VOLUME 18, NUMBER 3 AMERICAN FALL 2010 PALEONTOLOGIST A MAGAZINE OF EARTH SCIENCE PUBLISHED BY THE PALEONTOLOGICAL RESEARCH INSTITUTION AND ITS MUSEUM OF THE EARTH

EExploringxploring tthehe TTreeree ooff LLifeife

In this issue...

Th e Second Gulf of Mexico Oil Spill page 25

Paleontology: Biology of the Future page 27

...plus much more! US $5.00 FEATURE ARTICLE Why Study the Tree of Life? — Th e Scientists Speak

Edited by Paula Mikkelsen

Th e U.S. National Science Foundation provides the largest habitats, from the deep sea to coral reefs, and from mangrove and most prestigious chunk of federal funding to basic sci- swamps to freshwater lakes and streams. Given the growing ence in this country. Among its many initiatives, NSF funds concern over accelerating rates of biodiversity loss, we need a research to study the evolutionary relationships — the Tree of fuller appreciation of unique taxa for conservation purposes. Life — of a wide variety of organisms currently (and former- Finally, described sponges number approximately 8,122 valid ly) living on the Earth. Among the active and recently com- species, with half again as many — an estimated 4,000 spe- pleted projects in the "Assembling the Tree of Life" (AToL) cies — awaiting discovery or description. Recent molecular Program are large teams of investigators studying butterflies, research indicates that the current classifi cation system (with fish, beetles, clams, algae, bacteria, sponges, crustaceans, flag- 3 classes, 25 orders, 127 families, and 680 genera) is not a ellate protozoans, liverworts, seed plants, fungi, dinoflagel- particularly accurate refl ection of the group’s evolutionary lates, mammals, cnidarians, flowering plants, reptiles, birds, history. Th us, a well-supported Porifera Tree of Life will shed and bees. Each of these projects has assembled an authorita- light on new lineages, new relationships among lineages, and tive team of scientists, students, and technicians to examine new ways to view one of the earliest experiments in the evolu- the anatomy and molecular sequences of their organisms tion of multicellularity among the animals. and to run sophistocated phylogenetic analyses (or cladistics, - Malcolm Hill, University of Richmond, [email protected] which result in a cladogram or "tree") that will ultimately yield the best hypotheses of the evolution of these taxa. One RedToL — Th e Red Algal Tree of Life day, all of these pieces and parts will fi t together, providing http://dblab.rutgers.edu/redtol/home.php us with a complete picture of how life evolved, and continues Th e Rhodophyta (red al- to evolve, on Earth. gae) is one of the most But why are we doing this? Of what use is such informa- ancient groups, with fossil tion to everyday citizens? Each funded project is responsible evidence stretching back not only for their science, but for what NSF calls "broader 1.2 billion years. When impacts," which usually includes teaching at various levels anyone is exploring the and, importantly, interpretation of their science to the pub- rocky intertidal zone, lic. As American Paleontologist's contribution to those eff orts, these seaweeds are readily and to the United Nations' International Year of Biodiversity, visible, with their bright we asked AToL scientists to answer the question "Why do red to purple hues. Red al- we need to assemble the [xxx] Tree of Life?" Here are their gae contribute signifi cant- answers. ly to the ecology of rocky shores, providing food and PorToL — Th e Sponge Tree of Life shelter for many marine fi sheries. Th ese plants are not only https://www.portol.org key members of aquatic environments, they are sources of Assembling the Sponge Tree important human foods such as dulse and sushi wraps. Th ey of Life is important for a also have a multitude of pharmaceutical and industrial uses, number of reasons. Th e such as agarose and carrageenans. Perhaps most important appearance of sponges oc- is the role that red algae have played in the evolution of our curred at a critical point in planet through secondary endosymbiosis. More than one bil- the history of animal life, and lion years ago, a red alga was the donor of the chloroplast sponges provide clues about in chlorophyll-c containing algae. Th ese secondarily-derived the events that happened as algae rose to prominence in marine ecosystems after the end single-celled ancestors gave of the Permian Period (250 million years ago). Today, groups rise to multicellular animals. such as diatoms provide approximately 20% of the global Establishing a strong Tree of supply of fi xed carbon. Life for sponges will allow us Research by the RedToL team could potentially revolu- to explore ideas about the evolution of complex body forms. tionize algal biology by providing new hypotheses and clari- Sponges are also a common component of many benthic fying existing theories about the evolution of red algae and

10 AMERICAN PALEONTOLOGIST 18(3) Fall 2010 their place in the Tree of Life. One goal is to provide a red evolutionary history of all known organisms. Phylogenetic algal phylogeny based on multiple genes from the plastid, thinking is fundamental to understanding the diversity of nucleus, and mitochondrion genomes. Th is framework is life, and mapping the Tree of Life has enormous practical critical for supporting other types of research in such diverse potential to assist in ecological management decisions, un- fi elds as functional genomics, developmental biology, and derstanding the evolution of genomes and functional roles of ecology. A second goal is to learn about the evolution of red genes, and discovering new biological compounds. algae by sequencing the entire genomes of a number of key - Guillermo Orti, University of Nebraska Lincoln, [email protected] species. Th is part of the research will bring red algae into the - Richard Broughton, University of Oklahoma “genomic age” alongside better-studied groups like vascular - Teresa MacDonald, University of Kansas plants. - Morgan L. Vis, Ohio University, [email protected] AToL Decapoda — Th e Decapod Crustacean Tree of Life - Hwan Su Yoon, Bigelow Laboratory for Ocean Sciences http://decapoda.arthroinfo.org - Debashish Bhattacharya, Rutgers University Estimated to contain more - Juan M. Lopez-Bautista, University of Alabama than 15,000 species, the decapods are the most spe- EToL — Th e Euteleost Fish Tree of Life cies-rich and economically http://www.fi shtree.org important group of Crus- Euteleosts repre- tacea, including shrimp, crabs, crayfi sh, and lobsters. Fur- sent more than two thermore, many living families have well-documented fossil thirds of all fi sh and records. Accordingly, the decapods have been the subject of a third of all ver- more published papers than have all other crustacean groups tebrate species, in- combined. Given the prevalence of decapods in the public cluding virtually all and scientifi c mind, understanding the evolutionary history fi sh of economic im- of this signifi cant crustacean group is crucial. portance and those Our project brings together a team of international ex- used as model systems in scientifi c research. Despite their perts from a variety of disciplines, including comparative importance in medical research, and their vast potential for morphology (of both adult and larval decapods), paleontol- exploring a wide range of evolutionary trends and issues, the ogy, molecular biology, bioinformatics, evolutionary biology, higher-level relationships among fi sh taxa remain unclear — taxonomy, systematics, and fi eld biology, to collect samples, and for many, their status as natural groups has not been identify morphological characters and useful genes, sequence established. Th e Euteleost Tree of Life project (EToL) seeks DNA, and analyze the resulting data to develop a robust view to understand the diversity of euteleost fi sh by reconstruct- of the phylogeny of the Decapoda. Th is will allow us to ad- ing a well-supported "backbone" for the group using mor- just taxonomy to better refl ect evolutionary relationships, to phological and molecular data from 1,500 carefully chosen test hypotheses of the timing of diversifi cation events and of species. Project members are collecting DNA sequences and morphological change over evolutionary time, and to study compiling a comprehensive database of anatomical evidence. past and present trends in biodiversity and variables such as Th ese materials and the euteleost tree that results will help fu- time, morphology, and climate change. Th us, the Decapod ture researchers to better understand fi sh relationships, to test Tree of Life is the foundation for a wide variety of future hypotheses and make informed predictions for a wide range studies in evolutionary and comparative biology. of evolutionary issues such as character evolution, ecology, - Keith A. Crandall, Brigham Young University, biogeography, and fi sh diversity, and to expand the evolu- [email protected] tionary context for key model organisms (e.g., zebrafi sh and - Rodney M. Feldmann, Kent State University puff erfi sh) and for upcoming genomic projects. EToL research will become part of an online educational Early Bird — Th e Bird Tree of Life product targeted at high school students in the form of an in- http://www.biology.ufl .edu/earlybird teractive tree exploring the evolution of a few fi sh characters, Birds are among the most visible organisms in the environ- and an online module about molecular and morphological ment. Observing birds has delighted birdwatchers and pro- trees with activities that highlight the work of EToL scien- vided information to scientists for hundreds of years. Studies tists. Th ese resources will be disseminated through Under- of these beautiful animals have shaped biological thought. standing Evolution (http://evolution.berkeley.edu), a major For example, Charles Darwin’s theory of natural selection evolution education website that serves teachers, students, was infl uenced by observing closely related species that diff er informal educators, and the general public. markedly in the shape of their beaks. Since then, birds have EToL is part of the Tree of Life Web Project (http://tol- shaped our knowledge of topics such as speciation, behav- web.org/trees), an international endeavor to reconstruct the ior, ecology, development, and neurobiology. Given the level

AMERICAN PALEONTOLOGIST 18(3) Fall 2010 11 of attention from the public are among our most important resources. Seed plants set the and scientifi c communities, stage for the origin of agriculture, based on the cultivation of it might be surprising that grain, which provides the majority of calories consumed by the evolutionary relation- humans and the animals that feed them. ships among birds — the Avi- Despite the predominance of fl owering plants (angio- an Tree of Life — have been sperms) in most ecosystems and their inordinate contribu- declared intractable many tion to land plant diversity, they are just one of many lineages times over the past century. that comprise the seed plant clade, all others being gymno- Indeed, Erwin Stresemann sperms. Several gymnosperm lines are ancient, originating in wrote in 1959: the Paleozoic and reaching the height of their diversity in the Triassic and Jurassic Periods. Unlike the dinosaurs with which ...so many distinguished investigators have labored in this fi eld they coexisted, a few gymnosperms have persisted to the in vain, that little hope is left for spectacular break-throughs. present: the conifers, cycads, Ginkgo biloba, and the strange Only lucky discoveries of fossils can help us, but the chances of and enigmatic gnetophytes (Welwitschia, Gnetum, Ephedra). making such fi nds are very small. However, their diversity has decreased dramatically; fossils show evidence of at least 18 extinct groups. Angiosperms Th e lack of an Avian Tree of Life prevents us from putting all have fi gured heavily in attempts to understand the evolution of our knowledge about birds into context. Did the ability of seed plants, but this is like trying to understand the solar to learn songs – shared only by perching birds, humming- system without knowing the positions and composition of birds, and parrots – arise three times, or more, or less? Do most of the planets. Th e Gymnosperm Tree of Life Project hawks and falcons hunt in similar ways because their abilities is focused on extensive sampling in both living and extinct evolved once or separately in each bird? Did ostriches and clades of gymnosperms. Living gymnosperms comprise ap- emus lose the ability to fl y separately or through a common proximately 1,000 species, all of which are targets for DNA ancestor? sampling for our molecular phylogeny. So that evidence from By collecting large amounts of genetic data to compile extinct and living plants can be integrated, we are also focus the Avian Tree of Life, we now know to the answers to these ing on the morphology of fossils and a subset of living species questions. We now know that perching birds and parrots are (approximately 20% of species), broadly representing living related, and likely gained the ability to learn song from their diversity. Together these data will establish the context for ancestor, whereas hummingbirds learned independently. We understanding the evolution of seed plants. also know that hawks and falcons are not closely related, so Th e living collections found in botanic gardens and ar- their similar hunting methods are not derived from a com- boreta provide incomparable resources for teaching K-12 mon stock. Th e large fl ightless birds of Southern continents students about biology and evolution. We have capitalized — ostriches and emus — each lost the ability to fl y indepen- on these resources by working together with the educational dently. Continued eff orts to improve our understanding of staff of several such institutions to off er workshops to mid- the Avian Tree of Life will allow even more connections be- dle and high school teachers that demonstrate how gymno- tween our extensive knowledge of bird biology to their evo- sperms in nearby living collections can be used to teach key lutionary history, and will teach us more broadly about these biological and evolutionary concepts. Th e workshops have processes as well. been received very enthusiastically. - Edward L. Braun & Rebecca T. Kimball, University of Florida, - Sarah Mathews, Arnold Arboretum of Harvard University, ebraun68@ufl .edu [email protected]

Gymnosperm ToL — Th e Seed Plant Tree of Life BivAToL — Th e BivalveTree of Life http://www.huh.harvard. http://bivatol.org edu/research/mathews- Bivalves (clams, oys- lab/atolHtmlSite ters, mussels, scallops, Th e evolution of the seed is etc.) are a diverse and one of the most important familiar group of mol- events in the history of land lusks with an old and plants, leading to enhanced well-preserved fossil survival and dispersal capa- record, important eco- bilities and to greater mat- logical roles in marine ing control. Seed plants and freshwater ecosys- dominate the landscape and tems, and economic roles including fi sheries, the ornament today, forests and grasslands industry, and health sciences. Diversity-wise, bivalves – with

12 AMERICAN PALEONTOLOGIST 18(3) Fall 2010 20,000-30,000 living species – are the second largest class of living mollusks, which in turn constitute the second largest animal phylum and the largest in the marine realm. Despite the ubiquitousness of bivalves, past eff orts to study and understand their evolution have been uncoordi- nated and little consensus has been reached. Th e BivAToL team is taking a fresh look at bivalve anatomy (with special focus on gill and stomach anatomy, shell ultrastructure, and sperm morphology) and selected molecular markers (genes) for the same species investigated morphologically to be able to understand bivalve evolution in an integrated fashion. While national and international BivAToL teams as- semble morphological and molecular data in levels of detail never before attempted, other BivAToL participants are gen- erating outreach products that will engage various audiences in the project’s results and in evolutionary science in general. Most unusually, BivAToL is pleased to present, beginning in September 2010, the traveling exhibition "Science on the Half-Shell: How and Why We Study Evolution," extolling the beauty and scientifi c value of bivalves as model organisms for evolutionary studies in the laboratory and the classroom. Perhaps most important in this context, bivalves give us a Did You Know? Th e Tree of Life! unique opportunity to teach a complex subject in a unique  Th e coconut palm is called the "Tree of way, which we hope will resonate with museum visitors, web Life" because it is one of the most useful surfers, teachers, and students of all ages. trees in the world. In addition to its food - Paula M. Mikkelsen, Paleontological Research Institution, value, the tree and its fruit are used for [email protected] soap, cosmetics, rope, fertilizer, charcoal fi lters, and a host of domestic products woven from the leaves. References and Further Reading Other "Trees of Life" are the acacia in ancient Egypt, Stresemann, E. 1959. Th e status of avian systematics and its un- Yggdrasil (an ash or yew) in Norse mythology, the fi g solved problems. Th e Auk, 76: 269-280 tree in India, and the Cebia tree in Mayan culture. Tree of Life Web Project. http://tolweb.org/trees.  Elephants evolved from a pig-sized creature that lived in Understanding Evolution, http://evolution.berkeley.edu. northern Africa 55-60 million years ago. Today, their U. S. National Science Foundation, Assembling the Tree of Life closest living relatives are hyraxes and manatees. Initiative, http://www.phylo.org/atol.  Seahorses are more closely related to zebras than to Paula Mikkelsen is Associate Director for Science at Paleontological starfish, lobsters, or scallops. Seahorses and zebras are Research Institution, and a Principal Investigator on BivAToL (Assem- both vertebrates, whereas starfish, lobsters, and scal- bling the Bivalve Tree of Life). Email [email protected]. lops (although marine creatures like the seahorse) are all invertebrates (without a backbone). - Compiled by Sara Auer Perry, PRI Education Staff

Discovering Mississippi's Petrifi ed Forest

In the heart of the south, just northwest of Jack- son, lies Mississippi Petrifi ed Forest, the only pet- rifi ed forest in the eastern United States. Located in the small town of Flora, Mississippi Petrifi ed Forest is a registered National Natural Landmark, and off ers a campground, an Earth Science Museum, and a peaceful and well-maintained Nature Trail along which are strewn the left- overs of an ancient log jam deposited by a river 36 million years ago. Only a short drive off the beaten path between New Orleans, Mem- phis, and points north, it's well worth a visit! -Th e Editor

AMERICAN PALEONTOLOGIST 18(3) Fall 2010 13