The number of organisms per unit area Population Density The number of organisms per unit area

Which has a higher population size? United States New York City 0 of 5

Which has a higher population density? United States New York City 0 of 5

3 Types of Dispersion Draw Each Uniform Clumped Random

3 Types of Dispersion 1) Uniform 2) Clumped 3) Random Ex: ______ __________ ________

Type of dispersion: White-Tailed Deer Uniform Clumped Random 0 of 5

Type of dispersion: Black Bear Uniform Clumped Random 0 of 5

Type of dispersion: Bison Uniform Clumped Random 0 of 5

Type of dispersion: Mountain Lion Uniform Clumped Random 0 of 5

Type of dispersion: Seeds dispersed by wind Uniform Clumped Random 0 of 5

Type of dispersion: Caribou Uniform Clumped Random 0 of 5

Limiting Factors Items that influence population growth “Limit” growth

1. Density-dependent limiting factors “Depends” on “density” a) Affect large, dense populations more than smaller, less- crowded populations

Density-dependent limiting factors Predation: Fig. 5-7 Wolves & Moose on Isle Royale

Predator - Prey

Which increases first? Predator Prey 0 of 5

Density-dependent limiting factors ii. Disease & Parasites: Easily spread in large, dense populations

Density-dependent limiting factors iii. Competition: Fig. 5-5 - Compete for available resources Food, water, space

iv. Crowding & Stress: The higher population density, the more crowding and stress on individual organisms

2. Density-independent factors The density of the population DOES NOT MATTER It doesn’t matter if the population is 5 or 5,000, they will be affected

Density-independent factors Hot/Cold Weather Fires Floods/Hurricanes/Tornadoes Human Activities – toxic waste spills, pesticides, deforestation

Population Growth Rate How fast a population grows It depends on 4 major factors

Population Growth Rate a) Natality = birthrate “neonatal intensive care” – newborns/preemies b) Mortality = death rate

Population Growth Rate c) Emigration – “exit” or leaving population d) Immigration – “in” or moving into a population

Population Growth Rate Natality – Mortality + Immigration - Emigration

If natality is 10, mortality is 6, immigration is 3, and emigration is 2……the net effect on the population is… + 21 - 3 + 3 + 5 0 of 5

If the original population consisted of 10 individuals, what is the new population size? 20 15 5 0 of 5

If birth rate > death rate The population will increase The population will stay the same The population will decrease 0 of 5

If birth rate < death rate The population will increase The population will stay the same The population will decrease 0 of 5

1. Exponential Growth (J–shaped Curve) If ideal conditions continue, the population will continue to grow rapidly Doubling and re-doubling 1, 2, 3, 8, 16, 32, 64, 128…….. Does NOT last long in nature – WHY?

Exponential Growth (J–shaped curve) d) This is current human population growth worldwide How long can it last? Discuss

Exponential Growth e) Draw graph

2. Boom and Bust As ideal conditions continue, population grows exponentially until it reaches a “peak” size (boom) and then crashes (bust) Ex: Rabbit population

Boom and Bust c) Draw graphs

Yeast Population Growth

3. Logistic Growth (S-shaped curve) a) Exponential growth at first, eventually the population size levels off as the growth rate slows down b) Carrying capacity: Largest number of individuals that the environment can support

Logistic Growth c) Draw graph

Logistic Growth (S-shaped curve) d) Things that prevent the population from getting too big: Lack of food or water Home/shelter availability

Which of the following are NOT true about exponential growth? It occurs at the beginning of logistic growth curves It shows an S-shaped growth curve It occurs only if ideal conditions exist Populations have unlimited resources 0 of 5

Reproductive Patterns r-strategy: rate strategy Generally are small Short life spans Produce many offspring rat, fruit fly, locusts

Reproductive Patterns k-strategy: carrying capacity strategy Larger organisms, long life span Produces few offspring –better chance of survival Take care of the offspring, usually for a long time Kangaroo, elephant

Reproductive Pattern: Rabbits & Dolphins Both r-strategists Both k-strategists r-strategist & k-strategist k-strategist & r-strategist 0 of 5

Demography The study of human population size, density, distribution, movement, and birth and death rates

Demographic Transition A change in a population from high birth and death rates to low birth and death rates

Demographic Transition Stage 1: birth rate & death rate Stage 2: birth rate & death rate Stage 3: birth rate & death rate Stage 4: birth rate & death rate Discuss & answer questions on Notes handout

Zero Population Growth Birth rate = Death rate

Age-Structure Diagram # of males & females in 3 age groups: Pre-reproductive stage Reproductive stage Post-reproductive stage

Age-Structure Diagrams Fig. 5-13 – predict future population sizes… Pyramid shaped (pre-reproductive larger)  Every age group about the same  Smaller at the bottom (pre-reproductive #’s smaller) 

Population will increase Population will stay the same Predict future population sizes: Pyramid shaped (pre-reproductive larger) Population will increase Population will stay the same Population will decrease 0 of 5

Predict future population sizes: Every age group about the same size Population will increase Population will stay the same Population will decrease 0 of 5

Population will increase Population will stay the same Predict future population sizes: Smaller at the bottom (pre-reproductive smaller) Population will increase Population will stay the same Population will decrease 0 of 5

Education & Demographic Transition What does the first graph tell us? What does the second graph tell us? What is a key factor in reducing the overall worldwide population growth?