1. (biology) a hypothesis of directed evolution (as opposed to natural selection of random variations)

Encyclopedia: Orthogenesis

• western tamarack
• western tanager
• western toad
• western United States
• western wall flower
• western wheatgrass
• western whiptail
• western white pine
• western wood pewee
• western yellow pine
• western yew
• westerner
• Westernisation
• westernise
• Westernization
• westernize
• westernmost
• westing
• Westinghouse
• westland pine
• Westminster
• Westminster Abbey
• westmost
• Weston
• Weston cell