1. Section 1: Population Dynamics
Populations of species are described by density, spatial distribution, and growth rate. .

2. Essential Questions
What are the characteristics of populations and how they are distributed?
What are the differences between density-independent and density-dependent limiting factors?
What are the similarities between the different models used to quantify the growth of a population?
How does carrying capacity affect reproductive rates?

3. Vocabulary Review New population population density dispersion
density-independent factor
density-dependent factor
population growth rate
emigration
immigration
carrying capacity

4. Population Characteristics
Populations are groups of the same species in the same area.
Characteristics of populations include density, distribution, and growth rate

5. Population Characteristics
Population density
The number of organisms per unit area is the population density.

6. Population Characteristics
Spatial distribution
Dispersion is the spacing pattern of a population.
Can be uniform, clumped groups, or random
Pattern primarily driven by resources such as food

7. Population Dispersion

8. Population Characteristics
Population range
A species’ range is its distribution across the environment.
A species might not be able to expand its population range because it cannot survive the abiotic conditions found in the expanded region.

9. Population-Limiting Factors
Limiting factors are biotic or abiotic forces that keep populations from increasing indefinitely.
Limiting factors are either density-independent or density-dependent.

10. Factors that affect density
Density-independent factors- Abiotic factors in the environment that affect populations regardless of their density
  Ex. temperature
storms
habitat destruction
drought

11. Factors that affect density
Density-dependent factors- Biotic factors in the environment that have an increasing effect as population size increases
  Ex. disease
competition
parasites

12. Population-Limiting Factors
Population growth rate
The population growth rate (PGR) explains how fast a given population grows.
Natality: birthrate of a population in a given year
Emigration: number of individuals moving away from a population
Immigration: number of individuals moving into a population

13. Factors That Affect Future Population Growth
Immigration + + -
Population
Mortality
Natality -
Emigration

14. Population-Limiting Factors
Population growth rate
Exponential growth model:
Occurs when growth rate is proportional to population size
All populations grow exponentially until they encounter a limiting factor.

15. Time unit Births Deaths
Natural increase
Year
130,013,274
56,130,242
73,883,032
Month
10,834,440
4,677,520
6,156,919
Day
356,201
153,781
202,419
Hour
14,842
6,408
8,434
Minute
247
107
141
Second
4.1
1.8
2.3

16. Human Population Growth

18. Population-Limiting Factors
Population growth rate
Logistic growth model:
Occurs when a population’s growth slows or stops following exponential growth
A population stops increasing when the number of births < number of deaths, or when emigration > immigration.

19. Population-Limiting Factors
Population growth rate
Carrying capacity
Carrying capacity is the maximum number of individuals in a species that an environment can support.

20. Population-Limiting Factors
Reproductive patterns
Species vary in the number of births per reproduction cycle, age that reproduction begins, and in the life span.
Plants and animals are placed into groups based on their reproductive factors.

21. 2 Life History Patterns 2. K Strategists long life span
large body size
reproduce slowly
have few young
provides parental care
Ex: humans, elephants

22. 2 Life History Patterns 1. R Strategists short life span
small body size
reproduce quickly
have many young
little parental care
Ex: cockroaches, weeds, bacteria

23. Population-Limiting Factors
Reproductive patterns
r-strategy
k-strategy
Rate strategy
Carrying-capacity strategy
Adapted for fluctuating environment
Adapted to stable environment
Generally small
Generally large
Short life span
Long life span
Many offspring
Few offspring
Expend little energy to raise young
Invest more energy into nurturing young

24. Review Essential Questions Vocabulary
What are the characteristics of populations and how they are distributed?
What are the differences between density-independent and density-dependent limiting factors?
What are the similarities between the different models used to quantify the growth of a population?
How does carrying capacity affect reproductive rates?
Vocabulary
population density
dispersion
density-independent factor
density-dependent factor
population growth rate
emigration
immigration
carrying capacity

25. Section 2: Human Population
Ecosystems on land are grouped into biomes primarily based on the plant communities within them.

26. Essential Questions What aspects affect human population growth?
What are the trends in human population growth?
What are the age structures of representative nongrowing, slowly growing, and rapidly growing countries?
What might be the consequences of continued population growth?

27. Vocabulary Review New carrying capacity demography
demographic transition
zero population growth (ZPG)
age structure

28. Human Population Growth
The study of human population size, density, distribution, movement, and birth and death rates is demography.

30. Human Population Growth
Technological Advances
Historically, environmental conditions kept the human population at a relatively constant number below carrying capacity.
Humans have learned to alter the environment in ways that appear to have changed its carrying capacity:
Agriculture
Domestication of animals
Medicine
Improvements to shelter

31. Human Population Growth
Human Population Growth Rate
The human population continues to grow.
The human population growth rate is slowing.

32. Trends in Human Population Growth
Countries with similar economies tend to have similar population growth trends.
The change in a population from high birth and death rates to low birth and death rates is called a demographic transition.

33. Trends in Human Population Growth
Zero population growth
Zero population growth (ZPG) occurs when the birth + immigration = death + emigration.
At ZPG, the age structure should be more balanced, with numbers at pre-reproductive, reproductive, and post-reproductive ages approximately equal.

34. Trends in Human Population Growth
Age Structure
A population’s age structure is the number of males and females in each of three age groups: pre-reproductive, reproductive stage, and post- reproductive stage.
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Human Population

35. Trends in Human Population Growth
Human Carrying Capacity
Scientists are concerned about the human population reaching or exceeding the carrying capacity.
An important factor is the amount of resources from the biosphere that are used by each person.

36. Review Essential Questions Vocabulary
What aspects affect human population growth?
What are the trends in human population growth?
What are the age structures of representative nongrowing, slowly growing, and rapidly growing countries?
What might be the consequences of continued population growth?
Vocabulary
demography
demographic transition
zero population growth (ZPG)
age structure