Lecture 3 Flashcards
(31 cards)
Describe the curve of a population growth graph
S curve before 1800
Logistics growth, limiting factors
As the population reaches carrying capacity, growth slows.
J curve after the 1800s
Explosion growth
Since the industrial rev, we were able to produce more food a day vaccinations, etc
Equilibrium of population growth
Births + immigrants = deaths + emigration
Equation for ending population
Starting population + (reproductive activity × population × number representing distance from carrying capacity)
What happens to the population growth if it is not held in place by environmental resistance
There’s a population explosion resulting in overgrazing and them beginning to die off due to starvation
Biotic potential and environmental resistance
Biotic potential remains constant, resistance changes
R-strategists
Produce a lot of young,but leave their survival to nature
Low RECRUITMENT
Rapid reproduction
Rapid movement
Short life
Adapted to a rapidly changing env
“Boom-and-bust” population
“Weedy”
“Opportunistic”
K-strategists (equilibrial species)
Lower biotic potential
Care for and protect young
Live in a stable environment already populated by the species
Larger, longer lived, adapted to normal env fluctuations
Population fluctuates around carrying capacity
R-strategists when humans change the area
Become pests
K-strategists when humans change area
Become rarer
Unique human characteristics
Thinking, change the env
Five major revolutions in human history
Neolithic, industrial, medical, green, environmental
Demographic transition (Epidemiologic transition, fertility transition)
Epidemiologic transition happens before the fertility transition, so there is a burst in growth in the population, as fewer people die, until fewer people birth children and the growth steadies again.
Global average fertility rates
Globally declining
Major causes of mortality in developed countries
Cancer, old age, etc.
What caused decline in fertility rates
Education
Major causes for mortality rates in developing countries
Illnesses, common cold, treatable diseases
Keystone species do:
Moderate species that would take over and allow less-competitive species to flourish
Rain shadow
Reduce rainfall at leeward side of mountains
Hadley cell
Air rises
Soil top layer
Higher humus contents
Soil erosion (deforestation)
Increased deforestation to decreased trees to decreased roots to decreased soil stability to soil erosion
Soil and global climate change
Biomass decomposition and carbon storage in soils
Norman Borlaug (Green rev)
High yield plant properties
First gen vs. Second gen of pesticides
More human synthesized, organic matter
