ammonites
Basic options Subsampling options Raw data columns Subsampling columns

Diversity curve request form

Your name:
If you entered your name when you downloaded the data, you must enter the same name here.
If you didn't, leave this field blank.
Time scale:
Bin size, millions of years:
Required if you selected either of the Neptune options above.
Taxonomic level:
Diversity measure to report:
Only relevant to subsampling. Sampled counts are recommended.
Count references instead of taxa?
Range extant taxa through to the Recent? yes

This form allows you to request a diversity curve with assorted statistics.

  • A diversity curve shows the number of taxa that are counted in different time intervals like epochs
  • To make things work, you need to download an occurrence data file first
  • If you just want to see a regular curve, select a diversity measure and press submit
  • To run a standardized subsampling analysis, fill out the three required fields
  • Subsampling analysis and diversity measures are explained in Alroy et al. 2001 (PNAS 98:6261-6266)
  • Note: our server is fast, but requests still may take a minute or two to process

Subsampling method:
Required for subsampling. A "list" is a list of taxa in a collection.
Weighting exponent:
Required for occurrences-exponentiated subsampling, and otherwise ignored. 2.0 = occurrences-squared weighting; 0.0 = unweighted subsampling; 1.0 = occurrences-weighted subsampling.
Exact number of items (collections, occurrences, or occurrences-squared) to draw in each temporal bin:
Required for subsampling.
Number of subsampling trials:
Required for subsampling.
Intermediate numbers of items to report in subsampling curves:
Not required.
Print subsampling stats for intervals with less items than the exact quota?
Not required.
Maximum number of references to draw in each temporal bin:
The count may be exceeded for computational reasons. Works with unweighted, occurrences weighted, or occurrences-squared weighted subsampling. Important: don't combine this with the "Count references instead of taxa" or the following option.
Avoid collections coming from references that yield many collections?
Works only with unweighted or occurrences-weighted by-list subsampling.

Check all    Check estimates
Base (Ma) Midpoint (Ma) Sampled taxa Range-through taxa Boundary-crosser taxa
Two timer taxa Three timer taxa
First appearances Origination rate Last appearances Extinction rate Singletons
Gap analysis sampling stat Gap analysis diversity estimate
Three timer sampling stat Three timer diversity estimate
Chao-2 estimate Incidence-based coverage estimate Jolly-Seber estimate Evenness of occurrences (PIE)
Collections Occurrences Occurrences-squared or exponentiated Specimens/individuals
Mean richness Median richness

Check all    Check estimates
Base (Ma) Midpoint (Ma) Items sampled Median diversity 1-sigma CI Mean diversity
Mean three timers Corrected BC diversity Estimated midpoint diversity Estimated mesa diversity
Raw SIB diversity Corrected SIB diversity
First appearances Origination rate Origination percentage
Last appearances Extinction rate Extinction percentage Singletons
Gap analysis sampling stat Gap analysis diversity estimate
Three timer sampling stat Three timer diversity estimate
Chao-2 estimate Incidence-based coverage estimate Jolly-Seber estimate Michaelis-Menten estimate

To compute Michaelis-Menten diversity estimates, set the diversity measure to "sampled-in-bin" and the subsampling method to "by list (unweighted)."