Bio112 Lecture 18 Community ecology Flashcards
What is a predator-prey cycle?
A repeating pattern where prey populations rise and fall, followed by predator populations with a time lag.
What are common defense mechanisms in organisms?
Behavioral (hiding), physical (shells, spines), chemical (toxins), and visual (camouflage, warning coloration).
What is mimicry and what are its types?
When one species resembles another.
Batesian mimicry: harmless mimics harmful. Müllerian: both harmful and resemble each other.
What is symbiosis and its types?
Close interactions between species.
Mutualism (both benefit), commensalism (one benefits, other unaffected), parasitism (one benefits, one harmed).
What is species richness and why is it important?
The number of species in a community.
Greater richness usually means higher ecosystem resilience.
What is a foundation species?
A species that has a large influence on ecosystem structure, often primary producers like trees or corals.
What is an ecosystem engineer?
An organism that physically alters the environment (e.g., beavers creating ponds).
What is a keystone species?
A species with a disproportionately large effect on community structure and biodiversity.
What is ecological succession?
Natural changes in community structure over time.
What is primary succession?
Succession on newly formed land (e.g., volcanic rock), starting with pioneer species like lichens.
What is secondary succession?
Succession that occurs after a disturbance (e.g., fire, farming), where soil already exists.
How does pond succession occur?
Gradual filling in of ponds with sediment, often leading to wetland formation and eventual land.
