chapter 22 Flashcards
field of study that considers the spatial arrangement of habitats at different scales and examines how they influence individuals, populations, communities, and ecosystems
Landscape ecology
long-lasting influence of historical processes on the current ecology of an area.
Legacy effects
Eskers are the remnants of streams of water that flowed inside glaciers; as the streams flowed, they deposited soil and rock on the streambed.
After the glaciers melted, the streams appeared as long, winding hills.
This is an example of
legacy effects
How do humans act as ecosystem engineers?
constructing buildings, dams, irrigation channels, etc.
villages & farms built and abandoned by romans which broken down building materials contributed to minerals in soil is an example of what?
Habitat heterogeneity
the number of species in a relatively small area of homogenous habitat, such as a stream.
Local (i.e., alpha) diversity
the number of species in all of the habitats that comprise a large geographic area.
Regional (i.e., gamma) diversity
a graphical relationship in which increases in area (A) are associated with increases in the number of species (S); the curve can be described by the equation
Species-area curve
Species-area curve eqution
S=cA^z
causes an increase in the amount of edge habitat compared to the original unfragmented habitat.
Fragmentation
Species that prefer edge habitat increase in abundance when what occurs?
fragmentation
increase gene flow and genetic diversity
Corridors
Declining populations in habitat patches can be sustained by
the dispersal of organisms between patches via habitat corridors
small intervening habitat patches that dispersing organisms can use to move between large favorable habitats
Stepping stones
what did macarthur and wilson observe about islands closer to the mainland
islands closer to the mainland appeared to receive more colonizing species.
Among islands of similar size, near islands contained
more bird species than far islands.
They found that larger islands contained
more species
how did macarthur and wilson test the hypothesis that species richness is determined by both island area and isolation
they
measured bird species richness on
25 islands in the South Pacific.
The effects of patch size and isolation are similar
across multiple types of habitat.
Daniel Simberloff and E. O. Wilson conducted a manipulative experiment to test effects of
habitat size and isolation.
On a set of islands in the Florida Keys, they observed that islands closer to the mainland had
more insect species than islands farther from the mainland.
a theory stating that the number of species on an island reflects a balance between the colonization of new species and the extinction of existing species
Equilibrium theory of island biogeography
As more species colonize the island, more species are subject to
possible extinction due to chance and negative interactions (e.g., competition, predation, parasitism).
on a global scale where is biodiversity at its higherst
near the equator
where does biodiversity decline
towards the poles
examines ecological patterns and processes at large spatial scales
landscape ecology
the number of species increases with?
area
the equilibrium theory of island biogeography incorporates
area and isolation
Current diversity arose in response to
past environmental conditions
movement of landmasses across Earth’s surface
Continental drift
the single landmass that existed on Earth ~250 Mya and subsequently split into Laurasia and Gondwana
Pangaea
the northern landmass that separated from Pangaea ~150 Mya and subsequently split into North America, Europe, and Asia.
Laurasia
the southern landmass that separated from Pangaea and split into South America, Africa, Antarctica, and India
Gondwana
6 distinct biogeographic regions
- neartic
- neotropical
- afrotropical
- paleartic
- indomalayan
- australian
allowed species to independently evolve in different regions of the Earth
Separation of continents
allowed groups of organisms unique to one landmass to move into new areas
joining of continents
established six distinct biogeographic regions that contain unique groups of organisms
The separation and joining of continents
