If you don't see anything above, please install Java 1.4)
The database open for various ways to view the data fororrigination
and extinction of life on earth. First one select the sub-section of
data one wants to view by selecting a starting genera number N, and
how many genera one wants to view in total (dN). The genera are
numbered consecutively as in Sepkoski's database where more related
genera tends to be closer to each other.
In plots type=0,1,3,4 and the x-axis rank the data after the genera
number in the Sepkoski Database. The different plot types are:
plot type=0: show total life time of each genera.
plot type=1: show time period where each genera existed.
plot type=2: show duration matrix where we at genera give rice to a
count at position (x,y) where x is origination time and y extinction
time. Larger dots and lighter color indicate that many genera shared
plot type=3: show rice and fall of orders in terms of how many
genera they consisted of.
plot type=4: like type=3, but slightly differently plotted.
plot type=5: Total number of genera, color coded according to which
order they belong to.
plot type=6: like 5 but with uniform color.
Color code opens for various color schemes, where we in particular
recommend code=1. In any case color is graded according to
origination time (except in type=2). Further with Alternating
color=1, then each second taxonomic Order is colored according a
blue grading. Thereby one can separate orders visually.
This applet display a large part of the known fossil record. The
underlying data is from Sepkoski's extensive library studies,
collected in his database of origination and extinction of about
A genera is a group a species, like we humans for example are part
of the genera consisting of neandertals, cro-magnon etc. The
database of Sepkoski mainly consist of marine animals. The applet
deal with the 31363 genera in the database which are not existing
now. The data are grouped in Orders, a taxonomic unit which often
only contain a few genera, but sometimes consists of more than 1000
genera. In general closely related genera tends to be closer along
the genera number.
The various ways to present the data emphasize correlation between
extinctions across different taxonomic groups, it emphasize certain
large scale extinction events, and also one could see that closely
related genera often have similar lifetimes, even when they live at
widely different times. The data treatment are systematized in our
publication by Bornholdt, Sneppen and Westphal below.
J.J.Jr. Sepkoski and A.I. Miller (1988) Paleobiology 14, 364-369.
J.J.Jr, Sepkoski (2002) A Compendium of fossil marine animal genera.
Edited by D. Jablonski and M. Foote., M. buletin of American
Paleontology 363, 563 pages.
S. Bornholdt, K. Sneppen, H. Westphal. Longevity of orders is
related to the longevity of their constituent genera rather than
genus richness (2006). q-bio.PE/0608033