MIDTERM 3

Question 1

Eusthenopteron

Answer 1

Devonian early tetrapod 
    * 385 My ago
    * Strictly aquatic 
    * Upper arm bone (humerus) and two forearm bones (radius and ulna)
Could not support head or walk well

Question 2

Tik*taalik

Answer 2

Devonian early tetrapod 
 375 My ago 
intermediate b/w tetrapod and love-finned fishes 
    * No operculum 
    * Can lift head
    * Some support on fins

Question 3

Acanthostega

Answer 3

Devonian early tetrapod

* 365 Mya (end Devonian) 
* “Boris”
* Has fingers on limbs
* Weight support
* Limbs not strong enough for land support

Question 4

Ichthyo*stega

Answer 4

Devonian early tetrapod

• 365 Mya
  
  • Shoulder girdle and muscles
  • Fish-like tail and gills (and operculum)
  • Amphibian skull and lungs, ear to detect airborne sound

Question 5

Devonian early tetrapod order

Answer 5

Eusthenopteron 385
Tiktaalik 375
Acanthostega 365
Ichthyostega 365
(ETAI)

Question 6

Amniota

Answer 6

Embryos develop within a fluid filed sac

* Mammals 
* Birds
* Reptiles

Question 7

Anamniota

Answer 7

• Embryos develop without a fluid filed sac
  
  • Boney fishes
  • Sharks
  • Lampreys
  • Hagfishes

Question 8

Agnatha:

Answer 8

Vertebrates lacking jaws 
    * Hagfish 
    * Lampreys 
also extinct Ostracoderms 
(Heterostracans
Osteostacan
Anaspid)

Question 9

Ostracoderms

Answer 9

• Means shell skin
• Armoured jawless fishes
• Lacked paired fins
• Flourished for 150 million years
• All went extinct in Devonian Period
  (Heterostracans
  Osteostacan
  Anaspid) HOA

Question 10

Heterostracans

Answer 10

• Fixed slit mouth openings used to filter small food particles
  
  • Never evolved paired fins
  • Three layer dermal skeleton
  • Paired nasal openings

Question 11

Osteostacan

Answer 11

• Means bone shell
  
  • Had paired pectoral fins
  • Improved swimming ability
  • Small around 30cm in length

Question 12

Anaspid

Answer 12

• More streamlined

Question 13

What is a modern fish

Answer 13

• Aquatic vertebrate with gills,
  
  • Limbs in the form of fins,
  • Skin covered in scales of dermal origin

Question 14

Subphylum Cephalochordata

Answer 14

• Burrows in mud
• Expose their mouths to seawater
• Filter feeder
  
  • Water enters the mouth driven by cilia in the buccal cavity and pharynx

Question 15

Subphylum Urochordata

Answer 15

• Also called Tunicata
• About 3000 species
• All marine
• Tunicata: Refers to tough nonliving tunic that surrounds them
• Class Ascidiacea
• Class Appendicularia
• Class Thaliacea
  uAAT

Question 16

What makes a vertebrate?

Answer 16

• Cranium
  
  • Vertebral column
  • Tri-partite brain (forebrain, midbrain, hind brain)
  • Neural Crest = “quadroblastic”
  • Ectodermal placodes
  • Homeobox (Hox) genes double duplication

Question 17

Pikaia

Answer 17

Early Vertebrates

* Early cephalochordate
* no cranium, no vertebrae
* 505ma 
* Burgess Shale

Question 18

Haikouella

Answer 18

• Sister group to vertebrates
  
  • brain but no cranium
  • 515 ma, Chengjiang fauna

Question 19

• Myllokunmingia

Answer 19

• Earliest vertebrate
  
  • no vertebrae
  • A cranium
  • Segments out from notochord
  • 524 ma, Chengjiang fauna

Question 20

• Haikouichthys

Answer 20

• Cartilaginous gill supports
  
  • Sister group to Lamprey- dorsal fins
  • 524 Ma, Chengjiang fauna

Question 21

Earliest vertebrate

Answer 21

Myllokunmingia 524 ma, C
Haikouichthys 524 Ma, C
Haikouella 515 ma, C
Pikaia 505ma, BS
(MHHP)

Question 22

Clade Cyclostomata

Answer 22

Class Myxini (Hagfish)
Class Petromyzontida (Lampreys)
Distinct head with brain and cranium 1 pair of semicircular canals
Teeth made of keratin

Question 23

Class Myxini (Hagfish)

Answer 23

• No scales, no dorsal fins
  
  • One external gill opening
  • Have a notochord
  • Do not have vertebrae
  • Very flexible body
  • Have 6“tentacles”: protrusions to search out food
  • Have keratinized teeth on a protrusible “tongue”
  • Tail-to-head knot to stabilize

Question 24

Class Petromyzontida

Answer 24

• Vertebrae present
• Often parasitic
• Single nasal opening on the top of their head!
• Have 2 semicircular canals
• Have caudal (tail) and dorsal fins
  lampreys

Question 25

Class Chondrichthyes

Answer 25

* Appeared in Devonian period * Well developed sense organs * Powerful jaws * Cartilaginous skeleton * No swim blatter * Have internal fertilization * Clade Elasmobranchii * Clade Holocephali

Question 26

Clade Elasmobranchii

Answer 26

* Consists of Sharks, Rays and Skates

Question 27

Clade Holocephali

Answer 27

* 48 species of chimaeras * Diverged from shark lineage 380 million years ago * Only 33 species * Called Chimeras cause are ugly * No teeth have large flat plates * Oviparous

Question 28

Clade Osteichthyes

Answer 28

* Means boney fishes because they have a endochondral bone Includes boney fishes and tetrapods Monophyletic group Lungs or swim bladder derived from gut

Question 29

Class Actinopterygii

Answer 29

* Ray finned fished * Subclass Cladistia * Subclass Chondrostei * Subclass Neopterygii aCCN

Question 30

Class Sarcopterygii

Answer 30

Includes Actinistia, Dipnoi and tetrapods within clade Osteichthyes Unique supportive elements in skeleton and girdle of limbs

Question 31

* Class Ascidiacea

Answer 31

* Little bag * Sea squirts * Most abundant * Larvae: * Are free swimming * Do not eat * Have all 5 chordate c characteristics * Adult * Only have 2 chordate characteristics: Endostyle and Pharyngeal slits * Are sessile filter feeders * Compound, colonial or solitary * One of aquacultures worst enemies

Question 32

* Class Thaliacea

Answer 32

* luxuriant * The Salps * free-swimming, can be solitary or colonial * use water current for both feeding and gas exchange as well as for locomotion (form of jet propulsion) * feed using a mucus net

Question 33

Class Appendicularia

Answer 33

Ghost larva Larvaceans: pelagic, free-swimming, tiny Show all chordate characteristics in the adult form Secrete a mucous house to suspension feed