+
Related Flashcards
Related Topics
Cards In This Set
| Front | Back |
|
Biodiversity ____ over surface of Earth.
Where is the most?
|
Varies
tropics
|
|
More ___ variability = more ____ variability
|
Habitat, species
|
|
What is a depressing effect?
Augementing effect?
|
Deserts
mountains (high habitat heterogeneity)
|
|
Species richness:
different taxa<=>different ____ influences
examples?
|
Environmental
ex: moisture tends to affect trees and amphibian locations, temperature affects reptiles
|
|
Within latitudinal belts, diversity is correlated with...
|
Temp
precipitation
topographic heterogeneity within regions
structural complexity of local habitat
ecosystem productivity
|
|
Favorableness Hypothesis (to explain variation in global patterns of diversity)
|
Environment is more favorable in the tropics: less exreme -> less extinction -> higher diversity
|
|
Time-since-perturbation Hypothesis/Stability-Time hypothesis
|
Tropics are older and are climatically more stable and disturbed less frequently (no ice ages)
* more time for speciation
* lower extinction rates
= accumulation of species
|
|
Environmental Heterogeneity Hypothesis
|
Tropics have a higher structural complexity that allows for more species to coexist
ex: diversity of birds increases with foliage height diversity
|
|
Productivity Hypothesis
|
Tropics have higher productivity (higher input of solar energy)
more energy can sustain more species and larger populations, lower extinction rates
* relationship is not linear (eventually levels out) bc amount of energy doesn't matter at a certain point
|
|
What is sort of contradicting of this hypothesis?
|
Can have high productivity and low diversity (salt marshes)
can have low productivity and high diversity
(some deserts)
|
|
Intermediate Disturbance Hypothesis
|
In the tropics, intermediate levels of disturbance promote diversity (environmental heterogeneity over time)
|
|
How does different levels of disturbance relate to types of organisms there?
|
Frequent disturbance: colonist species will dominate
intermediate ": wider variety of species present
rare ": top competitors will dominate
|
|
What is gap dynamics?
|
Clearing created by a tree/branch fall: temporarily change in physical conditions (light, temperature, humidity)
* this promotes good dispersal and investment in rapid growth of gap specialists
|
|
Gap dynamics ___ total diversity by ____.
|
Increase
supporting patchwork of gap and shade specialists
|
|
What is a niche?
|
The way an organism obtains its resources (food, shelter, etc.)
n-dimensional hyper-volume
|
