Chordates Flashcards
(38 cards)
Hollow dorsal nerve cord
bundle of nerves running along body upper surface
Pharyngeal gill slits
vertical slits in pharynx (gas exchange, food gathering)
Endostyle
groove in pharynx produces mucus
Metameric segmentation
= division of body muscles into segments (=somites) arranged serially one behind another
what is in the subphylum urochordata and what are some attributes?
Tunicates which are marine animals
Exhibit neither a major body cavity nor visible segmentation
what are the Subphylum Cephalochordata?
Lancelets including Amphioxus
Lancelets characteristics
Scaleless, fishlike marine chordates
Notochord persists throughout animal’s life.
No head. burrow into the ground and look like a sword.
Vertebral column in subphylum Vertabrata
= encloses and protects the dorsal nerve cord
Neural crest
unique group of embryonic cells that forms many vertebrate structures
Fishes are the most diverse , true or false
True
Comprises over half of all vertebrates
Characterisitcs of fish
- Vertebral column - bone and/or cartilage
- Jaws
- Paired appendages
- Internal gills
- Single-loop blood circulation (2-chamber heart)
- Nutritional deficiencies = unable to make aromatic amino acids so must consume them, like all vertebrates
- Ectotherms = cold-blooded, most fishes
Class Chondrichthyes
Sharks
they are Light, flexible skeleton, and paired fins made them superior swimmers
Class Chondrichthyes are
cartilaginous fishes
Ampullae of Lorenzini
electroreceptor organ
lateral line system
Series of sensory organs under the skin that detects changes in pressure waves
Shark eggs are fertilized
internally, and pups are born alive.
Supraclass Osteichthyes
Bony fishes
They adopted a heavy internal skeleton made completely of bone
what is the swim bladder
A gas-filled sac that allows bony fishes to regulate their buoyant density
Gas addition = Gas gland
Gas release = Oval body
what is the Gill cover
A hard plate, the operculum, covers gills
Its flexing permits water pumping over gills
Ray-finned fishes (class Actinopterygii) are what percentage of all living fish?
90 percent
Lobe-finned fishes (class Sarcopterygii) have how many living species
7
Ancensters of Amphibians
Amphibians have several key characteristics
- Legs
- Lungs (no ribs, but pectoral and pelvic girdle)
- Cutaneous respiration = across skin
- Pulmonary veins
- Partially divided heart (3-chamber; 2 atria, 1 ventricle)
Successful invasion of lands by vertebrates required several adaptations
- Legs to support body’s weight
- Lungs to extract oxygen from air
- Redesigned heart to drive larger muscles
- Reproduction in H2O to prevent egg drying
- System to prevent whole body desiccation
Three orders of amphibians
Order Anura (“without tail”) Order Caudata (“visible tail”) Order Apoda (“without legs”)