POPULATION GROWTH. For most of human history, humans have not been very numerous compared to other species. It took all of human history to reach 1 billion. 150 years to reach 3 billion. 12 years to go from 5 to 6 billion. Human population tripled during the twentieth century.
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Checks and Balances limit growthA. Resources not yet limited, can grow at intrinsic rate of increaseB. Stabilizing at carrying capacityC. Capacity for growthD. Limiting abiotic factors
Estimated Human Population Growth: more than 90% of all growth in the twentieth century and projected for this century is in less-developed countries.
Exponential growth of reindeerA. low carrying capacity B. area of sustained indefinite growth, but organisms have exceeded the carrying capacity C. Dieback after overshoot
Total Fertility Rates in the U.S.A. signifies increase in birth rates B. # of children to keep a constant population growth rate.
Is the most useful measure of fertility used for projecting the future of a population.
N0= 20,000 so R0= 20,760/20,000 =1.038
OR use this! r= (b-d)/1000 + (i-e)/20,000
So r= (25-7)/1000 + (600-200)/20,000
r= 0.018 + 0.02 = 0.038 or .38%
Total would be 100% + .38% or 1.0 + 0.038= 1.038
.038 x 20,000 = 760 people from original problem!!!!!
Demographic transition: accompanies economic development & stabilization.A. High birth rate & high death rateB. Death rates decrease & birth rates are highC. Growth continues by slows D. ZPG
r, intrinsic rate of increase is the rate at which a population would grow if it had unlimited resources.
Also called population change.
r= b-d or (b-d)+(i-e)
b= birth rate/1000 d= death rate/1000
i= immigration e= emigration
(emigration: a one-way movements out of a particular population to another area)
For example, .0019 or 0.19%=r, resulting in slow population growth
Age Structure DiagramsA. Increasing rapidly (unless d increases)B. Demographically divided (not socially equal)C. Stable, similar # of pre & reproductive ages D. Declining population Age structure is the # or % of persons of each sex at each age level.