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
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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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.