Flashcards in Ch 34 Chordates - Fish Deck (89):
Three major groups of bilateral animals
What clade of bilaterians do humans belong to?
All echinoderms are what?
Echinoderms have what kind of symmetry?
Secondarily evolved radial symmetry
From where did the symmetry of echinoderms evolve?
A bilateral ancestor
What kind of symmetry is exhibited by echinoderm larva?
Echindoerms have what kind of internal support system?
A calcium-containing endoskeleton
What is the internal support system of echinoderms composed of?
Plate or tiny, scattered bony elements
Are any of the echinoderms parasites?
How do echinoderms move?
Via a water-vascular system
Fluid is pushed from muscular ampullae into tube feet, causing them to extend
What two things typically cover the surface of echinoderms?
Pedicellariae serve what purpose?
They keep the surface clear of debris and parasites
Changes rapidly between solid and liquid states in response to stimulation from the nervous system
What is a unique connective tissue of echinoderms?
What kind of symmetry is observed in sea cucumbers?
Secondarily evolved bilateral symmetry
How do sea cucumbers digest organic matter
In ingested sediment
How is the digestive system of sea cucumbers used as a defensive mechanism?
It can be expelled (and regenerated)
Four shared derived characters of chordates
2) Dorsal, hollow nerve cord
3) Pharyngeal slits/clefts
4) Muscular, post-anal tail
A semi-rigid rod of cells enclosed by a fibrous sheath
Function of the notochord
Functions as a skeletal muscle
Dorsal and hollow
Runs length of body
Openings in the pharyngeal cavity (throat) to the outside of the animal
In later chordates, what gave rise to the structures of the middle ear, tonsils, and internal gills?
The evolution of pouches between the pharyngeal slits
Evolved for locomotion in water
Two clades of the chordates that divered early in the evolution of vertebrates
Small, thin filter feeders
Found in sandy bottoms in coastal waters
Cephalochordates lack what?
Cephalochordates posses what?
A closed circulatory system
Are urochordates or cephalochordates more closely related to chordates?
How do urochordates (tunicates) feed?
Draw water in through an incurrent siphon
Do all urochordates (tunicates) posses all four chordate traits?
No, only the free-swimming larva have all four traits
Chordates that have a head
Craniates posses what?
1) Heat with at least two chambers
2) Red blood cells with hemoglobin
Feature unique to craniate embryos
The neural crest gives rise to what structures?
Some bone of the cartilage of the skull
Among the most primitive of chordate fossils
How long ago did Haikouella live?
Haikouella possesed what?
1) Well formed brain
3) Muscular segments
Haikouella lack what?
Is "fish" a good monophyletic group within the chordates?
Two groups of jawless fishes
Myxini skeletal system
Notochord only "backbone"
Petromyzontida skeletal system
Fibrous and cartilaginous skeleton
No paired fins
No paired fins
Myxini circulatory system
Partially open circulatory system with four hearts
Petromyzontida circulatory system
Closed circulatory system with one heart
Chordates with jaws
Gnathostomes include (six):
1) Sharks, etc
2) Ray-finned fishes
3) Lobe-finned fishes
5) Reptiles (including birds)
Two advantages of jaws
1) Improved respiratory efficiency
2) Facilitated prey handling
How did jaws improve respiratory efficiency?
Closing jaws prevent backflow when water is passed over the gills
How did jaws facilitate handling prey?
They allows for grasping, biting, and suction feeding
From what structures may the jaws of gnathostomes evolve?
Skeletal supports of the pharyngeal slits
What are the earliest gnathostomes in the fossil record?
An extinct lineage of armored vertebrates
How long ago did placoderms live?
Chondricthyans have a skeleton composed primarily of what?
The largest and most diverse group of chondrichthyans include what?
What is a derived trait of chondrichthyes?
The lack of mineralization in their cartilaginous skeleton
The vertebrate ancestors of chondrichthyes possessed what?
Calcified bony skeletal elements
What kind of scales are found on chondricthyans?
Modified to form horns, spines, and teeth
The teeth of skates and rays are modified into what?
Plates for crushing molluscs, crustaceans, or fish
What is one intestinal adaptation of the chondrichthyans?
Slows the passage of food and increases the surface area for absorption
What contributes to buoyancy in sharks?
A huge, oily liver
Why must sharks continually swim?
Because they are denser than water and will sink if they stop swimming
Modifications of the pelvic fins used in copulation
Are shark eggs fertilized internally or externally?
Three ways shark eggs develop:
Eggs hatch outside the mother's body
The embryo develops within the uterus and is nourished by the egg yolk
The embryo develops within the uterus and is nourished through a yolk sac placenta from the mother's blood
What clade of gnathostomes do a vast majority of vertebrates belong to?
1) Bony fish
Nearly all the familiar osteichthyans belong to what?
Osteichthyans have what kind of skeletal system?
A bony skeletal system
What covers the gills of osteichthyans?
A plate-like operculum
Allows fish to breath efficiently without forward movement
How are bony fishes more diverse than the chondricthyes?
They have more diverse teeth and digestive system