Population Ecology ORTIS Project: Lesson 11

Follow-Up to Lesson 10 What factors can limit a population?

Limiting Factors for Populations Limiting Factors can affect the number of organisms (i.e. population of people, animal, or plants) in a region/country

Limiting Factors for Populations Limiting factors can be: Density Dependent or Density Independent *Density = number of individuals per unit of area (Ex. = 65 people per square mile)

Density Dependent Limiting Factors Density dependent factors (factors affected by the number of people/animals /plants living in the particular area.) Amount of food available Living space Disease Competition Predation In other words, these factors are directly related to how many individuals there are.

Density Independent Limiting Factors Density independent factors (these have nothing to do with the number of people/ animals/plants living in a given area) Weather Seasonal cycles Natural disasters Human activities The number of individuals is irrelevant to how these factors will affect the population.

Specific examples of Density Independent factors Natural disasters Drought Fire Volcanic eruption Human activities Housing development Road building Farming

7,000,000,000 7 Billion People What does this number mean to you? In M&M’s? You would have to eat 10 every second of every minute of every day for 22 years!!! That is 13,117,504.6 pounds or 276,744 school buses

7 Billion People: National Geographic Video 7 Billion People: National Geographic

Question Generation Open discussion about video

Human Population Growth In groups of 2-3 make conclusions about the human population graph.

Human Population Growth A.D. 2000 1000 1 B.C. 3000 4000 5000 6000 7000 1+ million years 8 7 6 5 2 4 3 Old Stone Age New Stone Age Bronze Iron Middle Ages Modern Black Death — The Plague 9 10 11 12 1800 1900 1950 1975 2100 Future Billions

Why? The Germ Theory Food Production Food Distribution Sanitation Antibiotics Food Production Food Distribution

Germ Theory We began to understand that diseases were caused by germs (microbes). This led to new sterile techniques in the operating room. More sterile techniques when handling food and water. A better understanding of sanitation. A better understanding of disease transmission. A better understanding of disease treatments and ultimately antibiotics. Bottom line is a decreased deathrate leads to an increase in population size.

Food Production and Food Distribution Advances in the preservation of foods. Advances in the transportation and distribution of foods. Advances in farming methods using new technologies to decrease labor.