The scientific study of short- and long-term changes in the size and age composition of populations and the processes driving these changes.
Questions tagged [population-dynamics]
170 questions
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Smallest viable reproducing population
What is the smallest viable reproducing population, such as in a human population. By viable I mean a population which keeps genetic defects low (enough).
A very strongly related question: what is the expected number of generations a given…
John Smith
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How many organisms have ever lived on Earth?
I've looked for some information on this, but couldn't find anything useful. Has there been any noteworthy attempt to estimate the sum amount of individuals of all species that have ever lived on Earth?
mo.
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What prevents predator overpopulation?
I've often heard that a population, human or otherwise, will continue to grow as long as there is food available (assuming nothing else is killing them off). It makes sense: if you have food you can live, and if nothing is hunting you you'll…
Nerrolken
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How many humans have been in my lineage? Is it almost the same for every human currently living?
If I were to count my father, my grandfather, my great-grandfather, and so on up till, say chimps, or the most common ancestor, or whatever that suits the more accurate answer, how many humans would there have been in my direct lineage?
And would it…
laggingreflex
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Why aren't native predators in Australia able to handle the mice problem?
Australia is currently dealing with a mouse infestation problem, but Australia is awash with different types of predators that presumably eat lots of mice like animals. Snakes in particular are well suited to kill mice, especially in close…
Krupip
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How many mice are on the Earth?
We are 7 billion human beings on the Earth. But how many mice are there? How would you estimate such a number?
Gianpaolo R
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Vaccination and population dynamics of an epidemic
I'm trying to figure out how should a vaccination model be built to correlate with population density, and I'm having problems to understand meanings of the results I receive when I apply theory on specific data I'm provided with.
Theory(i):
The…
Khaloymes
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What is the percentage of people living in England in 1500 AD whose lineage is still alive?
This sounds a bit random, but it stems from a lecture in statistical genetics which I attended a while ago. We were shown a population lineage graph from which it was clear that most lineages eventually go extinct. The further you go in to the past,…
Nick
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How big should the human population be, as predicted by body mass?
I would guess there is a theory in biology which states that the population size for a given species is inversely proportional to the body mass of individuals in that species. In other words, there are zillions of ants, billions of mice, millions…
SlowMagic
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When are population dynamics models useful?
When are population dynamics models useful? There seems to have been a lot of research about it, but how does it help? If I need data about how a population will evolve under what conditions, I need it because I need data for a decision (such as…
thejh
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Human genetic diversity in Africa in comparison with the rest of the world
Background
The claim ...
Most of the genetic diversity in humans is in Africa
... is quite common. On Biology.SE, it is easy to find posts that make this claim. Consider for example:
Do humans have enough biological differences to be grouped into…
Remi.b
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Is global life expectancy normally distributed?
I am trying to find out what the world distribution of life expectancy looks like.
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How does Natural Selection shape Genetic Variation?
Background
Importance of the additive genetic variance
As stated here, the fundamental theorem of Natural Selection (NS) by Fisher says:
The rate of increase in the mean fitness of any organism at any time ascribable to NS acting through changes in…
Remi.b
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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 determines the strength of selection, with weak selection…
Artem Kaznatcheev
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Expected time for a neutral allele to reach a frequency of $p_1$ when starting at frequency $p_0$
Kimura and Ohta (1968) showed that the expected time for a neutral allele to reach fixation (given that it will reach fixation) is
$$\bar t(p_0)=-4N\left(\frac{1-p_0}{p_0}\right)\ln(1-p_0),$$
where $p_0$ is the initial frequency and $N$ is the…
Remi.b
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