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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:
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N1 + births + immigrations – deaths – emigrations = N2
Evolutionary theory:
• In a given geographic range:
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D1 + originations + immigrations – extinctions – emigrations = D2
• Worldwide:
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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
• Phanerozoic, curent geologic timescale
Allmon et al. 2014
Key questions in Macroevolution
• Key questions:
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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:
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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
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Continental drift has been used to explain the
distribution of marine benthic taxa in the Antarctic
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But timing and mode of process?
Studied direct developers and booders
Poulin et al. 2014
Example: the Southern Ocean
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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