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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Is there any recent evidence for the aquatic ape theory of human evolution?

aquatic ape theory suggests that many features that distinguish humans from their nearest evolutionary relatives emerged because the ancestors of humans underwent a period when they were adapting to ...
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96 views

When did CRISPR/Cas9 evolve and what is the likelihood that a superior system for live cell genome editing has already evolved on earth since then?

I've read that CRISPR/Cas9 is currently being implemented and tested for its ability to edit genomes in live cells, and that it is supplanting other genome editing tools in labs, such as TALENs and ...
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1k views

What is the evolutionary reason behind the fragility of teeth?

Almost all organs in the human body have a rather large threshold within which the organ or tissue is capable of repairing itself using materials supplied by the body, whether it's made from organic ...
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280 views

When does weak selection produce qualitatively different results from strong selection?

In evolutionary game theory, it is typical to model organisms as having a base fitness that is modified slightly by the game interaction. The ratio of the game effect versus the base fitness ...
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4k views

Did animals evolve from plants?

Did animals evolve from plants? Did animals' ancestors have chloroplasts in their cells?
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2k views

Why is Galapagos island so special?

I am not a biologist so the question may be very stupid. I have no idea. Why did Darwin formulate his theory of evolution just after his visit to the Galapagos island? Why is it so special from the ...
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3k views

Why can't humans drink sea water?

Why can't humans drink sea water? It would seem to be a huge evolutionary advantage for an animal to be able to drink sea water rather than have to rely on fresh water, and it's provably not ...
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504 views

Do plant-animal cross races exist?

Plants and animals have the following distinct properties: Plants live from solar energy by photosynthesis, they use solar energy to make sugar and oxygen out of carbon dioxide, which gives them ...
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3k views

Why doesn't recombination occur in male Drosophila?

"Males do not show meiotic recombination, facilitating genetic studies." For a while I have known that this phenomenon occurs, this quote comes from the Wikipedia page on Drosophila melanogaster, ...
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178 views

Is there a dominant gene for right-handedness?

Has there been any definitive research about handedness being genetic? Also, why is right-handedness clearly dominant in humans? I'm interested in evolutionary theories, as well as any molecular ...
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1k views

why is AUG the initiation codon?

Is there any reason why AUG is the initiation codon ? Why is there a need for an initiation codon ? Can't translation start with different codons?
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151 views

What do we know about LUCA?

All life on Earth (bacteria, archaea, eukarya) is thought to have evolved from a common ancestor, or last universal common ancestor (LUCA). What do we know about the characteristics of LUCA based upon ...
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418 views

Could humans and chimpanzees hybridize?

In some cases two species can hybridize. For example, Tigers and lions can hybridize to produce "Ligers". Would it also be possible for humans and chimpanzees (or any other species) to hybridize ? ...
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134 views

Did Darwin ever reach the conclusion that selection will remove variation?

According to simple models of selection the genetic variance in a population should be reduced by selection. (Fisher's fundamental theorem states that the rate at which a population can evolve is ...
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137 views

How can a three-base codon evolve from a two-base codon?

Inspired by this question among others. It's widely suggested that the current 3-base codon system of encoding protein sequences in DNA evolved from an earlier 2-base codon system. This makes sense ...
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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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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 ...
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300 views

What does fitness really mean?

Fitness is certainly the most important concept in the theory of evolution. My question does not have to do with practical measures of fitness but with the theoretical definition of it. I am a bit ...
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155 views

Genetic Drift: Models, assumptions and empirical observations

There two main mathematical models to describe the process of genetic drift are Moran model and Wright-Fisher model. My questions concern the assumptions of these models, the existence of other ...
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60 views

What does the evidence suggest about how Neanderthals became extinct?

According to "Neanderthals: Facts About Our Extinct Human Relatives" (Szalay, 2013), Neanderthals dominated Europe during the last Ice Age, but may have died out before the arrival of Homo Sapiens ...
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92 views

Predators faking to be not hungry?

I believe that there are predator/prey combinations where the prey can easily spot that the predator is not hungry and will not try to flee from it. I’m thinking, for example, of gazelles who will ...
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982 views

Disadvantages of unihemispheric sleep

Is is well known fact that marine mammals and some birds can sleep with one brain hemisphere at a time, since it's essential for their survival. However, at least in my opinion, such mechanism would ...
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135 views

Is there a comprehensive database of fossils (with images) online?

Not sure if this is the best stackexchange to ask... I have not been able to find a decent database of fossils on the web, does one exist? Here are some of the links I have found through Wikipedia ...
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851 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 ...
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129 views

Genetic Models for Natural Selection?

My question is simple: Given that evolution is described by random genetic mutations allowing certain members of a species to gain a reproductive advantage over others that coexist in the particular ...
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522 views

The evolution of dogs through domestication and artificial selection

I am currently reading Richard Dawkins's book 'The Greatest Show On Earth: The proof for evolution' and in the second chapter he talks very much about the evolution of dogs. He says centuries ago ...
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154 views

How should I put a large phylogeny into a scientific paper?

I've been trying to put a phylogeny tree into a scientific paper. This tree includes ~220 species, which is too too large for one page for journal articles (Letter or A4 size). But in my paper it is ...
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199 views

Why Did 6 Great Ape Species Survive But Only 1 Hominid Species?

My dad asked this question when I explained some circumstances surrounding Homo sapiens survival against all odds. We know there is only one hominid species left in the world, Homo sapiens. We also ...
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Why is the Kakapo more attracted to humans than its own kind?

The Kakapo can be seen in this video by BBC. It is said that the species is strongly sexually attracted to humans. Why could this be the case?
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308 views

Extinction of species

I barely know anything about biology and realize that this might be a stupid question, but I'll ask anyway! I know that species "transform" into other species through the process of evolution. Many ...
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62 views

Why do Mangoes have a single large seed, and not multiple small ones?

I was just thinking about this, wouldn't it make more sense for a mango to have multiple seeds, as it would allow more seed propagation?
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498 views

Which phylum appeared most recently

I'm aware that our earliest records of many major animal and plant phyla come from the Cambrian or Precambrian periods, and I'm also vaguely aware of some of the objections raised with general concept ...
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722 views

Why did abiogenesis only happen once?

If the "primordial soup" theory of abiogenesis is to be believed, self-reproducing organisms spontaneously arose on Earth at least 3.5 billion years ago, surprisingly soon after the Earth cooled down ...
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819 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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508 views

Which sex has higher variance of reproductive rate in modern societies - male or females?

Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
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601 views

Did human hairs actually evolve from scales?

What is the evolution of hairs? Did they evolve from scales?
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101 views

Why does botulinum toxin seem to be more dangerous to humans than to other mammals?

Various mammals seem to get away with eating parts of carcasses that we would prefer to not even touch, and that we assume will make us sick. Because of that, I assume botulinum toxin is more ...
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214 views

What preceded ATP synthase?

ATP Synthase is ubiquitous throughout life on earth and so most probably evolved within the last universal common ancestor (LUCA) before that lineage diversified into the various kingdoms of life. ...
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222 views

Does becoming martyr have an evolutionary advantage?

This is related to How does "be altruist to those who are similar to you" evolve? Altruism that is Not reciprocal Not familiar has little explanation. One possible explanation is that ...
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84 views

Selection on linked loci in a diploid population

Let’s consider two linked loci $A$ and $B$ that are both bi-allelic. In consequence, we have four different possible haplotypes $A_1B_1$, $A_1B_2$, $A_2B_1$, $A_2B_2$, which frequencies are $X_1$, ...
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122 views

Fisher's Geometric Model for Dummies

Fisher's geometric model is still today one of the most important and fundamental model in evolutionary biology but it seems to me that most student in evolutionary biology don't really understand it ...
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282 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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144 views

The Assumption of Weak Selection?

I was reading this question and I failed to fully understand the introductory part of it. The OP (@Artem Kaznatcheev) says: Most analytic models like to assume weak selection because it allows ...
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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 ) ...
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174 views

What measures are commonly used for the complexity of an organism?

I'm aware of measures like number of distinct cell types being used as a measurement of complexity in biology, for example in the G-value paradox. But this doesn't really help for unicellular ...
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96 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and energy)? time to copy is ...
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465 views

Why would stablising selection ever happen?

If the aim of evolution is to allow an organism to better compete against rivals, why would stabilizing selection ever happen? If you're not selecting the most highly adapted competitors at either end ...
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298 views

How does “be altruist to those who are similar to you” evolve?

There are many cases when people commit altruism. One is relationship. I am willing to die for 2 of my children or 8 nieces, say an evolutionary psychologist. Another is reciprocal altruism, which is ...
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165 views

Why, specifically, does each generation, on average, improve upon the design of the species rather than degrade it?

In every non-life example I can envision, a copy of a copy is always a degraded or less pure version of the original unless some outside influence acts to correct the copy back toward the ideal ...
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355 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 ...