Ch 32 Animals 3 Flashcards
• Include echinoderms, chordates
• Synapomorphies include
– radial, indeterminate cleavage
– blastopore becomes anus
Deuterostomes
• Marine animals
– “spiny skin”
• endoskeleton of calcium plates and spines – water vascular system
• feeding and gas exchange
• locomotion: tube feet move when filled with fluid
• Larvae exhibit bilateral symmetry
– Most adults exhibit derived pentaradial symmetry • i.e. likely evolved from a bilaterally symmetrical ancestor
• Five classes recognized
Echinoderms
• Sea lilies, feather stars – oral surface turned upward – suspension feeders • tube feet are long and sticky – some crinoids are sessile • this feather star is motile
Class Crinoidea
• Sea stars – central disc with five or more arms – use tube feet for locomotion – most are slow - moving predators • especially of bivalves – unlike most animals digest food before ingestion
Class Asteroidea
• Brittle stars
– most diverse (in species richness) class
– arms longer, more slender than sea stars
– arms more distinct from central disc
– use arms for locomotion
– tube feet lack suckers
Class Ophiuroidea
• Sea urchins, sand dollars – lack arms – have a solid shell (test) • endoskeletal plates fused – many herbivorous • graze on algae – covered with prominent spines – locomotion: tube feet & spines
Class Echinoidea
• Sea cucumbers
– bottom dwellers
• many grazers and scavengers
– elongated flexible bodies
– circle of modified tube feet surrounds mouth
– reduced endoskeleton of microscopic plates
Class Holothuroide
Classes in Echinoderms
Crinoidea Asteroidea Ophiuroidea Echinoidea Holothuroidea
• At some time during life have – flexible, supporting notochord – dorsal, tubular nerve cord – pharyngeal (gill) slits – muscular postanal tail – endostyle (or thyroid gland)
Chordate
Ciliated groove on the pharynx which produces mucus to gather food particles.
Endostyle
The endostyle in larval lampreys metamorphoses into the thyroid gland in adults.
Subphylum for Chordata • Tunicates – marine animals with tunics – superficially like sponges – filter-feeders (using endostyle) – Larvae are free swimming • show chordate characteristics – Most adults are sessile
Subphylum Tunicata
Subphylum for Chordata • Lancelets – small, filter-feeders – notochord extends from tip to tip – no paired fins, sense organs, heart, “brain”
Subphylum Cephalochordata
• Vertebral column – backbone • Cranium – braincase • Neural crest cells – determine development of many structures • Living endoskeleton • Blood with hemoglobin
Vertebrates
• Jaws and paired fins absent – limited feeding styles • Hagfishes – probably have lost vertebrae – mostly scavengers • Lampreys – mostly parasites
Jawless fish
• Includes sharks, rays, skates • Cartilaginous fishes have – jaws – two pairs of fins – placoid scales: tooth-like
Class Chondrichthyes (Cartilaginous Fishes)
• All have internal fertilization • Oviparous – lay eggs • Ovoviviparous – young enclosed by eggs – incubated in mother ’s body • Viviparous – young develop in mother’s uterus – nutrients transferred from mother’s blood
Chondrichthyes Reproduction
– ray-finned fishes
– more species than other vertebrate groups combined
Class Osteichthyes
Bony Fishes:
Paraphylletic Group
• Two groups of lobe-finned fishes
– Actinistia • coelacanths
– Dipnoi • lungfishes
• Class Actinopterygii • Extreme diversity – more that half of vertebrates • Lungs modified as swim bladder – air sac for regulating buoyancy
Ray-Finned Fishes
Sarcopterygii: old class, also paraphylletic
What is its 2 classes
Coelacanth
Lungfish
– previously considered living fossils
linking fishes to tetrapods
Coelacanths
– tetrapods:
amphibians, reptiles, birds, mammals
– ancestors of lungfishes gave rise to tetrapods (land vertebrates)
– based on molecular data
Lungfishes
