UNIT 3 APES TEST!
Stage 5 of DTM
A Modern Industrialized Country with a very low CBR, an increasing CDR, and a negative NIR
population
A group of individuals that belong to the same species and live in the same area
Sample
A relatively small proportion of people who are chosen in a survey so as to be representative of the whole.
Demographic Transition Model
A sequence of demographic changes in which a country moves from high birth and death rates to low birth and death rates through time. PHASE 1: slow population growth; PHASE 2: rapid population growth; PHASE 3: stable population growth; PHASE 4: declining population growth The demographic transition refers to the transition from high to lower birth and death rates in a country or region as development occurs and that country moves from a pre industrial to an industrialized economic system. This transition is typically demonstrated through a four-stage demographic transition model (DTM). Characteristics of developing countries include higher infant mortality rates and more children in the workforce than developed countries.
logistic population growth
As resources become limited, a population's growth slows or stops Carrying Capacity The number of individuals in a population that the environment can support Population size eventually levels off Referred to as an S Curve S-Shaped Curve: the shape of the logistic growth model when graphed
infant and child mortality
Clean water, immunizations, and nutritious food have all had a dramatic impact on: The average number of years an infant born in a particular year in a particular country can be expected to live Takes into account the given current average life span and death rate in that country
Corridor
Corridor: strips of natural habitat that connect populations; connect spatially distinct populations
Crude Birth Rate
Crude Birth Rate (CBR): the number of births per 1000 individuals per year
Crude Death Rate (CDR)
Crude Death Rate (CDR): the number of deaths per 1000 individuals per year # of death/total population x 1000
Stage 3 of DTM
Decreasing growth: Industrializing society with a CBR that declined significantly, a CDR that continues to decline, and a NIR that begins to moderate.
Economics and Fertility
Developed Countries: High levels of industrialization and income Replacement-Level fertility of 2.1 Developing Countries: Low levels of industrialization and income ($3/day) Higher levels of mortality in young people Replacement-Level Fertility of >2.1
exponential growth model
Exponential Growth Model: a growth model that estimates a population's future size (Pt) after a period of time (t), based on the intrinsic growth rate ( r ) and the number of reproducing individuals currently in the population (P0) ⇒ e is just the base of natural logs - total population after time = P0 (starting population) x e (euler's number)^rt (percent rate of growth x time)
Exponential Population Growth
Exponential growth In perfect conditions individuals can reproduce at a constant rate Many births, fewer deaths When resources are plentiful and there are no predators or disease Referred to as a J curve J-Shaped Curve: the curve of the exponential growth model when graphed Early growth is exponential → growth begins to slow → growth eventually falls to zero at K (carrying capacity)
Population Growth Rate formula
For a single nation: population growth rate = [(CBR + Immigration) - (CDR + emigration)] / 10
survivorship curve
Graph showing the number of survivors in different age groups for a particular species. A survivorship curve is a line that displays the relative survival rates of a cohort—a group of from birth to the maximum age reached by any one cohort member. There are Type I, Type II, and Type III curves. Survivorship curves differ for K-selected and r-selected species, with K-selected species typically following a Type I or Type II curve and r-selected species following a Type III curve.
Gross Domestic Product (GDP)
Gross Domestic Product (GDP): a measure of the value of all products and services produced in 1 year in one country Urban Areas: an area that contains more than 386 people per square kilometer
Stage 2 of DTM
High Growth: Industrializing society with a CBR that remains high but stable, a CDR that declines dramatically, and a NIR in rapid increase.
Doubling Time
If we know the growth rate of a population and assume that growth rate is consistent: rule of 70 → Doubling time (in years) = 70 / growth rate
What adds to population density?
Immigration (+) Emigration (-) Birth Rate (+) Death Rate (-)
IPAT equation
Impact = Population * Affluence * Technology IPAT equation: an equation used to estimate the impact of the human lifestyle on the environment: impact = population x affluence x technology
interbreeding depression
Interbreeding Depression: when individuals with similar genotypes - typically relatives - breed with each other and produce offspring that have an impaired ability to survive and reproduce
Intrinsic Growth Rate
Intrinsic Growth Rate ( r ): the maximum potential for growth of a population under ideal conditions with unlimited resources
carrying capacity
Largest number of individuals of a population that a environment can support When a population exceeds its carrying capacity (carrying capacity can be denoted as K), overshoot occurs. There are environmental impacts of population overshoot, including impacts of population overshoot, including resource depletion. A major ecological effect of population overshoot is dieback of the population (often severe to catastrophic) because of the lack of available resources leads to famine, disease, and/or conflict.
density independent factors
Limiting factors are natural disasters or climate change affecting population Regardless of size
Stage 4 of DTM
Low Growth: A Modern Industrialized Country with a low CBR, low CDR, and virtually no NIR
Stage 1 of DTM
Low Growth: A pre-industrial agrarian society with a High CBR, High CDR, and a Zero NIR
Metapopulation
Metapopulation: a group of spatially distinct populations that are connected by occasional movements of individuals between them
Overshoot vs Die-Off
Overshoot: when a population becomes larger than the environment's carrying capacity vs. Die-Off: a rapid decline in a population due to death When a population exceeds its carrying capacity (carrying capacity can be denoted as K), overshoot occurs. There are environmental impacts of population overshoot, including impacts of population overshoot, including resource depletion. A major ecological effect of population overshoot is dieback of the population (often severe to catastrophic) because of the lack of available resources leads to famine, disease, and/or conflict.
Population Growth Rate
Population Growth Rate: the number of offspring an individual can produce in a given time period, minus the deaths of the individual or its offspring during the same period
Explain how resource availability affects population availability affects population growth.
Population growth is limited by environmental factors, especially by the available resources and space. Resource availability and the total resource base are limited and finite over all scales of time. When the resources needed by a population for growth are abundant, population growth usually accelerates. When the resource base of a population shrinks, the increased potential for unequal distribution of resources will ultimately result in increased mortality, decreased fecundity, or both, resulting in population growth declining to, or below carrying capacity.
life expectancy
The average number of years an infant born in a particular year in a particular country can be expected to live Takes into account the given current average life span and death rate in that country
Type I, Type II, Type III Survivorship Curve
Type I - high survivorship until old age, then rapidly decreasing survivorship Type II - survivorship decreases at a steady, regular pace Type III - high mortality early in life, but those that survive early years live long lives Type I Survivorship Curve: a pattern of survival over time in which there is a high survival throughout most of the life span, but then individuals start to die in large numbers as they approach old age Type II Survivorship Curve: a pattern of survival over time in which there is a relatively constant decline in survivorship throughout most of the life span Type III Survivorship Curve: a pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood
niche generalist
a species that can live under a wide range of abiotic and biotic conditions generalist species tend to be advantaged in habitats that are changing.
r-selected species
a species that has a high intrinsic growth rate, which often leads to population overshoots and die-offs --> do not remain near carrying capacity, exhibit rapid growth, overshoots, and die-offs - typically small organisms - reach reproductive maturity early - reproduce frequently - produce many small offspring - little to no parental care r-selected species tend to be small, have many offspring, expend or invest minimal energy for each offspring, mature early, have short life spans, and may reproduce only once in their lifetime. Competition for resources in r-selected species' habitats is typically relatively low. r-selected species, which are minimally affected by invasive species. Most invasive species are r-selected species. r-selected species following a Type III curve.
niche specialist
a species that is specialized to live in a specific habitat or to feed on a small group of species Specialist species tend to be advantaged in habitats that remain constant
k-selected species
a species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity - abundance determined by K and their population fluctuations are small --> typically large organisms --> reach reproductive maturity relatively late --> produce a few, large organism --> provide substantial parental care --> large mammals and birds K-selected species tend to be large, have few offspring per reproduction event, live in stable environments, expend significant energy for each offspring, mature after many years of extended youth and parental care, have long life spans/life expectancy, and reproduce more than once in their lifetime. Competition for resources in K-selected species' habitats is usually relatively high. K-selected species are typically more adversely affected by invasive species than r-selected species K-selected species typically following a Type I or Type II curve
Age Structure Diagrams
broad base = rapid growth; narrow base = negative growth; uniform shape = zero growth Basic interpretation of an age-sex pyramid: a population or age-sex pyramid can tell us a lot and you can gain this information by examining the shape of it Population growth rates can be interpreted from age structure diagrams by the shape of the structure. A rapidly growing population will, as a rule, have a higher proportion of younger people compared to stable or declining populations.
Total Fertility Rate
estimate the average number of children that each woman in a population will bear throughout her childbearing years Puberty to menopause Measured as births per woman 2.1 for US women EDUCATION IS OFTEN DIRECTLY CORRELATED W/ TFR Total fertility rate (TFR) is affected by the age at which females have their first child, educational which females have their first child, educational opportunities for females, access to family planning, and government acts and policies. If fertility rate is at replacement levels, a population is considered relatively stable. Factors associated with infant mortality rates include whether mothers have access to good healthcare and nutrition. Changes in these factors can lead to changes in infant mortality rates over time.
density dependent factors
factor that limits a population more as population density increases Density-dependent Larger populations = faster resources are used Leads to competition for food, water, space, mates, etc.
Population Growth Models
mathematical equations that can be used to predict population size at any moment in time
Malthus (1798)
studied human populations came up with Malthusian catastrophe and basis for Darwin's "struggle for existence" Observed exponential human population growth rate Food supply was growing linearly Proposed human population size would exceed the food supply "Earth does not have a fixed carrying capacity" Intellect leads to increasing amounts of innovation (produce food at a faster rate) Alter Earth's carrying capacity IE technological advances in food production
percent error
the absolute value of the error divided by the accepted value, multiplied by 100%
Replacement level fertility
the total fertility rate required to offset the average number of deaths in a population in order to maintain the current population size Replacement-Level Fertility = the TFR to offset the average # of deaths in a population so the current population size remains stable
United States Population Issues
→ The US will continue to have lots of young people to sustain and help the aging population. This is because America takes in a large immigrant population every year which is able to maintain the population, as well. This benefits the US because they do not need to worry as much about a harsh decline in the economy due to the larger aging population.
Sub-Saharan Africa Population Issues
→ When women are forced to drop out of school, they have to sell their bodies to get money or meals. They are paid more when they do not use a condom. Condoms are also rarely used when families are expected to be large. → Population could nearly double over the next 50 years; increase of over 5 billion people. stage 2
India Population Issues
→ Women have little say over their rights and their actions. The men in their life choose most of the big decisions in their life (such as, how many children they have). → The majority of marriages are arranged and they often barely know each other when they get married. Since the families plan it, they often get married very young. → The fertility rates rise because families do not approve of birth control which makes them have more children. → India's population is majority children/younger people and the younger generations are majority male.
Japan Population Issues
→ Women have to work in order to sustain their families. It makes women want to have less children since they want to remain wealthy or in the middle class. → There are not enough working people entering the work force to support the retired population. If less people are working younger, it causes for the retired population to not be able to be supported as well by the economy. → The population pyramid is centered around the older population (around 35-65). The younger population and elderly population are at the same population level. This pattern represents how the population is declining and there is a lack of teens and children in Japan.
