Ecosystem Dynamics and Human Impact

The video discusses ecosystem disturbances, both natural and human-induced, and their impact on biodiversity. It highlights the concept of ecosystem resiliency and the role of keystone species in maintaining ecological balance. Human activities such as deforestation, pollution, and unsustainable fishing practices are examined for their detrimental effects. The video also covers fishing methods like gill nets and purse seines, emphasizing the issue of bycatch. Finally, it addresses the human population's impact on ecosystems and the concept of carrying capacity.

What is a disturbance in an ecosystem?

• An event that increases the number of species

• An event that changes biodiversity by removing organisms or altering resources

• A human activity that benefits all species

• A natural disaster that only affects plants

Which of the following is an example of a positive disturbance?

• Overfishing

• Water pollution

• Forest fires followed by secondary succession

• Deforestation

How does the removal of decomposers affect an ecosystem?

• It increases the growth of trees

• It provides more nutrients to plants

• It disrupts the nutrient cycle, affecting the entire food web

• It has no significant impact

Why is the sea otter considered a keystone species?

• It is the most numerous species in the kelp forest

• Its presence or absence has a large impact on the ecosystem

• It is the primary producer in its ecosystem

• It is the largest predator in its ecosystem

What happened to the game fish population when alligators were hunted to near extinction?

• It was unaffected by the change

• It decreased because gars, which prey on game fish, increased

• It remained stable

• It increased due to less predation

What is bycatch in the context of fishing?

• A type of fishing net

• A method to increase fish population

• Organisms caught unintentionally in fishing nets

• The target species caught in nets

Which method is used to reduce bycatch in fishing?

• Using larger nets

• Fishing in deeper waters

• Attaching acoustic devices to deter marine mammals

• Increasing the number of fishing vessels

What is carrying capacity?

• The total biomass an ecosystem can produce

• The maximum number of species an ecosystem can support

• The number of predators an ecosystem can sustain

• The maximum human population possible with limited resources

Which factor does NOT limit the carrying capacity of humans?

• Disease

• Food supply

• The number of keystone species

• Fresh water availability

How have humans historically exceeded projected carrying capacities?

• By decreasing the human population

• By increasing the number of predators

• By modifying the environment and finding new resources

• By reducing biodiversity