Time Tree - evolutionary distance between organisms

This is a pretty cool site. You plug in two different taxa (from species on up) and if they're both in the database, it gives you how long it's been since they're shared a common ancestor.
http://ift.tt/2d8AX8Y

spiders
Araneae

Dungeness crab
Metacarcinus magister

669.7 Million Years Ago
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organ-pipe cactus
Stenocereus thurberi

maidenhair fern
Adiantum capillus-veneris

404.6 Million Years Ago

via International Skeptics Forum http://ift.tt/2cCbbfK