Lecture 11 - Fish

Question 1

What is vertebrata?

Answer 1

All chordates besides the invertebrate animals

Question 2

Vertebrate features (5 traits)

Answer 2

they exhibit all chordate features during some stage of development, dorsal hollow nerve cord becomes the spinal cord, typically have post anal tail, notochord induces folding of neural tube during development and provides skeletal support in adults of some species, pharyngeal slits typically develop into gills or jaws

Question 3

Chordate features in humans (4 traits)

Answer 3

Dorsal hollow nerve cord becomes spinal cord, post anal tail is reabsorbed during embryogenesis (40% of embryo’s body length), notochord is lost after embryogenesis, pharyngeal slits develop into jaw ear larynx and throat

Question 4

Synapomorphies of vertebrata (4 traits)

Answer 4

Vertebrae, cranium-skull, forebrain midbrain hindbrain, paired sense organs - eyes ears nostrils

Question 5

Jawless fish (5 traits)

Answer 5

Hagfishes and lampreys, notochord in adults, cartilaginous skeleton, breathe with gills, no paired appendages

Question 6

Hagfish (a jawless fish) (3 traits)

Answer 6

no vertebrae, produce slime for defense, scavengers and predators

Question 7

Lampreys ( a jawless fish) (4 traits)

Answer 7

have vertebrae, larvae filter feed, some adults are ectoparasites on fish, other adults don’t eat

Question 8

Jawed animals (4 traits)

Answer 8

Aka gnathostomata, jawed fishes and tetrapods, must have paired appendages aka fins in fish and limbs in tetrapods, all but chondrichthyes have bony skeletons

Question 9

Chondrichthyes (a type of jawed animal) 7 traits

Answer 9

Cartilaginous skeletons, breathe with gills, includes sharks rays and skates, most are predators but some are suspension feeders, sexual or parthenogenisis, internal fertilization, ovi - ovovivi- or viviparous

Question 10

Ostrichotyces (a type of jawed animal) 4 traits

Answer 10

Bony skeleton, mostly sexual reproducers some parthenogenesis, external fertilization in marine and freshwater species, internal fertilization in terrestrial species

Question 11

Actinopterygii (a type of jawed animal) 4 traits

Answer 11

Have ray-like fins, all breathe with gills, some also breathe with lungs, lungs function as swim bladder in others

Question 12

Acinistia (jawed) (5 traits)

Answer 12

Coelacanth, lobed fins, breathe with gills and has vestigial lungs, originally thought to have gone extinct 65mya, discovered in fish market in South Africa in 1938

Question 13

Dipnoi (jawed) (4 traits)

Answer 13

Lung fish, lobed fins for swimming and walking, breathe with gills, use lungs to breathe air when oxygen levels drop

Question 14

Vertebrate diversity 3 traits

Answer 14

Ray-formed fishes are the most diverse lineage of vertebrates, actinistia has only two species, dipnoi has only 6 species

Question 15

Jaws and gills evolution

Answer 15

Jaws evolved from gill arches, gill arches develop from pharyngeal slits