Chapter 6 Flashcards
population dynamics
the study of how and why populations change in size over time
Why is population dynamics useful?
So the ecologist knows the size and distribution of a population, and how these factors change over time.
Exponential
the increase is proportional to the number of organisms that already exist.
J-shaped growth factors
a type of exponential growth that is slow at first then increases rapidly
S-shaped growth form
starts off like the j-shaped form but eventually slows and finally stabilizes at the carrying capacity.
carrying capacity
the amount that a region can support without environmental degredation
fertility rate
number of birth that an individual female will have in her lifetime
What are reproductive strategies (k vs. r)
Characteristics that have the effect of increasing the number of fertile offspring an organism bears.
k-selected species
usually larger, longer lived, aka equilibrium species. reproduction involves motherly care. They are density dependent.
density dependent
factors like food supply and living space affect a population as it grows
r-selected species
opportunist species, rapid reproduction, usually small, short lived, density-independent.
density-independent
physical forces on the environment like frost, temperature, and rain.
How is human population changing? Is it growing linearly or logistically? Why?
Human population is growing at an exponential rate.
Summarize Dr. Hans Rosling’s video on population (box by box)
The only way to get the world population to stop is to continue to improve child survival.
How many humans are there on Earth?
7.6 billion.
What is the difference in human population growth rates among the different levels of development?
Populations are growing faster in poor nations while populations are declining in industrialized nations.
What is the demographic transition for economic development? Where is the most growth - which phase?
Phase 2 - birth rates increase while death rates drop.
how is fertility rate correlated with income?
Fertility rates tend to be high when incomes are low.
How is fertility rate correlated with education level in females?
Lower education rates in females means higher fertility rates
Reasons for large families in developing countries?
Old age security, infant and childhood mortality rates, and children are an asset.
What factors influence family size?
children viewed as economic assets or liabilities, status of women, and cultural views on child-bearing
How is poverty linked to environmental degredation?
Overusing resources for survival which leads to environmental degradation
The poverty cycle
Poverty > environmental degradation > high fertility > less resources because more people need them > more poverty
How can we reach a sustainable human population?
Lower fertility rates, consumption must decrease, protect the environment.
Affluence in the US
eat more than 3 times the global average in meat, lead the world in paper consumption, environment improves with increasing affluence.
How is development level of a place linked with its ecological footprint?
The average American puts 20 times the demand on Earth’s resources as does an average person in Bangladesh.
The 1994 Cairo Conference
All nations agreed that population is an issue of crisis proportions that must be confronted.
The 1994 of ICPD Program of Action
Enhancing productivity of natural resources, empowerment of women, emphasis on family.
limiting factors
factors that affect the size of a population as it increases but can also be affected by density-independent factors
environmental resistance
the sum of limiting factors that drive a population to change.
The IPAT model
our total impact (i) on the environment results from the interaction among population (p), affluence (a), and technology. I = P x A x T
How does human population affect the environment?
intensifies impact on the environment as more individuals take up space, use natural resources, and generate waste.
How does affluence affect the environment?
through greater per capita resource consumption. Lower affluence can affect the environment too.
How can technology affect the environment?
enhances our abilities to exploit minerals, fossil fuels, forests, or fisheries, but can also reduce impact.
Demography
a social science that applies the principles of population ecology to the study of change in human population
demographers
study population size, density, distribution, age structure, sex ratio, birth and death rates, immigration, and emigration of people.
demographic transition
a model of economic and cultural change to explain declining birth and death rates in Western nations as they industrialized.
During which stage of the demographic transition does the population increase the most?
The transitional stage.
Is growth toward the beginning or the end of the demographic transition?
The end.
Pre-industrial stage
birth and death rates are high because medical care is scarce. Birth rates are high because of infant mortality.
