Vertebrates

Question 1

Homologous structure

Answer 1

Two structures derived from the same tissue during developmental

Don’t have to perform the same function

Eg. Pentadactyl limb

Question 2

Divergence often leads to:

Answer 2

Closely related organisms with strikingly different morphology, physiology and/or behaviour

Question 3

Convergence often occurs when:

Answer 3

Species from the different lineages occur in similar environments and are subject to similar selection pressures

Question 4

The origins of chordates are _______. Most agree that _________ and _________ are the closest relatives of chordates.

Answer 4

Uncertain
Echinoderms
Hemichordates

Question 5

Paedomorphosis

Answer 5

The evolutionary process in which larval or juvenile features of an ancestral organism are displaced to the adult forms of its descendants

Hypothesis that bilateral larval forms gave rise to primitive filter feeding vertebrates is popular

Question 6

Recent molecular data suggests that _______ and not _______ are the closest loving relatives of vertebrates

Answer 6

Tunicates

Cephalochordates

Question 7

Metameric segmentation

Answer 7

Idea that organisms got longer by adding identical segments

Eg earth worm

Segments started as identical but have evolved diversification through Hox genes

Question 8

Hox genes

Answer 8

Segment identification genes

Identified in fruit flies

Originally only 1 or 2 but duplicated- now many arranged in clusters

Question 9

Name and give the effect of two Hox mutations

Answer 9

Antennapedia: legs instead of antenna

Bithorax: halteres become wings

Question 10

___________/______________ have the most Hox genes as include many diverse species

Answer 10

Ray finned fish

Actinopterygian fish