m k,m Flashcards
jhbn (20 cards)
What do lottery models in ecology explain?
Openings are filled at random by recruits from a large pool of potential colonists
Species diversity is maintained through random allocation of space
What are the conditions for species persistence in lottery models?
Low adult mortality and high fecundity
These conditions allow species to persist until opportunities for recruitment occur
What is the Priority Effect?
The importance of being first in colonizing an area
It influences species diversity and community structure
According to the Intermediate Disturbance Hypothesis, where is species richness highest?
At intermediate levels of disturbance
High diversity is found under conditions of moderate disturbance
What happens to species diversity at low levels of disturbance?
Low levels of diversity
Competition leads to dominance by a few species
What is the effect of high levels of disturbance on species diversity?
Reduces diversity through disruption
High disturbance resets community structure
What is the relationship between disturbance frequency and community diversity?
Frequent disturbances lead to few species; intermediate disturbances lead to higher diversity
Seldom disturbances allow competitively strong species to dominate
What was the focus of the empirical test of the Intermediate Disturbance Hypothesis?
Disturbance in marine intertidal boulder fields
It involved counting species and distributions after manipulating boulder sizes
What did the experiment in intertidal boulder fields reveal about species diversity?
Highest diversity was found on boulders with intermediate disturbances
Low disturbance had few species, and high disturbance had one species
What do equilibrium and non-equilibrium theories in ecology aim to explain?
Rules for processes leading to observed species richness in communities
No single theory fits all community patterns
What is the Storage Effect in ecology?
A mechanism of species coexistence in variable environments
Changes are random and occur infrequently
What conditions promote the Storage Effect?
- Variable conditions favoring some species over others
- Long-lived organisms enduring unfavorable conditions
Organisms must have low adult mortality and high fecundity
What does the paradox of plankton illustrate?
How multiple species coexist in an isotropic or unstructured environment
It highlights competition for the same resources
What is a stable equilibrium in ecology?
A dynamic balance between predator and prey populations
It is characterized by a stable negative feedback loop
What does classical competition theory state about coexistence?
The number of limiting resources must equal or exceed the number of species
Limiting similarity requires species to be dissimilar in resource use
What do non-equilibrium theories focus on?
Identifying processes beyond immigration and extinction affecting community organization
They explore fluctuations and disturbances in ecosystems
What is resource partitioning?
Allows coexistence of ecologically similar species
It enables multiple species to exploit different resources
What does the Competitive Exclusion Principle state?
Two species with complete niche overlap cannot coexist stably
This occurs under stable conditions
What is Gap Dynamics in ecology?
A process that may lead to forest replacement and species filling gaps
It acts as a priority effect depending on favorable environmental conditions
