Bell work Week 35 Pick a science word and write the definition. Chapter 14 in Life Science book Check calendar! Poster board due 5/1

Title of notes: Carry Capacity/Limiting Factors Pg. 37 & 38 RS Goal for the lesson: write on your self assessment worksheet I can explain what factors determine if a population will grow or decline.

What is a Limiting Factor? Limiting Factors are… (two similar definitions) conditions of the environment that limit the growth of a species. biotic and abiotic factors that prevent the continuous growth of a population.

What is a Limiting Factor? Populations would continue to increase if they had all of the resources they require in unlimited amounts, but there are always factors that limit their increase. Limiting factors control population growth.

Density-dependent limiting factors A factor that stops a populations growth and is influenced by pop. density.

Density-independent limiting factors A factor that stops a populations growth and isn’t influenced by pop. density.

What is Carrying Capacity? Carrying capacity is the number of individuals of a species that an ecosystem can support.

What is Carrying Capacity? Because of these limiting factors, each ecosystem has a finite capacity for growth connected to its carrying capacity.

Carry capacity When a population is BELOW its carrying capacity, it will INCREASE in size Birth rate exceeds death rates But if it increases too much and rises ABOVE its carrying capacity, it will DECREASE in size Death rate exceeds birth rate This happens over and over… but the increases and decreases get smaller and smaller… Until eventually, the population size BECOMES STABLE AT THE CARRYING CAPACITY Birth rate = death rate

Population Growth Curves Exponential Growth - J Logistic Growth - S

J-shaped curve (exponential growth) Draw this on pg. 37 LS Nu m b e r J-shaped curve (exponential growth) Carrying Capacity (k) S-shaped curve (logistic growth) Ok so Time

Exponential Growth Occurs when there is unlimited resources Causes a population to increase in size rapidly J-shaped curve No limiting factors! Biotic potential = the estimated population size under optimal environmental conditions

Logistic Growth Occurs when there are limited resources Causes a population to grow and then stabilize at carrying capacity (k) S-shaped curve Limiting factors control population size (aka environmental resistance)