Predators can shape evolution in their prey
description
Transcript of Predators can shape evolution in their prey
Predators can shape evolution in their preyUroplatus phantasticus
Dendrobates azureus
Cruziohyla craspedopus
Dermal fringes
Predator evolution pushed by prey
Thamnophis sirtalisTaricha granulosa+/- tetradotoxin
Ecologicalcontext
Resistance to tetradotoxin
Predator-prey coevolution
Predator-prey coevolutionSnakes and cane toadsBufotoxin
Brood parasites; e.g., cuckoos and cowbirds
Cuculus canorusEuropean cuckoo
Calls same
Acrocephalus scirpaceus, Reed warbler
Co-evolutionto egg rejection
Social Interactions• Actor and Recipient• Fitness possibilities (offspring units):• 1. both actor and recipient increase their
fitness: cooperative behavior • 2. fitness of actor increases, fitness of
recipient decreases: selfish behavior • 3. fitness of actor decreases; fitness of
recipient increases: altruistic behavior.
Maximizing fitness by selfish behavior
Conflict between cells and groups of cells
Slime molds: amoeboid and slug forms
Sporangium
chtA mutant Selfish behavior
Vegetative
Reproductive
Altruistic Behavior• The actor will perform an act
– places the actor at a disadvantage– benefits the recipient
• Intuitively, the fitness of the actor should decrease, and the fitness of the recipient should increase.
• Natural selection should eliminated altruistic acts.
Cooperation and Altruistic Behavior
• Slime mold• A gene for altruism • csA allele: adhesion protein• Cell differentiation in the slug• 1. Cells that form spores: DNA perpetuated• 2. Cells that form the reproductive stalk: die• Therefore, sacrifice made by some cells for the
benefit of others.
• Paradox resolved by inclusive fitness• For social animals, two categories of fitness• 1. direct fitness = personal reproduction. • But, because it is likely that relatives share some of
the same alleles…• 2. indirect fitness = assistance of actor results in
greater success in raising relatives to reproductive maturity.
• Actor’s fitness increased by an increase in frequency of alleles shared with relatives.