Lab 7

Question 1

4 characteristics of Chordates

Answer 1

Notochord
Dorsal, hollow nerve chord
Pharyngeal slits
Muscular, post anal tail

Question 2

Notochord

Answer 2

flexible rod, located between digestive tube and nerve chord that provides support along the length of the animal

Question 3

Dorsal, hollow nerve chord

Answer 3

a bundle of nerve cells that runs the length of the body. All other animals have solid nerve chords and they are usually ventral

Question 4

Pharyngeal slits

Answer 4

slits in the pharynx that opens to the outside of the animal, allowing water to enter the mouth and leave the body without passing through the entire digestive tract

Question 5

Muscular, post anal tail

Answer 5

initially evolved for locomotion in water

Question 6

Cephalochordata

Answer 6

(lancelets) resemble the ideal chordate, have all 4 characteristics, as larvae they are free swimming and filter feed on plankton suspended in the water. As adults they bury themselves in sand and filter feed by drawing water through their pharyngeal gill slits.

Question 7

Urochordata

Answer 7

(Tunicates) resemble chordates in their larval stage where 4 traits are found. As adults they are sessile and use pharyngeal slits for suspension feeding. Adults are characterised by their 2 siphons. One siphon draws water into the organism, from which food is collected in a mucous net and the other expels the filtered water. This can be done quite rapidly, giving the tunicates their more common name of sea squirts

Question 8

Myxinoidea

Answer 8

(hagfishes) first to posses neural crest and skull, so they belong to caraniates. Skull is of cartilage, but now jaw or backbone, technically a invertebrate. Live at bottom of ocean, live as deposit feeders, scavenging worms and sick or dead fish.

Question 9

Lampreys

Answer 9

Oldest living lineage of vertebrate chordates. Have skull and backbone but no jaws. Most are parasitic, feed by sucking on prey and using rasping tongue to break the skin and digest blood.

Question 10

Notochord and post anal tail innovation

Answer 10

Provides support and propulsion for underwater movement

Question 11

Pharyngeal slits innovation

Answer 11

allows suspension feeding and gas exchange

Question 12

Cephalisation innovation

Answer 12

the is toward increased cephalisation and development of a larger brain allowing better sensory perception and reaction to the surrounding environment

Question 13

Jaws innovation

Answer 13

increases food diversity

Question 14

Mineralised and joint skeleton innovation

Answer 14

more flexibility , protection and support

Question 15

Lungs

Answer 15

breathing on land

Question 16

Limbs

Answer 16

walking on land

Question 17

Heart chambers

Answer 17

2 – 3 – 4 increased heart complexity allows improved circulation and separation of oxygenated and deoxygenated blood.

Question 18

Amniotic egg

Answer 18

reproduction without water

Question 19

Heart

Answer 19

a. 2 chambered: fish
b. 3 chambered: amphibians and reptiles
c. 4 chambered: birds and mammals

Question 20

3 over 2

Answer 20

has double circulation, 2 has single

Question 21

4 over 3

Answer 21

4 has separated oxygenated and deoxygenated blood

Question 22

Double verses Single

Answer 22

Double circulation in faster than single and it flows through the lungs, in single in flows through the capillaries and it is much slower

Question 23

Gnathostomes

Answer 23

Jaw and mineralised skeleton

Question 24

Osteichthyans

Answer 24

Lungs and lung derivatives

Question 25

Terapods

Answer 25

legs

Question 26

Amniotes

Answer 26

Amniotic eggs

Question 27

Amphibians

Answer 27

limbs, lungs, jaws, vertebral column, cranium, eggs in water, feed on land, gas exchange. Still tied to aquatic because they lay eggs in water, skin needs to stay moist and gas exchange.

Question 28

Amniotic eggs

Answer 28

The amniotic egg is composed of 4 membranes, including a yolk that provides nutrients to the developing embryo. Most amniotic eggs have a shell; however, in mammals, the shell has been lost and the embryo develops within the amnion within the mother instead. Significantly reduce hydration of egg in air. Allows amniotes to occupy wider range of habitats

Question 29

Reptiles on land

Answer 29

limbs for walking, breath on land

Question 30

Reptiles and Birds

Answer 30

Share: Jaws, vertebral column, limbs, amniotic egg, cranium, eyeballs
Birds: Eggs shell calcaneous and hard, wings, feathers, porous skeleton easier for flight