UNDERSTANDING POPULATION DYNAMICS If you had to pick ONE issue that is causing all environmental problems…what would it be?

Exploding white tail deer population in the us Read the CASE STUDY in your TEXTBOOK…p. 114-115 Answer the following… Outline the growth of the deer population since 1900 (give #s & conditions) Discuss the impact of the current deer population on our ecosystems Describe several measures to try to control the population

WHAT Limits the growth of populations?? Think of factors that might promote growth of a population Or...what ecological conditions might limit population growth?

Limiting factors DENSITY INDEPENDENT DENSITY DEPENDENT Depends on the size of the population Space Disease Competition predation Size of the population does not matter Weather Natural disasters Human activity seasons

Population dispersion Clumped dispersion is most advantageous... Resources vary place to place so species cluster where resources are available Moving in groups increases chances of finding patches of resources Moving in groups offers protection Groups increases predator chances of finding food See Figure 5-14 p. 112

Range of tolerance: range of conditions that must be maintained for particular species to be able to survive…grow…function normally

Factors that influence population growth BIRTHS DEATHS IMMIGRATION EMIGRATION POPULATION CHANGE = (births + immigration) – (deaths + emigration) Population growth rate describes the change in a population over specified intervals of time Zero Growth Rate: population NOT growing…remains the same

Population growth patterns View various population growth graphs Draw each in your notes Identify and describe the growth for each

Linear growth curve Population is growing the same amount at regular intervals EX: a population that increases by 2 individuals each month

Exponential growth (j curve) Rate of increase is continually rising Resources are plentiful Few/no predators Little disease Low death rate

No population can grow indefinitely… There are limits on resources…there is competition…predation…disease…natural disasters… ENVIRONMENTAL RESISTANCE…combination of all factors that limit growth of populations Read the CASE STUDY in your TEXTBOOK…p. 114-115: Exploding White Tail Deer Population in the US…Answer the following… Outline the growth of the deer population since 1900 (give #s & conditions) Discuss the impact of the current deer population on our ecosystems Describe several measures to try to control the population

CARRYING CAPACITY/ S CURVE Populations will eventually run out of resources…fail to find mating partners; or other factors such as disease or predators will cause a population to reach its carrying capacity Population will remain relatively stable …but there may be fluctuations Carrying capacity is the size of a population an ecosystem can support based on the resources available and the other species present in the ecosystem.

POPULATION CRASH Rapid decrease in population What factors could cause this to happen in a population? Population decline is inevitable when a population exceeds its carrying capacity Look in your textbook (end of ch. 5) and find 3 examples of events that have/could cause this pattern in the human population

Phases of growth LAG: all population begin slow EXPONENTIAL: as more individuals are added to a population & each are reproducing…growth increases rapidly STATIONARY: growth will eventually slow as resources run low/out DEATH: population can crash if all resources are depleted or perhaps a predator or disease is introduced

How is the human population growing? CORE CASE STUDY: p. 122: Planet Earth: Population 7 Billion List when the human population hit each 2 billion increment Also give the amount of time that passed between each 2 billion increment Provide reasons why the human population is growing like this Discuss the impact of the current growth of the human population

AGE STRUCTURE A-Expanding/growing population- pyramid shape, has more children than any other age group.- Nigeria B- Stable populations- Number of children is roughly the same as the number of reproductive adults- US C- Declining population- Pre-reproductive group is smaller- Germany