14 votes
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Is global life expectancy normally distributed?

Let's see! I took the most recent WHO data from here and did a quick an dirty analysis in R. Here is the histogram as well as a normal distribution with the same mean and standard deviation as the ...
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  • 1,234
9 votes

What is called the "area size that an animal usually lives in"?

Are you looking for 'Home range' (see also the definition in Encyclopaedia Britannica)? Generally, 'home range' is defined as the entire area an individual animal uses, while the 'territory' is the ...
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9 votes

How is (Insect) population control through male sterilization effective

Sterile insects are typically produced by radiation. A sufficient dose is used to cause substantial DNA damage in the gametes of the males. However, this doesn't mean the sperm are completely non-...
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  • 36k
8 votes

Effect of sex-ratio on the effective population size

The reason that an unequal sex ratio affects the effective population size is because offspring are produced by one male and one female parent, and an unequal sex ratio increases the rate at which ...
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  • 16k
7 votes

To what extent is immature eggs in insects (beetles) a good approximation for maximum fecundity?

There are a number of things to clarify here; Fecundity is the number of offspring that is produced by an individual, and this can be separated into potential fecundity (maximum reproductive capacity) ...
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7 votes

Exponential growth equation and bacteria

Considering your assumption: I'm just looking at the exponential part, where the simple exponential equation works. If we assume there's sufficient nutrients for bacteria to grow unchecked for ...
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7 votes
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Understanding expected mean number of breeding seasons

It's just a continuous version of the discrete calculation. The discrete version is the (infinite series) sum $$ \sum_{i = 0}^\infty S^i \cdot bp $$ adding up every (chance of survival to season $i$) ...
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  • 1,699
7 votes

Understanding expected mean number of breeding seasons

I think your explanation is correct. The expected value of the exponential distribution is: $$t \sim \text{e}^{-\lambda t} \implies \langle t \rangle = \int_0^\infty t \ \text{e}^{-\lambda t} \; \text{...
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  • 759
6 votes
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How should species density be calculated for a clumped distribution?

To me, there are two issues that are mixed up here (if I understand you correctly). First, do you want to estimate the mean and variance for a statistical population (i.e. to characterize a larger ...
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6 votes
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Viruses in human history

We don't know a whole lot about the direct evolution of the genomes of many viruses yet, though as methods for recovery of ancient nucleic-acid sequences improve, I would expect to see increases in ...
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  • 6,918
5 votes
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What is called the "area size that an animal usually lives in"?

To avoid confusion I just want to add to fileunderwater's answer the equivalent words we use to describe the "area size a population/species lives in". The spatial range a single individual occupies ...
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5 votes
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Defining: Evolutionary (quantitative) Genetics and Population Genetics

According to Hartl & Clark on population genetics: "Population genetics deals with Mendel's laws and other genetic principles as they apply to entire populations of organisms.... also ...
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5 votes
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Various Genetic Loads and their Definitions

The genetic load is a population construct, a way of quantifying the fitness reduction in a population due deviations from the optimal genotype. One type of load comprises all the others, namely ...
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5 votes
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Why does the number of mutations per individuals follow a Poisson distribution?

A Poisson process follows these postulates: $\lim\limits_{h\to0+}\frac{P(N_h=1)}h=\lambda$ i.e. the probability of occurrence one event in a very small interval of time is equal to the macroscopic ...
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5 votes
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Mathematical model about the relationship between two animal species

The model you present here is a special case of the Lotka-Volterra competition equations, where the two species have the same effect on each other (i.e., symmetric competition). Some things to think ...
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  • 4,846
5 votes

What happens to male turkeys?

This article from the humane society suggests that the male-female ratio in wild turkeys is generally 1:1 1. It's likely that nothing 'happens' to the male turkeys. Possibly you and your family may be ...
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5 votes
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Can SARS-COV2 strain competition be modelled by inter-species lotka volterra equations?

Presumably by "interspecies Lotka-Volterra equations" you mean the L-V competition equations (the predator-prey version is much better known). Let's start with a two-strain epidemiological ...
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  • 4,846
4 votes
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Coalescent theory - independence of coalescent times

As long as members of a generation "randomly choose" their ancestor in the previous generation the law of independent probability (your equation) will hold. Any study of coalescent theory ...
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  • 2,759
4 votes
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Inbreeding depression and dominance

Recap of the question: Looking at a single locus trait ($A$) controlled by two alleles, $A_1$ and $A_2$, the phenotypic mean is only affected by inbreeding depression, $f$ (Wright's inbreeding ...
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  • 16k
4 votes
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Why do genetic drift generates negative linkage disequilibrium?

Genetic drift is the change of allele frequencies in a population due to random sampling during reproduction. This can cause some allele combinations to become more or less common than would be ...
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4 votes
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Fixation rate at neutral loci

First of all, the $\mu$ is not expected time for a mutation to occur and get fixed; it is the rate at which mutations are fixed in the population. The basic result states that if neutral mutations ...
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  • 1,771
4 votes
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How many eukaryotes are there on Earth?

Could not fit in a comment.... To make sure we all understand your question... Is your question how many (eukaryote) species are currently living? or ...
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  • 67.5k
4 votes

Evolution: One big population vs. many small populations

Note: This is not an area where I know the litterature well Where are many counteracting processes to consider for this question. For instance, the rate of evolution will be affected by the rate of ...
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4 votes

How could one calculate the gene flow between two populations?

Theoretical Background From Slatkin 1991, at equilibrium $$F_{ST} = \frac{1}{1+4Nm\left( \frac {d}{d-1} \right) ^2}$$ , where $N$ is the per island population size, $m$ is the migration rate and $d$...
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4 votes
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What is the global average BMI?

The answer might be a little late, but it was published after you asked the question. See the following publication for estimated global BMI averages from 1975 to 2014: http://thelancet.com/journals/...
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4 votes

Is global life expectancy normally distributed?

A few people thought it would be interesting to see what the distribution looked like if we plotted the number of people dying at each age, so I took data from the SSA (which admittedly isn't global ...
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  • 460
4 votes
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What are the migratory patterns of Orcas in the Pacific Northwest? Do they pass by Vancouver in the Fall?

There are three ecotypes of orcas which are all members of the same species but tend to display different behaviours, communicate differently and have different prey preference. The most common ...
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  • 891
4 votes

Have there ever been as many mammals as there are now?

There can be perhaps 10 trillion rodents and bats on the planet, so the humans and livestock probably are small compared to a rainforest rodents and bats. The biggest bat colony is 40 million, they ...
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4 votes

Value of r (intrinsic rate of natural increase)

NCERT shows per capita value is divided by 1000, not hundred (%). So the data you see is 22.50 per thousand! So, the per capita rate is 22.50/1000 = 0.02250 that is almost equal to 0.0205 given in ...
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4 votes

What proportion of the people who lived 1000 years ago have genetic descendants alive today?

Expanding on @heracho's answer and Wikipedia, assume pi denotes the probability of having (exactly) i children, and that dm denotes the probability of extinction by the mth generation (note that this ...
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