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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What is the outcome of a human population starting with only 2 individuals? [closed]

Starting with a human population N = 2, is there any way the genetic variability seen today could have come about? I don't know that much about meiosis, but isn't there a very limited number of ...
4
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1answer
95 views

Are there any cases of observed extreme speciation [closed]

Is there an observed (direct not indirect) speciation on record showing a species shift within the span of history of recorded science?
2
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1answer
214 views

Why are men stronger than women?

What are the evolutionary explanations for why women are weaker than men (on average), and is this difference adaptive? I suppose that something puts pressure on men to be stronger than women, but I ...
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2answers
1k views

Why do humans find baby animals cute?

Why do humans find baby animals like cats, dogs, ... so cute? As these are potential competitors or even natural enemies (like e.g. tigers, leopards, ..), the protection instinct (reasonable for the ...
2
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1answer
37 views

How did the Chromosome #2 Fusion propagate?

There is strong evidence that chromosome 2 in humans is a fusion of two chromosomes of a common ancestor of chimps and humans as explained at wikipedia here Was it necessary for the common ancestor ...
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1answer
63 views

Do species which have a closer common ancestor to humans tend to be more intelligent?

Q: Do species which have a closer common ancestor to humans tend to be more intelligent? Our closest living relative, the chimpanzee, seems to be regarded as intelligent: Chimpanzees make ...
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1answer
93 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 ...
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0answers
44 views

Odds of Fusion of Chromosome #2

There is strong evidence that chromosome 2 in humans is a fusion of two chimp chromosomes (i.e. common ancestor of chimps and humans) as explained at wikipedia here The question is what are the odds ...
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2answers
172 views

Is this statement in agreement with Darwin's theory of evolution?

Is the following statement in agreement with Darwin's theory of evolution? The number of offspring is not related to fitness. If so, why? This is not a homework assignment, I just want to ...
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1answer
66 views

Why do hummingbirds build nests with live ferns instead of dead materials?

Hummingbirds prefer to build their nests with spore-bearing ferns, and mosses. This is helpful for the reproduction of the ferns, which are then better able to spread their seeds. But how is this ...
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Does pheomelanin have a useful biological function?

Melanin is a natural pigment that is categorized into two main forms, eumelanin and pheomelanin. It's well documented in the science literature that increased eumelanin levels reduces the risk of ...
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1answer
74 views

Has any creature ever devolved to be cold blooded? [closed]

Is this even possible? Because I have a non-scientific gut feeling that it is irreversible. Whales and dolphins are evolved from land mammals, and they've remained warm blooded while it doesn't give ...
2
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1answer
69 views

Senescence, immortality and evolution?

Many have heard about the fabled "immortal" jellyfish, Turritopsis dohrnii, which doesn't die from aging (senescence) and can revert the aging process indefinitely. It is rather remarkable that only ...
5
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3answers
137 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 ...
5
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5answers
138 views

What are some examples of evolving networks in biology?

I'm a master student working on networks analysis in general. A network is something that has nodes and there are links between the nodes. Nodes and links could have attributes. An evolving network is ...
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0answers
67 views

Can human change its morphology or anatomy due to ecological changes?

According to Charles Darwin, as the surrounding environment changes, so changes the anatomy or morphology of a specific organism. But nowadays, humans have become very advanced in the technology and ...
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2answers
126 views

On evolution statistics [closed]

This basic evolution theory question has been haunting me since childhood and I'm kind of embarrassed that I can't explain it yet: Consider a butterfly. It's wings have evolved to look like the eyes ...
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2answers
724 views

Chromosome 2 fusion?

I read this article by Jeffrey Tomkins and Jerry Bergman claiming to debunk chromosome 2 fusion. Is there anything wrong with these conclusions? " 1.The reputed fusion site is located in a ...
2
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2answers
80 views

What is doubling of genetic material invented in flowering plants?

David Attenborough in his Kingdom of Plants 3D said, that flowering plants made two inventions: (1) doubling of genetic material and (2) symbiosis with animals. What was meant by "doubling of genetic ...
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4answers
2k views

Why do parasites sometimes kill their hosts?

It's bothered me for a while now. I understand why a parasitoid would do this, as it only temporarily requires the host, and that not all parasites kill their hosts. There seems to be no evolutionary ...
26
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2answers
466 views

Is there evidence that some non-human species perform sexual selection based primarily on intelligence? How do they do this?

I'm a biology amateur, but it seems like sexual selection is almost always performed based on physical characteristics, the outcome of physical contests, or some sort elaborate courtship. But do any ...
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1answer
1k views

Difference in length of Okazaki fragments

The length of Okazaki fragments in the lagging strand is about 100-200 nucleotides in eukaryotes and about 1000-2000 nucleotides in prokaryotes. What (molecular mechanism, enzyme type ) ...
7
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3answers
830 views

Why don't all ants have wings?

Since the new queens-to-be have wings, it means that ants either evolved from insects that can fly, or insects that can fly evolved from ants, or that we have a case of parallel evolution (which is ...
2
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1answer
62 views

Why is duck fat less saturated than cow fat?

Why does the composition of fat in animals vary? Is there an evolutionary advantage to producing fat that is less or more saturated?
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0answers
43 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 $F_{ST}$: $$V_{Among Pop} = 2 F_{ST}V_G$$ ...
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3answers
101 views

Are hens and roosters the same species?

I know that one is a female chicken and the other is male chicken. Are the chickens laying eggs considered the same species as those that we use for poultry meat? Or, are they different sub-species, ...
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1answer
69 views

Why are hens so different from other birds? [closed]

Hens lay many eggs during their lifetime (at least, I don't know of one which can lay more eggs) and they can't fly. Compared to other domestic animals it seems to me they are the least capable of ...
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3answers
968 views

What evolutionary adaptations cause trees to grow tall?

I think there are some obvious costs for trees to grow tall. Carbon and other nutrients costs, maintenance cost, energy cost (for growing, to bring water (and nutrients) up to the higher leaves, ...
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38 views

Does healthcare and therapy affect natural selection adversely? [duplicate]

In the last 200 years or so, healthcare and therapy has been revolutionized. Mortality rates are going down everywhere. Even if the disease is terminal, medicine can prolong life for quite a while. ...
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1answer
28 views

Assumptions of the models for haploid and diploid selection

For a bi-allelic locus, the model for haploid Natural Selection is: $$\frac{dp}{dt} = \frac{pW_A}{pW_A + (1-p)W_B}$$ , where $p$ is the frequency of the allele $A$, which relative fitness is $W_A$. ...
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1answer
42 views

$F_{ST}$ when considering a multi-allelic locus

Sewall Wright defined the $F_{ST}$ in a metapopulation as being: $$F_{ST} = \frac{\text{Var}(p)}{\bar p (1-\bar p)}$$ , where $p$ is a vector of frequencies of a given allele and $\bar p$ and ...
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271 views

Help with the Price equation

The Price equation describes mathematically the evolution of a population of units from one generation to the next. $\bar{w}\Delta \bar{z}$ = $Cov (w_i,z_i) $+$ E(w_i\Delta z_i)$ I would like ...
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4answers
735 views

Refutation of Darwin's Random Evolution Theory [closed]

I saw this refutation online of Darwin's Random Evolution Theory and cannot see any holes with the logic. Can anyone crack this simple refutation? Refutation of the Theory of Random Evolution ...
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1answer
67 views

Why are some scorpion species fluorescent under UV light?

It's known for some scorpion species such as Pandinus imperator, Heterometrus Petersii etc. to be shining under UV light. That makes them easier to capture and collect by humans. Is there any ...
3
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4answers
132 views

Bad Eyesight and Evolution

Why do many humans have bad eyesight, such as near-sightedness, which hampers performance in a wide variety of tasks? Shouldn't there be evolutionary pressure towards better eyesight?
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1answer
33 views

Metapopulation structure - book recommendations

What book would you recommend me to study: the dynamics of metapopulations, the structure of metapopulations, the evolution in structured metapopulations? I am not looking for an introduction ...
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1answer
37 views

Distribution of fitness in wild populations

If I get out in the wild observe wild populations and measure the distribution of fitness $f(w)$ in a given population. What will I find out? Will I observe a Gaussian distribution, a Poisson ...
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3answers
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Were there any flying dinosaurs?

I've seen some articles which came in contradiction with each other. The first article was talking about flying dinosaurs, dinosaurs with feathers and so on. A couple of other articles are talking ...
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1answer
72 views

What is the evolutionary reason behind human preference for salty foods?

It's been established that food palatability is related to it's caloric density. This hypothesis is used to explain why humans are partial to sugar and fat. But it is also said that humans are partial ...
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1answer
92 views

What is the difference between these terms: clade, monophyletic group and taxon?

Wikipedia definitions for these terms are pretty similar: http://en.wikipedia.org/wiki/Clade http://en.wikipedia.org/wiki/Monophyletic_group http://en.wikipedia.org/wiki/Taxon They sound like the ...
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1answer
90 views

What is the evolutionary cause for various finger lengths?

Why are the lengths the way they are with middle finger the longest?
6
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1answer
72 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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57 views

Can animals distinguish other animals? [closed]

Are animals able to tell the difference between other animals. I dont mean like a cat seeing a dog and thinking "Oh no its a dog". I mean how does prey distinguish predator or threat? Say for instance ...
3
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3answers
5k views

Evolutionarily speaking, why do humans have 46 chromosomes

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Monkeys, chimpanzees, and Apes have 24 pairs (twenty-four pairs), for a total of 48. What caused humans to have 46? ...
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1answer
45 views

Various Genetic Loads and their Definitions

In population genetics, we talk about several types of genetic loads (also called just loads). I am asking for a exhaustive list and a short definition. Here are for example some genetic loads that ...
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3answers
766 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
35 views

Inbreeding depression and dominance

From this article, second paragraph of the second page A classic theoretical result is that the mean of a character controlled by a single locus $i$ with two alleles $A_{i1}$ and $A_{i2}$ is only ...
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3answers
159 views

Why do our eyes close when we sleep?

Why do our eyes close when we sleep? Is it to relax our eye muscles? How can it be explained from an evolutionary point of view?
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2answers
67 views

Is there an evolutionary explanation for the black spots around a pandas eyes?

I couldn't seem to find one elsewhere, at least not with a scientific source. It would seem as it's quite a striking feature there would be an advantage it would infer.
2
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1answer
84 views

“selective pressure” or “selection pressure”?

Editing a manuscript of mine, a co-author changes "selection pressure" to "selective pressure". Are those two terms interchangeable? Or are there subtle differences that I'm not aware of? The ...