Trophic Cascades and Invasive Species

Organisms at the top of food webs who don’t have predators are called

• Keystone Species

• Prey

• Apex Predator

• Quaternary Consumer

• Change in population size (N) over the time period being used (T)

• Change in time (T) over population size (N)

• Carrying capacity

• Maximum growth rate

Powerful indirect interactions that can control entire ecosystems; occurs when predators limit the density and/or behavior of their prey and enhance survival of the lower trophic levels.

(a)  

Organisms that play an important role in how an ecosystem functions; without them, the ecosystem would be different.

• Apex predators

• Consumers

• Herbivores

• Keystone species

Explains that the number of herbivores is also limited by predators from the top down.

• Bottom-up

• Green world hypothesis

• Trophic cascade

• Density-dependent factors

This model assumes that changes happen instantly and a population is changing at any time.

• Continuous-time logistic model

• Discrete-time logistic model

• Stochastic model

• Exponential model

This graph can be an example of which two models?

• Stochastic model

• Discrete-time logistic model

• Continuous-time logistic model

• Exponential model

Describes how a population with density-dependent growth changes over specific time periods.

• Continuous-time models

• Discrete-time models

• Exponential model

• Stochastic model

An organism or plant that is introduced to an environment in which it is not native.

• Priority species

• Umbrella species

• Keystone species

• Invasive species

What would happen to the lower trophic levels if the eagle was removed from the food web?

• The entire collection of producers and herbivores would go extinct.

• The herbivore population would increase and the producer population would begin to dwindle.

• Nothing would happen to the food web.

• The higher trophic levels would increase in population size and the lower levels would decrease.