Population Ecology Chapter 4

Balancing Populations Environmental factors must be in balance for a population to survive. What are some environmental factors that could upset or disrupt this balance? (You are going to have to think about this; it’s not in your book!)

Answers Drought, pollution, habitat destruction, no food source, etc.

Limits on Populations A limiting factor is an environmental factor that prevents or stops a population from growing. What would be some examples of limiting factors? (pg. 97 will help with at least one example; the others you will have to think about)

Answers Some limiting factors --- natural disasters, weather, disease, living space, competition, predation, etc.

Population Growth Please show what a J-curve graph looks like. Explain what a J-curve graph expresses.

Answers A J curve represents a growing population. initial increase is slow because the number of reproducing organisms is small, but soon it increases rapidly because the number of reproducing organisms increases.

Environmental Limits Give me some examples of a density- dependent limiting factor. Give me some examples of a density- independent limiting factor. What is the difference between the 2 types of factors?

Answers Density Dependent --- A factor that has an increasing affect as a population increases. Examples --- disease, competition, parasites, and food. Density Independent --- affect all populations no matter what their size or density is. Examples – temperature, floods, storms, drought, and habitat destruction.

Demographic Trends What are 4 factors that are going to effect growth rate? (pages ) Explain what each factor means.

Answers Birth rate --- How fast they are reproducing Immigration --- Moving into an area Death rate --- How fast they are dying Emigration --- Moving out of an area These determine if a population grows, stays the same, or shrinks!!