Summary Environmental Science Midterm Exam Study Guide (BIO 220)
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Course
BIO 220 ENVIRONMENTAL SCIENCE (BIO220)
Institution
Grand Canyon University
Directions: This study guide was created from the exam bank of questions. It is designed to give indications about what concepts will be important to review in preparation for the midterm. Use the PowerPoint slides along with reading the textbook and notes taken during lecture to study effectively....
Directions: This study guide was created from the exam bank of questions. It is designed
to give indications about what concepts will be important to review in preparation for the
midterm. Use the PowerPoint slides along with reading the textbook and notes taken
during lecture to study effectively. Do not concentrate solely on the definitions.
Population Growth and Environment
Factors that limit population size (disease, war, famine, etc.)
o Population growth is checked by famine, disease, and cultural factors
(e.g., late marriage).
o Regulate population through cultural taboos, abstinence and infanticide.
Effects of population on the environment are not due to numbers alone.
o I = PAT
I = environmental impact
P = population size
A = affluence
T = technology
Carrying capacity (K)
o the maximum number of individuals that the environmental resources of a
given region can support.
Physical carrying capacity = “packing density, limited only by
space and resources”
Cultural carrying capacity is always less
Malthus vs. Marx
o Malthus
Human population growth causes environmental degradation
Thomas Malthus (1798) wrote An Essay on the Principle of
Population in which he showed that human populations
increase exponentially.
o Karl Marx
Human population growth results from poverty and resource
depletion
Demography
o the application of population ecology to the study of humans
Demographers study population size
Density and distribution,
Age structure, sex ratio,
And birth, death, immigration, and emigration rates
Encompasses vital statistics about people such as births,
deaths, distribution, and population size
, Crude birth and death rates
o Crude Birth Rate
Number of births in a year per thousand. (Not adjusted for
population characteristics such as number of women of
childbearing age.)
o Crude Death Rate –
number of deaths per thousand persons in a given year
Poor countries average about 20 while wealthier countries
average about 10.
Some rapidly growing countries have very low crude death
rates due to a high proportion of young people.
Total fertility rate and zero population growth
o Total Fertility Rate - number of children born to an average woman in a
population during her life
o Zero Population Growth - Occurs when births plus immigration in a
population equal death plus emigration.
ZPG Is a rate of 2.1 children per couple, not 2.0, because some
people do not have children and some children do not survive to
reproductive age.
Population momentum
o Even if total fertility rates were to fall, the population would continue
growing as young people enter reproductive age
Natural growth rate
o Natural Increase - crude birth rate minus crude death rate
o Total growth rate- includes immigration, emigration, births and deaths.
Factors that affect life expectancy
o Agricultural developments,
o Better sources of power
o Better health care and hygiene
Dependency ratio
o The number of non-working compared to working individuals in a
population.
Poverty and population growth factors
o Poorer societies have higher growth rates than wealthier societies
o They have higher fertility and growth rates, with lower contraceptive use
Consistent with the demographic transition theory
, Be able to read an age structure diagram
o Structure types and explanations
Pyramid- population w/ many young and high death rate (short
average lifetime)
This is what you want to have
Inverted pyramid- top heavy
Column- birth rate and death rate are low and
Pyramid Colum column w bulge a high % of pop is elderly
Column w/ a bulge- event in the past caused a
high birth or death rate for some age group
Demographic Transition
o a model of economic and cultural change to explain the declining death
and birth rates in industrializing nations
Stable preindustrial state of high birth and death rates change to a
stable post-industrial state of low birth and death rates
As mortality decreases, there is less need for large families
Parents invest in quality of life
Life Span
o is the oldest age to which members of the species survive.
Life Expectancy
o average age a newborn can expect to attain in any given society
Declining mortality is making the life expectancy go up as well as
the use of different medicines and other technology advances.
Toxins in the Environment
Infectious diseases and Pathogens
o Pathogens are disease- causing organisms. They include:
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