Respuesta :
Populations that exhibit a logistic growth model fluctuate around their carrying capacity point. 1) the population increases in size. 2) the population fluctuates around 100 individuals. 3) K = 100 individuals.
What is the logistic growth model?
In the logistic growth model, population growth depends on density. Natality and mortality depend on the population size, meaning there is no independence between population growth and population density.
When a population grows in a limited space, density rises gradually and, eventually, affects the multiplication rate.
The population per capita growth rate decreases as population size increases.
The population reaches a maximum point delimited by available resources, such as food or space. This point is known as the carrying capacity, K.
K is a constant that equals the population size at the equilibrium point, in which the natality and the mortality rate get equal.
Assuming that the population size is N, when
- N<K, the population can still grow.
- N approximates to K, the population's growth speed decreases.
- N=K the population reaches equilibrium,
- N>K, the population must decrease in size because there are not enough resources to maintain that size.
The sigmoid curve represents the logistic growth model.
The carrying capacity might be affected by different factors, known as limiting factors, which might be a result of the population density (for example, competition) or might be density-independent.
Dense-independent factors might be human impact or natural disasters (fires, volcanic eruption, flooding).
According to the information provided in the exposed example,
→ Before 1962 approximately 75 and 100 lions were living in Ngorongoro Crater, Tanzania.
→ In 1962, unusually heavy rains occurred, causing the massive build-up of blood-sucking flies in the crater.
→ These flies attacked several lions, and many individuals got infected and sick, ending in death.
→ Lions population sharply decreased between 1962 and 1963 to only 12 individuals.
According to this research,
- between 1950 and 1962 the lions' populations fluctuated between approximately 68 and 92 individuals.
- between 1962 and 1963 the lions' population size decreased from 70 individuals to 12.
In this example, we can see how the occurrence of dense-independent factors such as heavy rains during the dry season caused the emergence of blood-sucking flies, which negatively interacted with lions and decreased their carrying capacity point.
1. Draw a graph of your predictions of the lion population after 1963.
To answer this question, we will assume that after this unusual event, the fly population returned to normal levels, and the surviving lions got to reproduce again.
We will also assume that, after these heavy rains, the crater was full of available resources.
Under these assumptions, we expect the lions' population to grow until reaching a new carrying capacity. The reproductive rate is expected to be higher than the mortality rate.
Since there are more available resources, we expect this new carrying capacity to be higher than during the period 1950-1962.
You will find this graph in the attached files. Remember this is only an estimation of what might occur, so the red line does not represent real data, just a prediction of population growth until reaching a new K point.
2. Draw a graph of your prediction of the lion population from 1980-2012.
Assuming this lions' population is not affected by any other anusual event, we will predict that from 1980 to 2012 this group fluctuated around 100 individuals.
You will find the graph in the attached files. Remember the red line is a prediction, it does not represent real data.
3. Draw a predicted carrying capacity on this second graph.
We expect the new carrying capacity to be arround 100 individuals, so this is the new K. It is represented with a thinner red horizontal line.
You will learn more about the logistic growth model at
https://brainly.com/question/15631218
https://brainly.com/question/2102628
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