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BIS2C: Lecture 31: Deuterosomes I: Echinoderms & Hemichordates
The document is a set of slides for a lecture on deuterostomes, specifically echinoderms and hemichordates. It includes a phylogenetic tree of animals showing the relationships between major groups like sponges, cnidarians, protostomes, deuterostomes. It also notes some of the key innovations along the branches, such as the development of multicellularity and tissues in the common ancestor of all animals.
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Introduces the lecture by Prof. Jonathan Eisen for BIS2C at UC Davis, focusing on Deuterosomes I, covering Echinoderms & Hemichordates.
Highlights key topics of deuterostome innovations, focuses on Echinoderms and major groups, symmetry, and tube feet.
Discusses Metazoans, evidence for their ancestral state (colonial vs multicellular), and presents a phylogenetic tree identifying relationships.
Shows the phylogenetic relationships among major groups of animals including Echinoderms and Chordates, emphasizing multcellularity and common ancestry.
Discusses unique features of deuterostomes, including cell adhesion, embryonic development, and their fewer species compared to protostomes.
Presents three main deuterostome clades: Echinoderms, Hemichordates, and Chordates, illustrating their evolutionary relationships and characteristics.
Defines Ambulacrarians, discussing the symmetry and development of echinoderms and hemichordates, highlighting their shared larval traits.
Introduces Xenoturbellids, their classification, and ecological impact, leading to discussions about their evolutionary significance.
Explores the definition, traits, and examples of Chordates, including Notochord, dorsal nerve cord, and pharyngeal slits, showing their importance in evolution. Summarizes the characteristics of deuterostomes and chordates, examining their features such as vertebral columns and embryonic structures.
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BIS2C: Lecture 31: Deuterosomes I: Echinoderms & Hemichordates
- 1. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Lecture 31: Deuterosomes I: Echinoderms & Hemichordates BIS 002C Biodiversity & the Tree of Life Spring 2016 Prof. Jonathan Eisen 1
- 2. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 • SLIDES AVAILABLE AT http://tinyurl.com/BIS2CL31 2
- 3. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Where we are going and where we have been… 3 •Previous lecture: •30: Triploblasts: Protostomes: Ecdysozoans II I •Current Lecture: •31: Deuterosomes I: Echinoderms & Hemichordates •Next Lecture: •31: Deuterosomes II: Chordates
- 4. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Topics .. 4 • Deuterostome innovations and uses of these innovations • Major Groups of Deuterostome • Focus on Echinoderms • Innovations • Symmetry • Tube feet • Chordate Introduction
- 5. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Animals - AKA Metazoans 5 Metazoans
- 6. Clicker What evidence supportsthe assertion that the common ancestor of metazoans at least colonial, if not multicellular? A. Comparisons of modern metazoans B. Comparisons of metazoans to choanoflagellates C. Neither A nor B D. Both A and B !6Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 7. Clicker What evidence supportsthe assertion that the common ancestor of metazoans at least colonial, if not multicellular? A. Comparisons of modern metazoans B. Comparisons of metazoans to choanoflagellates C. Neither A nor B D. Both A and B !7Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 8. Clicker What is thebest evidence that sponges are the deepest branching group within the metazoa? A. They are the most primitive animals B. They have cells similar to those seen in choanoflagellates C. All other animals are more complex D. Sponges are not bilaterally symmetric E. Branching patterns in molecular phylogenies !8Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 9. Clicker What is thebest evidence that sponges are the deepest branching group within the metazoa? A. They are the most primitive animals B. They have cells similar to those seen in choanoflagellates C. All other animals are more complex D. Sponges are not bilaterally symmetric E. Branching patterns in molecular phylogenies !9Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 10. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans
- 11. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Common ancestor
- 12. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Common ancestor •Colonial •Cell adhesion systems
- 13. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Common ancestor •Colonial •Cell adhesion systems
- 14. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Common ancestor •Colonial •Cell adhesion systems
- 15. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems
- 16. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges)
- 17. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges)
- 18. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Eumetazoans
- 19. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Eumetazoans
- 20. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges)
- 21. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Diploblasts
- 22. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Diploblasts Triploblasts (Bilaterians)
- 23. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Simplification; loss of nervous system Notochord Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Diploblasts Triploblasts (Bilaterians)
- 24. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Simplification; loss of nervous system Notochord Bilateral symmetry along an anterior-posterior axis; three embryonic cell layers Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Diploblasts Triploblasts (Bilaterians)
- 25. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Simplification; loss of nervous system Notochord Bilateral symmetry along an anterior-posterior axis; three embryonic cell layers Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Blastopore develops into mouth Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Diploblasts Triploblasts (Bilaterians)
- 26. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Simplification; loss of nervous system Notochord Bilateral symmetry along an anterior-posterior axis; three embryonic cell layers Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Exoskeleton moltingBlastopore develops into mouth Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Diploblasts Triploblasts (Bilaterians)
- 27. Figure 31.1 APhylogenetic Tree of the Animals !10Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 Silicaceous spicules Choanocytes; spicules Simplification; loss of nervous system Notochord Bilateral symmetry along an anterior-posterior axis; three embryonic cell layers Blastopore develops into anus Hemichordates DEUTEROSTOMES (Chapter 33) Chordates Echinoderms Radial symmetry Placozoans Cnidarians Arrow worms Lophotrochozoans Calcareous sponges Demosponges Glass sponges Ecdysozoans PROTOSTOMES (Chapter 32) Exoskeleton moltingBlastopore develops into mouth Centopheres Sponges (Chapter 33) Diploblastic animals (Chapter 31) Bilaterains (triploblastic) Eumetazoans Unique cell junctions; collagen and proteoglycans in extracellular matrix Two embryonic cell layers; nervous system Multicellularity, Blastula Common ancestor •Colonial •Cell adhesion systems Monoblasts (Sponges) Diploblasts Triploblasts (Bilaterians)
- 28. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Animal Diversity 11 Triploblasts (Bilaterians)
- 29. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Protostomes 12 Protostomes
- 30. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Protostomes 13 Deuterostomes
- 31. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Deuterostomes 14
- 32. Figure 33.1 Phylogenyof the Deuterostomes !15Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 33. General/Common Features ofDeuterostomes Common Ancestor !16Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 34. General/Common Features ofDeuterostomes Common Ancestor !17Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 • Development !Radial cleavage !Blastopore becomes the anus and mouth forms on opposite side !Coelom develops from mesodermal pockets that bud off from the gastrula cavity !Triploblastic, coelomate animals with internal skeletons !Complete gut. • There are far fewer species of deuterostomes than protostomes.
- 35. Three Main Clades !18Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 Echinoderms Hemichordates Chordates
- 36. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 19 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Ambulacrarians • Two main groups: echinoderms and hemichordates • Have ciliated, bilaterally symmetrical larvae • Adult hemichordates are also bilaterally symmetrical.
- 37. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 19 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Ciliated larvae Ambulacrarians • Two main groups: echinoderms and hemichordates • Have ciliated, bilaterally symmetrical larvae • Adult hemichordates are also bilaterally symmetrical.
- 38. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 19 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians • Two main groups: echinoderms and hemichordates • Have ciliated, bilaterally symmetrical larvae • Adult hemichordates are also bilaterally symmetrical.
- 39. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians - Others - Xenoturbellids 20 Xenoturbellids Xenoturbellids (two species): wormlike organisms that feed on or parasitize mollusks in the north Atlantic.
- 40. Xenoturbella in thenews !21Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 41. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 • VIDEOS 22
- 44. !25Slides by JonathanEisen for BIS2C at UC Davis Spring 2016
- 45. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 26 Xenoturbellids
- 46. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 27 Xenoturbellids Acoels Acoels: also wormlike, live as plankton, between grains of sediment, or on other organisms such as corals.
- 47. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 28 Xenoturbellids Acoels s Not clear exactly where acoels branch in the tree
- 48. Figure 33.4 HighlyReduced Acoels Are Probably Relatives of the Ambulacrarians !29Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 49. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 • See http://www.nature.com/news/ 2011/110209/full/470161a.html for discussion of acoels • http://www.latimes.com/science/ sciencenow/la-sci-sn-churro-sea-worm- bilateria-20160205-story.html • http://www.nature.com/nature/journal/v530/ n7588/abs/nature16545.html 30
- 50. Clicker Which of thefollowing topics would studies of Xenoturbellid evolution be most useful for? A. Origin of diploblasty B. Origin of radial symmetry C. Origin of bilateral symmetry D. Origin of segmentation E. Origin of blastulas !31Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 51. Clicker Which of thefollowing topics would studies of Xenoturbellid evolution be most useful for? A. Origin of diploblasty B. Origin of radial symmetry C. Origin of bilateral symmetry D. Origin of segmentation E. Origin of blastulas !32Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 52. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Protostomes 33 Xenoturbellids
- 53. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 34 Xenoturbellids Acoels s Focus on Two Main Lineages of Ambulocrarians
- 54. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Hemichordates 35 Xenoturbellids Acoels s Focus on Hemichordates Hemichordates
- 55. Hemichordates Body Plan !36Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 Saccoglossus kowalevskii ProboscisCollarTrunk
- 56. Hemichordates Body Plan !37Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 Saccoglossus kowalevskii Proboscis Proboscis used for feeding and locomotion and sometimes protection
- 57. !38Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Saccoglossus kowalevskii Collar Collar contains a stomochord similar to the notochord of chordates Hemichordates Body Plan
- 58. !39Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Saccoglossus kowalevskii Trunk Trunk contains pharynx and pharyngeal gill slits Hemichordates Body Plan
- 59. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 For Your Personal Enjoyment 40
- 60. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Group 1: Acorn worms • Up to 2 m long, burrow in soft marine sediments • Digestive tract is a mouth, pharynx, and intestine • The pharynx opens to the outside via pharyngeal slits. • Vascularized tissue around the slits is a gas exchange surface. • Prey is captured with the large proboscis, which is covered in sticky mucus. 41
- 61. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Acorn Worms 42
- 62. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 43
- 63. Group 2: Pterobranchs •Sedentary marine animals that live in tubes secreted by the proboscis. • Some are solitary, others form colonies. • The collar has one to nine pairs of arms with tentacles for prey capture and gas exchange. !44Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 64. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 45 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians Focus on Echinoderms
- 65. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Ambulacrarians 45 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians Focus on Echinoderms Echinoderms
- 66. Diversity !46Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 ~7,500 species
- 67. Symmetry Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Larvae are bilateral
- 68. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Echinoderm Symmetry 48
- 69. Body Plan !49Slides byJonathan Eisen for BIS2C at UC Davis Spring 2016 Aboral (top) Oral (bottom) No head or brain
- 70. Water Vascular System !50Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 Water enters through pores known as madreporites Circulates through canals that lead to tube feet Hydraulic system used for locomotion, feeding, waste transport, respiration
- 71. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Echinoderm Video 51
- 72. Endoskeleton • Endoskeleton derivedfrom mesoderm • The endoskeleton is covered in epidermis • The skeletal plates are connected by collagen which can be stiff or flexible which controls body tone without muscle !52Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 73. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Echinoderm Endoskeleton 53
- 74. For your personalenjoyment !54Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 75. Crinoidea- Sea Lily’sand Feather Stars !55Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 • 600 described extant species, many more in the fossil record • Both shallow water and deep trenches • Oral surface in dorsal, aboral surface is ventral • Sea Lily’s are attached to the surface by a stalk Fossil Sea Lily’s, 330 mya Feather Star
- 76. Asteroidea- Sea stars !56Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 • 1500 described species, both shallow and deep habitats • Mostly predaceous with an evertable stomach • Remarkable capacity for regeneration Pycnopodia- sunflower star
- 77. Asteroidea- Evertable stomach !57Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 • When feeding, sea stars can extend their stomach pushing it through very small openings • The water vascular system is used to slowly pull muscles apart along with specialized ‘catch collagen’
- 78. Asteroidea- Crown ofThorns !58Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 • Among the largest sea stars, spines have neurotoxins • Voracious predator of coral (Great Barrier Reef) • Introduced species that is difficult to control
- 79. Ophiuroidea- Brittle starsand basket stars !59Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 • 1,900 described species • Long, slender arms often with spines; fast moving • Secretive predators, some are bioluminescent Brittle Star Basket Star Basket Star
- 80. Echinoidea- Sea Urchinsand Sand Dollars !60Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 • 950 described species • Slow moving, grazers on algae (Aristrotle’s lantern) • Protected by spines (urchins) and a calcareous test Strongylocentrotus Aristotle’s lantern
- 81. Echinoidea- Sea Urchinsand California Kelp !61Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 • Urchins feed on kelp (brown algae) • Kelp forests in California harbor a great diversity of species • If unchecked, urchins can create ‘urchin barrens’ • Sea otters prey on urchins (using tools) keeping populations in check; they are a keystone species Kelp forest, Monterey Bay
- 82. Holothuroidea- Sea Cucumbers !62Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 • 1,200 described species, scavengers and filter feeders • Soft-bodied, secondary bilateral symmetry* • Catch collagen allows them squeeze into tight places • Unique defense (evisceration), some are toxic
- 84. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Chordates 64 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians Focus on Chordates
- 85. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Deuterostomes 65
- 86. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Deuterostomes 65
- 87. Chordate Derived TraitsMost Apparent in Juveniles !66Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 88. Notochord !67Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 • Notochord is a dorsal supporting rod. • Core of large cells with fluid-filled vacuoles, making it rigid but flexible. • In tunicates it is lost during metamorphosis to the adult stage. • In vertebrates it is replaced by skeletal structures.
- 89. Dorsal hollow nervecord !68Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 • Formed by an embryonic folding of the ectoderm • Develops to form the central nervous system in vertebrates
- 90. Post Anal Tail !69Slidesby Jonathan Eisen for BIS2C at UC Davis Spring 2016 • Extension of the body past the anal opening • In some species (e.g., humans) most visible in embryos • The combination of postanal tail, notochord, and muscles provides propulsion
- 91. Pharyngeal Slits !70Slides byJonathan Eisen for BIS2C at UC Davis Spring 2016 • The pharynx is a muscular organ that brings water in through the mouth (via cilia) which then passes through a series of openings to the outside (slits). • Ancestral pharyngeal slits present at some developmental stage; often lost or modified in adults. • Supported by pharyngeal arches.
- 92. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Clicker 71 Why are pharyngeal slits NOT considered a synapomorphy of chordates? A. They occur in other deuterostomes B. They are lost in some chordates C. They are modified into gills in vertebrates D. They only occur in the embryo of some chordates
- 93. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Clicker 72 Why are pharyngeal slits NOT considered a synapomorphy of chordates? A. They occur in other deuterostomes B. They are lost in some chordates C. They are modified into gills in vertebrates D. They only occur in the embryo of some chordates
- 94. Figure 33.1 Phylogenyof the Deuterostomes !73Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016
- 95. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Chordates 74 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians Focus on Chordates
- 96. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Chordates 75 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians Three Major Groups *Lancelets *Tunicates *Vertebrates
- 97. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Lancelets (aka Cephalochordates) 76 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians Focus on Lancelets
- 98. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 77 Branchiostoma lanceolatum Gut TailAnus Dorsal hollow nerve cord NotochordPharyngeal slits Lancelet Has Key Chordate Features
- 99. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 78 Branchiostoma lanceolatum TailAnus Dorsal hollow nerve cord NotochordPharyngeal slits Lancelet Features • Lancelets (aka amphioxus) are very small, less than 5 cm. • Notochord is retained throughout life. • Burrow in sand with head protruding; also swim. • Pharynx is enlarged to form a pharyngeal basket for filtering prey from the water. • Fertilization takes place in the water. • Segmented body muscles
- 100. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Lancelet development 79
- 101. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Tunicates 80 Chordates Common ancestor (bilaterally symmetrical, pharyngeal slits present) Echinoderms Hemichordates Lancelets Tunicates VertebratesVertebral column, anterior skull, large brain, ventral heart Notochord, dorsal hollow nerve cord, post-anal tail Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits Ciliated larvae Ambulacrarians Focus on Tunicates
- 102. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Adult Tunicates 81 • Tunicates (sea squirts or ascidians, thaliaceans, and larvaceans): • Sea squirts form colonies by budding from a single founder. Colonies may be meters across. • Adult body is baglike and enclosed in a “tunic” of proteins and complex polysaccharides secreted by the epidermis.
- 103. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Adult Tunicates 82 • Solitary tunicates seem to lack all of the synapomorphies of chordates? • No dorsal hollow nerve cord, no notochord, no postanal tail
- 104. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Adult Tunicates 83 • Solitary tunicates seem to lack all of the synapomorphies of chordates? • No dorsal hollow nerve cord, no notochord, no postanal tail HOW ARE THESE CHORDATES?
- 105. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Juvenile Tunicates 84 Ascidian tunicate larva • Sea squirt larvae have pharyngeal slits, a hollow nerve cord, and notochord in the tail region. • The swimming, tadpolelike larvae suggest a relationship between tunicates and vertebrates. • Larvacean tunicates do not undergo the metamorphosis and retain all of the chordate features. Larvacean tunicates
- 106. Slides by JonathanEisen for BIS2C at UC Davis Spring 2016 Vertebrates 85