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Adaptation A trait or integrated series of traits, that increases

Adaptation A trait or integrated series of traits, that increases the fitness of its possessor is an adaptation (such traits are said to be adaptive). Adaptations are the product of selection. Evolution by natural selection - individuals are phenotypically variable

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Adaptation A trait or integrated series of traits, that increases

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  1. Adaptation A trait or integrated series of traits, that increases the fitness of its possessor is an adaptation (such traits are said to be adaptive). Adaptations are the product of selection. Evolution by natural selection - individuals are phenotypically variable - variation is heritable - in every generation more offspring are produced than can survive - survival and reproduction are not random *the next generation differs from the last---favorable variants accumulate in the population

  2. Differences are not always due to adaptation Not every trait of an organism is an adaptation Adaptation is not perfection

  3. Differences are not always due to adaptation Not every trait of an organism is an adaptation Adaptation is not perfection

  4. Differences are not always due to adaptation Not every trait of an organism is an adaptation Adaptation is not perfection

  5. Approaches to Studying Adaptation Observational Experimental Comparative

  6. Experimental Approach to Studying Adaptation test the effect of variation in a single factor -- randomize effect of other factors test predictions made by several alternative hypotheses importance of controls large sample size; adequate replication

  7. Seasonal polyphenism and thermoregulatory adaptation in Pieris butterflies (Kingsolver-Wiernasz 1985, 1995) P. occidentalis % % &spring form P. protodice % % &spring form

  8. dark V Reduced D light V Darker D

  9. Question: is seasonal variation in melanin pattern adaptive? General Hypothesis: melanin pattern affects survival 1. Crypsis --- probability of being eaten 2. Temperature regulation --- reflectance basking *

  10. Prediction 1: changing the amount of melanin in specific regions of the wing will increase or decrease body temperature H0: changes in melanin pattern do not change temperature regulation HA1: increased melanin on basal dorsal surfaces will increase body temperature HA2: increased melanin on medial dorsal surfaces will decrease body temperature HA3: increased melanin on the ventral hindwing will increase body temperature Experiment: “add” melanin with a black magic marker, measure body temperature and onset of flight Control: “clear” magic marker added to the same region of the wing Additionally, control for age (wing wear); size

  11. Pieris napi black base treatment black distal treatment

  12. lighter darker

  13. Prediction 2: butterflies with the appropriate phenotype survive longer in the field H0: field lifespan is independent of melanin pattern HA1: short-day phenotypes will survive longer than long-day phenotypes in the spring HA2: long-day phenotypes will survive longer than short-day phenotypes in the summer Experiment: split-brood rearing under long-day (16L:8D) and short-day (10L:14D) conditions to induce phenotypic differences. Release and recapture during the spring and (in a separate experiment) during the summer.

  14. long-day phenotypes survived significantly better in 1992, for two time periods in 1991

  15. Comparative Method test hypothesis by comparing patterns of variation among species - variation in two characters associated among species - variation in a character is associated with variation in an environmental character across species

  16. A B C D* E* A* B C D E* vs. two kinds of potential confounds- - allometry - common ancestry

  17. Hippocampus lesion

  18. Pine Vole % % Meadow Vole % & & % % & & & & & & &

  19. % Cowbirds-- Brood parasite &

  20. Analyses that overlook phylogenetic relationships may be misleading mating system sexual size dimorphism plumage dimorphism present absent present absent Lekking 69 18 55 33 Non-lekking 13 13 8 18 (Hoglund 1989)

  21. Centrocercus urophasianus Dendragapus falcipennis D. canadensis D. obscurus Lagopus leucurus L. mutus L. lagopus Tetrao urogallus T. parvirostris T. textrix T. mlokosiewiczi Bonasa sewerzowi B. bonasia B. umbellus Tympanuchus cupido T. pallidicinctus T. phasianellus Phasianinae (outgroup)

  22. Mating system sexual size dimorphism plumage dimorphism present absent present absent Lekking 69 18 55 33 Non-lekking 13 13 8 18 after phylogenetic correction: Lekking 11 9 11 8 Non-lekking 6 9 6 7 (Hoglund 1989)

  23. Concordant evolution of locmotor behavior, display rate, and morphology in Anolis lizards Losos 1990

  24. morphology of appendages and locomotor behavior are correlated among flying, running, and swimming animals habitat matrix model -- different microhabitats select for morphology and behavior ---> appropriate locomotor mode two predictions: - morphology and behavior should have evolved in tandem - concordant evolution of locomotor patterns, morphology, social behavior three types of locomotion—running jumping walking are there morph specializations for each behavior? 13 species from Jamaica and Puerto Rico measured 15 individuals from each species

  25. Anole species from different habitats cluster in behavioral space PCA I II III % walk -0.86 0.45 0.08 % run 0.95 -0.15 0.06 % jump -0.13 -0.88 -0.32 move rate 0.34 0.80 -0.38 display rate 0.79 0.15 -0.39 max. jump 0.51 0.07 0.79 % var expl. 44 28 17 trunk-ground spp. crown-giant grass-bush  trunk-crown  * twig

  26. species with relatively long hind limbs (relative to body size) walk less frequently than species with short hind limbs (r = -0.753, p < 0.005)

  27. species with relatively short forelimb (relative to hindlimb length) jump more frequently than species with long forelimbs (r = -0.713, p < 0.01)

  28. species with high display rates have a higher frequency of running and jumping (r = 0.677, p , 0.025)

  29. Adaptations are the product of natural selection Three approaches to studying adaptation are: correlation of trait and fitness (observational) experimental manipulation comparative method Experimental approach--importance of clear hypotheses, good experimental design, including appropriate controls Seasonal polyphenism in wing pattern in Pieris manipulations of phenotype produce predicted effects on thermoregulatory performance mark-release-recapture in different seasons did not uphold predictions Comparative method—corrects for shared ancestry and correlated effects Hippocampus size and food caching Locomotor behavior and morphology in Anolis

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