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-...
- 47.2k
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 $i$) ...
- 1,721
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{...
- 1,925
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 ...
- 13.9k
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 ...
- 5,589
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 ...
- 337
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 ...
- 5,589
5
votes
How much land would dinosaurs have actually needed?
The estimate for t-rex is 100 square kilometers of land per animal. Given the land area over which we find t-rex fossils the estimated population at any on time is ~20,000 individuals.
there is a ...
- 15.4k
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/...
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 ...
- 931
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 ...
- 10.5k
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 ...
- 41
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 ...
- 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
...
- 2,359
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) = \...
- 393
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 ...
- 6,997
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 ...
- 68.3k
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 ...
- 535
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 ...
- 16.8k
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 ...
- 435
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 ...
- 5,589
2
votes
Calculation of Malthusian fertility and mortality from birth and death rates
If every member of the population breeds, the mean number of children born from a single individual during their whole life is $\beta$ times the duration of their life. The mean life duration is $1/\...
- 131
2
votes
Human Demography - Where can I find this statistic?
The CDC has some good stuff. http://www.cdc.gov/nchs/data/nhsr/nhsr051.pdf
But keep in mind that number from your book is likely based on yearly findings in which more than half the women would not ...
- 15.4k
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, ...
- 88
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
...
- 10.8k
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 ...
- 10.8k
2
votes
Is it mostly true that predators or parasites traverse wider spatial areas than their prey or hosts?
The ability of prey to find refuge in predator-free habitats is a fundamental hypothesis for predator-prey stability. The availablility of predator-free patches allows the prey metapopulation to ...
- 176
2
votes
Accepted
Is there a reliable estimate of the number of cells on Earth?
Okay so I looked around a bit, and there are surprisingly few papers related to this question.
This paper is the best I cold find, but it's almost 20 years old. There's also this one, which slightly ...
- 4,401
2
votes
How can I measure bee and wasp population?
Short Answer
No. You cannot appropriately examine population dynamics using the approach you've described.
You can, however, examine how foraging frequencies vary/correlate with field spraying (...
- 30.4k
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