Background: When organisms face limiting factors, they show logistic growth (S-shaped curve, curve B: Figure below ). Competition for resources like food and space cause the growth rate to stop increasing, so the population levels off. This flat upper line on a growth curve is the carrying capacity. The carrying capacity (K) is the maximum population size that can be supported in a particular area without destroying the habitat. Limiting factors determine the carrying capacity of a population. Recall that when there are no limiting factors, the population grows exponentially. In exponential growth (J-shaped curve, curve A: Figure below ), as the population size increases, the growth rate also increases.

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: food alimiting or non limiting factor for herd sized?

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Do predators increase or decrease herd sizes?

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Do larger herds increase or decrease predator populations??

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Do smaller herds increase or decrease predator populations??

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Do smaller predator populations  increase or decrease herd sizes ?

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Do larger predator populations  increase or decrease herd sizes ?

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: If lions become extinct will herds increase or decrease?

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Will larger herds eat more or less grass?

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Do predators limit  herds or have no effect?

Situation: Mark had always wanted to go on a safari now that he was here he was amazed at the  huge herds of animals on the African Savannah but there is only grass to feed them part of the year and there are predators that hunt them for food.

Question: Do predators and prey exist independantly or together?

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: What was a limiting factor on the deer and elk population?

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: When was the deer and elk population at capacity?

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: When was the deer and elk population above capacity?

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: When did the growth rate of the elk and deer increase?

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: Would bringing wolves back decrease or increase the deer and elk population??

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: What population is growing un checked?

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: What population is growing exponentially?

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: =What would return the elk and deer population to logistic growth??

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: What would make the growth rate of the deer population stop growing??

Situation: Wolves, elk and deer lived in Yellowstone National Park. While wolves lived there the elk and deer population was stable. When wolves became extinct in the area the elk and deer population exploded. Soon the forest showed signs of being damaged by the grazing Elk and deer.

Question: What would make the growth rate of the elk population stop growing??