Final Flashcards
Current view on equilibrium
Communities are chance assemblies of species, NOT integrated units
Following a disturbance the community will change and not return to original state
Levels of disturbance
Intermediate levels : greater diversity in a community
High levels- exclude slow-going species
Low evels- dominant species exclude less competitive ones
Ecological succession
Community and ecosystem change after a disturbance
Ecological Sucession
-Primary Succession
Glacier Bay, Alaska
No soil exists when succession begins
Steps:
Pioneer
Dryas (nitrogen fixing bacteria)
Alder
Spruce
Each one facilitates the colonization of a later species
Ecological succession
Secondary Sucession
Where soil remains after a disturbance
Large scale factors that contribute to species diversity
Latitude of community
Size and location of the area a community occupies
Why does species diversity decrease as latitude increases?
Evolutionary History:
Tropical environments tend to be older
Growing season is longer = bioogical time is faster (more generations per season)
Climate-
High temp and sunlight
Evapotranspiration
The evaporation of water from soil and plants
S=cA^z
S: number of species in a habitat
C: constant
Aa: area of the habitat
Z= how many species should be found as area increases
Continual turnover of species
Bc equilibrium is dynamic
Not yet reached levels of big 5
T
⁸u
