Population+Collaboration

Populations

In this second picture, the first graph is one form of expansion. The second is another form of expansion. The third is a type of stable population, and the fourth is a population that is beginning to contract. 

This is an age structure of China's population in 2005. They had a highly expanding population until the 1960s, then they implemented their they One-Child policy, creating a graph like this where it grows wider and wider, then sharply drops for a time. China's population is still growing, but at a much lower rate.

7. Describe the three types of survivorship curves. Give an example of organisms for each. Find a labeled picture similar to the one in the book. - Jessica Type 1: In humans or elephants, for instance, the likelihood of dying is small until late in life, when mortality increases rapidly. This pattern of mortality produces the Type I survivorship curve.

Type 2: For other organisms, such as some species of birds, the probability of dying does not change throughout life, giving a linear, or Type II, survivorship curve.

Type 3: Many organisms are very likely to die when young. If an individual survives this early period, however, it has a good chance of surviving to old age. This type of survivorship curve, called Type III, is characteristic of animals such as oysters and salmon, and of many insects.

 The pictures shows examples of the living things that are in that Survivorship Curve. 8. Define growth rate. What four processes determine a populations growth rate. What is the formula for growth rate? - Luke

Growth rate- amount by which a population’s size changes in a given time.

The processes that determine a population's growth rate are birth, death, emigration, immigration.

Formula for growth rate = birth rate- death rate= growth rate 9. Define exponential growth. What shape does the graph take? Insert a picture of a line graph showing exponential growth. Payton 10. Does exponential growth model apply for all populations? Define and give an example of limiting factors. E. Hardy PLease give more examples The exponential growth model does not apply to most populations. Populations cannot keep growing indefinitely because resources that are needed are scarce. Limiting factors are any factors, such as spaces, that restrain the growth of a population. All populations are ultimately limited by their environment. As a population grows, competition increases between individuals. The population’s birth rate decreases and the death rate increases, because each individual’s ability to grow, fight off diseases, and reproduce decreases. Lastly, the amount of shelter available is a limiting factor.  11. What does the logistics growth model look like(find a picture)? What letter is used to describe logistics growth. Define carrying capacity. What is the symbol for carrying capacity? E.O.  The graph of logistic growth is of populations in environments. In the first phase, the population shows rapid, nearly exponential growth. In the second phase, the growth rate slows until the carrying capacity, K, is reached. In the third phase, the population has become stable, neither increasing nor decreasing in size. Real populations may fit this pattern for some period of time but rarely remain stable. It looks like a stretched out “S”. Carrying Capacity is the number of individuals the environment can support over a long period of time. “K” is the symbol for carrying capacity on the logistic growth model.



12. Define density independent factors and density dependent factors. Give several examples of each. May need to go to the Web for more examples. Amy 13. Describe the predator prey model on pg 388-may need to use the Web. Find this graph on the Internet and insert. Describe what is happening to the lynx population as the hare population increases. What happens to the hare population as the lynx population increases? What type of population regulation is this an example of? Look at question 12 for the two types. Savanna- The predator prey model show the relation ship between the lynx, the predator, and the hare or the prey. When the population of snowshoe hares increases, providing more food for the <span style="display: block; font-family: Times New Roman,serif; line-height: 200%; margin: 0in 0in 0in 0.5in; text-align: left; text-indent: -0.25in;">lynxes, the lynx population also increases. The increased lynx population then consumes more hares, causing the hare population to decrease. With less food, more lynxes starve and the lynx population declines, allowing the hare population to increase and start the predator prey cycle over again. <span style="display: block; font-family: Times New Roman,serif; font-weight: normal; line-height: 200%; margin-bottom: 0in; text-align: left;"> This regulation is a Density-dependent factor 14. Why is it so bad to have small populations of organisms? What is inbreeding? Why is it a bad thing? Small populations, such as the cheetahs are particularly vulnerable to extinction. Environmental disturbances can kill off the entire population or leave too few individuals, increasing the likelihood of inbreeding. <span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">Inbreeding is mating with relatives. In breading in small populations often leads to decreased genetic variability. Over evolutionary time, populations with low variability are less likely to adapt to changing environmental conditions. Kandace <span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">15. Describe the bottleneck effect. Find a picture to represent the bottleneck effect. Cole

<span style="display: block; font-family: Times New Roman,serif; font-size: 13pt; text-align: left;">Bottleneck Effect <span style="display: block; font-family: Times New Roman,serif; font-size: 13pt; text-align: left;">--The genetic variation in a population can be reduced when the size of that population is reduced.

16. Describe the history of the human population. Include Include a graph. Sinclaire Please include how the Agricultural age and the industrial revolution and how each affected the human population. Also find a picture or graph of the human populatoin growth curve. Looks good so far--mr. b <span style="display: block; font-family: "Calibri","sans-serif"; margin: 0in 0in 0pt;">From the origin of //__Homo sapiens__//, more than 500,000 years ago until about 10,000-12,000 years ago, the human population grew very slowly. During this time, human population grew very slowly. During this time, humans lived in small nomadic groups and obtained food by hunting animals and gathering roots, berries, nuts, shellfish, and fruits. This way of life is called the hunter-gatherer lifestyle. By studying the few hunter gatherer societies that exist today, scientist have learned that a low rate of population growth results from small populations and high mortality rates. Population growth is slowed especially when mortality is high among infants and young children, because fewer individuals reach reproductive.

<span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">17. What are the characteristics of developing nations? Give examples. Henry Y. <span style="display: block; font-family: Times New Roman,serif; font-size: 10pt; font-weight: normal; margin-bottom: 0in;">About 80 percent of the worlds population lives in a developing country, in these growing countries their population grows a lot faster then in developed countries. Most developing countries are around in Africa, Asia, Central America, South America. <span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">18. Describe the Industrial Revoluluton. How did this effect the human population. How is our population growing totday? Henry A. Industrial Revolution occurred in the late 1800s and early 1900s when the people moved from living and working on farms to working in factories and living in cities.The Industrial Revolution made the population increase. <span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">19. How many people are on earth? What is the growth rate for the human population? How many people are expected to be on earth by the end of your life time? Walker <span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">20. What is the carrying capacity for earth? Do you think that we will ever reach it? Will need to research this one on the Web. There are many proposed answers for this one. Dylan The carrying capacity of a biological species in an environment is the population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment. Humans require other things for being able to sustain such as sanitation and medical care. As population increases birth rate decreases and death rate decreases. An example is Easter Island it had 2000-3000 people at one point, but the island didnt have enough room for 2000 people to be there so the population started to go down all the way to 111

<span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">21. What are the characteristics of developed nations. Give examples. Kelsey Some characteristics of a developed nation is high literacy rate, low growing population, and a high life expectancy.

22. What is the demographic transition model? Include a picture. Cason **Demographic Transition Model** - shows the growth and downfall of population in different countries. The reason behind this model is that industrial development causes economic and social progress that then affects the population growth rates. 23. Answer question 6 from pg 392. Ambernique The question was "which general model of population growth most closely resembles that seen in Figure 19-13, explain your answer. " - This most closely resembles a population explosion. The reason being is that in a population explosion, the human population begins to grow faster and the mortality rate begins to decline. As you can see, at the beginning of the graph, the birth and mortality rates are the same. In stage two of the graph, the mortality rate begins to decline as the population size increases. In stage three, the population size steadily increases. However, there is a point where the population size changes. The birth rate decreases sp much that it is the same as the mortality rate.In the last stage, every thing begins to decrease. The birth rate is the lowest out of all of the different rates. <span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">24. Answer question 7 from pg 392. Darryl

<span style="display: block; font-family: Times New Roman,serif; text-align: right;">Darryl Davidson <span style="display: block; font-family: Times New Roman,serif; text-align: right;">Biology 2nd <span style="display: block; font-family: Times New Roman,serif; text-align: right;">09/ 21/ 2010

<span style="display: block; font-family: Times New Roman,serif; text-align: left;">pg. 392 7. How might vaccines against diseases affect population growth rates? <span style="display: block; font-family: Times New Roman,serif; text-align: left;">Growth rates are affected by nutrition, hygiene, education, and I believe medicines. If a reliable and effective vaccine for a newborn children's disease is created, then more babies will stay alive. Therefore, the population will grow. Another example is if there is a vitamin that is created, and most people in a country begin to take it, then a study comes out that it causes a non- curable form of cancer. The growth rate will decrease because there will be less people to have babies. <span style="display: block; font-family: Times New Roman; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">25. Answer question 8 from pg 392. Jonathan <span style="display: block; font-family: Frutiger-BoldCn,sans-serif; text-align: left;">**Johnathon Martin** <span style="display: block; font-family: Frutiger-BoldCn,sans-serif; text-align: left;">**Question 8 : How is it possible for some countries with low birth rates to have high rates of population growth?** <span style="display: block; font-family: Frutiger-BoldCn,sans-serif; text-align: left;">**Answer: If the birth rate is low but it is close to the death rate the population growth will stabilize and if the population was high it would stay pretty high. Also if people immigrate into the area the population growth will be high.**