reproductive strategies

logistic growth

• follows an S curve

reproductive strategies

• k-selected species/k-strategists: populations that tend to stabilize over time near carrying capacity and maximize survival

  • eg. elephant, oak tree

• r-selected species/r-strategists: populations that have a high biotic potential who invest their energy into producing lots of offspring in a short time, maximizing reproduction

  • eg. cockroach, dandelion

• survivorship: the percentage of a cohort that survives at certain ages

  • can be recorded in life tables and survivorship curves

demography

development

• more developed country (MDC): a country with a higher GDP per capita

• less developed country (LDC): a country with a lower GDP per capita

demography

• demography: the study of statistics such as births, deaths, income, or the incidence of disease, which illustrate the changing structure of human populations

• natality: the production of new individuals by birth

• birth rate: the number of live births per 1000 people in a population per year

• life expectancy: the probable number of years of survival for an individual of a given age

  • often calculated at birth

  • good estimate of the overall life quality of a country

• infant mortality rate (IMR): the number of deaths of infants under one year old per year per 1,000 live births

  • people tend to have more children when they don’t think their kids will live to adulthood

  • high IMR → high fertility rate

demographic transition model

• demographic transition: falling death and birth rates due to improved living conditions that come with economic development

age structure

• total fertility rate (TFR): the number of children born to an average woman in a population during her entire reproductive life

• replacement fertility rate (RFR): the number of births at which the population is simply replacing itself

  • more developed countries, ~2.1 per couple (over 2 because children die)

• total fertility rates are decreasing globally, but are mostly still about replacement fertility rates

• age structure: the proportion of the population at each age level

  • helps develop our understanding of the number/percentage of male and female people in the pre-reproductive, reproductive, and post-reproductive ages

  • represented through population pyramids

• population momentum explains why a population will continue to grow even if the fertility rate declines

solving the population problem

the infamous overpopulation bet

• Stanford biologist Paul Ehrlich predicted that millions of people would starve to death as the population increased faster than the food supply

  • drew from Thomas Malthus’ idea that population growth would outpace food supply

  • 1968 book “the population bomb”

• Julian Simon found no historic correlation between increased population and decreased standards of living — he found the opposite

  • believed in human ingenuity

solutions to overpopulation

• ecological footprint: a figure that expresses the impact that a person or population has on the environment

  • often measured in terms of land and water needed to provide resources and dispose of waste

overpopulation vs. overconsumption

• reducing world population growth

  • birth → population (N) → death

    • decrease natality, not mortality

  • reduction of poverty

  • improvement of the status of women

    • women are largely in charge of childcare and domestic work

    • women work 2/3 of all hours worked globally but receive 1/10 of the pay

    • women own a small fraction of the world’s property

      • women can’t own land or property in some countries

    • women constitute 2/3 of the illiterate population

    • women receive less health care and often die of pregnancy-related health issues

  • encouragement of family planning