1. Population Growth
Ellsworth 2015

2. What is a population?
A population is a group of individuals of the same species living in the same geographic area.
Population Dynamics
The study of factors that affect growth, stability, and decline of populations is population dynamics.

3. What 3 phases do populations go through?
All populations undergo three distinct phases of their life cycle:
growth
stability
decline

4. What is meant by population growth?
Population growth occurs when available resources exceed the number of individuals able to exploit them.
Reproduction is rapid
Death rates are low
Immigration Occurs
Growth is experience when rapid reproduction, immigration and low death rates combine to produce a net increase in the population size.

5. What is population stability?
Population stability is represented when a population is not experiencing rapid growth or great decreases over long periods of time.
Stability is experienced when fluctuations in populations stay within an average count range despite minor disturbances over long periods of time.

6. What is population decline?
Decline is the decrease in the number of individuals in a population, and eventually leads to population extinction.
Decline is experienced when decreases in population are greater than increases.

7. 4 Factors that influence population growth rate
Birth Rate
Death Rate
Immigration
Emigration

8. Birth Rate
The proportion of births to the total  population in a place in a given time, usually expressed as a quantity  per 1000 of population.

9. Death Rate
The number of deaths per unit, usually 1000, of population in a given place and time.

10. Immigration
The movement of individuals into an area in order to settle there

11. Movement of individuals out of an area.
Emigration
Movement of individuals out of an area.

12. 4 Social Factors Four social factors that influence human populations:
Birthrates
Death rates
Age-Structure
Limiting Factors

13. Age-Structure
Another characteristic of populations that ecologists measure is population age structure. This characteristic is as simple as it sounds: it’s a summary of the number of individuals of each age in the population. Age structure is useful in understanding and predicting population growth.

14. Population Pyramid Shows Age-Structure

15. Limiting Factors
Any biotic or abiotic factor that restricts the numbers, reproduction or distribution of organisms. Examples Food Supply Water Supply Predators Shelter Prey Space

16. Carrying Capacity
The maximum sustainable size of a resident population in a given ecosystem.

17. Modes of population growth

18. Exponential & Logistic Growth

19. Human population growth over the past 10,000 years

20. Two modes of population growth
The Exponential curve (also known as a J-curve) occurs when there is no limit to population size.
The Logistic curve (also known as an S-curve) shows the effect of a limiting factor (in this case the carrying capacity of the environment).

21. Human Population
Near 1650, the slow population rate increases exponentially for humans.
Annual growth rate reached its peak in the late 1960s, when it was at 2% and above.
Population in the world is currently (as of ) growing at a rate of around 1.13% per year.

22. Human Population
New technologies for medical care, hunting and farming have enabled this rapid increase.
It took over 100,000 years to reach a total population of 1 billion,
but only 123 years to reach 2 billion,
and a mere 33 years to reach 3billion.

23. Human Population
The annual human growth rate is currently declining and is projected to continue to decline in the coming years. Replacement–Birthrate The level of fertility at which a couple has only enough children to replace themselves, or about two children per couple.

24. Human Population
Replacement Birthrate for developed countries is 2.1%.
2.33 for the world and much higher for developing countries.
Birthrate for USA for 2014 is 1.97%.
Birthrate for Japan for 2014 is 1.41%
Birthrate for Niger for 2014 is 7.58%

25. Human Population Previous Milestones
1 Billion: Over 100,000 years
2 Billion: years
3 Billion: years
4 Billion: years
5 Billion: years
6 Billion: years
7 Billion: years

26. World Population

27. Arizona Populations Arizona State 6.7 Million as 2014
Phoenix: 1,445,632
Tempe: ,719
Tucson: ,116
Peoria: ,065
Mesa: ,041
Surprise: 117,517
Chandler: 236,123
Yuma: ,064
Glendale: 226,721
Avondale: 76,238
Scottsdale:217,385
Flagstaff: 65,870
Gilbert: ,453
Goodyear: 65,275