Chapter 8Population Change

Overview of Chapter 8o Principles of Population Ecologyo Reproductive Strategieso The Human Populationo Demographics of Countrieso Demographics of United States

Principles of Population Ecologyo Population Ecology• Study of populations and why their numbers change over time• Important for••o Population•

Population Densityo Population density

• Ex: minnows per Liter of pond water

Change in Population SizeCalculating Population Change

Birth (b), Death (d), Immigration (i) and Emigration (e) are calculated per 1000 people

Maximum Population Growtho Intrinsic Rate of Growth (Biotic Potential)••

Environmental Resistanceo Environmental limits (resistance)••o Carrying Capacity (K)••

Population Crasho Overshooting carrying capacity can lead to population crash

Factors That Affect Population Sizeo Density Dependent Factor•• Examples:•••• Sometimes cause Boom-or-Bust Population Cycles

Boom-Or-Bust Population CyclesCase Study- Predator Prey Dynamics on Isle Royale

o As wolf population increases, moose population decreases (and vice versa)

Factors That Affect Population Sizeo Density Independent Factors

• Examples:• Killing frost• Severe blizzard• Fire

Reproductive StrategiesSurvivorship

Some populations fit two curves

o Herring Gullso Type III & Type II

Human Population

o Demography•o

Human Population

Population Increase in Mexico

Projecting Future Populations

o Population is increasingo Growth rate (r) has started to declineo Projections for 2050• Low = 7.7 billion• High = 10.6 billion• Most likely = 9.1 billion

Demographics of CountriesDemographic Stages

o Pre-industrial Stage••o Transitional Stage••o Industrial Stage••o Post Industrial Stage••

Demographic Stages

Age Structureo The number and proportion of people at each age in a population

Demographics of Specific CountriesWorld-wide

o 29% o Could

Education of Immigrants into US