lab 6 intro
TRANSCRIPT
![Page 1: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/1.jpg)
Lab 6 Population Growth Model
Dr. Davenport
![Page 2: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/2.jpg)
Objectives
• To understand the population growth models under different conditions.
– Geometric population growth– Exponential population growth– Logistic population growth
![Page 3: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/3.jpg)
Geometric Growth• When generations do not overlap and there is no
resource limitation, growth of a population can be modeled geometric population growth
• (such as annual plant…)
Nt = No t
– Nt = Number of individuals at time t.– No = Initial number of individuals.– = Geometric rate of increase.– t = Number of time intervals or generations.
3
![Page 4: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/4.jpg)
11_03.jpg
4
![Page 5: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/5.jpg)
Exponential Growth• When a population is a continuous population (does have
generation overlap), and in an unlimited environment this population growth can be modeled as exponential population growth
dN/dt = rN
• dN/dt = the rate of population growth.• r= per capita rate of increase.• N = population size• It is appropriate to model the over-lapping generation,
continuous population under unlimited environments.
5
![Page 6: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/6.jpg)
11_05.jpg
6
![Page 7: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/7.jpg)
11_07.jpg
7
![Page 8: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/8.jpg)
• However, the exponential growth cannot continue indefinitely.
• The limited environmental resources will slowdown the population growth.
• The effect of the environment on population growth is reflected in the shapes of population growth curves.
8
![Page 9: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/9.jpg)
Why does population growth slowdown????
• limited environmental resources will slowdown the population growth. ---- but why????
• When environmental resources become limited, the individuals in the population will compete with each other for limited resource. This competition will slowdown the population growth.
![Page 10: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/10.jpg)
Logistic Population Growth
• As resources are depleted, population growth rate slows and eventually stops: logistic population growth.
dN/dt = rN(1-N/K)
– Carrying capacity (K) is the number of individuals of a population the environment can support.
– Finite amount of resources can only support a finite number of individuals.
10
![Page 11: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/11.jpg)
Logistic Population Growth
11
Sigmoid (S-shaped) population growth curve.
![Page 12: Lab 6 intro](https://reader035.vdocument.in/reader035/viewer/2022081414/58849b5c1a28ab26058b6611/html5/thumbnails/12.jpg)
• So, dN/dt = rN(1-N/K)• Represent the effects of competition on
population growth.
• Which term in the model describe the intraspecific competition???
• N/K