Vertebrate Evolution

Question 1

What is a chordate?

Answer 1

Anything with a Notochord.

Question 2

Give an overview of the Urochordata?

Answer 2

Include the Tunicates a.k.a Sea Squirts, mostly sessile, filter feeding, larval forms posses all of the basic characteristics of a chordate.

Question 3

What characteristics are present in Tunicate larva?

Answer 3

Dorsal-hollow nerve cord, Notochord, tail, pharynx with slits (modified gills), muscles (somites) for swimming.

Question 4

Give an overview of Cephalochordates?

Answer 4

Include the Lancelets, retain chordate body plan throught life, somites (blocks of musculature in segments along bodies).

Question 5

How is the Class Myxinin an inter-mediate area?

Answer 5

The Hagfish (slime eel) has a cartilaginous skulls but no jaws and no vertebrae.

Question 6

What are Hagfish?

Answer 6

Slime eels, jawless invertebrate chordates, more like sophisticate lancelets (very early fish).

Question 7

How is the class Petromyzontida represented?

Answer 7

In extant lineages by Lampreys (Jaw-less fish).

Question 8

What are Lampreys?

Answer 8

Jawless fish with vertebrae but no jaw, lack paired fins, forerunners of the jawed fish.

Question 9

What belongs to the class Chondrichthyes?

Answer 9

Sharks and rays.

Question 10

What are members of the Chondrichthyes class named for?

Answer 10

Their cartilaginous skeletons i.e. unmineralised skeletons.

Question 11

What features of common of fish in that belong to the super class Gnathsomata?

Answer 11

Jaws, skulls, vertebrae, paired fins.

Question 12

What are the Osteichthyans?

Answer 12

Bony fish

Question 13

What fish belong to the class Sarcopterygii?

Answer 13

Lobe-fined fish

Question 14

What fish belong to the class Actinpterygii?

Answer 14

Ray-finned fish

Question 15

What evolutionary importance does the Swim bladder have?

Answer 15

Same structure as the lung, lung derivative.

Question 16

What belongs to the class Dipnoi?

Answer 16

The Lung fish

Question 17

Where did Amphibia descend from?

Answer 17

The earliest tetrapod (terrestrial vertebrate)

Question 18

What is the evolutionary importance of Amphibia?

Answer 18

First vertebrates to combat out and exploit terrestrial environment.

Question 19

What restricts Amphibia?

Answer 19

Dependant on water as eggs are not desiccation resistant, employ their skin for gas exchange, meaning skin must be moist,

Question 20

What are Amniotes?

Answer 20

A clade formed by Reptiles and Mammals.

Question 21

What are defined features of amniotes?

Answer 21

Keratinised (waterproof) skin and the amniotic (shelled) egg.

Question 22

What is the difference between Diapsids and Synapsids?

Answer 22

Diapsids have two holes in skull for muscle attachment, whereas Synapsids have only one hole in the skull.

Question 23

What characteristics formed with the evolution of mammals?

Answer 23

Hair, Mammary Glands, differentiated teeth, extended parental care, large brains.

Question 24

What is Paedo Morphosis?

Answer 24

Sexual maturation in juvenile form.

Question 25

What is the endostyle?

Answer 25

Early model of thyroid gland, control of metabolic rate.

Question 26

What characteristics are shown by Vertebrates?

Answer 26

Vertebral column backbone, cranium, tripartite brain, kidneys, endoskeleton (Bone or Cartilage).

Question 27

What are Jawless fish know as ?

Answer 27

Agnathans

Question 28

List features of Agnathans ?

Answer 28

Covered by bony plates which acted similar to jaws, notochord was main axial support.

Question 29

List some facts about Hagfish?

Answer 29

Tie themselves in knots to increase grip, slime defence, used as model for examine early vertebrates (Immune system and development)

Question 30

Define the structure of the Agnathan Head?

Answer 30

3 lobed brain, teeth on tongue, olfactory sac.

Question 31

Give some features of Lampreys?

Answer 31

Single nasal opening, Endostyle, kidney, can osmoregulate (specialised Chloride cells), 7 pairs of gill pouches, large well-developed eyes.

Question 32

What was the evolutionary importance of the appearance of jaws and paired fins?

Answer 32

Expanded the niches which can be used, allowed jaws vertebrates to grasp hold/ tear away, became apex predators, paired fins meant better control during swimming.