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Populations in the Ecosystem
A. Population Growth1. Biotic Potential –the rate at which a
population would produce young if every new individual lived and reproduced at its maximum capacity
2. Carrying Capacity- (K) Maximum number of individuals an environment can support
3. J-Curve Population
* J-curve organisms have a tendency to reproduce rapidly and overshoot carrying capacity by a large amount. This results in a population crash.
S-Curve Population
S-curve populations reproduce until their habitat cannot support any new members. Mortality will approximate natality. This is called Stabilization
K
4. Limiting Factors and Population Density A) Limiting Factors- environmental factors that stabilize
populations and prevent them from reaching their biotic potentials
B) Density Dependent Limiting Factors1) Factors that increase their pressure as the population size
increases2) Water, sunlight, stress, waste accumulation, disease and
predators are all density dependent limiting factors.
c) Density Independent Limiting factors1) Factors that operate independent of population density2) Factors such as weather, landslides, fire, floods and other
natural disasters that affect populations regardless of their size
5. Changes in Population Sizea) Predator and Prey
* Predator and prey populations rise and fall in response to each other
b) Population Change = (Births + Immigration) minus (Deaths + Emigration)
B. Human Population Growth 1. The History of the Human Population
A) Hominids have existed for 500,000 yearsB) Population size was relatively low until 10,000
years ago when agriculture increased the human carrying capacity
C) 1840- 1 billion people. Industrial RevolutionD) Advances in Medicine decreased mortalityE) 1930- 2 billion peopleF) 1975- 4 billionG) Present- ≈ 7 billion US population
Human Population Size (Follow Link)
Who Are We?
(Information is from the Miniature Earth Project http://www.miniature-earth.com/me_english.htm)
Where Do We Live? 61% Asians 12% Europeans 14% from North
and South America
4.6% from United States
13% Africans 1% Oceania
What is Our Sex, Race and Faith? 50.5% female 49.5% male 70% nonwhite, 30% white 67% Non-Christian (Muslims,
Hindus, Buddhist and other Religions) Only 33% are Christian
(Catholics, Protestants, Orthodox, Anglican and
other Christian groups)
What is Our Socioeconomic Status? 59% of the entire world’s wealth belongs to only
0.06% of the people in the world 80% live in substandard housing (Ex. Lacking a
source of clean water, basic sanitation, plumbing or electricity). 13% dying from malnutrition
53% struggle to live on less than $2.00 a day 14% are unable to read. Only 7% have graduated
high school and merely 1% have a college degree 88% of them will not see this message, because
only 12% have a computer and only 3% have a internet connection
So…….Keep this in Mind: If you keep your food in a
refrigerator If you keep your clothes in a
closet If you have a bed to sleep in And if you have a roof over
your head
You are Richer than 75% of the Entire World Population!
So Even on Your Worst Day
3 out of 4 people in the world will gladly trade you places
Appreciate what you have got!
2. Future of the Human Population
2. Future of the Human PopulationA) If current population trends continue, the
human population could reach 9 billion by 2050
B) As the human population grows, it will need more food, space, clean air, soil and water
C) Humans will need more material goods which will require more clean energy
D) Industries will produce more wastes so we will need better waste disposal
"There is no exception to the rule that every organic being naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair. Even slow-breeding man has doubled in twenty-five years, and at this rate, in less than a thousand years, there would literally not be standing-room for his progeny." Charles Darwin (1809-1882) On the Origin of Species by Natural Selection, 1859
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