lec 27- macroevolution Flashcards
what determines species diversity?
speciation and extinction
D1 (diversity) + origination (first discovered fossil) - extinction (newly discovered fossil)/ (all over time) = D2 (new diversity)
what pattern is seen after a typical extinction boundary?
Turnover
what type of group of species tend to have higher origination rates than extinction rates?
diverse groups
origination rates a > omega extinction rate
when does diversity decline?
when extinction rates increases or origination rates decreases
omega > a
what are the three major fauna of earth?
Cambrian, Paleozoic, and Modern
when does true extinction occur?
when the last member of a clade dies, can be a species or a group of species
how many Mass Extinctions are there?
5
what is Biogeography?
the study of present and past geographical patterns of diversity
what controls biodiversity patterns?
climate, dispersal, vicariance, time, and history
what are the biogeographical regions?
-neararctic region
-neotropical region
-ethiopian region
-palearctic region
-oriental region
-australian region
what leads to vicariance (separated populations)?
continental drift
what split the continent during the Cretaceous?
North American seaway
where did the oldest marsupial fossils come from?
came from North America an eurasia
what southern supercontinent had many marsupials?
Gondwanaland
how did marsupials evolve?
through both vicariance and dispersal
do south american and Australian marsupials form a large clade?
yes, earliest ancestors from south america
are all native Australian mammals marsupials during the last 25 million years?
yes
when does adaptive radiation occur with respect to origination and extinction?
when origination is higher than extinction
a > omega
how many species of Hawaiian Honeykeepers exist?
50 species, many now extinct
what is the ancestor of Hawaiian honeykeepers?
the Eurasian rosefinch
how many species of silversword plant in Hawaii?
50 endemic species, an example of adaptive radiation
what are some examples of key innovations that led to adaptive radiation?
double jaws, Cambrian radiation of invertebrates (hard exoskeletons eyes etc.), flower evolution during cretaceous and pollination, dispersal to and colonization of new habitats with under contested niches
do cichlid fish show convergent evolution with other fish?
yes
what was the largest supercontinent called?
Pangaea
when did the largest mass extinction event occur?
at the end of the Permian period, on Pangaea
when did Pangaea start to break?
during the Mesozoic era, created more shallow shelves/ marine habitats and increased marine diversity
