Human Population Flashcards
The human population is currently growing at a rate of ___ million per year; that is 2.8 people added every second.
88
The human population didn’t reach ____ until after 1800.
1 billion
This is an example of ___________, where a small percentage growth rate still produces a large increase due to the size of the base population.
exponential growth
Global doubling time is 70/1.2%, or ________
58 years.
Improved sanitation, modern medicine, and higher agricultural output have all helped to reduce the ___________, the frequency of children dying in infancy.
infant mortality rate
British economist___________-argued that the number of people would eventually outgrow the available food supply.
Thomas Malthus
Paul and Anne Ehrlich of Stanford University have been called “___________” because they have made similar warnings.
neo-Malthusians
Despite a quadrupling of the human population, these predictions have not fully materialized.
____________ has intensified.
Enhanced prosperity, __________, and ________________ have helped to slow birth rates.
Food production
education
increasing gender equity
The I P A T model represents how our total ________ (I) on the environment results from the interaction of _____ (P), __________ (A), and __________ (T).
I = PAT
impact
population
affluence
technology
Increased population means that more ________ take up space, use resources, and generate waste.
Affluence leads to greater per capita resource ___________.
Technology can _______ impact by enhancing our ability to exploit resources or ______ impact by improving efficiency.
individuals
consumption
increase
decrease
A sensitivity factor (S) may also be added to denote the _________ of a given environment.
I = PAT*S
For example, the arid lands of western China are more sensitive to human disturbance due to the slow growth rate of the plants there.
vulnerability
Modern-day _____ has many examples of how I P A T elements can create environmental impact.
Intensive agriculture has caused _____ in western China similar to the _______
____________are heavily withdrawn.
Air quality is very ______
China
erosion
Dust Bowl.
Aquifers and rivers
poor
demography
Principles of population ecology can be applied to the study of statistical changes in the human population.
Demographers study several characteristics of the human population:
Size
Distribution
Age structure
Sex ratio
Rates of birth, death, emigration, and immigration
Predicted to surpass __________ by 2050
9.8 billion
Age structure diagrams, also called ___________ describe the relative numbers of individuals in each age class within a population.
population pyramids,
A pyramid with a ______denotes a potential for rapid future growth.
A pyramid with an ______ indicates a stable population.
A pyramid with a ____________ indicates a shrinking population.
wide base
even age distribution
narrow base
The global population is aging: the median age today is ___; in 2050 it is predicted to be 38.
This creates _____ in social welfare programs as ____ young workers are supporting more elderly.
28
strain
fewer
The naturally occurring sex ratio is ___ males born per every ___ females born.
106
100
The cultural gender preference for male children, coupled with the one-child policy, has resulted in roughly _______ born for every 100 girls.
116 Chinese boys
Infant mortality rates are closely tied to a nation’s level of __________.
industrialization
In recent decades, falling __________ in many countries has led to an overall decline in the global growth rate.
This is primarily due to a steep drop in _______
growth rates
birth rates.
______ describes the movement of individuals between countries.
Migration
_______ is people entering a country.
Immigration
