BIO Exam 4: Vertebrate evolution and jawless fishes lecture

What has the Subphylum Vertebrata’s evolution been shaped by adaptations of?

living endoskeleton: grows with body, cartilage, then bone

What is the function of the Pharynx?

increases respiratory function and supports high metabolic rates

What is the function of the nervous system?

evolution of new cell types (neural crest cells) promoted development of head and sensory organs

What is the function of the paired appendages?

pectoral limbs; balance for swimming

What are the 5 distinguishing traits of Vertebrates?

1. Vertebral column

2. Cranium

3. Endoskeleton

4. Neural crest cells

5. Internal organs

What is the vertebral column?

the once notochord is replaced by a column of interlocking vertebrae

What is the cranium?

anterior end of the nerve cord forms a brain

What is the endoskeleton?

cranium and vertebral column are part of the endoskeleton

What are the neural crest cells?

embryonic cells that contribute to the development of the cranium

What are the internal organs?

they possess great diversity and complex internal organs 

What are the 2 critical innovations of the Subphylum Vertebrata in the Phylum Chordata?

Veterbral column and cranium

What is Garstang’s hypothesis?

tunicate larvae begin to reproduce

What is the term for when tunicate larvae begin to reproduce?

paedomorphosis

What are the earliest vertebrates called?

Ostracoderms

What are Jawless fishes called?

Agnatha

True or false: Jawless fishes have paired fins

False

What were extinct jawed vertebrates called?

Gnathostomata

What do Gnathostomata have that Agnatha do not?

presense of jaws and paired fins

What are the characteristics of Placoderms?

tooth plates

What are the characteristics of Acanthodians?

operculum (gill cover); gave rise to bony fishes

What are jaws?

modified cartilaginous gill arches

What are the 3 pieces of evidence for jaws?

1. jaws and gill arches have lower and upper hinge bars

2. both arose from neural crest cells

3. jaw muscles are homologous with original gill support muscles

True or false: Living fishes make up half of all vertebrate species 

True

What evolutionary innovation are paired fins precursors for?

tetrapod limbs

What is another word for Agnathans?

Hagfish or Lamprey (jawless fishes)

What are the characteristics of Hagfish?

no jaws, scales, or paired fins, lack a vertebrae but have a cranium, slime glands along body

What are the characteristics of Lamprey?

no jaws, scales, or paired fins, possess a vertebrae, some parasitic with rasping tongue and oral disc with teeth, affect lake fish species (parasitic when in lakes), reproduce in steams and migrate towards lakes