Chapter+Seven

Chapter Seven Populations: Characteristics and Issues

Please watch the video on population. The first three of you can watch and then ask to questions each...then the rest of you should answer those questions.

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Freddie Kelcie: What was the reason behind first introducing the wolfs to Yellowstone? What causes Stage 3 animals to have a lower survival rate? The reintroduction of grey wolves into Yellowstone National Park was due to the dangerously high elk population, which the wolves hunt, and the dangerously low total population of wolves.

Max: What type of survivorship curve do humans represent, why? Explain the Population terms, K, R and N. K is the carrying capacity of a population how many individuals an area can support, R is the rate of growth in a population, so how fast a population increases or decreases, and N is the number of individuals that make up the population, how they are distributed, and how densely they are in any area. What type of population growth do humans represent, and what factors have lead to this pattern? Humans exhibit a logistic growth population. This means that our population will increase steadily until resources become too limited for increase to be possible, and the death rate will equal the birth rate, causing the R to become zero. Eventually our population will even out and stop increasing or decreasing. What is an ecological footprint? The ecological footprint of our population is when the population increasing, the amount of food produced bas to increase proportionally, and since our population is, food production must follow it. When food production increasing, forests are torn down to make room for farm land, and ecological systems are disturbed in order to increase food production.

Who was [|Thomas Malthus] and what did he have to do with Charles Darwin?

Kelcie: Thomas Robert Malthus was a British writer on political economy and population. Malthus popularised the economic theory of rent, and was the first to use the phrase struggle for existence. Malthus was the stepping stone for Darwin's theory of natural selection. When Malthus noted that in nature plants and animals produce far more offspring than can survive, and that Man too is capable of overproducing if left unchecked. This eventually lead Darwin to his theory on Natural Selection, although somewhat different from Malthus' he would not have gotten here without him.

Watch the following videos about world population ... it is slow to start ...but very purposely made, so stick with it. I would like you to react in writing to the video...and then respond to each other.

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Answer three of the questions below and respond twice to your classmates answers.

1. Describe the Demographic Transition Concept: Charles: This concept involves the transition from high birth and death rates to low birth and death rates as countries become more developed and industrialized.

2. How is the biotic potential related to the rate at which a population will grow? Catie : Biotic potential is the inherent reproductive capacity, or the maximum reproductive capacity of a population if resources were unlimited. The higher the biotic potential, the greater the population will increase because the population will reproduce more. Therefore, populations that meet their biotic potential, have an exponential population growth rate. However because of morality and limiting factors, populations do not continually increase exponentially.

3. List and describe three characteristics populations might have.
 * Logan :**Populations may have formidable disease within the population, distinct food source and method/ or means or creating shelter.

4. Why do some populations grow? What factors help to determine the rate of this growth? Catie : The population growth rate is the rate of increase (either through births or immigration) of a population, minus the rate of decrease (either through deaths or emigration) of a population. Therefore, when there are more births and greater immigration, and fewer deaths and less emigration, populations begin to grow. Population growth is influenced by the sex ratio of the population, the age distribution, and the density. The number of females in a population determines the number of offspring produced by a population, The younger the population, the faster a population will grow. Density can cause individuals to leave a population because of competition. T 5. How do K-strategists and R-strategists differ? Max: K-type species have fewer offspring, live longer, and invest more into the survival of a few young, while R-type species produce as many offspring as possible to ensure that some survival based on statistical chance.

6. List 10 differences between your standard of living and that of some one living in a less developed country? Kelcie: 1. Amount of food per meal 2. The homes in which we live in 3. Working conditions and jobs 4. Amount of fossil fuels used 5. Carbon Dioxide given off per person 6. Total level of consumption 7. Amount of freshwater available 8. Access to resources such as family planning resources 9. Empowerment of Women 10. Number of Children per family

7. Describe three reasons why women in the less developed world might desire more than two children? Max: The conditions that exist in developing countries make for a higher rate of infant and childhood mortality, so women may want more children so that statistically more survive. Secondly, the more children, the more help a women has with gathering the essentials for survival in these poor conditions. Lastly, children often can take the role of their mothers if they succumb to an illness, and thus raise their siblings.

8. Why do you suppose some organisms display high natality and others display lower natality? For example, why do cotton tail rabbits show high natality and wolves show low natality? Why wouldn't all organisms have high natality?

9. Consider the differences between R and K stategies. What costs are incurred by adopting either strategy? What evolutionary benefits do each strategy enjoy? Alex: R strategy organisms face shorter life spans, typically inhabit unstable environments, and don't reach carrying capacity due to the fact that they provide almost no care to their many offspring. However, because they live shorter life spans, they are able to use short-term resources more effectively, especially when the species is monopolizing it, shutting out other species and therefore increasing their survival. The fact that r strategies reproduce many offspring also gives the species the ability to reproduce rapidly. K strategy organisms are faced with density-dependent limiting factors, meaning that once the species reaches carrying capacity the population growth rate will decrease. It is also harder for k strategies to recover from damage to their population, for example from an epidemic, because they produce less offspring and take a longer time to reproduce. The k strategists do benefit from relatively longer lives, the ability to occupy stable environments for long periods of time, and are cared for as offspring by their parents.

10. Do you think that demographic transition will be a viable option for world development? What evidence leads you to your conclusion?

11. Imagine a debate between an American and a Sudanese person about human population and the scarcity of resources. What perspectives do you think the American might bring to the debate? What perspectives do you think the Sudanese might bring to the debate? What might be their points of common ground? On what might they differ?