History of fish

Question 1

Similar due to common ancestry (eg. the humus, radius, and ulna bones in whales, humans, birds, etc.)

Answer 1

Homology

Question 2

When the similarity is NOT due to a common answer (eg. human eyes and cephalopod eyes)

Answer 2

Homoplasy

Question 3

When did the first recognizable fish arise and what were they called?

Answer 3

470 million years ago. Craniates.

Question 4

What were the features of Craniates and what part of water did they occupy?

Answer 4

They were jawless and finless. Occupying shallow seas or estuarine habitats.

Question 5

Give three examples of developments that fish passed onto higher vertebrates.

Answer 5

Any of the following:
Bony endoskeletons
Brain cases
Teeth
Jaws
Brains
Appendages
Internal organ systems

Question 6

Pre-fishes were called what and lived around what time?

Answer 6

Conodonts. Lived between 600-200 millions of years ago.

Question 7

The earliest protoconodonts may have been…

Answer 7

Invertebrates

Question 8

What were the first fishes and what were their features?

Answer 8

Agnathans. Ostracoderms (shell-skinned)-jawless craniate fishes with a bony shield covering the head and thorax

Question 9

What were the innovations of Pteraspidomorphi?

Answer 9

Reduction of armor through fusion of plates
Narrowing of the head shield
Development of lateral projections

Question 10

What were the innovations of Anaspida?

Answer 10

A body covering overlapping scales
Flexible muscularized lateral finlike projections
Internal skeleton

Question 11

What were the innovations of Theolodonti?

Answer 11

Covered with denticles rather than bony plates
Had dorsal and anal fins

Question 12

What were the innovations of osteostracomorphi?

Answer 12

Formed their armor from true bone cells
Another innovation is ossification of the endoskeleton
Paired lateral appendages are through to be homologus to pectoral fins in future fishes

Question 13

What were some innovations in the earliest gnathostomes?

Answer 13

Jaws are present
Paired limbs usually present with skeletal support
Dentine-based teeth

Question 14

What did the evolution of jaws allow for the first gnathostomes?

Answer 14

Diversification of the food types that early fishes could eat
Active defenses against predators eventually leading to de-emphasis on armor.
A supportive skeletal system

Question 15

What period did the Placodermi occupy, and what were their features?

Answer 15

Devonian. Plated jaws with no teeth. Thought to have color vision. Heavily armored.

Question 16

What were the features of Acanthodii?

Answer 16

Small fish occurring in fresh and salt water with spines and cartilaginous skeletons.
Large head, lare eyes, and streamlined bodies indicate that they were water column feeders.

Question 17

What’s a feature we see in more advanced gnathostomes than the primitive ones?

Answer 17

Innovations of serially replaced teeth and of jaws that could create suction

Question 18

What lineages are derived from gnathostomes?

Answer 18

Chondrichtyans (cartiliganous fish, sharks and rays).
Living Osteichthyans (bony fishes, coecalanths).
Dipnoi (lungfish).
Tetrapodomorphs (tetrapod ancestors).

Question 19

What are some homologous features between tetrapodomorphs and humasn?

Answer 19

Bone arrangement. Skull bones. Rib-like structure. Eye placement.

Question 20

When did the chondrocytes arise, and what were their evolutionary trends?

Answer 20

About 450 million years ago. Tooth replacement
Calcification of cartilaginous skeleton. Hardening skeletons with cartilage embedded with calcium deposits to make them more capable.

Question 21

When did Actinopterygii, and what were their features?

Answer 21

Likely around 400 million years ago. Ray-finned fishes. Made up the majority of fish diversity at the time.

Question 22

When did the Teleostei arise?

Answer 22

200 million years ago.

Question 23

What were some evolutionary trends of Teleostei?

Answer 23

Reduction of bony elements
Change in position and function of dorsal fin
Change in gas bladder morphology and function
Change in jaw morphology and feeding specialization