Major Events In The History Of Life

Humans evolve; many large mammals become extinct

Diversification of birds, mammals, flowering plants, and insects

Dinosaurs continue to diversify; flowering plants and mammals diversify. Mass Extinction at end of period (=76% of species disappear)

Diverse dinosaurs; radiation of ray-finned fishes

Early dinosaurs; first mammals; marine invertebrates diversify; first flowering plants; Mass Extinction at end of period (=65% of species disappear)

Reptiles diversify; amphibians decline; Mass Extinction at end of period (=96% of species disappear)

Extensive "fern" forests; first reptiles; insects diversify

Fishes diversify; first insects and amphibians. Mass Extinction at end of period (=75% of species disappear)

Jawless fishes diversify; first ray-finned fishes; plants and animals colonize land

Mass Extinction at end of period (=75% of species disappear)

Most animal phyla present; diverse algae

Ediacaran fauna

Eukaryotes evolve; several animal phyla appear

Origin of life; prokaryotes flourish before the ages of the eras and periods were known. The scale at the left of Table 22.1 gives a relative sense of geological time and the vast expanse of the Precambrian era, during which early life evolved amid stupendous physical changes on Earth.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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