en:ecovirt:roteiro:den_ind:di_ed_base
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en:ecovirt:roteiro:den_ind:di_ed_base [2017/09/19 17:56] melina.leite |
en:ecovirt:roteiro:den_ind:di_ed_base [2022/09/19 13:42] 127.0.0.1 external edit |
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| ===== Only deaths ===== | ===== Only deaths ===== | ||
| - | Let's start with a population of $N_0$ individuals in which there are no births and no migration. Individuals die at a //per capita// [[ecovirt:roteiro:den_ind:di_rcmdr#taxa_instantanea_de_crescimento|instantaneous rate]] of $\mu = 0,693 \ \text{yr}^{-1}$. The simplest model to figure out the population size over time is the [[ecovirt:roteiro:den_ind:di_rcmdr|exponentia modell]]: | + | Let's start with a population of $N_0$ individuals in which there are no births and no migration. Individuals die at a //per capita// [[ecovirt:roteiro:den_ind:di_rcmdr#taxa_instantanea_de_crescimento|instantaneous rate]] of $\mu = 0,693 \ \text{yr}^{-1}$. The simplest model to figure out the population size over time is the [[ecovirt:roteiro:den_ind:di_rcmdr|exponential model]]: |
| $$N(t)=N_0e^{(\text{births}-\text{deaths})t} \ = \ N_0 e^{-0,693t}$$ | $$N(t)=N_0e^{(\text{births}-\text{deaths})t} \ = \ N_0 e^{-0,693t}$$ | ||
| Line 149: | Line 149: | ||
| We can test this by simulating several populations with initial size $N_0=20$ and averaging the time they take to reach $N=10$. Set the simulation to: | We can test this by simulating several populations with initial size $N_0=20$ and averaging the time they take to reach $N=10$. Set the simulation to: | ||
| - | * ''Maximum time'': 3 | + | * ''Maximum time'': 3 |
| - | * ''Number of simulations'': 1000 | + | * ''Number of simulations'': 1000 |
| - | * ''Initial size'' : 20 | + | * ''Initial size'' : 20 |
| - | * ''birth rate'' : 0 | + | * ''birth rate'' : 0 |
| - | * ''death rate'': 0.693 | + | * ''death rate'': 0.693 |
| The graph will be covered with lots of lines, but we are interested in the value of //Halving time//. Is it near the theoretical value? Now change the population initial size to 80, keeping the other options unchanged and run the simulation again. | The graph will be covered with lots of lines, but we are interested in the value of //Halving time//. Is it near the theoretical value? Now change the population initial size to 80, keeping the other options unchanged and run the simulation again. | ||
en/ecovirt/roteiro/den_ind/di_ed_base.txt · Last modified: 2022/09/19 13:43 (external edit)
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