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WorksheetsCambrian Radiation & Mass Extinctions I
Total questions: 15
Worksheet time: 8mins
The Cambrian Radiation is characterised by the evolution of....
skin
skeletons
feathers
lungs
In the deep divergence model for the Cambrian Radiation, animal body plans (phenotypes) evolved....
rapidly after the genotype
long after the genotype
during the Cambrian
none of the above
Why are deep divergence dates for basal animal groups hard to estimate?
Rates of genetic change may be wrong
We haven't got any fossil calibration points
Both of the above
None of the above
This is Cloudina, a member of the famous "smally shelly fossil" assemblage. It proves that....
Animals evolved skeletons during the Cambrian Radiation
Animals evolved skeletons after the Cambrian Radiation
Animals evolved skeletons shortly before the Cambrian Radiation
None of the above
Which of these groups probably arose around 700 Ma?
What was the biggest impact of the evolution of the gut during the Cambrian radiation?
change in ocean circulation
microbial extinction
decrease in atmospheric oxygen
evolution of faecal pellets
Most of the coloured circles in the blue vertical bar on this phylogenetic tree occur in the late PreCambrian-Early Cambrian. This shows that most major animal groups originated....
before the Cambrian
during the Cambrian
after the Cambrian
none of the above
Why were the Late PreCambrian and Cambrian oceans so rich in phosphate?
extinction of the Ediacarans
changes in the Earth's orbit
increased upwelling
more skeletons
On a phylogenetic tree, what's a calibration point?
A node where a new group originates
A known fossil occurrence
An extinction event
A polytomy
The Cambrian Radiation may not be a typical adaptive radiation because the animal groups involved....
may not have existed before the event
all existed before the event
aren't preserved
got smaller
A mass extinction....
affects many clades
results in reduced global diversity
Happens quickly in geological terms
All of the above
Do the taxa in the red box represent a clade?
Yes
No
We don't have enough information to say
Marine regression has been proposed as a causal agent for mass extinctions because it results in....
global cooling
global warming
volcanism
reduced ecospace on the continental shelf
The anhydrite country rock at the site of the Chicxulub impact is important because...
it generated molten glass spherules
it triggered collapse of the seafloor
it generated lots of sulfur aerosols that absorb solar energy
it ignited on impact
This figure shows that four years after the impact of a 10 km asteroid, global temperatures....
are significantly lower than pre-impact
are a little lower than pre-impact
are the same as pre-impact
are higher than pre-impact
