POPULATIONS

1. S curve = Logistic growth Resource availability will cause the population to level off over time When we look at how populations grow, we can observe 2 types of growth curves: 1. S shaped curve- Logistic growth 2. J shaped curve-Exponential growth

2. J curve = Exponential growth “J” Shape Happens during ideal conditions Plenty of food, shelter etc. Unlimited resources No limiting factors POPULATION EXPLOSION

Horizontal line where growth of the population has leveled off is the CARRYING CAPACITY Carrying Capacity = The number of individuals in a population that an environment can support over a long period of time As growth continues, the environment's resources are shared by more and more individuals. Eventually, some resources are in short supply and become a limiting factor Determine an environment’s carry capacity things that prevent a population from growing any larger

In the graph below, what factors would cause the growth rate to decrease or level off?

Limiting Factor = a factor that causes the growth of a population to decrease. 1.Density dependent: (biotic) Competition: may use same food, or shelter. Predation : predator–prey curve (pop. control) Parasitism and disease 2.Density independent (abiotic): Natural disasters Human disturbances (construction…) Weather

How does the difference in water temperature affect the growth rate of the three species of fish depicted in the graph?

GROUP ACTVITY. GROUP ACTVITY. QUESTION: Has the Earth reached its carrying capacity for Humans? Based on what you have learned about carrying capacity, answer the following questions. 1. Some scientists believe we have passes Earth’s Carrying capacity for humans. Some believe we may reach it when the human population reaches 12 billion. 2. In your opinion, has the earth passed its carrying capacity? Justify your answer. - Give 3 reasons to support each argument. 3. What would limit humans from increasing its population indefinitely?

EXPONENTIAL & LOGISTIC GROWTH CURVES WKST A B C D

PREDATOR – PREY CURVE