Vertebrate Evolution Flashcards
What is a chordate?
Anything with a Notochord.
Give an overview of the Urochordata?
Include the Tunicates a.k.a Sea Squirts, mostly sessile, filter feeding, larval forms posses all of the basic characteristics of a chordate.
What characteristics are present in Tunicate larva?
Dorsal-hollow nerve cord, Notochord, tail, pharynx with slits (modified gills), muscles (somites) for swimming.
Give an overview of Cephalochordates?
Include the Lancelets, retain chordate body plan throught life, somites (blocks of musculature in segments along bodies).
How is the Class Myxinin an inter-mediate area?
The Hagfish (slime eel) has a cartilaginous skulls but no jaws and no vertebrae.
What are Hagfish?
Slime eels, jawless invertebrate chordates, more like sophisticate lancelets (very early fish).
How is the class Petromyzontida represented?
In extant lineages by Lampreys (Jaw-less fish).
What are Lampreys?
Jawless fish with vertebrae but no jaw, lack paired fins, forerunners of the jawed fish.
What belongs to the class Chondrichthyes?
Sharks and rays.
What are members of the Chondrichthyes class named for?
Their cartilaginous skeletons i.e. unmineralised skeletons.
What features of common of fish in that belong to the super class Gnathsomata?
Jaws, skulls, vertebrae, paired fins.
What are the Osteichthyans?
Bony fish
What fish belong to the class Sarcopterygii?
Lobe-fined fish
What fish belong to the class Actinpterygii?
Ray-finned fish
What evolutionary importance does the Swim bladder have?
Same structure as the lung, lung derivative.
What belongs to the class Dipnoi?
The Lung fish
Where did Amphibia descend from?
The earliest tetrapod (terrestrial vertebrate)
What is the evolutionary importance of Amphibia?
First vertebrates to combat out and exploit terrestrial environment.
What restricts Amphibia?
Dependant on water as eggs are not desiccation resistant, employ their skin for gas exchange, meaning skin must be moist,
What are Amniotes?
A clade formed by Reptiles and Mammals.
What are defined features of amniotes?
Keratinised (waterproof) skin and the amniotic (shelled) egg.
What is the difference between Diapsids and Synapsids?
Diapsids have two holes in skull for muscle attachment, whereas Synapsids have only one hole in the skull.
What characteristics formed with the evolution of mammals?
Hair, Mammary Glands, differentiated teeth, extended parental care, large brains.
What is Paedo Morphosis?
Sexual maturation in juvenile form.
What is the endostyle?
Early model of thyroid gland, control of metabolic rate.
What characteristics are shown by Vertebrates?
Vertebral column backbone, cranium, tripartite brain, kidneys, endoskeleton (Bone or Cartilage).
What are Jawless fish know as ?
Agnathans
List features of Agnathans ?
Covered by bony plates which acted similar to jaws, notochord was main axial support.
List some facts about Hagfish?
Tie themselves in knots to increase grip, slime defence, used as model for examine early vertebrates (Immune system and development)
Define the structure of the Agnathan Head?
3 lobed brain, teeth on tongue, olfactory sac.
Give some features of Lampreys?
Single nasal opening, Endostyle, kidney, can osmoregulate (specialised Chloride cells), 7 pairs of gill pouches, large well-developed eyes.
What was the evolutionary importance of the appearance of jaws and paired fins?
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.
