Chapter 18 Flashcards
Biogeography
the study of variation in species composition and diversity among geographic locations
Environmental conditions are
important regulators of species distributions
Endemic
when a species occurs nowhere else on earth
Species richness and composition vary with latitude
Lower tropical latitiudes have more and different species than higher temperate and polar latitudes
Spatial scales are connected hierarchal way
Global, regional, local
Global scale
Contain most variations with changes in latitude and longitude, species are isolated by long distances, differences in speciation, extinction, and dispersal rates
Regional scale
has smaller geographic areas where climate is roughly uniform and where species are restricted by dispersal limitation
Regional species pool or gamma diversity
encompasses all species contained within a region
Regional biogeography is related in two ways
Local scale, and beta diversity
Local Scale
Is equivalent to a community and
describes suitability of biotic and abiotic factors for species
Beta diversity
tells the change in species diversity and composition or the turnover of species as one moves from a community type to another across the landscape
Relationship 1 Local Species Richness
Local species richness and regional species richness are equal, then all species will be found in communities of that region (slope=1)
Relationship 2 Local Species Richness
Local species is simply proportional to regional species richness (local species richness increases with regional species richness but is not 1:1)
Relationship 3 Local Species Richness
Local species richness levels off despite increase in regional species pool, local process limits social species richness (limitation)
alpha diversity vs beta diversity
Alpha diversity measures the species physiology and interactions, while beta diversity measures the change in species diversity and composition across different communities
Witman’s studies of marine invertebrate communities demonstrated that
local species richness is determined largely, but not completely, by regional species pools.
2 reasons why local processes are not unimportant for determining local species richness
Local processes can be attributed to unexplained variation among local communities and species interactions are sensitive to the spatial scale chosen.
Alfred Russel Wallace
was the father of biogeography,
he co-discovered natural selection, studying species distributions across large spatial scales and
discovered mammals in Philippines were similar to those in Africa rather than the ones nearby
What pattern does the gradient depict in terms of species diversity across Earth’s land masses?
The gradient shows that species diversity is highest in the tropics and decreases toward the poles.
What are the three major types of boundaries between tectonic plates?
The three major types of boundaries are mid-ocean ridges, subduction zones, and faults.
How many biogeographic regions are there, and what do they correlate with
There are 6 biogeographic regions, each correlating with specific tectonic plates.
What is continental drift
How scientists hypothesized that the continents drifted over Earth’s surface.
mid-ocean ridge
a chain of underwater mountains formed by seafloor spreading at divergent plate boundaries.
subduction zone
One plate is forced down under another plate, this area has lots of earthquakes, volcanic activity, and mountain range formations.