Vertebrates

Question 1

vertebrae

Answer 1

small skeletal elements that form a backbone

Question 2

characteristics of vertebrates

Answer 2

• dorsal vertebral/spinal column
• anterior cranium(skull), with a large brain
• well developed circulatory system with a ventral heart

Question 3

examples of the agnathans

Answer 3

lamprey and hagfish

Question 4

agnathans

Answer 4

jawless fish

Question 5

hagfish

Answer 5

-skeleton of cranium and cartilage only (no bone)
-no jaws, teeth made of protein (keratin), used to escape tissue from dead organisms
-can secrete tons of slime
(hag gag) to remember slime

Question 6

lamprays

Answer 6

• also have cartilaginous skeleton/skull
• mostly parasites of fish
• no jaws but attach to host with sucker like mouth, scrape hot tissue with teeth of keratin

Question 7

gnathostome

Answer 7

synapomorphy for vertebrates that have jaws and mineralized skeleton

Question 8

how did jaws evolve?

Answer 8

• from gill arhches that supported pharynx around slits
• evolution of mineralized teeth made jaws more effective
• with evolution of jaws, gill slits no longer used for suspension feeding

Question 9

common ancestor of gnathostome also evolved what?

Answer 9

fins

-allowing for efficient movement through water

Question 10

chondrichthyans

Answer 10

• sharks and rays

- cartilagenous fishes

Question 11

sharks

Answer 11

mostly predators (bulk feeding great white sharks) but some large sharks suspension feed (whale sharks)

Question 12

rays

Answer 12

body is dorsoventrally flattened
some live on sea floor (sting rays, predators on invert)
-others inhibit the open ocean (manta rays)
-suspension feeders bring water and prey into mouth with large fleshy extensions

Question 13

actinopterygii and sarcopterygii

Answer 13

• actin: ray fins
• sarco: lobe fins
• ancestor evolved outgrowths of gut (sacs) that could be filled with air
  
  • sacs evolved into swim bladders in most ray finned fishes
  • lungs in lobe fin lineage including tetrapods

Question 14

actinoptergyii

Answer 14

• ray finned fishes
• fins are supported by delicate bones
• skeleton mineralized with calcium phosphate
• surface of refined fishes are often covered with scales
• gills covered by a hardened flap of tissue (operculum)

Question 15

sarcopterygii

Answer 15

• lobe fins
• novel bones surrounded by muscle arose in these fins
• allowed common ancestor of lobe fins to support itself in shallow water

Question 16

coelocanths

Answer 16

• thought to have gone extinct

- living organisms found in deep waters off africa

Question 17

lung fish

Answer 17

• live only in swamps/ponds in the tropics of the southern hemisphere
• have functional lungs for breathing air!
• also have gills but in most the gills are not functional

Question 18

tetrapods

Answer 18

• tetra:4 pod: foot

- skeletal changes in pectoral fins gave rise to tetrapod forelimbs (arms)

Question 19

amphibians

Answer 19

• most have 2 life stages:
  
  • aquatic larvae
  • lack limbs
  • respire via gills
  • swim with muscular post anal tail
• adults may be aquatic, amphibious, or mostly terrestrial
  
  • usually have limbs
  • respire via lungs and across skin
  • may or may not have a tail
• confined to moist habitats because:
  
  • eggs have no shell, vulnerable to desiccation
  • most have larvae that are aquatic

Question 20

there clades of amphibians

Answer 20

• caudata
• anurans
• caecilians

Question 21

caudata

Answer 21

• 500 species
• salamanders
• elongate, tailed body with 4 legs

Question 22

anurans

Answer 22

• 5400 species
• frogs and toads
• anura means no tail
• elongated hind legs, webbed feet for hopping or swimming

Question 23

caecilians

Answer 23

• 170 species
• legless, burrowing amphibians
• wormlike, burrow in soil in the tropics
• larvae not fully aquatic, develop in soil near water

Question 24

sister clades of animals

Answer 24

reptiles and mammals