Global Patterns Of Diversity Flashcards
What is conservation Biology?
is an integrated, multidisciplinary scientific field that has developed in response to the challenge of preserving species and ecosystems
What is biodiversity ?
the variety of life, in all of its many manifestations… encompassing all forms, levels, and combinations of natural variation, at all levels of biological organization, this includes:
- diversity within species
-between species
- and ecosystems
3 levels of biodiversity
- ecological diversity
- genetic diversity
- organismal diversity
ecological diversity includes
- biogeographic realms
- biomes
- provinces
- ecoregion
- ecosystems
- habitats
- populations
genetic diversity includes
- populations
-individuals - chromosomes
- genes
- nucleotides
organismal diversity includes
- domains / kingdoms
- phyla
- families
- genera
- species
- subspecies
- populations
- individuals
genetic diversity
- encompasses the components of genetic coding that structure organisms
- variability allows species to potentially adapt to changing. envr
Biological species concept
- a group of individuals that can potentially breed and don’t breed with individuals of other groups
- limits : fossil species + hybrids
morphological species concept
a group of individuals that appear different from others, that is, are morphologically distinct
- can be referred to as ‘morphospecies’
evolutionary species concept
a group of individuals that share unique similarities in their DNA & their evolutionary past
Species richness
the number of unique species in a collection or set of observations
- difficult to measure, strongly influenced by sampling effort
species accumulation curve
number of species found per sampling effort (e.g. # of transects sampled, or # of days of sampling)
extrapolation curve
can be fit from a species accumulation curve to estimate how many species there might be (asymptotic richness)
species diversity index
species are weighted by some measure of their importance
e.g. shannon- wiener index
- when a community is dominated by only one or a few species, it may be that rare or uncommon species are at risk
constraints and limitations to species counts
- inventories are incomplete
- described species tend to be larger bodied, more abundant, and more widespread
- distributions are best known for temperate regions
What are biomes?
ecological units based on dominant vegetation in terrestrial systems, and in the sea, on ocean currents and patterns of primary productivity
why are biomes useful?
useful for assessing global biodiversity and ecosystem services
How can we identify biodiversity hot spots?
- locations with exceptional concentrations of endemic species that are undergoing exceptional loss of habitat
- also consider ecosystem services provided + level of primary productivity
Biodiversity hotspots must meet two strict criteria.
they must….
1 - contain at least 1,500 species of vascular plants found nowhere else on earth
2 - have lost at least 70% of its primary native vegetation
As of 2016, there was _____ designated hotspots?
36
what are Common characteristics amongst ‘hot spots’?
- population dense
- home to some of the world’s poorest communities
- mostly rely directly on healthy ecosystems for their livelihood and well-being
Patterns of biodiversity : latitudinal gradients in species richness
- species richness of many taxonomic groups peak near the equator
explanations for the latitudinal gradients include 30+ hypotheses
including
- historical perturbation
- environmental stability
- habitat heterogeneity
- productivity
- interspecific interactions
patterns of biodiversity –> species-energy relationships
the amount of available energy in an area affects level of diversity
–> energy availability generates and maintains richness gradients
Species- energy relationships : climatically based energy hypotheses
e.g. as monthly summer temperature increases, so does richness of breeding birds in Britain
what is evapotranspiration?
- sum of evaporation and plant transpiration from land to atmosphere
- measure of the simultaneous availability of water and solar energy
what is potential evapotranspiration?
- max amount of water lost from the surface due to evapotranspiration when water is not limiting
- reflects energy available to evaporate water to atmosphere
‘increase potential evapotranspiration as well as richness of beetles in North America’ is an example of what pattern of biodiversity?
Species - energy relationships –> climatically based energy hypothesis
what is the productivity hypothesis?
( species - energy relationships)
energy constrains richness via trophic cascades
- i.e. plant richness is limited by solar energy and water, herbivores are limited by plant production, predators are listed by herbivores…. etc..`
how does the the ambient energy hypothesis explain patterns of biodiversity?
i.e. solar energy inputs affect organisms through they physiological response to temperature
environments at higher altitudes have mean conditions farther from organismal optima ( thermal neutral zone)
- e.g. it it more costly to live at high latitudes because the ambient temp. in polar regions is outside the thermal neutral zone of many organisms throughout the year
Meta-analysis by Hawkins (2003)
- where on the globe and for which taxa pure energy variable or water-energy variables best predict diversity?
Plants
- water-dependent
-tropics and subtropics –> water variables were best predictors or richness
- cooler areas –> dependent on water-energy variables
Vertebrates
- water-energy variables accounted for global patterns
- warm climates –> richness was affect by water or water-energy variables
- cold climates -> ambient energy had the largest affect
