Vertebrate Origins

Question 1

What is systematics?

Answer 1

The study of biological diversity using phylogeny, the evolutionary relationship between groups of organisms

Question 2

What is taxonomy?

Answer 2

The description, identification and classification of species

Question 3

What is classification

Answer 3

The arrangement and hierarchy of taxa

Question 4

What is a monophyletic group?

Answer 4

Groups of taxa that consist of a common ancestor plus all descendants

Question 5

What is a paraphyletic group

Answer 5

A group that contains an ancestor but not all of its descendants

Question 6

What is a polyphyletic group give an example

Answer 6

A group of organisms that do not all share the same ancestor (Indian river dolphin does not share same ancestor as other river dolphins)

Question 7

What 2 infraphylums does vertebrata split into?

Answer 7

Agnatha - jawless fish

Gnathosomata - jawed vertebrates

Question 8

What are the cyclostomata?

Answer 8

The living jawless dish (superclass)

Question 9

Why are the Chondrichthyes

Answer 9

Cartilaginous fish

Question 10

What are the Osteichthyes

Answer 10

Bony fishes

Question 11

Common features of chordates

Answer 11

• bilateral symmetry
• notochord (dorsal rod of specialised nerves
• pharyngeal pouches - gill slits

Question 12

How long ago did the chordates evolve/ how many species

Answer 12

540 May

52,000 species

Question 13

What are the extant lower vertebrates?

Answer 13

Hagfishes
Lampreys
Cartilaginous fishes
Ray finned fishes
Love finned fishes
Lungfishes 
Amphibians

Question 14

Why are vertebrates a good model for studying evolution?

Answer 14

• monophyletic group
• free living
• basic anatomy and development in common
• diversity of form and function can be related to adaption and evolution
• vest studied eukaryotic group
• good fossil record

Question 15

What are the extant higher vertebrates? (Amniotes)

Answer 15

• testudines - turtles etc.
• lepidosaura - snakes lizards etc.
• crocodilia - crocodiles etc.
• aves - birds
• mammalia

Question 16

from where and when did amniotes arise?

Answer 16

From a tetrapods amphibian 370mya

Question 17

What are the common features of vertebrates

Answer 17

• post anal tail
• vertebral column
• specialised sensory organs
• brain at anterior end or nerve cord
• closed loop circulatory system
• myomeres (muscle segments)
• have cranium

Question 18

What are the 10 systems the organisms of vertebrates are organised into?

Answer 18

Skeletal
Muscular
Integumentary
Digestive
Respiratory
Circulatory
Excretory
Immune
Nervous
Reproductive

Question 19

When did the agnatha originate

Answer 19

500mya

Question 20

What are the two extant groups of agnathans

Answer 20

Lampreys

Hagfish

Question 21

Features of agnathans

Answer 21

• absence of paired fins
• seven or more paired gill pouches
• no identifiable stomach or appendages
• fertilisation and development are external

Question 22

When did the Osteichthyes originate

Answer 22

410mya

Question 23

How many species are there

Answer 23

25,000, 60% are marine

Question 24

Characteristics of bony fish?

Answer 24

• scales
• gills
• cold blooded (apart from swordfish and tuna)

Question 25

When did Chondrichthys appear and how many species?

Answer 25

420mya
1200 species (500 sharks, 600 rays and skates)