Tiktaalik—A Fishy 'Missing Link'
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Tiktaalik: Reconstructed at Left Tetrapod Testimony
Fa m i liar Fossils Tiktaalik fossil at right and Fossil site Tiktaalik: reconstructed at left Tetrapod Testimony IMAGINE a creature that looks like a crocodile with a neck but which also has gills like a fish! The stuff of nightmares, did you say? But it is just Tiktaalik roseae – a fish-like fossil that was introduced to the year old rocks. world on April 2006 by a team of researchers led by Neil They had a pretty Shubin, Edward Daeschler and Farish Jenkins, who clear idea about uncovered this bizarre specimen. It has been hailed as what sort of being the species that blurs the boundary between fish animal they were and the four-legged tetrapods. looking for. Tiktaalik was found on Ellesmere Island, Canada, However, success not too far from the North Pole in the Arctic Circle. It has was not been described as, “a cross between a fish and a crocodile.” immediate. It took It lived in the Devonian era lasting from 417m to 354m them five separate years ago. The name Tiktaalik is the Inuktitut word for expeditions to the freshwater fish burbot (Lota lota). The name was Canada before they suggested by Inuit elders of the area where the fossil was raised the discovered. The specific name roseae holds the clue to Tiktaalik. the name of an anonymous donor and is a tribute to the Tiktaalik was dubbed a “fishapod” by Daeschler. The person. media called it a “missing link” between fish and the Tiktaalik was a fish no doubt but a special one. Its four-legged tetrapods. -
Center for Systematic Biology & Evolution
CENTER FOR SYSTEMATIC BIOLOGY & EVOLUTION 2008 ACTIVITY REPORT BY THE NUMBERS Research Visitors ....................... 253 Student Visitors.......................... 230 Other Visitors.......................... 1,596 TOTAL....................... 2,079 Outgoing Loans.......................... 535 Specimens/Lots Loaned........... 6,851 Information Requests .............. 1,294 FIELD WORK Botany - Uruguay Diatoms – Russia (Commander Islands, Kamchatka, Magdan) Entomology – Arizona, Colorado, Florida, Hawaii, Lesotho, Minnesota, Mississippi, Mongolia, Namibia, New Jersey, New Mexico, Ohio, Pennsylvania, South Africa, Tennessee LMSE – Zambia Ornithology – Alaska, England Vertebrate Paleontology – Canada (Nunavut Territory), Pennsylvania PROPOSALS BOTANY . Digitization of Latin American, African and other type specimens of plants at the Academy of Natural Sciences of Philadelphia, Global Plants Initiative (GPI), Mellon Foundation Award. DIATOMS . Algal Research and Ecologival Synthesis for the USGS National Water Quality Assessment (NAWQA) Program Cooperative Agreement 3. Co-PI with Don Charles (Patrick Center for Environmental Research, Phycology). Collaborative Research on Ecosystem Monitoring in the Russian Northern Far-East, Trust for Mutual Understanding Grant. CSBE Activity Report - 2008 . Diatoms of the Northcentral Pennsylvania, Pennsylvania Department of Conservation and Natural Resources, Wild Rescue Conservation Grant. Renovation and Computerization of the Diatom Herbarium at the Academy of Natural Sciences of Philadelphia, National -
Phylogeny of Basal Tetrapoda
Stuart S. Sumida Biology 342 Phylogeny of Basal Tetrapoda The group of bony fishes that gave rise to land-dwelling vertebrates and their descendants (Tetrapoda, or colloquially, “tetrapods”) was the lobe-finned fishes, or Sarcopterygii. Sarcoptrygii includes coelacanths (which retain one living form, Latimeria), lungfish, and crossopterygians. The transition from sarcopterygian fishes to stem tetrapods proceeded through a series of groups – not all of which are included here. There was no sharp and distinct transition, rather it was a continuum from very tetrapod-like fishes to very fish-like tetrapods. SARCOPTERYGII – THE LOBE-FINNED FISHES Includes •Actinista (including Coelacanths) •Dipnoi (lungfishes) •Crossopterygii Crossopterygians include “tetrapods” – 4- legged land-dwelling vertebrates. The Actinista date back to the Devonian. They have very well developed lobed-fins. There remains one livnig representative of the group, the coelacanth, Latimeria chalumnae. A lungfish The Crossopterygii include numerous representatives, the best known of which include Eusthenopteron (pictured here) and Panderichthyes. Panderichthyids were the most tetrapod-like of the sarcopterygian fishes. Panderichthyes – note the lack of dorsal fine, but retention of tail fin. Coelacanths Lungfish Rhizodontids Eusthenopteron Panderichthyes Tiktaalik Ventastega Acanthostega Ichthyostega Tulerpeton Whatcheeria Pederpes More advanced amphibians Tiktaalik roseae – a lobe-finned fish intermediate between typical sarcopterygians and basal tetrapods. Mid to Late Devonian; 375 million years old. The back end of Tiktaalik’s skull is intermediate between fishes and tetrapods. Tiktaalik is a fish with wrist bones, yet still retaining fin rays. The posture of Tiktaalik’s fin/limb is intermediate between that of fishes an tetrapods. Coelacanths Lungfish Rhizodontids Eusthenopteron Panderichthyes Tiktaalik Ventastega Acanthostega Ichthyostega Tulerpeton Whatcheeria Pederpes More advanced amphibians Reconstructions of the basal tetrapod Ventastega. -
Teacher's Guide: Tiktaalik: a Fish out of Water
Teacher’s Guide: Tiktaalik: A Fish Out of Water Recommended Grade Level: 5–8 (also applicable to grades 9–12 for students requiring significant support in learning) Suggested Time: About 50–60 minutes spread over one or more class periods, plus additional time to complete a writing assignment Goals Vocabulary Following are the big ideas that students • fossil should take away after completing this lesson: • characteristic • Transitional fossils help scientists establish • transition how living things are related • tetrapod • Physical features and behaviors may • species change over time to help living things sur- vive where they live • amphibian • evolution Key Literacy Strategies Following are the primary literacy strategies students will use to complete this activity: • Categorizing basic facts and ideas (screen 10) • Making inferences (screens 4 and 7, writing assignment 2) • Identifying and using text features (screens 4, 6, and 9) • Determining important information (screen 7, writing assignment 1) • Sequencing events (screen 9) Note: In addition to using the key literacy strategies listed above, students will use each of the strategies below to complete this lesson: • Monitoring comprehension • Synthesizing • Making predictions • Developing vocabulary • Connecting prior knowledge to new learning • Developing a topic in writing • Identifying and using text features (photographs, captions, diagrams, and/or maps) Overview Tiktaalik: A Fish Out of Water is a student-directed learning experience. However, while students are expected to work through the lesson on their own, teachers should be available to keep the lesson on track, organize groupings, facilitate discussions, answer questions, and ensure that all learning goals are met. Teacher’s Guide: Tiktaalik: A Fish Out of Water 1 The following is a summary of the lesson screens: Screen 1: Students learn that they will explore evolutionary relationships between animal groups that do not appear to be related. -
Reconstructing Pectoral Appendicular Muscle Anatomy in Fossil Fish and Tetrapods Over the Fins-To-Limbs Transition
Biol. Rev. (2017), pp. 000–000. 1 doi: 10.1111/brv.12386 Reconstructing pectoral appendicular muscle anatomy in fossil fish and tetrapods over the fins-to-limbs transition Julia L. Molnar1,∗ , Rui Diogo2, John R. Hutchinson3 and Stephanie E. Pierce4 1Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Northern Boulevard, Old Westbury, NY, U.S.A. 2Department of Anatomy, Howard University College of Medicine, 520 W St. NW, Numa Adams Building, Washington, DC 20059, U.S.A. 3Structure and Motion Lab, Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire AL9 7TA, UK 4Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, U.S.A. ABSTRACT The question of how tetrapod limbs evolved from fins is one of the great puzzles of evolutionary biology. While palaeontologists, developmental biologists, and geneticists have made great strides in explaining the origin and early evolution of limb skeletal structures, that of the muscles remains largely unknown. The main reason is the lack of consensus about appendicular muscle homology between the closest living relatives of early tetrapods: lobe-finned fish and crown tetrapods. In the light of a recent study of these homologies, we re-examined osteological correlates of muscle attachment in the pectoral girdle, humerus, radius, and ulna of early tetrapods and their close relatives. Twenty-nine extinct and six extant sarcopterygians were included in a meta-analysis using information from the literature and from original specimens, when possible. We analysed these osteological correlates using parsimony-based character optimization in order to reconstruct muscle anatomy in ancestral lobe-finned fish, tetrapodomorph fish, stem tetrapods, and crown tetrapods. -
Film Guide for Teachers
FILM GUIDE FOR TEACHERS KEY CONCEPTS • The human body contains genes and structures that we inherited from distant animal ancestors. • Evolution, including human evolution, is a story of losses and gains in both genes and anatomy. • Research in various scientific disciplines — including paleontology, comparative anatomy, developmental biology, and genetics — provides evidence of our evolutionary history. • Humans are related to all other life on the planet. The phylogenetic tree of life is a representation of the evolutionary relationships among all species, including humans. • Relationships among species are deduced from shared characteristics, including sequences of DNA. • Humans are descendants of extinct species. While all species, both living and extinct, are related to humans, most of them are not in our direct lineage. • Transitional fossils provide evidence for the origin and divergence of major biological lineages — a lineage being a sequence of species that evolved from a common ancestor. Transitional fossils represent the ancestors of new groups of organisms and show us how new lineages evolved. • Very similar genes control the development of related structures in different animals. Examples of such structures include fins and limbs; scales, hair, teeth and sweat glands; and brains and nerve networks. CURRICULUM CONNECTIONS Textbook/Curriculum Chapter Sections/Curriculum Topics Miller and Levine, Biology (2010 ed.) 16.4, 17.4, 19.1, 25.2, 26.2, 26.3 Reece et al., Campbell Biology (9th ed.) 22.2, 22.3, 25.2, 25.5, 26.2, 26.4, -
Tiktaalik Roseae Fossil Analysis Provides New Details on the Origin of Vertebrate Legs 13 January 2014
Tiktaalik roseae fossil analysis provides new details on the origin of vertebrate legs 13 January 2014 Robert R. Bensley Distinguished Service Professor of Anatomy at the University of Chicago and corresponding author of the study, which marks his inaugural article as a member of the National Academy of Sciences. "But it looks like this shift actually began to happen in fish, not in limbed animals." Discovered in 2004 by Shubin and co-authors Edward Daeschler, PhD, Associate Curator of Vertebrate Zoology at the Academy of Natural Sciences of Drexel University, and the late Farish A. Jenkins, Jr., PhD, of Harvard University, Tiktaalik roseae represents the best-known transitional species between fish and land-dwelling tetrapods. A lobe-finned fish with a broad flat head and sharp teeth, Tiktaalik looked like a cross between a fish and a crocodile, growing up to a length of 9 feet as it hunted in shallow freshwater environments. It had gills, scales and fins, but also had tetrapod-like features such as a mobile neck, robust ribcage and This is an updated illustration of Tiktaalik roseae in its primitive lungs. In particular, its large forefins had natural environment. Credit: University of Chicago, Neil shoulders, elbows and partial wrists, which allowed Shubin it to support itself on ground. However, only specimen blocks containing the front portion of Tiktaalik have been described thus far. The discovery of well-preserved pelves and a As the researchers investigated additional blocks partial pelvic fin from Tiktaalik roseae, a 375 million- recovered from their original and subsequent year-old transitional species between fish and the expeditions to the dig site in northern Canada, they first legged animals, reveals that the evolution of discovered the rear portion of Tiktaalik, which hind legs actually began as enhanced hind fins. -
I Ecomorphological Change in Lobe-Finned Fishes (Sarcopterygii
Ecomorphological change in lobe-finned fishes (Sarcopterygii): disparity and rates by Bryan H. Juarez A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science (Ecology and Evolutionary Biology) in the University of Michigan 2015 Master’s Thesis Committee: Assistant Professor Lauren C. Sallan, University of Pennsylvania, Co-Chair Assistant Professor Daniel L. Rabosky, Co-Chair Associate Research Scientist Miriam L. Zelditch i © Bryan H. Juarez 2015 ii ACKNOWLEDGEMENTS I would like to thank the Rabosky Lab, David W. Bapst, Graeme T. Lloyd and Zerina Johanson for helpful discussions on methodology, Lauren C. Sallan, Miriam L. Zelditch and Daniel L. Rabosky for their dedicated guidance on this study and the London Natural History Museum for courteously providing me with access to specimens. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ii LIST OF FIGURES iv LIST OF APPENDICES v ABSTRACT vi SECTION I. Introduction 1 II. Methods 4 III. Results 9 IV. Discussion 16 V. Conclusion 20 VI. Future Directions 21 APPENDICES 23 REFERENCES 62 iv LIST OF TABLES AND FIGURES TABLE/FIGURE II. Cranial PC-reduced data 6 II. Post-cranial PC-reduced data 6 III. PC1 and PC2 Cranial and Post-cranial Morphospaces 11-12 III. Cranial Disparity Through Time 13 III. Post-cranial Disparity Through Time 14 III. Cranial/Post-cranial Disparity Through Time 15 v LIST OF APPENDICES APPENDIX A. Aquatic and Semi-aquatic Lobe-fins 24 B. Species Used In Analysis 34 C. Cranial and Post-Cranial Landmarks 37 D. PC3 and PC4 Cranial and Post-cranial Morphospaces 38 E. PC1 PC2 Cranial Morphospaces 39 1-2. -
Fins to Limbs: What the Fossils Say1
EVOLUTION & DEVELOPMENT 4:5, 390–401 (2002) Fins to limbs: what the fossils say1 Michael I. Coates,a,* Jonathan E. Jeffery,b and Marcello Rutaa aDepartment of Organismal Biology and Anatomy, University of Chicago, 1027 E57th Street, Chicago, IL 60637, USA bInstitute of Evolutionary and Ecological Sciences, Leiden University, Kaiserstraat 63, Postbus 9516, 2300 RA Leiden, The Netherlands *Author for correspondence (email: [email protected]) 1From the symposium on Starting from Fins: Parallelism in the Evolution of Limbs and Genitalia. SUMMARY A broad phylogenetic review of fins, limbs, and highlight a large data gap in the stem group preceding the first girdles throughout the stem and base of the crown group is appearance of limbs with digits. It is also noted that the record needed to get a comprehensive idea of transformations unique of morphological diversity among stem tetrapods is somewhat to the assembly of the tetrapod limb ground plan. In the lower worse than that of basal crown group tetrapods. The pre-limbed part of the tetrapod stem, character state changes at the pecto- evolution of stem tetrapod paired fins is marked by a gradual re- ral level dominate; comparable pelvic level data are limited. In duction in axial segment numbers (mesomeres); pectoral fins of more crownward taxa, pelvic level changes dominate and re- the sister group to limbed tetrapods include only three. This re- peatedly precede similar changes at pectoral level. Concerted duction in segment number is accompanied by increased re- change at both levels appears to be the exception rather than gional specialization, and these changes are discussed with the rule. -
Tinkering and the Origins of Heritable Anatomical Variation in Vertebrates
biology Review Tinkering and the Origins of Heritable Anatomical Variation in Vertebrates Jonathan B. L. Bard Department of Anatomy, Physiology & Genetics, University of Oxford, Oxford OX313QX, UK; [email protected] Received: 9 October 2017; Accepted: 18 February 2018; Published: 26 February 2018 Abstract: Evolutionary change comes from natural and other forms of selection acting on existing anatomical and physiological variants. While much is known about selection, little is known about the details of how genetic mutation leads to the range of heritable anatomical variants that are present within any population. This paper takes a systems-based view to explore how genomic mutation in vertebrate genomes works its way upwards, though changes to proteins, protein networks, and cell phenotypes to produce variants in anatomical detail. The evidence used in this approach mainly derives from analysing anatomical change in adult vertebrates and the protein networks that drive tissue formation in embryos. The former indicate which processes drive variation—these are mainly patterning, timing, and growth—and the latter their molecular basis. The paper then examines the effects of mutation and genetic drift on these processes, the nature of the resulting heritable phenotypic variation within a population, and the experimental evidence on the speed with which new variants can appear under selection. The discussion considers whether this speed is adequate to explain the observed rate of evolutionary change or whether other non-canonical, adaptive mechanisms of heritable mutation are needed. The evidence to hand suggests that they are not, for vertebrate evolution at least. Keywords: anatomical change; evolutionary change; developmental process; embryogenesis; growth; mutation; patterning in embryos; protein network; systems biology; variation 1. -
[SHUBIN:] Tiktaalik Was Headline News the Day It Was Described in 2006
[SHUBIN:] Tiktaalik was headline news the day it was described in 2006. And I remember going in to drop one of my kids off at school. And the teacher asked me, "You know, I read about your discovery in the newspaper. Can you bring it in to show the children?" So, you know, my office was just down the block, so I grabbed a cast of the fossil and came in to show the fossil to the children, and it was amazing what I saw. [SHUBIN:] Hey guys, how are you? [STUDENTS:] Good. [SHUBIN:] Hi, guys. Hi, Hannah, how are you doing, baby? [TEACHER:] Hannah, would you like to introduce our guest? [SHUBIN:] Did I konk your head? I'm sorry, Maurice. I'm such a head-konker. What can I say. Hi, guys, how are you doing? [STUDENTS:] Hi. [SHUBIN:] Hello. Did you want to introduce today's special guest? [TEACHER:] Hannah, would you introduce our guest, please? [HANNAH:] This is my daddy. [SHUBIN:] And that's my daughter. Hi, guys. [SHUBIN:] My name is Neil Shubin. And I'm a scientist. I'm a paleontologist. Does anybody know what that... [SHUBIN:] [voiceover] The kids listened quietly as I told them about what paleontologists do and how we search for fossils. [SHUBIN:] So let me show you a puzzle, let me show you something that shows you what I was looking for, and then you're going to try to identify what it is. This is taken from a college textbook, so it's really hard. I want to show you something. -
Late Devonian Paleontology and Paleoenvironments at Red Hill and Other Fossil Sites in the Catskill Formation of North-Central Pennsylvania Edward B
West Chester University Digital Commons @ West Chester University Geology & Astronomy Faculty Publications Geology & Astronomy 2011 Late Devonian paleontology and paleoenvironments at Red Hill and other fossil sites in the Catskill Formation of north-central Pennsylvania Edward B. Daeschler Academy of Natural Sciences of Philadelphia Walter L. Cressler III West Chester University of Pennsylvania, [email protected] Follow this and additional works at: http://digitalcommons.wcupa.edu/geol_facpub Part of the Paleobiology Commons, and the Paleontology Commons Recommended Citation Daeschler, E.B., and Cressler, W.L., III, 2011. Late Devonian paleontology and paleoenvironments at Red Hill and other fossil sites in the Catskill Formation of north-central Pennsylvania. In R.M. Ruffolo and C.N. Ciampaglio [eds.], From the Shield to the Sea: Geological Trips from the 2011 Joint Meeting of the GSA Northeastern and North-Central Sections, pp. 1-16. Geological Society of America Field Guide 20. This Article is brought to you for free and open access by the Geology & Astronomy at Digital Commons @ West Chester University. It has been accepted for inclusion in Geology & Astronomy Faculty Publications by an authorized administrator of Digital Commons @ West Chester University. For more information, please contact [email protected]. FLD020-01 1st pgs page 1 The Geological Society of America Field Guide 20 2011 Late Devonian paleontology and paleoenvironments at Red Hill and other fossil sites in the Catskill Formation of north-central Pennsylvania Edward B. Daeschler Vertebrate Paleontology, Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania 19103, USA Walter L. Cressler III Francis Harvey Green Library, 25 West Rosedale Avenue, West Chester University, West Chester, Pennsylvania 19383, USA ABSTRACT The stratifi ed red beds of the Catskill Formation are conspicuous in road cut expo- sures on the Allegheny Plateau of north-central Pennsylvania.