The passage mainly presents about carrying capacity including details and descriptions. The professor supports this arguments and gives an example about a population of wolves.
20 years ago, there was a massive population of rabbit but the wolves were low in terms of population. The population of wolves was not yet fulfilling the carrying capacity and rabbits were the primary sources of wolves’ food. This supports the argument in the passage alleging that relative richness of resources causes a variable number of organism.
The passage later describes when the population of organisms hits the carrying capacity, the excess organisms either have to leave or perish. The professor also says the same way that eventually when the population of wolves hits the carrying capacity limit, the wolves will starve or leave that habitats.
Then the population of plants, the food sources of rabbit, will increase as the population of rabbit goes down. Finally both the passage and the professor describes that this would lead to the rise and fall of carrying capacity.