Questions pertaining to populations of organisms.

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Predator prey interaction

I went through a line in my text book which read 'But for predators, prey species could acheive very high population densities and cause ecosystem instability'... I was not able to intrepret the ...
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What is the effective population size of a simple two deme metapopulation?

I am confused as to how to compute the effective population size $N_e$ of a theoretical structured population. Let's consider here a simple case study. Imagine a 2-deme metapopulation. Each deme is ...
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doubt with a multiple choice question [closed]

Permanent decrease in population would occur due to- A) Migration B) Natality C) Emigration D) Mortality E) Territoriality . It's obvious that C) & D) options are possible . But I'm confused ...
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Ecological specialization and relative abundance

I am reading Evolution in Changing Environments by R. Levin but have a hard time. Claim At page 25, Levin says as a conclusion The more efficient a caste at meeting the contingency for which it ...
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36 views

Relationship between genetic diversity within and between species

Here is a quote from Wagner (2008) A second line of evidence [against neutralism] comes from the relationship between the mean number of polymorphic differences between alleles within a species, $\...
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2answers
53 views

Exponential growth equation and bacteria

I'm a microbiologist, but I'm teaching some ecology in my intro-level course, so when we got to population growth, I thought I'd use the example of a microbial population. But, I hit a strange problem ...
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1answer
83 views

Guide to learning about Population biology / ecology / dynamics for a non-Biologist

I'm an applied mathematician who works in the field of feedback control systems but has been becoming interested in looking at population biology (e.g. Lotka-Volterra, Mathusian growth,etc.) from a ...
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Effective population size of a continuously spread population

Is there any model to calculate (theoretical predictions) the effective population size of a continuously spread population? Imagine for example a population spread over an infinite 2D landscape. ...
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Effective population size of a metapopulation structured on a grid

Scenario Consider a rectangular metapopulation consisting of $x \cdot y$ demes, where $x$ is the number of deme horizontally and $y$ is the number of demes vertically. The population size per deme is ...
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35 views

Hardy-Weinberg equilibrium generalized to add inbreeding (non-random mating)

Background Quoting from Gillespie's book The level of inbreeding is measured by the inbreeding coefficient, $F_I$, which is the probability that two alleles in an individual are identity by ...
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Evolution of parasite into ideal parasite [duplicate]

An ideal parasite is a parasite which thrives within a host without harming it (according to my NCERT textbook). Then, quite obviously, why hasn't that happened yet? I mean, natural selection can ...
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75 views

What type of Interspecific relationship does this graph depict?

The other day in class, our AP Biology teacher presented us with the following graph and asked us to determine which of the following interspecific relationships it represents: (A) ...
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Effect of sex-ratio on the effective population size

As stated on this wikipedia article, the effective population size $N_e$ when the sex ratio differs from $\frac{1}{2}$ is $$N_e = \frac{4N_mN_f}{N_m+N_f}$$ I understand the biased sex-ratio ...
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63 views

How many fish are there? [closed]

I am trying to research the estimated population of certain fish throughout time. The fish I cannot seem to find out what I want to know are: Tilapia; Trout; Salmon; Tuna; and Anchovies. Sources that ...
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1answer
45 views

Parametric Bootstrap Capture Recapture

I am using the (one sample) capture recapture for estimating hidden human population. One sample method uses purely frequencies of capture to estimate population. One of my colleague suggested ...
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62 views

Population growth curve for rabbit without predation [closed]

What should a growth curve look like when a rabbit population is introduced on an uninhabited island without predation or disease or natural calamity and plenty of food? The answer seems to be given ...
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1answer
46 views

What do “reduced antipredator defense” and “reduced antipredator vigilance” mean?

The book BIOMAT 2010 (International Symposium on Mathematical and Computational Biology, edited by Rubem P. Mondaini) mentions the terms reduced antipredator defense and reduced antipredator vigilance....
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60 views

How to determine the relationship of competition or cooperation?

I am currently studying the interaction of Twitter memes (two or many), such as competition and cooperation. Is there any model or method in biology that can identify the types of the relationship, ...
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257 views

Examples of prey predator interactions where density of predator is very low and prey form groups when the predator attacks the prey for food

Examples of prey predator interactions where density of predator is very low (has a threat of extinction) and prey form groups when the predator attacks the prey for food. I have searched this in ...
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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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1answer
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Where can I find a global life expectancy table?

I've found good information on specific countries and demographics, but I can't seem to find global numbers. I know that the world life expectancy is around 71.0, but I'm trying to get a percentile ...
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1answer
233 views

What is the global average BMI?

I have been looking for hours trying to find this number, and can't seem to get a straight answer. I've seen some studies that calculate the change in BMI, but for some reason they don't give you the ...
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2answers
85 views

Is it possible for two people to repopulate earth? [closed]

Today I was wondering this question whether it is possible for two people to repopulate Earth. What if everyone else disappeared, except for two people (man & woman)? Can they repopulate? In ...
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51 views

Who was the first to coin the terms of soft and hard selection?

Soft and hard selection are sometimes used with different definitions. I have been told that at first place hard and soft selection has been defined in the following way: soft selection: Each deme ...
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Variance in reproductive success and effective population size

Background The effective population size $Ne$ is the size of the Wright-Fisher population that experience the same amount of drift than the population under consideration. The higher the variance in ...
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1answer
39 views

What is the distribution of the number of heterozygotes in finite populations?

Consider a bi-allelic locus with alleles A and a. We denote the frequency of the A allele by ...
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1answer
50 views

How do we call a region of low carrying capacity?

I am looking for a convenient word to define a region of the landscape where the local carrying capacity (population size) for a given species is low but different from zero. The species is still ...
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95 views

How could one calculate the gene flow between two populations?

Imagine there are two populations X and Y, and for each population you have the genotypes of each individual in that population (e.g. Aa, AA, aa, etc.), but for multiple loci (e.g. AABb). How could ...
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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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Variance in Fst in the infinite island model

The most famous result in the study of structured populations come from Sewall Wright. He showed that in an island model, where each subpopulation is of size $N$ and the migration rate is $m$, then ...
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2answers
128 views

Within and Between Allelic Class Diversity

I am reading Charlesworth et al. 1997. They talk about diversity within and between allelic classes. Nucleotide diversities ($π$) at each neutral site were estimated from the mean of $2 \sum z_t (...
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1answer
197 views

Why does the number of mutations per individuals follow a Poisson distribution?

I was reading this review. On page 11, left column, first paragraph, one can read: [..] there is a Poisson distribution of the equilibrium number of mutations per individual, if fitness effects ...
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Understanding F-statistics in population genetics

I am reading a classical Weir and Cockerham 1984 paper about Fst estimation. At the beginning (first page, right column), they define 3 statistics. $F$ is the correlation of genes within individuals ...
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Expected reproduction rate of a dandelion and/or fern

I am working a basic mathematical/computer simulation of an ecosystem, and I need to know the birth rate of each organism in my simulation. However, I could not find any data for how often a small, ...
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3k views

How should species density be calculated for a clumped distribution?

Lets imagine 5 plots of different size are sampled for a target species: ...
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303 views

Was the recent “conservation hunt” of a black rhino supported by science?

CNN recently covered a sanctioned black rhino hunt in Namibia by Texan Corey Knowlton, who bid US$350,000 for the license. In the story, he claims that the hunt was actually supporting conservation of ...
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Analytical Methods for Estimating Probability of Fixation

The probability of fixation $P$ of an allele is an very important measure and there exists several solutions to estimate this probability. Each method has its own assumptions and it is often hard to ...
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1answer
93 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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63 views

Human population growth - where can I find the data?

Out of curiosity, I'd like play around with data of human global demography. Where can I find data that describe the "per region (per continent for example) population size" versus time since the "...
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200 views

Recessive alleles at Hardy-Weinberg equilibrium

I've run into a question that I disagree with others on but I would like to receive the input of others. The question is: If a population is at Hardy-Weinberg equilibrium, which of the following can ...
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1answer
37 views

Literature that demonstrates organisms have a competitive advantage in numbers

I'm studying two bird populations that are competing against each other for a resource: Population A and Population B. Population A is present in much higher numbers than Population B, and as a ...
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258 views

What sample sizes are ideal for carrying out Bayesian Skyline Plots?

I am interested in creating Bayesian Skyline Plots to look at demographic changes in certain population groups. However, these populations have very little within population variation. Around 5 ...
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151 views

Fixation rate at neutral loci

It is a classical result that the expected time for a neutral mutation to occur and to get fixed is $2 N \mu \frac{1}{2N} = \mu$, where $N$ is the population size and $\mu$ is the neutral mutation ...
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315 views

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

What is called the "area size that an animal usually lives in" or "needs for a normal life"? Is there any specific term?
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Why does death exist? [duplicate]

The biological purpose of an organism is to reproduce and as soon as reproductive age is passed, aging kicks in and eventually leads to death. (This is what I learned from a gerontologist.) But then, ...
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1answer
248 views

How do you convert mtDNA sequences in FASTA to FSTAT format?

I've got control region sequence data from a population of shark and I'm looking to convert this from FASTA to FSTAT in order to calculated the effective population size of females. The software I ...
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1answer
87 views

Mutation Rate in Multicellular Eukaryotes

I always hear people saying that the mutation rate is around $10^{-6}$ or $10^{-7}$. I don't even know if this number is the mutation rate of genes or of a single nucleotides and I actually (almost) ...
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81 views

How does the population fitness changes after a change in mutation rate

The mean population fitness as given by mutation load theory depends only on the genome-wide mutation rate ($U$). My question is: how many generations is needed to reach a new mutation load ...
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3answers
378 views

Evolution: One big population vs. many small populations

Let's say I want to evolve a bacterium that is resistant to an antibiotic. I want to do this by growing initially clonal populations of bacteria in presence of this antibiotic for a long time. I have ...
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241 views

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 ...