1 / 28

Origin and Evolution of Vertebrates: Unraveling the Chordate Story

Explore the evolutionary journey of vertebrates from their ancestral deuterostome roots to diverse modern forms, focusing on key characteristics and significant milestones in the development of chordates. Dive into the fascinating world of jawed and jawless vertebrates, amphibians, reptiles, birds, and mammals, understanding their adaptations and common evolutionary threads. This informative lecture sheds light on the fascinating complexities and diversity within the phylum Chordata and its subphyla. Learn about the transition from aquatic to terrestrial lifestyles, the emergence of unique features like wings, feathers, mammary glands, and more in vertebrate evolution. Discover how vertebrates have flourished and diversified over millions of years, shaping the world we see today. Join us on this educational journey through the intriguing origins and evolutionary pathways of vertebrates!

threatt
Download Presentation

Origin and Evolution of Vertebrates: Unraveling the Chordate Story

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Origin & Evolution of VertebratesCh. 34 Lecture Objectives 1. Intro to Phylum Chordata

  2. Echinodermata Cephalochordata ANCESTRAL DEUTEROSTOME Urochordata Notochord Myxini Common ancestor of chordates Petromyzontida Chondrichthyes Vertebrae Jaws, mineralized skeleton

  3. Phylum Chordata 1. Bilateral 2. Segmented Body 3. Triploblastic 4. Coelomate 5. Deuterostomes

  4. Chordate Hallmarks* May only appear during embryonic development. Dorsal, hollow nerve cord Muscle segments Notochord Mouth Anus Pharyngeal slits or clefts Muscular, post-anal tail Fig. 34.3

  5. Chordate hallmarks con’t: Notochord Notochord

  6. Chordate hallmarks con’t: Dorsal Hollow Nerve Cord

  7. Chordate hallmarks con’t: Pharyngeal Slits

  8. Chordate hallmarks con’t. Post-anal tail

  9. Broken into 3 subphyla: Cepahlochordata (lancelets) Urochordata (tunicates) Vertebrata (animals w/backbones) Class Agnatha Class Amphibia Class Reptilia Class Aves Class Mammalia Phylum Chordata

  10. Fig. 34-4 Subphylum: Cephalochordata (lancelets) Cirri Mouth Pharyngeal slits Atrium Notochord Digestive tract Atriopore Dorsal, hollow nerve cord Segmental muscles Anus Tail Fig. 34.4

  11. Subphylum: Urochordata (tunicates) Fig. 34.5

  12. 1. Chordates w/ a head 2. Higher metabolism 3. Increased muscle 4. 2 chambered heart 5. RBCs w/ hemoglobin 6. Pharyngeal slits  gills Subphylum Vertebrata: the craniates Segmented muscles Pharyngeal slits Fig. 34.9

  13. Extant craniates: SP: Vertebrata, Class Myxini 1.Cyclostomes - Jawless, Ex. Hagfish 2. Cartilaginous skull & skeleton 3. Long & slender, eel-like 4. Bottom scavengers that secrete slime 5. Ingest food by sucking

  14. Fig. 34-9 Slime glands Fig. 34.7

  15. Extant craniates: SP: Vertebrata, Class Pteromyzontida 1. Cyclostomes, Ex. Lamprey 2. Marine & freshwater 3. Mostly ectoparasites 4. Skeleton made of cartilage

  16. Fig. 34.8

  17. Gnathostomes (jaw mouth) Ex. Sharks, Fish, Amphigians, Reptiles, Birds, Mammals 1. Jaws that may have evolved from skeletal supports of the pharyngeal slits 2. An enlarged forebrain associated with enhanced smell and vision 3. lateral line system Fig. 34.12

  18. Tetrapods – gnathostomes with limbs • Four limbs, and feet with digits (from fins 365 mya) • Ears for detecting airborne sounds Fig. 34.19

  19. SP: Vertebrata, Class Amphibia 1. Gnathostomes & Tetrapods w/ moist skin  complements the lungs in gas exchange 2. Fertilization is external in most species 3. Eggs require a moist environment Figs. 34.22-34.23

  20. Amniotes: reptiles, birds, mammals 1. Tetrapods w/ terrestrially adapted egg 2. Relatively impermeable skin 3. Ability to use the rib cage to ventilate the lungs Fig. 34.25

  21. SP: Vertebrata, Class Reptilia 1. Scales that create a waterproof barrier 2. Lay shelled eggs on land (or live birth) 3. Ectothermic or endothermic 4. Ex. lizards, snakes, turtles, crocodilians, and the extinct dinosaurs

  22. Fig. 34.28

  23. SP: Vertebrata, Class Aves 1. Wings with keratin feathers 2. Lack of urinary bladder 3. Reduction in reproductive organs 4. Loss of teeth

  24. Finger 1 (b) Bone structure Palm (a) Wing Finger 2 Finger 3 Forearm Wrist Shaft Shaft Barb Vane Barbule Hook (c) Feather structure Fig. 34.29

  25. SP: Vertebrata,Class Mammalia 1. Mammary Glands 2. Hair 3. Larger Brains 4. Differentiated Teeth

  26. Variations in Class Mammalia 1. Embryo develops within a placenta in the mother’s uterus 2. Embryonic development completed while nursing in a maternal pouch • Marsupials 3. Egg laying mammals • Monotremes

  27. Marsupials & Monotremes Figs. 34.37-34.38

More Related