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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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 ...
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2answers
2k 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 ...
3
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0answers
87 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 ...
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0answers
107 views

Why are there no complex hermaphrodite land animals? [closed]

The title says it all. I know that 'complex' is a pretty ambiguous term to use, but I can't think of a more scientific term/definition for my meaning. I can't think of any large (larger then a small ...
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0answers
28 views

Wolbachia - cytoplasmic incompatibility

I read that cytoplasmic incompatibility in Wolbachia occurs when wolbachia-infected male insects mate with wolbachia-free female insects and produce non-viable offspring. By contrast, wolbachia-...
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25 views

What chordata evolve first limb

I try to search when and what specie develop first bone limb. I also want to know when second pair develop. And first pair was front or back one? And why it stop only at 2 pairs. Are there any fish ...
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1answer
79 views

why do marine organisms orient with their bellies facing downwards?

why do marine organisms orient with their bellies facing downwards (like most creatures) given that they have relatively fewer constraints on their orientations than land or air organisms?
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60 views

Name/Examples of Traits whose benefit is non-obvious and/or which evolve despite apparent mal-adaptivness?

I'm a graduate student in cognitive science doing work on people's explanations and learning, particularly having to do with natural selection. Often, students misunderstand natural selection as a "...
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4answers
574 views

Why people like to see pornographic scenes, but do not feel the same about eating scenes? [closed]

This question may seem funny, but I think biology must have good answers. I think no more explanation is needed. I really thought about this and searched for an answer, but there is nothing yet. If ...
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3answers
115 views

What fraction of sites are expected to be polymorphic?

Question Consider a very long (eventually infinite) DNA sequence of neutral sites. Consider a panmictic population of constant size $N$ with a per site mutation rate of $\mu$ where all individuals ...
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1answer
82 views

How does chromosome fusion get fixed in the population?

It's well known that one of human chromosomes is the result of fusion between two chromosomes in a primate ancestor. If we put anthropocentrism aside, it becomes clear that fusion events happened a ...
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0answers
97 views

Saline solution for animals

A popular "well-known fact" is that all creatures on Earth consist mostly of water (i.e. H2O). Indeed, a liquid called "normal saline solution" is just a solution of 0.9% sodium chloride in distilled ...
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5answers
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Why did life not evolve to use radio?

We use electromagnetic communication everywhere these days. Cell phones, wifi, old-school radio transmissions, television, deep space communication, etc. I'm curious about some of the possible ...
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0answers
42 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 ...
5
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1answer
403 views

Where do most mutations come from, mitosis or meiosis?

According to this (old) paper there are 10 times more mutations during meiosis than during mitosis. One reason for that is that recombination often causes replication error and therefore mutations. ...
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3answers
4k views

Why do humans find baby animals cute?

Why do humans find baby animals like cats, dogs, ... so cute? As these are potential competitors (when grown up!) or even natural enemies (like e.g. tigers, leopards, ..), the protection instinct (...
6
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1answer
178 views

Are there any theories why such an imbalance in chirality of molluscs?

Most gastropods exhibit sinistral (right hand) winding of their shells. But very few species are anti sinistral. Have there been any theories as to why such a great difference?
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154 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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2answers
424 views

Evolution of insects, spiders and jellyfish

Well we all learned at school the classic evolutionarily theory ...
8
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1answer
703 views

Do butterflies pass over migration patterns to their offspring?

So, earlier, I read online (http://io9.com/butterflies-remember-a-mountain-that-hasnt-existed-for-509321799) that Monarch butterflies veer east during their southward migration to avoid a mountain ...
8
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5answers
395 views

Theoretically, is domestication of (virtually) any animal possible?

Looking at ones that manage well alongside us human animals, such as dogs and cats, we see that this is possible for evolved, distant animals to have heritable, preferable traits around people. ...
4
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1answer
125 views

Forward versus backward numerical simulations in population genetics

My question is closely related to this post. There are a number of existing platforms to perform numerical individual-based simulation in populations genetics. An almost exhaustive list of such ...
6
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2answers
2k views

Are we more attracted to people of the same ethnicity? [closed]

Are humans more attracted to people from their own ethnic groups? I ask this because most of the time people have relationships with people of their own ethnicity, and I wonder if it's purely social, ...
0
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2answers
153 views

Has a new functional structure ever been observed arising spontaneously?

Have we ever observed a new functional biological structure arising spontaneously such as a new functional organ (sensory or otherwise. such as tracing some creature in the past few hundred years ...
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1answer
52 views
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833 views

What is meant in biology by the term “evolved”?

A student asked me this the other day and I thought that I would ask it again here. If one organism is said to be "more evolved" than another, what exactly does this mean?
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0answers
43 views

Why do human have continuously-growing hair on their head? [duplicate]

Why do hair continuously grow on human heads, while the same doesn't happen on other parts of the human body? Where there are hair, they only usually grow to a fixed length; but they seem to have no ...
2
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1answer
113 views

System biology and evolution: Book-recommendations

I have relatively good knowledge in evolutionary biology and in population genetics. I am getting more and more interested in the evolution of ... genetic developmental processes gene interactions ...
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0answers
80 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....
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2answers
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Why does human facial and head hair continue to grow?

Many people can grow extremely long head hair and facial hair. Are there evolutionary theories as to why this is the case? It seems like having long hair could be a disadvantage, and extremely long ...
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2answers
54 views

Is there a name for this phenomenon described in “Phylogenies and the Comparative Method”?

The figures below are from Felsenstein's paper "Phylogenies and the Comparative Method". I was wondering if there was a specific name for this effect where there is an apparant correlation that is ...
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1answer
62 views

Altruism in viscous (asexual) populations

The viscosity of a population is the tendency of offspring to remain near their place of birth. Taylor 1992 ("Altruism in viscous populations") provides a model to study how viscosity affects the ...
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1answer
2k views

How did the huge dinosaurs cope with gravity and loads on bones, etc.?

It's very costly to be a huge animal. Your mass grows in cube when you scale up, but you still only have two/four legs to support the same weight. This increases the pressure that your body needs to ...
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2answers
99 views

Characters do not make the genus, but the genus gives the characters?

In his Origin of species, in the chapter entitled 'Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs', Darwin, speaking of the nature of classification systems of living ...
4
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2answers
306 views

Why don't mosquitoes evolve towards muting themselves?

Quite certainly, muted mosquitoes would be much more effective as far as their blood-sucking pursuits are concerned, since mosquito sound is predominantly responsible for sealing their fate (between ...
3
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1answer
414 views

Opposite results between Blomberg's K and phylogenetic signal in Phylocom (AOT)

I've been trying to test for significant phylogenetic conservatism in some plant traits. So far I used R-package picante (Blomberg's K) and AOT in Phylocom. So far these two methods yield completely ...
9
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1answer
825 views

How and when did a dedicated immune system evolve?

I have recently been doing a lot of research into the interplay between the innate and adaptive immune systems in humans, and mammalian laboratory models. This has led to my reading some interesting ...
0
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1answer
69 views

What is a selectively neutral genotypic change?

I am reading the paper "Neutral evolution of mutational robustness". Because I am new to neutral evolution, I have a few questions. Firstly, from my understanding, genotypic neutrality means the ...
11
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2answers
545 views

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 ...
3
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1answer
189 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 ...
2
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1answer
54 views

Why is an increase in the amount of oxygen in the atmosphere favorable for life?

I have followed the David Attenborough series on 'First life' and heard, that an increase in the amount of oxygen in the atmosphere, as it took place just before the Cambrium, is generally favorable ...
6
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1answer
53 views

Independent contrasts with non-homologous traits

I have morphometric measurements for a trait across various animal taxa, and would like to study the relationship between the size of this trait, and the animals' body size. In theory, I can account ...
5
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1answer
95 views

How are behaviors genetically coded in animals?

I am curious as to how complex behavior is passed down genetically? For example, how is the building of a web genetically coded in a spider? And how is the complex behavior of constricting prey coded ...
2
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0answers
57 views

Differing number of “things” in mammals [closed]

I'm not a biology expert, but I have often wondered about the following facts of life: All mammals have precisely 5 fingers on each of our 4 extremities. Granted, some may not be seen, but the bone ...
1
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1answer
118 views

Why is the gene regulation in eukaryotic cells needs multiple level of control than in prokaryotic cells?

That "eukaryotic cells are more complex" and "compartmentalized" are used to justify the need of more level of control of gene expression. I get the basic idea but can't convince myself why complexity ...
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4answers
436 views

Why don't most animals have “heads” in the middle of their bodies? [closed]

For example, humans. It would seem like, to me, if our brains and eyes, ears, etc. were situated in our stomach area they would be more protected from harm and more central than up at the top in and ...
6
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3answers
534 views

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 ...
5
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1answer
77 views

Queller's 1985 version of Hamilton's rule

Queller 1985 ("Kinship, reciprocity and synergism in the evolution of social behavior") provides a generalization of Hamilton's rule that allows for non-additivity. To accomplish that, Queller writes ...
8
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1answer
97 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 ...
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Are amantadine and rimantadine MOAs unknown to evolution?

Are any natural (human or otherwise) antiviral mechanisms similar to the antiviral mechanisms of amantadine and rimantadine, or are these mechanisms undiscovered by evolution? Are drug researchers ...