Chapter 9 - From populations to community (SLIDES) Flashcards
What is density dependence in population dynamics?
A process where population growth is regulated by population density, such as competition, predation, or disease.
What is an example of a density-dependent disease?
COVID-19, which spreads more easily in high-density populations.
What are density-independent factors affecting population size?
Environmental disturbances such as storms, droughts, fires, and extreme temperatures.
What is primary succession?
The colonization of newly exposed land with no prior life, such as after a volcanic eruption.
What historical event serves as an example of primary succession?
The eruption of Mount Krakatoa in 1883.
What is secondary succession?
The re-establishment of a community after a disturbance that leaves soil and some life intact.
Give an example of an early successional plant species.
Ambrosia artemisiifolia (common ragweed).
Give an example of a late successional plant species.
Fagus grandifolia (American beech).
What is a zootic climax?
A climax community maintained by the influence of animals, such as through grazing and trampling.
How do bighorn sheep and elk affect plant succession in Yellowstone?
Their grazing prevents certain plants from dominating, influencing community composition.
What is an example of a non-resilient ecosystem?
Coral reefs, which struggle to recover after major disturbances.
What is robust stability in ecosystems?
The ability of an ecosystem to remain stable despite large disturbances.
How does species richness affect stability in ecosystems?
Higher species richness generally increases stability in terms of biomass and respiration.
What three factors are used to model food web complexity?
Total species number, connectance (interactions), and average interaction strength.
Why are sea otters considered a keystone species?
They control sea urchin populations, preventing the destruction of kelp forests.
What was the ecological impact of cougar decline in Zion National Park?
Deer populations increased, leading to overbrowsing and a decline in cottonwood tree recruitment.
