Questions tagged [evolution]
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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Are there limits to drug resistance?
It's well-known that indiscriminate use of a drug leads to resistance. My question is what the limits on resistance are. It seems obvious that there must be limits: for example I can hardly imagine a ...
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Assumptions of Hardy-Weinberg rule
The post Solving Hardy Weinberg problems offers an easy explanation of Hardy-Weinberg rule. The current top answer explicitly does not talk about the assumptions of Hardy-Weinberg. A model makes sense ...
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Is there an ideal evolutionary body?
I am a science fiction fan, and when I watch movies with aliens, I get annoyed at the fact that they're all humanoid. I think, "What are the chances that it will look that similar to humans?" But I ...
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What negative effects does cannabalism have in other species (like prion diseases) and how are they mitigated?
It is well known that human cannibals are likely to suffer from a variety of ailments, particularly prion diseases.
However a great many other species, from insect to ape practice cannibalism at much ...
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What does 'direction' mean in the statement "mutations are non-directional"?
I was reading the Mutation theory of De Vries; there I encountered this following statements
Mutations are discontinuous, random & non-directional.This is in contrast to Darwinism where ...
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Any evolutionary explanation for human blood groups?
What is the explanation of people having blood types from an evolutionary perspective?
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What is the "Spandrels" debate about?
In a former question, as a side question, I asked a clarification about the "Spandrels" paper. Being not a biologist, it was the first time I encoutered it.
Subsequently I tried to collect some ...
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Variation in MHC in humans
What evolutionary process lead to so much variation in MHC? What is the advantage of having such variation?
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What is the benefit for cells having the ATP production regulated in mitochondria compared to being from the nucleus?
Mitochondria have their own DNA and appear to be loosely connected to the nucleus and it role.
Why are the functions of mitochondria not in the nucleus? Why doesn't the nucleus control the ...
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How have some cancers "evolved" to be so aggressive and treatment-resistant?
[In this post, I may ascribe agency to processes, inanimate objects or microorganisms: this is rhetorical, I know they don't "intend" anything. I will also use "evolution" in a ...
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What is continuous selection?
I've been reading paper on ancient horse genome (Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse) and in abstract authors mention term continuous selection:...
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How much variation in mutation rate in there in the human genome?
In humans, the average mutation rate is estimated to be around $2.5 \cdot 10^{-8}$ (Nachman and Crowell, 2000). Of course this mutation varies from sequence to sequence.
Can you please give some ...
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In a fitness landscape, is fitness relative or absolute?
I was asked if the fitness of a fitness landscape is absolute or relative.
Fitness landscapes are usually graphed with a fitness function that uses either phenotypes or genotypes in relation to ...
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Learn Bioconductor the hard way!
I came to analyzing population genetics data from the background of a theoretician and a computer biologist but not with the standard tools that a bioinformatician (or empiricist in population ...
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Does an increased reproduction/mortality rate provide an evolutionary advantage?
If a species has a high mortality/birth rate, then it is able to adapt to changing environments more quickly than species that live for a long time.
Without a high mortality rate, food and other ...
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What animals have a blood-brain barrier?
I am curious about how old the BBB is, in terms of evolution. Is it present in all vertebrates? or just mammals? or what?
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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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Comparative Genomics
Are orthologs and paralogs examples of conserved genes? Orthologs are the genes or DNA that is present in 2 different species, having once been present in a common ancestor. It comes about by a ...
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Why do human ears have a lower boundary for the lowest energy perceivable signal than eyes?
I am currently hearing a lecture about human machine interaction. The lecturer is not a biologist (neither am I, we are both computer scientists), but he makes some statements about biology which I ...
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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 ...
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Why don't fish groom each other?
Fish are often plagued by external parasites, which are presumably difficult for them to remove.
There are well known cases where large fish come to coral reefs and allow smaller fish to pick off ...
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Drake's Law. What is the genome-wide mutation rate and what are the estimates?
Drake's rule
Drake's rule states that the genome-wide mutation rate is more or less constant across all species — from E.coli to the house sparrow.
Data
From what I think being Drake's original ...
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Why are the genomes of some trees so large?
For example, the current largest known genome belongs to a tree: http://motherboard.vice.com/read/the-largest-genome-ever-sequenced-belongs-to-a-tree
I have heard that this could potentially be ...
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Simulating substitution rate of neutral mutations
I am trying to computationally simulate a population based on the Wright-Fisher model I would like to get to the classic result of the neutral theory of molecular evolution that the rate of neutral ...
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Components of the concept of Developmental Noise?
Developmental noise is a concept that correspond to the amount of possible phenotypic variance of a given genotype in a given environment.
Intrinsic noise (aka Cellular noise) is a component of ...
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Lost Ability to Regenerate Body Parts during the Transition from Amphibians to Mammals
Why have higher-order animals lost the ability to regenerate body parts during evolution? Wouldn't it be better for survival? What is the evolutionary theory behind it?
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Evolution and the levels of selection
Reading Okasha's "Evolution and the levels of selection" he talks about "the levels of selection problem." There is a bit of a problem with this opening chapter because, while he talks about why the ...
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Evolution in fruits
So, I saw a video on YouTube that says the banana we eat today is not what a banana looked like years ago. Since the banana has been genetically modified over the years, does that qualify as evolution?...
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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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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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Is there any advantage of having mitochondria for aerobic respiration?
If we consider the pathway of breakdown of glucose which includes glycolysis, the citric acid cycle and the electron transport chain, all these processes takes place in some prokaryotes and ...
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Is there theory that connects longevity, time-scale of environmental disturbance, and adaptation?
I'm thinking here about environmental disturbance or like climate change-driven warming. It seems as if there are two macroevolutionary ways to deal with environmental change:
1) Have short ...
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Extraretinal photoreception in mammals? [duplicate]
A Finnish firm Valkee sells light-ear-plugs against thing such as jetlag. I asked a researcher in Aalto university how do they really work and he responded ...
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Why does the apex of the human heart usually point to the left?
In the majority of human beings, the apex of the heart (left ventricle) points towards the left side of the body. Sometimes however (approx. 1/12000 births), a person is born with a condition known ...
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How to get smallest subtree containing a set of nodes from BioPhylo?
I'm testing out various phylogenetic libraries in Python. I want to read in a Newick tree, then, given a list of taxa, generate the smallest tree that contains them all. This task is quite simple and ...
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Darwin's views on Lamarckian Heredity?
Currently I'm reading She Has Her Mother's Laugh: The Powers, Perversions, and Potential of Heredity, a fascinating book about heredity by the popular science author Carl Zimmer.
While reading this I ...
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Why do marmosets have claws when most primates don't? What is the structure of their hands like?
The majority of primates have really thick nails, though not as broad or flat as humans'. However, marmosets have 18 claws, and only their big toes have nails. What differences in evolutionary ...
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What is the most basic organism to respond to Classical conditioning (capable of learning)? [duplicate]
I have been doing some reading of Classical conditioning which is considered to be an indication of animal's ability to learn...
Before this I considered insects to be machine like - devoid of any ...
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Why do we like to touch fluffy things?
I read this article but it didn't explain much. Is the fact people like to cuddle pets with fur connected anyhow with our past when our ancestors had fur as well - and therefore could evolve an ...
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What traits make mountain goats so well adapted to mountain living?
I've never really understood how mountain goats manage to survive so well in mountainous regions. I've seen them scale almost sheer cliff faces with apparent ease, and they can almost sprint ...
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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 ...
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If evolution is a gradual and continuous process, how can we say humans came about 200k years ago? What is so special about that point in time?
It just seems arbitrary to me to say "ok, now THIS is officially a human" when you could look at its parents and find no noticeable differences. At no point in the line of my ancestral history is ...
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Soft and Hard selection
Seems to me that these two sources (M. Whitlock, B. Wallace) use different definitions of soft and hard selection.
M. Whitlock: Soft selection occurs when the relative fitness of an individual is ...
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Linkage disequilibrium with multiple alleles and loci
Linkage disequilibrium $\left(D\right)$ for two bi-allelic loci is defined as:
$$D=X_{11}X_{22} - X_{12}X_{21}$$
where $X_{11},\ X_{12},\ X_{21},\ X_{22}$ are the frequencies of the haplotypes $...
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Is there any evidence telling us what the oxidation state of early earth's atmosphere was?
I ask this question in relation to the origin of life. I realise it would probably be better suited to a geology stack exchange, but it does not yet exist.
The Miller-Urey experiment gives a lab ...
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Randomness in living systems
The point of my question is not to talk about events that are uncontrolled by living organisms. My question is about controlled randomness, or I'd like to say adaptive random process. Process that are ...
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Do some colors trigger more neural activity in human brain?
On this webpage I found this:
The study found that “globs” in the brains of monkeys reacted differently to colored
stimuli, and reacted based on color. The brain was most triggered by specific ...
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What is the biology behind human population dynamics?
A paradox: Human population growth looks a lot like a simple logistic growth pattern. But the simplest interpretation of logistic growth doesn't seem to fit. Is this peculiar to humans, or does it ...
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Why is the manchineel tree so poisonous?
The machineel tree is incredibly toxic to humans. What advantage could Hippomane mancinella have for being so poisonous? It's name even apparently translates to “little apple that makes horses mad”.
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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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