Biogeography & evolution:
•Hypothesis: Biogeography and evolution of Skinneri Complex can be
explained by a ‘dynamic habitat’ hypothesis
similar to that proposed by Gregory & Chemnick (2004) for Mexican Dioon
•Driving factor: Periodic sea level rise and fall rather than (or in addition to) temperature fluctuations
•
ŕ Higher sea levels during inter-glacial
periods created geographical
barriers that isolated cycad populations, allowing them to evolve independently
ŕ Lowered sea levels during ice ages allowed
for renewed genetic
interchange as populations merged back into newly exposed land areas