Biodiversity Flashcards
T/F
There has been a decrease in plant species diversity over time
false
There has been an increase over time (generally) as more get established etc
biodiversity=
the number of different species living in a given area
species richness=
of species in a community
Do biodiversity and species richness tell us mostly everything we need to know?
No
Want to consider things like relative abundance, functional ecological roles, community structure, and evolutionary/ phylogenetic affinities
What are 4 other definitions that we can use besides species diversity?
- phylogenetic diversity
- functional diversity (eg biochemical)
- habitat diversity
- ecosystem diversity
Does species richness affect the health of an ecosystem?
Yes!
Related to net primary productivity
- more species= more resistant to change, better able to recover from disturbances like fire
How might functional ecosystems help us as humans?
Give up to 6 examples
- forests capture CO2 that we emit
- wetlands immobilize some toxins that we produce
- Ecosystems are a source of useful products like medicines
- aesthetic value
- spiritual/ cultural value
- recreational value (eg hiking)
Give a specific example of ecosystems providing medicines and improving human quality of life
Caterpillar fugus in China:
- used to treat the flu & tuberculosis
- worth lots of $, so has pulled lots of villages out of poverty
______ _____proposed that an area occupied by many species is more ecologically stable than one occupied by a small # of species
Charles Darwin
_______ ______ proposed more species added more functional stability
- this was an addition to Darwin’s proposal
Robert MacArthur
What is the Rivet Hypothesis? Who proposed it?
species are like rivets in an airplane (ecosystem or community)
- if you lose a few, the plane keeps flying, but if you lose too many, it fails
Paul Ehrlich
generally, ___(more/less) diverse ecosystems function better: they’re more productive and more stable
more
Alpha diversity=
species diversity in a certain area
eg in a plot or hectare
Beta diversity=
compares species diversity between adjacent locations (communities)
- related to habitat or niche diversity between sites
Gamma diversity=
overall species diversity within a large area
eg. entire ocean basin, continent, biomes, etc
Delta diversity=
compares species diversity between large areas
- eg between ocean basins/ continents/ biomes
-
- species richness
- species abundance
Species abundance curves often exhibit a shape where we see lots of ___ species and a few ____ species
(common or rare)
rare
common
ie. there may be 40 individuals in species A and species B, but there are 50 other species who only have 1 or 2 individuals in each species
Species richness=
the number of species in a defined area (usually a community)
What is an issue with using species richness?
It doesn’t differentiate between rare vs common species
Species evenness=
a comparison of the relative abundance of each species in a community
- evaluates the numbers of rare and common species
The greatest species evenness occurs when all species in a community have ___ abundances
equal
Explain when very low species evenness might occur
when one species is very abundant and the rest are extremely rare
Which metrics are used to find diversity?
Shannon Wiener Index and Simpson’s Index
Compare Shannon Wiener Index and Simpson’s Index
Shannon Wiener stresses richness component and rare species
Simpson= more emphasis on evenness component and on the dominant species
Linnaean shortfall=
the gap between what actually exists and what we’ve measured so far
(there is a lot we don’t know!)
T/F
monitoring and measuring varies with the method, definition, and sampling effort used
true!
= sampling bias
hotspots=
areas with high endemism and biodiversity
endemism=
taxa unique to an area (they have a limited distribution)
cosmopolitan species=
have a large distribution and are found all over the place
eg humans!
List 4 places that have high biodiversity
tropical biomes
Mediterranean biomes
coral reefs
many islands
Do latitudinal diversity gradients exist? Explain
Yes!
Higher species richness at lower latitudes, and it decreases as you go poleward
Vascular plants have increased diversity around the equator, except in Africa. Why is this?
Sahara desert! Many things cannot survive there; limited water
Birds have higher diversity (more species) in the southern hemisphere. Why?
The habitat south of the equator is simply more suitable compared to the northern hemisphere
Amphibians have greater species richness near the ___ and the ___ hemisphere
tropics
southern
Freshwater fish have greater species richness near the ___ and the ___ hemisphere
tropics
southern
Corals are most diverse between +/- __ degrees latitude. How might climate change alter that?
30
with climate change, corals are moving northward to stay in cold enough waters (their range of tolerance is very small, and the waters in their original habitat are getting too warm)
Both terrestrial and marine mammals have higher diversity towards the ____ and in the ___ hemisphere
tropics
southern
The effect of elevation:
Species richness of most terrestrial organisms:
- _____(inc/dec) along coastal plains
- ___ more rapidly with ascent to foothills or mid-elevations of mountains
- ___ approaching ice-covered summits
increase
increase
decrease
Peninsula effect=
the tendency for species richness to decrease from the mainland connection toward the most distal point on the peninsula
Why does the peninsula effect occur?
it’s hard to get to the end of a peninsula!
More of an isolated habitat out there
List (up to 6) abiotic factors affecting diversity
- energy availability (food)
- moisture
- time (age): generations/ millennia
- area
- environmental stability/ predictability
- intermediate disturbance hypothesis
t/f
The latitudinal gradient in diversity that we see appears to be an ancient pattern that varies among and within taxa over time
true
There has been a long-term diversity ___-__ over evolutionary time
build-up
