Chapter 2 Flashcards
Longitudinal Diversity Gradient
The pattern that exists that species richness
increases dramatically from the poles to the
equator.
This gradient exists for almost all taxa.
Simplicity is
a FALLACY
Biodiversity Measurement
-Simplest measure - Species Richness + Species Abundance
Boundaries of a community are
arbitrary
What is the weakness of sampling efforts
-Weakness because sampling efforts to calculate species richness means we are
altering the actual size of the population - which species richness measures are
sensitive to.
What does Species Richness not account for
-Species richness scales non-linearly with sample size
SR doesn’t account for genetic diversity, functional diversity, phylogenetic
diversity
Robert Whittaker’s three ways to express species diversity
alpha diversity
beta diversity
gamma diversity
alpha diversity
number of species found at a local
scale (i.e. within a habitat)
Beta Diversity:
Beta Diversity: a measure of the difference in species
composition or species turnover, between two or more
habitats or local sites within a region
Gamma Diversity:
a measure of species richness in a region
region
generally defined as a large spatial scale that contains many
habitats and communities
biogeographic regions.
Many times these regions are on the continental scale, as these
regions can be definitively defined and each region has unique
evolutionary history.
beta diversity can be calculated two ways
book vs jaquard
book calculations of beta diversity porvide info on
Giving us a ratio of absolute richness
Jaccard Index: tells us about
Giving us quantitative information about species composition for beta divesity
