APES: Unit 3 Test Review
Density- dependent factors
Predation, disease, compitition for resources - biotic; Rise and fall with population density
What about the r - selected strategy allows them to be successful in a foreign environment)?
R-selected species are typically generalists, meaning they eat a wide variety of food. This allows them to adapt and survive in multiple environments, rather than be reliant on one food source or habitat. In addition, their ability to populate quickly allows them to spread throughout new environments more effectively.
Raccoons eat a variety of foods and can live in a variety of habitats, including locations near humans. Tiger salamanders eat an abundance of worms and insects and require wetland habitats so they do not dry out. Which of the following best identifies the two different species?
Raccoons are generalists, and salamanders are specialists.
What is the IPAT model? Give an example of how the model works.
The IPAT model is a formula that represents how humans' total impact (I) on the environment results from the interaction among three factors: population (P), affluence (A), and technology (T). I= P x A x T
total fertility rate (TFR)
The average number of children born per female member of a population during her lifetime.
A country has a birth rate of 35/1,000 individuals and a death rate of 13/1,000 individuals. The death rate was 37/1,000 individuals in 1950, 28/1,000 individuals in 1970, and 21/1,000 individuals in 1990. Which of the following statements best explains why the country has a declining death rate?
The country is in stage 2 of the demographic transition, and life expectancy has increased because of improvements in public health, sanitation, and access to food
What prediction can be made about the diagram in the middle that is balanced?
The diagram in the middle that is balanced indicates that a population will remain relatively stable in size.
What prediction can be made about the diagram on the left that is heavily weighted toward young age classes?
The diagram on the left that is heavily weighted toward young age classes indicates that a population will grow quickly.
What prediction can be made about the diagram on the right that is heavily weighted toward the older age classes?
The diagram on the right that is heavily weighted toward the older age classes indicates that a population will decline.
Explain why incidences of disease increase when the population is above carrying capacity.
The disease is able to spread throughout a large population, which is why incidences of disease is much higher. In other words, it cannot be contained.
Density-independent factors
Temperature extremes, catastrophic natural disasters; factors are unaffected by population density
Which of the following claims is best supported by the data in the graph for the population of wolves between 1975 and 1985?
The population declined following depletion of food resources after a population overshoot
Type III survivorship curve
-Concave Curve -Early loss: a large percent of the population dies early in life -Low mortality after maturity -Typical of r-selected species -Examples: oysters, small fish, trees
Type I survivorship curve
-Convex Curve -Late loss: a large % of the population survives from birth to death -High survivorship throughout their lifespan -Majority reaches maturity -Example: humans, elephants, and plants
Type II survivorship curve
-Diagonal Curve -Constant loss: death rate constant from birth to death -Independent of age -Examples: birds, rodents, hydra, perennial plants
Examples of limiting factors in the environment
-Resource availability -Temperature extremes -Predators and parasites -Disease
According to the United Nations Population Division, the world's population in 2050 will surpass...
9.8 billion
What is a survivorship curve?
A line that displays the relative survival rates of a cohort—a group of individuals of the same age—in a population, from birth to the maximum age reached by any one cohort member.
Pre-Reproductive
Birth to age 14 years - These are ages when most girls are pre-pubescent and unlikely to have the ability to bear children. But their fertile years are still in the future, they just haven't gotten there yet.
How has China's one child policy changed the age structure of the country? What are the benefits and drawbacks of having a "grayer" population such as China's?
China's one-child policy guaranteed that the nation's population age structure would change. In 1970, the median age in China was 20 and by 2050, it will likely be 45. Although graying populations have benefits- such as increased charitable contributions to society by retirees- the drastic shift in age structure will challenge China's economy, health care system, families, and military forces because fewer working-age people will be available to support social programs to assist the rising number of older people.
What factors do demographers study when predicting human population dynamics and environmental impacts?
Demographers study human population size, density, distribution, age structure, sex ratio, and rates of birth, death, immigration, and emigration.
What is the focus of demography?
Demography is a social science that applies the principles of population ecology to the study of statistical change in human populations.
What factors account for our unprecedented growth?
Factors that account for our unprecedented growth are technological advances, improved sanitation, better medical care, and agricultural development.
exponential growth
Growth pattern in which the individuals in a population reproduce at a constant rate; J-shaped curve; only occurs when a population is small, competition is minimal, and environmental conditions are ideal
Phase Three Demographic Transition
Industrial Phase High education, low infant mortality Birth Rate: Declining Death Rate: Declining Slow population growth
Which of the following characteristics in the table best supports the claim that Country A is a more developed country and that Country BB is a less developed country?
Infant mortality rate
Where are infant mortality rates higher around the globe?
Infant mortality rates are highest in poorer nations, such as in sub-Saharan Africa, and lowest in wealthier nations.
Describe why the reproductive strategies of K - selected species cause them to be more adversely affected by invasive species?
K-selected species have a late sexual maturity and have few offspring at a time. Therefore, they are not able to reproduce as quickly and invasive species are more likely to take over the population.
carrying capacity
Largest number of individuals of a population that a environment can support
Characteristics of k-selected species
Long life span, stable population, slow population growth, density dependent limitations
Characteristics of r-selected species
Low parental care, reproduces many offspring at once, quick to sexually mature, small offspring, a lot of fluctuation in population size
Which of the following statements best describes the trends in the data shown in the graph above? (graph on AP Classroom)
More-developed countries tend to have lower total fertility rates than less-developed countries.
The tropical rain forests are known to have a large variety of animals. One example is the orchid mantis that is highly camouflaged when standing on a certain species of orchid found in tropical environments. Another species, the tropical cockroach, can live anywhere in the rain forest where it can find water and a food source. Which of the following statements best describes why it is predicted that the orchid mantis will be more affected by global climate change than the tropical cockroach will be?
Orchid mantises tend to be advantaged in habitats that remain constant; the rain forest habitat is likely to shift because of global climate change
What happens when a population exceeds its carrying capacity?
Overshoot occurs, which leads to resource depletion; Causes dieback of the population (often severe to catastrophic) because of the lack of available resources leads to famine, disease, and/or conflict.
Which of the following best explains the change in the moose population from 1995 to 1997?
Plants in the area could not support the large population of moose in 1995.
Where are population growth rates typically higher around the globe? Where are population growth rates slowing around the globe?
Population growth rates vary greatly from place to place. Populations are growing fastest in poorer nations, while populations are beginning to decrease in some highly industrialized nations.
Describe what would happen to the population of prey if the predators were removed from this ecosystem. What would be the limiting factor? Explain the idea of overshoot and the impact that would have on the prey over time.
Predators are a limiting factor on the prey population. Therefore, the prey population would increase greatly when the predators are not around to control their population. However, the prey will eventually run out of resources, causing them to adapt to changes or die out. An overshoot would cause the prey to be negatively impacted by their overpopulation because the environment in which they live is not meant for such a large population.
Describe why the reproductive strategies of r - selected species cause them to be less affected by invasive species?
R-selected species produce many offspring quickly and have an early sexual maturity. This prevents them from being affected by invasive species.
A fourth factor, S, can also be added to the equation. When added, what does S represent?
S stands for sensitivity (denotes how sensitive a given environment is to human pressures). I= P x A x T x S
What is the rule of 70? Use the rule of 70 to estimate the length of time (in years) it will take for a population to double if the growth rate of the population is 2.7%.
Take the number 70 and divide it by the annual percentage growth rate. 70/2.7=25.93 years
Generalists
This organism can be found all across North America; Omnivores are typically this type of species; This organism will likely adapt to environmental changes; Successful invasive species are typically this type of organism
Specialists
This organism has a narrow ecological tolerance; This organism is more prone to extinction; This organism will out-compete other organisms in its niche; This organism is found only on one small island chain; This organism is more threatened by invasive species; This organism only eats one particular plant
Demographic transition
a model that shows trends in 3 factors for a nation
Demographers
scientists who study population change, track the four key population factors
Based on the data in Figure 1, which of the following is the best estimate of the carrying capacity of the moose population?
1,500
The total world population is
7.7 billion
3 key factors for a nation
Birth Rate Death Rate Total Population
Which of the following countries has achieved replacement-level fertility? (Chart on AP Classroom)
Country C
Examples of specialists species
Owls and Pandas
Examples of generalists species
Rats and Coyotes
What are the four key population factors?
-Natality: births within the population -Mortality: deaths within the population -Immigration: arrival of individuals from outside the population -Emigration: departure of individuals from the population
What do survivorship curves tell us about the population?
-Type 1: a large percent of the population survives the adulthood because they provide care for their young and thus increase their chance of survival to old age -Type 2: a small percent of the population live to adulthood because they provide no parental care therefore there is high infant mortality
What kind of nations are in Demographic Transition Stages 1-2?
-Younger nations/populations usually have higher infant mortality -Children are needed in the workforce
Reproductive
Age 15 years to age 44 years - These are commonly referred to as the child-bearing years. It's the ages when females are most fertile and most likely to bear children.
Post-Reproductive
Age 45 years to end of life - These are the years during which females' fertility declines and bearing children again becomes unlikely. Their fertility will not increase again in the future.
logistic growth
An S-shaped curve produced as population growth slows as it reaches its carrying capacity.
What do environmental scientists argue in regards to human population growth? On what do they base their argument?
Environmental scientists recognize that not all resources can be replaced- such as the ecosystem services provided by a species that was driven to extinction. Thus, environmental scientists argue that population growth is indeed a problem if it depletes resources, stresses social systems, and degrades the natural environment, such that our quality of life declines.
How do carrying capacities change?
Environments are complex and dynamic, which is why this happens; Examples: Forest fires decrease carrying capacities for most animals; Humans altered their environment to increase its carrying capacity for our population
Describe Thomas Malthus' view on population growth? How do the views of Paul and Anne Ehrlich compare to those of Malthus? Have their fears materialized? Why or why not?
Malthus argued that if society did not reduce its birth rate, then rising death rates would reduce the population through war, disease, and starvation. Although his concerns were reasonable for the time, agricultural improvements in the 19th century increased food supplies, and his prediction did not happen. Paul and Anne Ehrlich had similar views on population growth. They believed that human population growth would soon outpace food production and unleash massive famine and conflict in the latter 20th century.
Phase Four Demographic Transition
Post-Industrial Phase High education, low infant mortality, older population become a tax burden 0 or negative population growth
Phase One Demographic Transition
Pre-Industrial Phase Birth Rate: High Death Rate: High Children in the workforce, high infant mortality Low to 0 population growth
Salamanders, ospreys, snapping turtles, and beavers all live in aquatic habitats. Salamanders lay their eggs in small freshwater pools and feed on insects. Osprey habitats include rivers, bays, and swamps and the birds feed on fish and other animals in the water or on land. Snapping turtles live in fresh or brackish water and feed on plants, fish, frogs, and snakes. Beavers build lodges on islands, pond banks, and lake shores and eat a variety of shrubs, grasses, and crops. Based on the information provided above, which of the following species would best be classified as a specialist?
Salamanders
Which type of species is most in danger of decline due to the effects of climate change? Explain your reasoning.
Specialist species are most in danger of decline due to the effects of climate change because they are less likely to be able to adapt to the changing conditions.
In a certain country, the birth rate is high, the death rate is high, and there are many children that are part of the workforce. The country is most likely in which of the following stages of the demographic transition?
Stage 1
While birth and death rates drive population change, how have technological advances changes these variables?
Technological advances that accompanied the industrial revolution led to a drastic decline in human death rates. This acts to widen the gap between birth rates and death rates and results in populations growing larger over time. In addition, technological improvements have been successful in reducing infant mortality rates.
Why is today's global population said to be "grayer" than it was in the past?
The global median age today is 28, but it is predicted that the median will be 38 by the year 2050.
How does sex ration affect population dynamics? Explain why the number of female births is slightly fewer than the number of male births in the human population.
The naturally occurring sex ratio at birth in human populations has a greater number of males; for every 100 female infants born, 106 male infants are born. This is likely an evolutionary adaptation to account for the fact that males are slightly more prone to die during any given year of life. A higher birth rate of males tends to ensure that the ratio of men to women will be about equal when people reach reproductive age.
The total fertility rate in country A was 6.8 in 1980. Which of the following statements best supports the change in the total fertility rate in country A between 1980 and 2015?
The total fertility rate decreased as a result of a delay in age of first marriage and increased contraceptive use.
replacement fertility rate
The total fertility rate that maintains a stable population size. 2.1
Phase Two Demographic Transition
Transitional Phase Improved medicine, sanitation, and food Birth Rate: High Death Rate: Decreasing Very high population growth
How to determine a population's rate of natural increase
by subtracting the death rate from the birth rate
