/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 26 Find the recursion for a populat... [FREE SOLUTION] | 91Ó°ÊÓ

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Find the recursion for a population that has a reproductive rate of \(1 / 3\) and that has 63 individuals at time \(0 .\)

Short Answer

Expert verified
The recursion formula is \( P_{t+1} = P_t \times \frac{1}{3} \) with \( P_0 = 63 \).

Step by step solution

01

Understanding the problem

We are tasked with finding the recursion formula for a population where the reproductive rate is \( \frac{1}{3} \) and the initial population size at time \( t = 0 \) is 63 individuals. Our goal is to create a formula that represents the population size at any time \( t \).
02

Define variables

Let \( P_t \) represent the population at time \( t \). Given that the initial population \( P_0 = 63 \). The reproductive rate is given as \( \frac{1}{3} \).
03

Establish the recursive formula

Since the population grows by the factor of the reproductive rate each unit of time, the population at time \( t+1 \) can be expressed as:\[P_{t+1} = P_t \times \frac{1}{3}\]
04

Base case

We know that initially, at time \( t = 0 \), the population size is \( P_0 = 63 \). This forms the base case required for our recursive formula.
05

Recursion formula result

Therefore, the recursive formula for the population size is:\[P_{t+1} = P_t \times \frac{1}{3}, \quad P_0 = 63\]This formula can be applied iteratively to determine the population size at any future time \( t \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Recursive Formula: Unraveling the Sequence
The concept of a recursive formula is a cornerstone in understanding how sequences evolve over time. In the context of population dynamics, a recursive formula defines how the population size at one point in time relates to the population size at the previous point. This type of formula is uniquely powerful because it helps model the changes in a population systematically from one time period to the next.

In our original exercise, we established the recursive formula as:
  • \[P_{t+1} = P_t \times \frac{1}{3}\]
This formula tells us that to find the population at time \( t+1 \), we multiply the current population \( P_t \) by the reproductive rate \( \frac{1}{3} \). This simple yet effective calculation allows us to predict the population size at any future time by consistently applying the formula. Recursive formulas are particularly helpful in scenarios with consistent proportional changes, as they provide a reliable method for calculating sequences without needing explicit formulas for each period.
Reproductive Rate: Understanding Population Growth
The reproductive rate is an essential factor in determining how a population grows or shrinks over time. It specifies the factor by which a population size changes in each time unit, such as a year or month. Knowing the reproductive rate allows scientists to predict whether a population is growing, shrinking, or remaining stable.

In our exercise, the reproductive rate is \( \frac{1}{3} \). This means that the population size is one-third of its previous size each time unit. This reproductive rate suggests a declining population, as the population decreases to a third of its size each period. The reproductive rate helps us understand the speed and direction of population changes. It's crucial in fields like ecology, conservation, and resource management, where understanding population patterns can be vital for decision-making processes.
Initial Population Size: The Starting Point
Initial population size is the starting level of a population at the beginning of observation, typically noted as \( P_0 \). It's a vital component in any population dynamics model, as it acts as the baseline from which population changes are measured over time. Understanding the starting point allows for accurate modeling and predictions.

In our scenario, the initial population size is 63 individuals at time \( t = 0 \). This number serves as the anchor for our recursive calculations, providing a reference point for all future changes modeled by our recursive formula. Whether you're working with wildlife populations, bacterial growth in a lab, or even studying human demographics, knowing the initial population is crucial for realistic and meaningful forecasting.

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Most popular questions from this chapter

Because of complex interactions with other drugs, some drugs have zeroth order elimination kinetics in some circumstances, and first order kinetics in other circumstances, depending on what other drugs are in the patient's system, as well as on age and preexisting medical conditions. Use the data on how concentration varies with time to determine whether the drug has zeroth or first order kinetics. Given the following sequence of measurements for drug concentration, determine whether the drug has zeroth or first order kinetics. $$ \begin{array}{lcccc} \hline \boldsymbol{t} \text { (Hours) } & 0 & 2 & 4 & 6 \\ \hline \boldsymbol{c}_{t}(\mathbf{m g} / \mathbf{m l}) & 40 & 36 & 32.4 & 29.16 \\ \hline \end{array} $$

Because of complex interactions with other drugs, some drugs have zeroth order elimination kinetics in some circumstances, and first order kinetics in other circumstances, depending on what other drugs are in the patient's system, as well as on age and preexisting medical conditions. Use the data on how concentration varies with time to determine whether the drug has zeroth or first order kinetics. Given the following sequence of measurements for drug concentration, determine whether the drug has zeroth or first order kinetics. $$ \begin{array}{lcccc} \hline \boldsymbol{t} \text { (Hours) } & 0 & 1 & 2 & 3 \\ \hline \boldsymbol{c}_{t} \text { (mg/liter) } & 16 & 12 & 9 & 6.75 \\ \hline \end{array} $$

Saving the Kakapo You are modeling the size of the population of kakapo (a rare flightless parrot) in an island reserve in New Zealand. You want to use the mathematical model to predict the size of the population. The data in this question are taken from Elliot et al. (2001) (a) You start by writing a word equation relating the population size \(N_{t}\) in year \(t\), that is, \(t\) years after the study began, to the population size \(N_{t+1}\) in the next year. umber of birds number of birds that \(N_{t+1}=N_{t}+\begin{array}{l}\text { number } 6 \pi \text { in } \\ \text { born in one vear }\end{array}\) die in one ve We will derive together formulas for each of these terms (i) To estimate the number of birds born, assume that half of the birds are female. A female bird lays one egg every four years. However, because of the large numbers of predators (mostly rats) only \(29 \%\) of hatchlings survive their first year. Explain how based on this data our prediction for the number of births is: \(N_{t} \cdot 0.5 \cdot 0.25 \cdot 0.29=0.03625 \cdot N_{t}\) (ii) Kakapo life expectancy is not well understood, but we will assume that they live around 50 years. That is, in a given year, one in fifty kakapo will die. What is the corresponding number of deaths? (iii) Assume that the starting population size on this island is 50 birds (i.e., \(N_{0}=50\). Calculate the predicted population size over the next five years (i.e., calculate \(N_{1}, N_{2}, \ldots, N_{5}\) ). (iv) When (if ever) will the population size reach 100 birds? What about 200 birds? (You will find it helpful to derive an ex plicit formula for the size of the population \(N_{\mathrm{t}}\). (b) Using your model from part (a) you want to evaluate the effectiveness of two different conservation strategies: (Strategy 1) If the kakapo are given supplementary food, then they will breed more frequently. If given supplementary food, then rather than laying an egg every four years, a female will lay an egg every two years. (Strategy 2) By hand-rearing kakapo chicks, it is possible to increase their one year survival rate from \(29 \%\) to \(75 \%\). (i) Write down a recurrence equation for the population size \(N_{t}\) if strategy 1 is implemented. Assuming \(N_{0}=50\), calculate \(N_{1}\), \(N_{2}, \ldots, N_{5}\) (ii) Write down a recurrence equation for the population size \(N_{t}\) if strategy 2 is implemented. Assuming \(N_{0}=50\), calculate \(N_{1}\), \(N_{2}, \ldots, N_{5}\) (iii) Which conservation strategy gives the biggest increase in population size?

Investigate the behavior of the discrete logistic equation $$ x_{t+1}=R_{0} x_{t}\left(1-x_{t}\right) $$ Compute \(x_{t}\) for \(t=0,1,2, \ldots, 20\) for the given values of \(r\) and \(x_{0}\), and graph \(x_{t}\) as a function of \(t .\) \(R_{0}=2, x_{0}=0.2\)

The sequence \(\mid a_{n}\) \\} is recursively defined. Compute \(a_{n}\) for \(n=1,2, \ldots, 5\) $$ a_{n+1}=-2 a_{n}, a_{0}=1 $$

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