Unit 5 - Human pop: past and present Flashcards
human pop
unlike other species, humans have increased the carrying capacity of their environment and, as a result, human pop has grown exponentially. In addition, humans r altering Earth in ways that might be detrimental to both humans and other pops
Human Pop Growth
HPG has some of the same characteristics as other pop, especially k-selected species. However, humans also alter their environment to a much greater extent than other species do
what is this dip
plague
Factors That affect growth
starting in the 1700s technological advances dramatically affected human pop growth and changed it from a logistic growth pattern to an exponential growth patter
(7) technological advances:
1) improved agricultural methods
2) domestications of animals
3) advancements in weaponary
4) breakthroughs in medicine
5) improved food storage and shelter
6) increase use of fossil fuels
7) expansion of geographic range
Exponential Growth
for the last 300y humans pop growth rate has benn 2% each year, but in recent years it reduced to 1.2%
calculate pop growth is to calc a pop doubling time
the time it takes the pop to double its number. at a growth rate of 1.2% per year, the world’s pop will double again in abt 58y. but not across the globe
Domestication of Plants and Animals
with the domestication of plants and animals, pop were transformed from small mobile groups of hunter-gathers into scientists in permanent villages and towns
crop cultivation
neutral environment was modified via irrigation and specilized CC
disease on rise; increase
pop density made it easier for disease-carrying organisms to spread
pathogen
a disease-causing agent such as a microbe or fungus
- only be sustained and evolve in high density pops
domestication of animals
contribute to the spread of pathogens, disease can jump from animals to humans
epidemic
the spread of disease beyond a v local pop
- large developed areas experienced the worst epidemics (due to pip density) but also developed resistance first
Industrial revoltion
was a period of great technological advancements from 1800s to 1900s during which machines were developed
- influences agriculture, manufacturing, mining, transportation, and technology profound effects on the socioeconomic and cultural conditions of time
- earth pop doubled
developments in chemistry
lead to the discovery to fertilizer and other compounds
- increase food production
- decrease labour needs
cell and germ theory of disease provided foundation for modern medicine
- increase survival rate due to the discovery of antibiotics and invention of vaccines
- increased life expectancy
vaccines; social and environmental impact
- decreased death and disfigurement via disease
- increased human pop and demand for resources
antibiotics ; social and environmental impact
- decreased incidence of and death from bacterial disease
- bacterial resistance due to overuse
water treatment; social and environmental impact
- decreased spread of water born disease, increased access to drinking water
- overuse of water resources
steam engine and internal combustion engine ; social and environmental impact
- increased productivity, transportation and manufacturing
- pollution, habitat destruction , and climate change
fertilizers and pesticides; social and environmental impact
-increased crop yields
-overuse of land, pollution of water supplies and soil, risks to human heath and wildlife
population pyramid
a tool that shows the distribution of ages among the males and females in a pop
horizontal bar graph
illustrates the distribution of different age groups in a population, with the number of males on left and females on the right
the conventional view
pop growth means more ppl competing for limited natural and economic resources
consequence of conventional view
more individuals to be cared for with lower per capita income and lower standard of living compared w countries that have a lower birth rate
demographic transition model
is a diagram that illustrates changes in how ppl live to explain the shift in pop size
- describes birth rate and death rates relative to pop size as a country passes through 4 states of economic development (bottom bar describes net pop growth)
Earth carrying capacity
pop grows rapidly until resources bc limited. so far, humans have been able to increase the carrying capacity of the earth, all environments have LIMITS
country wealth
20% if the earths pop consumes 86% of the world’s resources vs poorest countries use 1.3% of the world resource (consumption is linked to water production)
CO2 production
wealthy countries produce 53% of worlds co2 vs poorest is just 1.3%
Ecological footprint
is defined as the amt of productive land needed to support one person.
6 categories of ecological footprint
1) cropland
2) grazing land
3) fishing grounds
4) forest land
5) carbon absorption land
6) building area
avg. Canadians Ecological Footprint
7.3 hectares
Available Biocapacity
Earth’s carrying capacity for human pop is called AB. Ecologists have attempted to estimate available biocapcity by considering the same factors used in the ecological footprint cal.
comparing the ecologal footprint of earth pop to earth biocapacity reveals demand for resources has…
exceeded supply since the mid 1980s
in 2012 demand exceed supply by 23%
