Biology 102Lecture 10Outline of Last Lecture:I. Clicker QuestionsII. Sympatric Speciation and PolyploidyIII. Adaptive RadiationOutline of Current Lecture:I. Clicker QuestionII. Gradualism III. Evolutionary NoveltiesIV. Embryotic DevelopmentClicker Question- A large lizard population (1,000 individuals) on the coast contains mostly individuals thatare plain brown, but a few have white spots. Coloration is genetically determined. One day during a storm, two spotted lizards hitch a ride on a piece of driftwood to a nearby island, where they join a population of 100 lizards, some of which are spotted and some of which are plain brown. The island’s lizard population allele frequency has thus changed due to…. gene flow Gradualism- Speciation can happen gradually or sporadically- Gradualistic pattern- when the event or changes occur slowly or accumulate changesfrom one population to the nexto Can be either: Punctuated- when speciation occurs very quickly, we don’t know how it happened Once that species appears there’s not much change Fast paced- in response to quick environmental changes Ex. whales evolved in a Gradualistic patternEvolutionary Novelties Evolutionary novelties can occur in many ways- Complex structures: eyes- Evolved in many stages, started from one line of cells that could only tell whether or not it was light or darkBiology 102- Exaptation- the process by which a complex structure develops from a primitive structure- Evo-devo: a field that combines evolutionary and developmental biologyEmbryotic Development- Evo-devo theory came from studies of fruit flies- The fruit fly had antennae and then mutated and grew legs on their faces- Homeotic genes- the order in which these are turned on during development controls what
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