterns of symmetry (heart being on the left side while the liver is on the right side, etc.). It is a bit ...
3
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2answers
88 views

Evolution of protein and protein efficiency

Suppose we have a bacterial protein that performs a function and let's say we can measure the efficiency of the protein. Let's say we have two species, species A and B, both of which have this protein....
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2answers
565 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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8answers
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
68 views

How did evolution support sports, fun, entertainment etc [duplicate]

We know that many animals entertain themselves by playing games. But sports actually increases risks of death,or at least accidents. So why did evolution choose it? And why did evolution decide to ...
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2answers
167 views

Driving force for speciation for millions of species today

I would like to know if speciation really occurs (trans-speciation). Have we had enough time for millions of species? A creationist argument is that the slow changes in traits in organisms, taking ...
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1answer
207 views

Why does the number of mutations per individuals follow a Poisson distribution?

I was reading this review. On page 11, left column, first paragraph, one can read: [..] there is a Poisson distribution of the equilibrium number of mutations per individual, if fitness effects ...
2
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1answer
76 views

Is there a schema for how human behavior is genetically determined?

It seem one can distinguish three different kinds of genetic determinism of common patterns of human behavior: behavior that is directly wired into our nervous system, e.g. face-related mirror ...
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3answers
1k 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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3answers
142 views

Why are sight and sound prerequisites for intelligence?

Edward O. Wilson, in The Diversity of Life wrote (emphasis mine): Ninety-nine percent of the animals find their way by chemical trails. […] Animals are masters of this chemical channel, ...
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1answer
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What is variation in Speciation

I read a lot about speciation. To my knowledge, A species is often defined as a group of individuals that actually or potentially interbreed in nature and produce fertile offspring. Speciation is a ...
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1answer
112 views

Evolution of the Redundancy of the Genetic Code

In short Looking at the genetic code, it appears that most redundancy is on the third letter rather than on the first or the second letter of the codon. Why has it evolved this way? Longer version ...
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3answers
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There aren't any animals like hornets that hunt large prey (like a rabbit, or even up to a deer), right? Why not?

There aren't any eusocial animals (hives of wasps, ants, termites, etc) that hunt large prey, are there? I'm thinking prey in the size range of, say, a rabbit, or even a deer. I can't see a rabbit ...
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Why is there a seeming dichotomy between mobility and photosynthesis?

At least among more complex organisms, I cannot think of any examples of highly mobile species (like animals) that also incorporate photosynthesis. Perhaps there are examples that I'm unaware of, but ...