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-...
Bryan Krause's user avatar
  • 45.3k
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 ...
rg255's user avatar
  • 16.1k
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 ...
WYSIWYG's user avatar
  • 35.5k
7 votes
Accepted

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 $i$) ...
Armand's user avatar
  • 1,711
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{...
Domen's user avatar
  • 1,929
6 votes
Accepted

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 ...
bob1's user avatar
  • 11.6k
5 votes
Accepted

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 ...
Ben Bolker's user avatar
  • 5,354
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 ...
MZiegenhorn's user avatar
5 votes
Accepted

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 ...
Ben Bolker's user avatar
  • 5,354
4 votes
Accepted

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/...
Conrad Zygmont's user avatar
4 votes
Accepted

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 ...
hamilthj's user avatar
  • 921
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 ...
bandybabboon's user avatar
  • 10.4k
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 ...
YASH PATHAK's user avatar
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 ...
Kahovius's user avatar
  • 141
4 votes
Accepted

What are the long term consequences of settling an isolated territory with an extremely limited gene pool?

Minimum number of individuals needed to start a population But could just one woman be the progenitor of a healthy nation? And, if not, what is the minimum number of distantly-related individuals ...
user438383's user avatar
  • 2,351
4 votes

Is it possible to determine the initial population given the final one?

For the logistic equation, $$\frac{\mathrm{d}N(t)}{\mathrm{d}t} = rN(t)\left(\frac{K - N(t)}{K}\right)$$ the solution that allows you to calculate population population size at any time is: $$N(t) = \...
Chris Moore's user avatar
4 votes
Accepted

Which approach is the common one in the literature for determining the bacterial growth rate?

The simple logistic function that you are using here is a fine first-order approximation for modeling microbial growth. Both logarithmic and linear scales are reasonable, with different tradeoffs as ...
jakebeal's user avatar
  • 6,977
3 votes
Accepted

Accurate surveys of urban pigeon and bird populations

You can find population data for lots of species at The Global Population Dynamics Database, which can be used to test and fit population models. When searching for Columbidae (the dove family) I find ...
fileunderwater's user avatar
3 votes
Accepted

Predator prey interaction

I disagree with GForce's explanation; the meaning is not that growth of prey populations causes instability in predator species. The sentence is merely saying that without predation, prey population ...
rg255's user avatar
  • 16.1k
3 votes

doubt with a multiple choice question

I don't know if this is just me, but I'd consider this a pretty badly worded question. For models of population dynamics, the rate at which the size of a population changes over time is normally ...
arboviral's user avatar
  • 3,344
3 votes
Accepted

What type of Interspecific relationship does this graph depict?

Competition makes the most sense, IMO. For every other type of relationship, A and B should be dependent and roughly proportional: If parasites kill their host, they die in proportion. If predators ...
CKM's user avatar
  • 8,111
3 votes

How has the use and subsequent ban of DDT affected insect populations?

The most thorough study on the matter appears to be entitled "Anthropogenic impacts on mosquito populations in North America over the past century". Their broad conclusion is that various mosquito ...
user42909's user avatar
  • 535
3 votes

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

There are three seminal works that will give you an excellent grounding in the study of dynamical systems in population biology. The first details the foundations of population genetics: Crow, ...
Michael Andrew Bentley's user avatar
3 votes
Accepted

Value of r (intrinsic rate of natural increase)

From the UN database (this info is also reported on wikipedia), the growth rate in India in 2016 was $r=1.019$. It is computed as $r = \frac{N_{2017}}{N_{2016}}$, where $N_{y}$ is the population size ...
Remi.b's user avatar
  • 68.1k
3 votes
Accepted

How many giant kelp are there per square meter?

The density of Macrocystis pyrifera is pretty variable. According to Dayton et al. 1984 off of the Southern California coast it can range from less than 0.1 to to 1.0 $individuals/m^2$. The variation ...
Shawn's user avatar
  • 425
3 votes
Accepted

Finding population dynamics models for multi-generational species evolution with delays

You use the word "evolution" here to mean "change in populations over time", as is typical in (say) astrophysics (or, I guess, economics?). My initial comments and suggestions were ...
Ben Bolker's user avatar
  • 5,354
2 votes

Software to calculate Fst from sequence data

If You are familiar with R, try package adegenet. It contains very nice tutorials explaining its usage, including the very R basics. If You require graphical interface, install RStudio - very nice ...
Tilia's user avatar
  • 201
2 votes
Accepted

$F_{ST}$ when considering a multi-allelic locus

Short answer: yes, people have formulated ways to estimate $F_{ST}$ for multiallelic loci, e.g. microsatellites. For a review, see here. Specifically, Nei could define $F_{ST}$ for multiple alleles as ...
Maximilian Press's user avatar
2 votes

What percentage of the fitness variance is explained by the 'n'- most important loci?

This should be taken less as a holistic answer than as a case study describing an extreme example of very strong selection in a particular environmental context, yielding a particular natural ...
Maximilian Press's user avatar
2 votes

Expected reproduction rate of a dandelion and/or fern

Dandelions may have "from 54 to 172 seeds per head and a single plant can produce more than 2000 seeds" (https://fyi.uwex.edu/weedsci/2002/11/12/dandelion/), but the number of inflorescences depends, ...
Olga Świder's user avatar

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