The evolution of spiders has been going on for at least 400 million years, since the first true spiders (thin-waisted arachnids) evolved from crab-like chelicerate ancestors. Today, there are 42,473 described spider species within the diverse phylum of arthropods.
Major developments in spider evolution include the development of spinnerets and silk secretion.
Read more about Evolution Of Spiders: Early Spider-like Arachnids, Emergence of True Spiders
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“The evolution of a highly destined society must be moral; it must run in the grooves of the celestial wheels.”
—Ralph Waldo Emerson (1803–1882)
“The more specific idea of evolution now reached is—a change from an indefinite, incoherent homogeneity to a definite, coherent heterogeneity, accompanying the dissipation of motion and integration of matter.”
—Herbert Spencer (1820–1903)
“The mind cannot support moral chaos for long. Men are under as strong a compulsion to invent an ethical setting for their behavior as spiders are to weave themselves webs.”
—John Dos Passos (1896–1970)