Sexual selection stays directionally constant while physical natural selection oscillates

Evidence

Because social environments evolve in tandem with increases in weapon size, sexual selection can push populations along a path of unending directional change. Selection in this social context is not likely to oscillate. Measure selection in a beetle population now, measure it in a decade, measure it one thousand years in the future, and you’re likely to find the same thing: males with the biggest horns win. The particular weapon size performing best will change (one-half-inch horns give way to three-fourths-inch horns, and then to one-inch horns, and so on), but the direction of selection remains constant. All else being equal, this form of selection is going to generate a lot more change than selection oscillating back and forth or holding fast. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 185

Categorization

• XREF: connects to: Sexual selection is uniquely directional because the social environment itself evolves with the weapons; The boundary between biological and cultural evolution is dissolving — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 493; Oscillating selection can produce stasis despite strong directional pressure — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 701 (+6 more)

Related

• Sexual selection is uniquely directional because the social environment itself evolves with the weapons (similarity 0.95)
• Social competition environments evolve in tandem with weapons, unlike fluctuating physical environments (similarity 0.94)
• Sexual selection can be far stronger than natural selection and drives weapon extremes (similarity 0.92)
• Oscillating selection can produce stasis despite strong directional pressure (similarity 0.90)
• Competition for reproduction drives evolution of nature’s biggest weapons (similarity 0.89)
• Oscillating directional selection can produce net evolutionary stasis (similarity 0.89)
• Sexual selection drives weapons to extremes because payoffs for winners are enormous. (similarity 0.88)
• Weapon size in animal species is under stabilizing selection, not open-ended directional selection (similarity 0.88)
• Each weapon-size increase resets the competitive baseline, ratcheting populations upward (similarity 0.87)
• Natural selection usually favors modest weapon size because cost offsets benefit (similarity 0.87)
• Balancing selection normally curbs weapon size until some lineages escape into runaway arms races (similarity 0.86)
• Reproductive success, not survival, drives the largest animal weapons (similarity 0.86)
• Extreme weapon size faces stabilizing, not open-ended, selection in real populations (similarity 0.86)
• Markets and battlefields select among rifle designs like natural selection acts on weapons (similarity 0.86)
• Species with huge weapons often show weak current selection on them. (similarity 0.85)

Broader Connections

• Social competition environments evolve in tandem with weapons, unlike fluctuating physical environments #corroborates (0.75) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 182
• Weapon size in animal species is under stabilizing selection, not open-ended directional selection #contradicts (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 850
• Competition for reproduction drives evolution of nature’s biggest weapons #corroborates (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 136
• Human and animal arms races follow parallel evolutionary dynamics #expands (0.45) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 463