GALAPAGOS ISLANDS GALAPAGOS ISLANDS GALAPAGOS ISLANDS GALAPAGOS ISLANDS

GALAPAGOS ISLANDS

GALAPAGOS ISLANDS

GALAPAGOS ISLANDS

GALAPAGOS ISLANDS

GALAPAGOS ISLANDS

ADAPTIVE RADIATION (An Ancestral Species Diversifies into Separate Species, each Adapted to a Different Ecological Niche)

MECHANISM: NATURAL SELECTION 1) Organisms reproduce 2) Variation exists in populations, and is heritable 3) More offspring are produced each generation than can be supported by the environment 4) Some individuals, because of their physical or behavioral traits, have a higher chance of surviving than other individuals

OBSERVING NATURAL SELECTION

OBSERVING NATURAL SELECTION I Peppered Moth (Biston betularia) Biston betularia var. carbonaria Biston betularia var. typica

OBSERVING NATURAL SELECTION I Dark Bark 3 Light Bark

OBSERVING NATURAL SELECTION I England: Industrial Revolution 1800 1900

OBSERVING NATURAL SELECTION II Brown Anole (Anole sagrei) 5 10 8 9 6 7 Anoles (Anolis): 150 species in the Caribbean Islands

Observed Relationship of Hind Limb Length to Vegetation in Brown Anoles (Anolis sagrei) 13 11 14 12

Observed Relationship of Hind Limb Length to Vegetation in Brown Anoles (Anolis sagrei) Fig. 4. 13 in Molles 2008

TESTING FOR NATURAL SELECTION Introduction of Brown Anole Populations from Staniel Cay Island to 14 Caribbean Islands with NO PREEXISTING Anole Populations 15 Brown Anole (Anolis sangrei)

10 -14 Years Later. . Fig. 4. 12 in Molles 2008

Phenotypic Plasticity or Ecotypic Difference?

A TEST FOR HERITABILITY

OBSERVING NATURAL SELECTION III Trees in Soapberry Family (Sapindaceae) 17 18 Species Native to U. S. (3) Soapberry Bug (Jadera haematoloma) 19 Species Introduced to U. S. (3)

Size of Fruit in Native and Introduced Soapberries Florida Fig. 4. 15 in Molles 2008 South Central U. S.

Observed Relationship between Beak Length of Soapberry Bug and Fruit Radius (Both in FL, TX) Fig. 4. 16 in Molles 2008

Question: Phenotypic Plasticity (= Developmental)? Ecotype (with Genetic Basis)?

Lab Experiment to Test for Heritability of Beak Length • Rear Juveniles Bugs with Small Beaks on Large Fruited Soapberries • Rear Juvenile Bugs with Large Beaks on Small Fruited Soapberries

Results

Types of Natural Selection in Populations: DIRECTIONAL SELECTION 20 22 21 24

FITNESS (Number of Offspring Contributed by an Individual Relative to Number of Offspring Contributed by Other Members of the Population) 22 20 21 24 Which Members of this Rabbit Population have Higher Fitness?

Forms of Natural Selection in Populations: DIRECTIONAL SELECTION Fig. 4. 9 in Molles 2013

Forms of Natural Selection in Populations: DISRUPTIVE SELECTION 20 23 22 21 24

FITNESS (Number of Offspring Contributed by an Individual Relative to Number of Offspring Contributed by Other Members of the Population) 22 20 21 23 Which Members of this Rabbit Population have Higher Fitness?

Forms of Natural Selection in Populations: DISRUPTIVE SELECTION Fig. 4. 9 in Molles 2013

Forms of Natural Selection in Populations: STABILIZING SELECTION 20 22 Fig. 8. 15 in Molles 2006 21

FITNESS (Number of Offspring Contributed by an Individual Relative to Number of Offspring Contributed by Other Members of the Population) 22 20 21 Which Members of this Rabbit Population have Higher Fitness?

Forms of Natural Selection in Populations: STABILIZING SELECTION Fig. 4. 9 in Molles 2013