1 / 19

phylum Chordata

phylum Chordata. around AT LEAST since Cambrian 2 cm long, no appendages or eyes for 200 my restricted to ocean, ~360 mya evolved appendages, moved to land ~60,000 (?) extant species 5500 spp. mammals (and 1/5 th of those = bats) although numbers not impressive, size is:

shanae
Download Presentation

phylum Chordata

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. phylum Chordata • around AT LEAST since Cambrian • 2 cm long, no appendages or eyes • for 200 my restricted to ocean, ~360 mya evolved appendages, moved to land • ~60,000 (?) extant species • 5500 spp. mammals (and 1/5th of those = bats) • although numbers not impressive, size is: • land = 90,000 lbs, ocean = 220,000 lbs

  2. debated… so going to follow your frosh textbook… phylum Chordata • subphylum Urochordata - sea squirts, tunicates • subphylum Cephalochordata - lancets, amphioxus • subphylum Craniata • class Myxini - hagfish • class Cephalaspidomorphi - lamprey • class Chodrichthyes - sharks, rays, mantas • class Osteichthyes - bony fish • class Amphibia - amphibians • class Reptilia - lizards, turtles, snakes • class Aves - birds • class Mammalia (Prototheria, Theria, Eutheria) Gnathostomes Vertebrates

  3. What makes a chordate? • notochord • present in all embryos, not all adults • flexible rod, between digestive tube and (maybe) nerve cord - support, purpose = muscle attachment • dorsal hollow nerve cord • develops from ectoderm • in some develops into central nervous sys. • pharyngeal gill slits or pouches • embryos develop pouches, which develop into slits in some (humans becomes ear, thymus, etc.) • post-anal tail • chordate tail extends past anus • all embryos have, lost in many adults (locomotion)

  4. hemichordates • closest chordate outgroup • deuterostome, no watvasc sys • studies focus on development • embryogenesis homologs • <200 spp. • Camb-Carbon fossils • extinct graptolites (sawblades)

  5. subphylum Urochordata • tunicates (“tunic”), sea squirts • ~3000 spp., all marine, filter feeders • solitary or colonial • have all 4 as larvae • adults retain only gill slits • larval stage = dispersal • short (few minutes?) • adult stage = sessile

  6. subphylum Cephalochordata • lancelets, amphioxus • ‘both pointed’ • brain but no head • have all 4 as larvae AND adults • ~25 marine spp, fish like, reduced nervous system • locally common, food resource • naturally Jamaica (Discovery Bay), Asia commercial harvest

  7. subphylum Craniata • chordates with a head • have all 4 as larvae and adults, 9 classes • hagfish, lampreys & 7 classes of gnathostomes e.g., BF1 and Otx cause swelling of dorsal nerve cord tip in lancelets same genes regulate fore, mid, and hind brain in craniates

  8. class Myxini • hagfish, agnathans, slime eel • ~30 spp., all marine • cold oceans, both hemispheres • skull of cartilage, no jaws or vertebrae • dead/dying fish, mostly annelids • slow metabolism – months w/o eating • most ~1’ long, some 2-3’ • spontaneously change sex

  9. class Cephalaspidomorphi • lamprey, have vertebrae of cartilage • some highly reduced • blood suckers • mouth best way to tell apart • ~30 spp., marine and freshwater • cold water only

  10. amphioxus: • notocord • epidermis • myomeres • digestive • reproductive? lamprey external: • eyes • buccal funnel/mouth/teeth • nostril • gills • fins • cloaca lamprey internal: • heart and ostia • brain • pineal gland • liver • olfactory sac • cranial cartilage • eye • notocord • nervous tissue • myomeres • ovary • intestine • gills • kidney? (up by liver)

More Related