vertebrate evolution

Question 1

invertebrates

Answer 1

lack notochord

Question 2

vertebrates

Answer 2

variety of forms ie fish mammals reptiles

Question 3

the chordates

Answer 3

include both non-vertebrates and vertebrates

dorsal hollow nerve chord
notochord
post anal tail
pharyngeal gill slits

Question 4

3 subphyla of chordates

Answer 4

urochordates (tinucata- sea squirts)

cephalochordates (lancelet)

craniates (hagfish and vertebrates)

hermichordates considered separate phylum

Question 5

paedomorphasis

Answer 5

sexually mature without reaching adult body form

Question 6

neoteny

Answer 6

retention larval characteristcs past reproductive maturity

Question 7

progenesis

Answer 7

accelerated development of reproductive organs relative to somatic tissue

Question 8

non vertebrate chordates live in the seas

Answer 8

urochordata-3 classes sea squirt scalps and larvaceans- ascideans (sea squirt), adults sessile, larvae free swimming

Question 9

craniates are chordates that have a cranium

Answer 9

neural crest- embryonic source of many unique craniate chractersitics

reaised metabolism

more extensive musculature

heart with atleast 2 chambers

haemoglobin in red blood cells

kidneys

Question 10

neural crest

Answer 10

special type of embryonic tissue forms PNS and myelin sheath

Question 11

origin of craniates

Answer 11

fossils found in china

mouth structure

large well formed brain

no skull or ear organs

lack vertabrae

Question 12

hagfish??? myxini

Answer 12

tooth like formations made of keratin

60 cm in length

bottom dwelling scavengers

slime glands that can repulse other scavengers

Question 13

vertebrates are craniates that have a vertabral column

Answer 13

after branching off from other craniates verts underwent another gene duplication

function of vertabral column- supports body, attahcment site, protects nerve cord and brain

Question 14

oldest living lineage of vertabrates

Answer 14

most adults are parasytic

petromyzontida- lamreys

cartilaginous pipe around notochord