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November 28, 2012
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Sexual selection in prehistoric animals: misidentifications and false positives

 

Prof Kevin Padian, Department of Integrative Biology & Museum of Paleontology, University of California, Berkeley

 

Tuesday 11th December 2012
Neil Chalmers Seminar Room, DC2, NHM, 1330

 

Darwin acknowledged that the roles of some morphological structures are difficult to determine.  But he was clear about what sexual selection is, and the role of sexual dimorphism in it.  Because Darwin invented sexual selection, and based it on observations that have never been falsified, his definition cannot be wrong.  It has three components: (1) it explains why sexual dimorphism exists, and its central role in sexual selection; (2) the dimorphic structures or behaviours are used by one gender to attract mates or repel rivals for mates; and (3) these structures and behaviours help the bearer gain access to mates.  Strangely, palaeontologists and neontologists have largely ignored him.  Assertions of sexual selection/dimorphism in the fossil record suffer from a lack of statistical rigor and an unwillingness to test hypotheses through independent lines of evidence.  No such study has had any independent assessment of the chronological age or stage of its individuals, although such information is frequently available.  We show why much alleged sexual dimorphism in fossil tetrapods is more likely simply ontogenetic change, and why both a statistically significant population sample and an independent assessment of age of specimens are needed before the hypothesis of sexual dimorphism can be tested.

 

 

For additional details on attending this or other seminars see http://www.nhm.ac.uk/research-curation/seminars-events/index.html

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The big bang: the impact of twenty years of molecular systematics on understanding the algae.

 

by Professor Juliet Brodie, NHM

 

Wednesday 28 November 2012

6pm (following AGM at 5pm)

Linnean Society, Burlington House, Piccadilly, London W1J 0BF

 

Molecular systematics occupies a minute fraction of time in the history of science, but its impact has been transformative in revealing hitherto unrecognised diversity of life on earth. Furthermore, it has enabled us to see the extent of genetic diversity that is not necessarily reflected in the morphology of organisms. This has led to a fundamental shift in species concepts and as a consequence has profound implications for understanding distribution, rarity and endemism. In this talk Juliet Brodie will explore these ideas using examples from algal groups that she has studied and attempt comparisons with other organisms. She will also argue the necessity of using molecular systematics in understanding the impact of environmental factors such as climate change and ocean acidification.

 

 

The meeting is open to visitors

 

Wine will be served after the lecture to members and guests

 

http://www.systass.org/events/presidents_lecture_2012.shtml