- Bigger is better
One of the 'laws' of evolution is that animals tend to become larger over time until extinction does them in.
( 1 ) Of course, this rule of thumb is not universal. I tend to think that Deperet's Rule always applies to
the ruling classes of herbivores and their predators because they engage in an arms race over thousands
of years. Whatever the case, the intriguing part is that although the paleo-mathemagicians discovered this
trend, they never associated it with the mass extinctions that occurred at the end of the major periods. For
instance, how would an asteroid or a volcano know that it has to strike ALWAYS at the end of a period
when the animals have grown big and strong rather than at a time near the beginning of a radiation?
| Cope's Rule |
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| The History of Life on Earth |
Animals that die in a mass extinction are the last of their long dynasties. Following Cope's Law, they have
grown big over the millions of years since their progenitors founded the lineages. Random examples follow:
- "During the Devonian, land plants underwent a hugely significant phase of evolution.
Their maximum height went from 30 cm at the start of the Devonian, to 30 m at the
end of the period. This increase in height was made possible by the evolution of
advanced vascular systems, which permitted the growth of complex branching and
rooting systems. In conjunction with this, the development of seeds permitted
reproduction and dispersal in areas which were not waterlogged, allowing plants to
colonise previously inhospitable inland and upland areas. The two factors combined
to greatly magnify the role of plants on the global scale. In particular, Archaeopteris
forests expanded rapidly during the closing stages of the Devonian."
Late Jurassic
"But it wasn't just the variety of dinosaurs that made this a golden age. The Late
Jurassic was also the era of the giants."
Oligocene - Miocene
"The pig from hell [Entelodont] was about to show it could withstand the test of
evolution... by getting bigger... One of the selective factors that we see going on
is animals becoming larger because it enables them to cover larger distances to
find the food resources that they need to survive... It's like an arms race. If the
prey become much larger, they become too big for carnivores to handle and so
the carnivores have to get much larger to feed on these larger prey items."
- Toward the end of their reign, the dominant herbivores and carnivores tend to have fewer -- usually one --
offspring. Their gestation periods have become longer. By now the animals are essentially sedentary.
They have found their Garden of Eden -- lush forests and jungles where herbivores find their favorite plants
and carnivores their favorite victims. Therefore, the animals don't need to travel all over the planet. They
will all make their last stand wherever they ended up stranded.
We can also infer that toward the end of their reign, the dominant animals have conquered most of the
diseases that had periodically affected their forefathers. Predators and victims have shared endemic
diseases for thousands of years. Whatever mutations occur in the viruses and bacteria at this point affect
an ever smaller percentage of the population. This allows the populations to expand. In general, we should
see a peak population shortly before extinction. We can safely say, for example, that the elephant is
an old species about to become extinct because...
- 1. it's long lineage extends 5 million years at least
2. they have grown big as a result of the arms race.
3. they are the last of their kinds of a once more diverse dynasty that includes
161 extinct cousins.
The elephants are a product of Cope's Rule
Animals grow larger over thousands of years as a result of the arms race between predators and victims. Why doesn't the asteroid strike or the volcano erupt when the lineages are just starting out? Why do mass extinctions always occur at the end of the process? |