biozone pg 88-95 (population attributes)

PAGE 95 1. explain why populations tend to to increase exponentially in an environment

1. An environment cannot sustain an exponentially growing population for extended periods of time because resources are eventually depleted. There are limiting factors like food and disease (density dependent) and extreme weather events (density independent)

3. using the formula, determine the annual rate of population change for the us and mexico in 1972

a) USA- 1.73% - 4.3% + -2.57%

2. using the terms B, D, I and E construct equations to express the following (b= birth d= deaths i= immigration e= emigration a) a population in equilibrium b) a declining population c) an increasing population

a) b + i = d + e

4. a) explain why a newly introduced consumer (e.g. rabbit) would initially exhibit a period of exponential population growth b) describe a likely outcome for a rabbit population after the initial rapid increase had slowed

a) because they are newly introduced, the rabbits would have no natural predator to limit their growth b) the rabbit population will reach an equilibrium level around the carrying capacity

3. a) explain wha is meant by carrying capacity b)explain the importance of carrying capacity to the growth and maintenance of population numbers

a) carrying capacity is the maximum population size an environment can sustain (limiting factors prevent population from continuing to grow forever) b)Carrying capacity is important because it keeps population numbers in check so that the environment can still sufficiently sustain resources for the population's survival. Without it, populations would grow out of control and the members would starve or die of disease.

PAGE 92 1. define the following terms used to describe changes in population numbers a) death rate b) birth rate c) net migration rate

a) is the total number of live births per 1,000 of a population in a year. b) is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. c) is the difference of immigrants and emigrants of an area in a period of time, divided (usually) per 1,000 inhabitants (considered on midterm population). A positive value represents more people entering the country than leaving it, while a negative value means more people leaving than entering it.

2. a) identify the population attributes that can be measured directly from the population b)identify the population attributes that must be calculated from the data collected

a) migration, sex ratios, age structure, natality, mortality , population growth rate b)population density, carrying capacity and distribution

PAGE 89 1. Describe one example of a population attribute that would be a good indicator of each of the following a) whether the population is increasing or decreasing b) the ability of the environment to support the population

a) population size, migration, density, total abundance, population growth rate, natality b) population density, density

3. describe the value of population sampling for each of the following situations a) conservation of a population of an endangered species b) management of fisheries resource

a) to try to decrease/increase the birth and death rate or calculate how the population is exhausting their resources b)to see if the fishery is causing a fish population to go extinct

3. Discuss similarities between the events at Tikal and on the Easter Islands and how they can help us plan for the future

both Tikal and Easter Island depleted the soil by supporting their populations by subsistence farming for long periods of time. Over this time, the soil became infertile, unable to support food, and the people starved and died

2. explain what is meant by environmental resistance.

environmental resistance is the collective forces of limiting factors which together stabilize a population size at its carrying capacity

PAGE 88 1. Describe the general trend of human population growth over the last 100,000 years

the human population growth has been exponential over the last 100,000 years`

2. explain why the human population has grown at such an increased rate in the last 60 years

the human population has grown at such a rate over the last 60 years because of industrialization due social, economic and technological changes and advancements that have caused lower death rates while birth rates remained high during transitional stages and still remains high i developing countries

5. describe the effect that introduced grazing species might have on the carrying capacity of the environment

they might lower the carrying capacity of the environment by depleting resources (e.g. grasses, shrubs other vegetation). Less of an important resource lowers carrying capacity