Human Ecology Flashcards
How many humans are born every second in comparison to the number that die every second?
4 humans born and 2 die (Gain 2.3 humans every second)
Describe the variables in the equation G=ΔN/Δt and describe what the equation measures
G=Rate of change in the population size
ΔN= the change in the number of individuals
Δt= interval of time
Describe variables in G=rN
G= Rate of change in population size
N=Number of individuals in population
r=per capita rate of increase = birth rate – death rate
Specifically discuss r and what happens to population size when r> or r
r= per capita rate of increase
r>0 means that population is increasing
r=0 population size is constant
r
What is K and what happens to G when K is ,= N?
K=carrying capacity (number of individuals earth can sustain)
When K=N: Growth rate is zero
When K>N: Growth rate is positive
When K
What two types of factors influence population growth in nature?
1) Density Independent Factors
2) Density Dependent Factors
Describe birth rate:
Number of deaths per year per person
Total Fertility Rate
number of children born on average during a woman’s reproductive life
Doubling time:
Time it takes population to double in size
What percent of the worlds population and what percent of the world population growth do developing countries represent?
80%, 90%
What four factors determine total fertility rate?
Culture
Economic
Demographic
Political
What is the demographic transition model?
model of economic and cultural change to explain declining death rates, declining birth rates, and rising life expectancies in as become industrialized
What are the four transition stages in the demographic transition model?
1) Pre-Industrial Stage
2) Transitional Stage
3) Industrial Stage
4) Post Industrial Stage
What is happening to birth and death rates in Pre-Industrial stage?
Both rates are very high
What is happening to birth and death rates in transitional stage?
Birth rate is constant put death rate is decreasing due to food production and increased medical access
What is happening to birth and death rates in Industrial stage?
Death rates hit a constant level while birth rates begin to decline due to increased opportunity for woman and increased access to birth control
What is happening to birth and death rates in post Industrial stage?
Birth rates and death rates are low
What is the optimist economist view of human population growth?
world population growth will stabilize this century due to demographic transitions in developing countries.
Pessimist view of human population growth?
eloping countries of the world are too environmentally and/or politically unstable, and will not experience a demographic transition. Aid to developing countries will decrease death rates but not birth rates.
Technologist View
Improving in technology and investing in technology TODAY will outpace demands of increasing populatioins
Social Justice View
Population is a SYMPTOM not a problem. We must redistribute resources.
Ecologist View
Population growth is the problem. The earth has a carrying capacity. If developing countries proceed through the demographic transition the same way developed countries have, per capita resource consumption will put us over the carrying capacity.
What are two consequences of a growing population like that of the baby boom era?
Not enough people paying into social security to support the population when they get old AND medicare/medicaid increases 7x
China’s One Child Policy
They said a legal married age for males and females, contraceptives are free, and people are limited to having one child (except some circumstances Ex: twins)
What is the 4-2-1 problem in china?
Each child has 2 parents and four grandparents
What is the sex ratio problem in china?
There are 1.2 males for every female do to selective abortion and infanticide of females
How do we ensure the high trajectory scenario is not the path taken?
1) educate women
2) Family Planning
3) increased access to healthcare
4) Providing contraception
How did Bangladesh reduce TFR?
using education and investing in family planning!!
What is the Easter Island Metaphor?
Deforestation, degradation of topsoil, and over-harvesting of animal explains the collapse of this civilization. THEY EXCEEDED CARRYING CAPACITY
Carrying Capacity
The number of people a geographical area can support before people need more resources than are available
Ecological Footprint
Basically measures how much we consume (demand of human activity on biosphere)
Biocapacity
The amount of area (land) available to generate resources and absorb waste
Global Hectares (gha)
A unit weighted based on ability of land to produce resources (need more pastures than crops to make the same amount of resources so they have different hectares) Cropland has larger gha
What are the 6 assumptions for ecological footprint:
1) Amount of resources used and the waste generated can be quantified and tracked
2) Resource/waste flow measured by productivity area necessary to MAKE them
3) Global hectares are accurate
4) Each hectare represents a single use of a particular resource
5) Human demand (ecological footprint) can be compared to biocapacity in hectares
6) Area demanded can exceed area supplied if demand on an ecosystem exceeds that ecosystems regenerative capacity.
Ecological Footprint Equation:
EF=demand for product(P)/ National Yield of product (Y) * the conversion to hectares
Biocapacity Equation:
BC= A(area available) X YF (yield factor a ratio of national to world average yields) X EQF (global hectares per hectare)
What is the equation for Ecological Footprint of Consumption?
EFc=EFp+EFi-EFe C: consumption P: Production I: Imported Commodity E: Exported Commodity
What are the six limitations of the ecological footprint of production? ?
1) availability of non renewable resources excluded
2) Some inherently unstable activites can not be accounted for (radioactivity)
3) Doesn’t take environment management into account
4) Doesn’t look at ecosystem degradation over time
5) Doesn’t measure resilience of eco
6) Doesn’t account for use/contamination of water
How does all this add up in the global context?
Basically we are consuming more than earth can generate (EF has exceeded capacity since the 60’s)
What countries account for the majority of EF?
Developed countries
How many countries house half of the biocapacity?
8!! Brazil highest because of forest
How does this all play out in terms of america?
If everyone on earth consumed at the rate of americans, we would need 4.5 earths to sustain us.
What Continent has the smallest EP per person but largest EP overall?
Asia
What Continents are ecological debtors
Asia, North America, Europe
Discuss North America specifically interms of EP
Has the highest biocapacity in the world, use 17% of worlds EP per person but only have 5% of worlds population
EF vs. Income Level
Low income has stable EP, middle have growing EP, high income has high carbon footprint but similar to middle
Human Developtment Vs. EP
We want to raise HDI while maintaining a low EF
HDI
composite measurement of life expectancy, education, income
How do we achieve high HDI and low EF?
sustainable energy, eating local, recycling waste, guided development, reduce dependency on wood, public trans
Food Chain efficieny
proportion of energy transferred from one trophic level to the next
What is the best things for humans to eat to keep EP low?
Grains!
How are crop yields and the chronically undernourished related?
In order to sustain the improvement in calorie intake of people in developing countries, we must increase the crop yield or this will not be sustained
What is a system?
an set of connected components that interact to for a unified whole
What is an ecosystem?
he assemblage of organisms (organic) together with their physical and chemical environment (inorganic)
What are the two rules of an ecosystem?
Energy flows THROUGH ecosystems and and elements cycle WITHIN ecosystems
Where does primary production fit into the food chain?
It is the base
Why is transforming energy into biomass not 100% efficient?
Because of secondary Biomass production which creates waste in the form of urine and feces
How much energy is assimilated in each level of the food chain and how much of primary production energy reaches the top?
10% each level so only 1% of primary reaches the top
For the reasons associated with energy assimilation in the food chain what foods SHOULD humans be eating?
GRAINS because they give you “more bang for your buck”