Macroevolution Macroevolution - Definition • Changes that occur at or above the level of species • Describes the processes and patterns of originations, adaptations and extinctions • Reconstructs climates and environments in which species lived Motors of macroevolution: speciation and extinction • Ecological theory: • N1 + births + immigrations – deaths – emigrations = N2 Evolutionary theory: • In a given geographic range: • D1 + originations + immigrations – extinctions – emigrations = D2 • Worldwide: • D1 (diversity) + originations – extinctions = D2(new diversity) • Why study origination α and extinction Ω? Rates of origination and extinction • Terms: Standing diversity and turnover Seafood over time Allmon et al. 2014 • Phanerozoic, curent geologic timescale Key questions in Macroevolution • Key questions: • Why would taxa have characteristic ranges of duration in the fossil record? • Why would taxa have different ranges? • What is cause of these characteristic durations? Challenges in Macroevolution • Question: • What are key challenges in studies in macroevolution? • How are they overcome? Challenge: the species concept Anagenesis? Punctuated equilibria Challenge: representation Rates of turnover over time Biogeography • Study of patterns of biodiversity over time and space • Dispersal and vicariance • Vicariance explains why phylogenies match landmass history Example: the Southern Ocean • Continental drift has been used to explain the distribution of marine benthic taxa in the Antarctic • But timing and mode of process? • Studied direct developers and booders Poulin et al. 2014 Example: the Southern Ocean • Median-joining haplotype networks constructed using COI sequences from Antarctic (blue) and Magellanic (red) taxa. A) Sterechinus (n= 150), B) Nacella (n= 191); C) Yoldia eightsii (n=20); D) Parbolasia corrugatus (n=20); E)muricid gastropods (n=20). A circle represents each haplotype and its size is proportional to its frequency. Pairwise divergence sequences (uncorrected p-distances) between Antarctic and South American lineages are included. Example: the Southern Ocean .