Chapter 34 Flashcards
What is the outgroup in figure 34.2?
Echinodermata
Describe the major features in a basic chordate.
Most are vertebrates, embryonic forms have notochord (becomes spine), nerve chord (nervous system), gill structure (pharyngeal slits), and post anal tail.
How do lancelets feed?
The larvae swim upward and then sink, trapping plankton and other particles in the pharynx. Adults swim to the bottom and bury themselves except their anterior. Cilia draw water into the mouth and secreted mucus across the pharyngeal slits captures food which then passes into the intestine.
How have the loss of Hox genes affected the Tunicates?
It indicates that the chordate body plan of a tunicate larva is built by using a different set of genetic controls than other chordates.
What are the derived traits of the vertebrates?
Development of skull and backbone of vertebrae, dorsal, ventral and anal fins.
What traits to lampreys and hagfish lack when compared to other fish?
Jaws and backbones
What traits define the clade Gnatostomes?
Jaws, duplicated genome, lateral line systems (sense vibrations)
What chordate structure was modified by evolution to become jaws?
Skeletal rods
What is the major derived trait of the Osteichthyans?
ossified (bony) skeleton with a hard matrix of calcium phosphate
Are humans in the Osteichthyan (bony fish) clade?
Yes
Compare the ray-finned to the lobe-finned fish.
Main difference is that lobe-finned fish have rod-shaped bones with a thick layer of muscle in their pectoral and pelvic thins that they may have used to “walk”
What is a tetrapod?
A vertebrate clade whose members have limbs with digits. Mammals, amphibians, and birds and other reptiles
What traits of Tiktaalik were more fish-like, what traits were more tetrapod-like?
Fish-like: Scales, fins, gills, lungs
Tetrapod-like: Neck, ribs, fin skeleton, flat skull, eyes on top of skull
Where do amphibians lay their eggs? How do their sperm reach the egg?
Water or moist environments. The male spills his sperm over the eggs as the female releases them.
Describe the importance of the evolution of the amniotic egg.
It allowed the embryo to develop on land on its own without the need for a moist environment.
