global biodiversity patterns Flashcards
define biodiversity
Biodiversity is the variety of life in all its manifestations (note that it is a highly value-laden concept)
complicated biodiverse def
Biological diversity means the variability among living organisms from all sources including, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and ecosystems
define biological species
‘biological species’ – individuals that cannot interbreed successfully with other individuals that are classified as belonging to different species (species are therefore surrounded by a ‘reproductive barrier’)
define morphological species
individuals that look sufficiently similar and are assumed to interbreed successfully - most common to employ this def
what is commonly used as a measure of biodiversity
species richness/diversity
why is it advantage to use species richness a measure of biodiversity
- intergrates many facets of biological complexity
- easy to measure
- patterns in species richness are well know
how many different species
4-50million
name and explain the biological equivalent of the big bang
explosion of diversity from the Cambrian onwards 550mya- best illustrated in the Burgess Shale discovered in Canada by Charles Walcott
by when had all modern day phyla evolved?
end of the Cambrian
what is adaptive radiation
the diversification of a group of organisms into forms filling different ecological niches.
describe the increase in adaptive radiation
non linear
periods of increase, stabilization and periods of diversity loss - mass extinction events
name the three major phases of rapid diversification
Cambrian
Ordovician
Mesozoic-cenozoic
name the five mass extinction events
- end Ordovician
- late Devonian
- end Permian
- end Triassic
- end Cretaceous - K-T, kpg end of dinos
evidence of a tsunami
fish fossils ended up in north Dakota from mexico
name the three patterns of biodiversity
endemic
pandemic
disjunt
endemic
restricted - not the same an indigenous
belongs to a place and nowhere else
pandemic
found everywhere (cosmopolitan) very widespread
disjunct
divided
where you have populations that are divided by considerable distances
example of endemic species
waboom protea nitida
example of pandemic
bracken fern pteridium aquilinum
disjunct
proteacae
what is the latitudinal diversity gradient
- consistent global pattern - an increase in diversity towards the tropics
- works for altitude and depth
some examples of the latitudinal div gradient
- swallowtail butterflies
define a biological hotspot
places outside the tropics that have an exceptional concentration of plant and animal species
how did norman myers define a biodiversity hotspot
area where exceptional number of species found nowhere else are undergoing massive habitat loss
how many species are collectively found in these hotspots
at least one third
25 hotspots
on 1.4% of earth’s land
what would preserving these hotspots do
significantly reduce possible mass extinctions
areas that are typically hotspots
islands
winter rainfall areas
figure analysis of hotspots
- 25 hotspots
- 44% plant species
- 35% vertebrates
- associated habitats have been reduced in area by 88% - humans
- Prominence of tropics in general (16/25), tropical forests (15/25), islands (9/25), Mediterranean-climate regions (all 5 are included)
where are the hottest hotspots
Madagascar Philippines Sundaland Atlantic Forest of Brazil Caribbean Indo-Burma Western Ghats/Sri Lanka East African forests
direct uses of biodiversity
- food
- medicine
- biological control
- industrial materials
- recreational harvesting
- ecotourism
indirect uses of biodiversity
- atmosphere/climate regulation
- nutrient cycling
- photosynthesis
- soil formation
non-use value of biodiversi
- option value’ – keeping our options open
- intrinsic value (ethical responsibility)
