Take Out The Following Labs SPECIATION MICROEVOLUTION & ALLELE FREQUENCY
“When The Student Is Ready, The Master Appears”-Buddhist Proverb
Cladistics Has Shown That Insects Have Evolved Through CONVERGENT evolution SIX DIFFERENT TIMES!
Evolution of Insects • 75% of all animals on earth are insects • Insects were NOT the first animals • Evolved during the Devonian (~400 mya) • The path of insect evolution is very different from all other animals
Gradualism Slow, incremental changes in allele frequency and phenotype over time Punctuated Equilibrium Long periods of no change in allele frequency and/or phenotype interrupted by rapid “bursts” of drastic change Different Models For Rate of Evolutionary Change
Divergent Adaptive Radiation Due to selective pressures, variations are favored and ancestral species become physically and reproductively isolated Convergent Organisms of different ancestry are acted upon by selective pressures that favor similar variations Divergent v. Convergent Evolution
Mainland Sympatric: Changes In Habitat/Food Source
Windsor Sympatric No Founder’s Effect
Microevolution Lab Results • Which atoll had highest frequency of black carapaces? • Wotho • Why? Founder’s Effect, Outbreeding or Selective Pressures? • Founder’s effect. No outbreeding or selective pressures • What about frequency of four legs? • Same
Microevolution Lab Results • How do frequencies of carapace color correlate with phenotypic frequencies? • Direct relationship. Highest frequency of black correlates with highest frequency of recessive allele • How do frequencies of appendages correlate with allele frequencies? • More direct due to incomplete dominance
Microevolution Results • Similarities with pollenpeeper analysis? • Reproductive isolation amplifies single phenotypes • Is artificial selection influencing any of the atolls? • Lae, human selection against red • Which atoll was most likely to exhibit Hardy-Weinberg equilibrium? • Wotho, due to no selective pressures or outbreeding
How do scientists evaluate the direction and pattern of evolutionary change?
Cladistics • Clade: from Greek word klados (branch) • Group of closely related organisms with shared derived properties
Cladogram • Diagram showing time and direction of divergence (or, occasionally, convergence)
Defining Cladistics By Phenotypic Traits • Plesiomorphy = Ancestral trait shared by members of a clade • Apomorphy = a newly evolved trait that separates taxa from their clade