unit 8 chapter 29 echinoderms and invertebrate chordates
TRANSCRIPT
Unit 8Chapter 29
Echinoderms and Invertebrate Chordates
What is an Echinoderm?
Radially symmetrical, with spiny skin
Endoskeletons of calcium carbonate and pincerlike appendages
What is an Echinoderm?
Water Vascular System For locomotion, food-getting, and gas
exchange Tube feet =
tiny suction cups
Diversity of Echinoderms
Sea stars
Brittle stars
Diversity of Echinoderms
Sand dollars
Sea urchins
Diversity of Echinoderms
Sea cucumbers
Sea lilies & feather stars
What is a Chordate?
Phylum Chordata includes:– Urochordates
(Sea Squirts)– Cephalochordates
(Lancelets)– Vertebrates
(all vertebrates)
Dolphin embryo
What is a Chordate?
All Chordates have the following characteristics at some time during their life:
Notochord = rod-like structure (replaced by backbone in vertebrates)
Dorsal nerve cord = hollow cord (becomes spinal cord in vertebrates)
Gill slits (pharyngeal pouches) develop into gills or disappear
Tail (develops or disappears)
Invertebrate Chordates
Tunicates or sea squirts Have all chordate characteristics as larva,
but not as adults
Invertebrate Chordates
Lancelets The only chordate to
retain all characteristics as an adult