Aim How is the size of a population

Aim: How is the size of a population limited? Do Now: Ecology Worksheet HW #7: Ecology Regents Questions

What does the word limit mean? • the most • maximum • to keep • to maintain • no more

Michigan's Isle Royale National Park • Isle Royale is located in the NW of Lake Superior. portion • Isle Royale is home to a population of wolves and moose. • The wolves are the only predator of the moose representing 90% of the wolves’ diet. • The interactions between the wolves and the moose have been studied continuously and intensively since 1958. This is the longest study of any predator-prey system in the world. Interactive Graph: http: //vicksta. com/wolf%20 and%20 moose%20 graph 7. html

Hypothesize: What are some factors that may limit the population size of the moose? Hypothesize: What are some factors that may limit the population size of the wolves?

Limiting Factors • Anything that “limits” or controls the size of a population • Resources that are finite (limited!) • Abiotic Factors Biotic Factors

Abiotic Limiting Factors • Energy • Temperature • Water • Carbon dioxide • Oxygen • Soil • Minerals • p. H

Biotic Limiting Factor #1 Predator - Prey Relationships • Analyze the graph below: • As the number of prey increase, the number of predators increase. WHY? • Predators have more to eat so there is less competition and more survive. • As the number of prey decrease, the number of predators decrease. WHY? • Predators have less food to eat so there is more competition and less survive.

Biotic Limiting Factor #2: Competition • • • Organisms fight over the same resources Analyze the graph to the left. What happens to the competing populations? Best adapted population will increase and the other population will die off or migrate

Why are Limiting Factors Important to an Ecosystem? • They determine a species’ CARRYING CAPACITY • Maximum number of organisms that an ecosystem can support • Limited by the available abiotic and biotic factors Carrying Capacity

What can Cause the Carrying Capacity to Change? • Natural Catastrophe • Human Impact • Volcanoes, Forest Fires, Tsunamis, Hurricanes • Deforestation • Habitat Destruction

Exceeding Carrying Capacity Competition • The population decreases, few survive • WHY? • Limited food, water, shelter • Disease spreads more easily Carrying Capacity

The Human Population • Is increasing due to more births and fewer deaths • Due to: • Medical advances • Lack of predators • Little competition

Carrying Capacity – A Different Twist • The graph below shows the carrying capacities of an ecosystem for three different species, 1, 2, and 3 that inhabit an area and the actual population sizes of these three different species in the area. • Identify which species population would most likely have the greatest competition among its members. Support your answer using information from the graph. • Explain how an ecosystem can have three different carrying capacities.

Predator – Prey Relationships The Moose of Isle Royale +200 -140 -66 -150 -126 -52 +46 +20 +30

2800 28 2600 26 2400 24 2200 22 2000 20 1800 18 1600 16 1400 14 1200 12 1000 10 800 8 600 6 400 4 200 2 0 0 1 9 7 1 1 9 7 2 1 9 7 3 1 9 7 4 1 9 7 5 1 9 7 6 Year 1 9 7 7 1 9 7 8 1 9 7 9 1 9 8 0

Case Study: The Return of Canis lupus? http: //sciencecases. lib. buffalo. edu/cs/collection/detail. asp? case_id=691&id=691 How Wolves Change a River: http: //sustainablehuman. com/how-wolves-changerivers/