predators can shape evolution in their preyuroplatus phantasticus dendrobates azureus cruziohyla...
Post on 19-Dec-2015
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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.