Origins of Orchids

For November 6, 2019                Please share this with your friends & neighbors.
Hi WN@TL Fans,
Sometimes, one picture really is worth all those words.
Orchids enchant us with the protean range of their shape-shifting flowers.  They also baffle botanists trying to parse their pedigrees. 
This week (November 6) Tom Givnish, professor of Botany, returns to share with us a new map of the origins and diversifications of the orchids.
Here’s how he describes his presentation, entitled “Drivers of Megadiversity in the Orchids, the Largest Family of Flowing Plants”:
“Orchids are the most diverse family of angiosperms, with more species than mammals, birds, and reptiles combined. Many ideas have been advanced to account for their extraordinary diversity, but they have – until quite recently – been impossible to test because we lacked a good phylogeny (family tree) for the orchids. 
“My colleagues and I have now developed a well-resolved phylogeny for the orchids, based on large numbers of chloroplast genes, and I will show how we can use this phylogeny to identify the age and place of origin of the orchids, assess the role of different orchid traits in driving high rates of speciation, and reconstruct the geographic spread of orchids across the planet. 
“I will also describe some of the remarkable aspects of the ecology of this endlessly fascinating group that have recently come to light, mention some of the notable aspects of orchid diversity in Wisconsin, and sketch some interesting scientific and conservation issues that should be explored in the future.”
About the Speaker
Thomas J. Givnish is a plant evolutionary ecologist and holds the Henry Allan Gleason Chair in Botany at the University of Wisconsin-Madison. He received his Ph.D. from Princeton in 1976, and taught at Harvard until 1985 before moving to Madison. He is a Fellow of the Linnean Society of London and of the American Association for the Advancement of Science. His interests focus on plant adaptation, speciation, and the analysis of species relationships, historical biogeography, adaptive radiation, and the determinants of diversity. Givnish analyzes the connections of key physiological and morphological traits to a plant’s ability to maximize energy capture and compete successfully in different environments, and has used these connections to provide several pioneering explanations for patterns in plant form, physiology, and distribution along ecological gradients, as well as in the diversification, adaptive radiation, and geographic spread of plant lineages through time and space. He and his students have conducted field studies in several remote areas of North and South America, Hawaii, Australia, and Africa.

Givnish has recently led two international consortia to reconstruct the evolutionary history of bromeliads and monocots as a whole, as well as smaller research groups studying orchid diversification, adaptive evolution of the Hawaiian lobeliads, and maximum tree height in Eucalyptus. He and his colleagues are now using a series of common gardens, physiological measurements, and models to assess how variation in physiological and hydraulic traits maximizes the local competitive ability of Eucalyptus species and determines their distributions along a steep rainfall gradient in Australia.
Next week (November 13we get an especially timely presentation at a special location:  Room 1100 Grainger Hall, 975 University Avenue, Madison WI.  Robert Streiffer, professor of Medical History & Bioethics and of Philosophy, will provide his insights & analyses into the ethics of human genome editing.  
He’ll be comparing differences between edits to somatic cells versus germline cells, and between edits intended to treat a disease or disorder versus to enhance a trait.  He’ll delve into the particulars of the announcement from China last year of the birth of the first human babies with edited genes, which used Crispr technology.
Hope to see you soon at Wednesday Nite @ The Lab.

Thanks again!
Tom Zinnen
Biotechnology Center & Division of Extension