Punctuated Equilibrium.

Punctuated Equilibrium

01. Environments and ecosystems tend to remain unchanged for long periods of time.
a. This favors a wide range of successful life forms.
b. The downside is the dependence and reliance on a narrow range of food and climatic conditions, a limited number of predators, with offspring whose characteristics are based on prolonged and static conditions.
02. Environments change slowly over very long periods of time.
a. Uniformitarianism.
03. All otherwise static environments are subject to large and sudden changes.
a. Catastrophism / Punctuated Equilibrium.
04. Slow and gradual, versus swift and dramatic. Environmental pressures that strain survivability, favor subtle, beneficial improvements via mutation. Over time, subtlety becomes common diversity.
05. Lesser species that, because of competing foragers and dominance of larger animals, plus highly adapted predators, develop the abilities and assets to survive within a broad range of both harsh and friendly environmental conditions.
06. Greater demands or requirements foster keener, more plentiful talents and attributes. Tree dwellers need (are selected for) stereoscopic color vision, manual dexterity for maneuvering through trees. Such virtues act as additional, albeit coincidental, benefits when creatures descend to ground level. An enhanced but unintended set of survival qualities. Incidentally fortuitous attributes.
07. Small size is also helpful. In a prehistoric world where brute force is a common, thoroughly evolved trait, diminutive stature plays an equally powerful, significant role. Fast and cunning outwits and outruns large, less intelligent predators. Many carnivores and omnivores (snakes, reptiles, cats, dogs) are also small, and feed on an abundance of small prey.

A Time When Three Prominent Land Animals Outnumbered All Others, But Only One Dominated All Its Rivals.

01. Small dinosaurs.
02. Small mammals.
03. Large dominant hybrids (pig-like) that are part dinosaur, part mammal.

Times Of Periodic, Small And Large Extinction Events.

01. Types of pigs, which embody mammalian/reptilian characteristics, grow dependent on specific types of food.
02. Big extinction events produce major changes/big opportunities for both plants and animals.
03. Small extinction events produce minor changes that may result in large ripple effects.
04. Keystone species, deprived environments, impoverished environments, stressed environments and species.
05. Survival favors those already most adapted to change. Those whose offspring, via previous adaptations, are suitable to newer, wider ranges of change.
06. Change favors separation of dinosaurs and mammals. Each is uniquely adapted to ever more stressful demands of ever-changing ecosystems.
07. Pigs go extinct during next crisis event. Dinosaurs then take over as dominant species.
08. Dinosaurs also mimic limitations of pigs. The price of dominance is remaining in highly defined niches for too long. Bodies adapt to precise requirements which then disappear suddenly during the next extinction event.
09. Mammals (also pig descendents) trade places, take over from dinosaurs.

After common, domesticated cats were introduced into the Hawaiian ecology, they decimated the uniquely adapted life forms that possessed no defenses against these previously nonexistent predators. Most species have gone extinct as a result of this and other intrusions, whose sudden appearance did not allow for a gradual and more natural process of assimilation. As a result, biologists consider Hawaii as an impoverished environment, meaning the ecosystems that remain contain relatively few varieties of plant and animal species, many of which are themselves endangered. As a result, four groups have emerged as successful, opportunistic life forms:

01. Cats.
02. Prey animals who eat dead cats.
03. Those who scavenge on leftover carcasses of prey animals killed by cats.
04. Those who are good at hiding from cats.

Hawaiian cats, who have no natural enemies, except humans, have undergone an explosion of their feral population. Given a hypothetical extinction event where cats die off, life forms dependent on cats, uniquely adapted to their existence, then wither and also go extinct. Subsets of predator and prey thrive, occupy newly open niches now available from the absence of cats. Some of those previously adapted to the former circumstances, where cats reigned supreme, may, because of slight differences among them, be well suited to an onset of new changes. All others are doomed. A system that is elegant in a fiercely efficient way.