Chapter 24: Fishes

Question 0

Describe the very general characteristics of a modern fish! (3)

Answer 0

• aquatic vertebrate with gills, limbs (if present) in the form of fins, skin covered in scales of dermal origin.

Question 1

What are the five classes of Fishes?

Answer 1

• Myxini
• Petromyzontida
• Chondrichthyes
• Actinopterygii
• Sacropterygii

Question 2

Do fishes form a monophyletic group?

Answer 2

• no they do not

- in evolutionary terms, they can be defined as all vertebrates that are not tetrapods.

Question 3

Fishes share a common ancestor with what?

Answer 3

land vertebrates

Question 4

They have adapted to live in a medium that is ___ times denser than air.

Answer 4

• 800

Question 5

They can adjust to the __ and __ balance of their environment.

Answer 5

• salt

- water

Question 6

Gills are efficient at extracting oxygen from water that has __/__ the oxygen of air

Answer 6

• 1/20

Question 7

What does their lateral line system detect?

Answer 7

• detects water currents and vibrations, a sense of “distant touch”

Question 8

How did an evolution in an aquatic environment affect this group?

Answer 8

• it shaped and constrained its evolution

Question 9

The term “fish(es)” refers to what?

Answer 9

• one or more individuals of one species or to more than one species.

Question 10

What are the earliest fish like vertebrates categorized as? What does this category contain? EX!

Answer 10

• Agnathans (jawless)
• Extinct ostracoderms
• Living Hagfishes- lack vertebrae
• Lampreys which have rudimentary vertebrae

Question 11

What is the phylum and subphylum of these classes?

Answer 11

• Chordata

- Vertebrata

Question 12

Those that do not belong to the category Agnathans belong to what category? Characteristics?

Answer 12

• Gnathostomes

- paired appendages and join tetrapods as a monophyletic lineage of gnathostomes.

Question 13

Gnathostomes:

• What fossil record do they belong to?
• Are there intermediate forms between agnathans and this group?
• What time period is called the Age of Fishes?

Answer 13

• Silurian
• no
• Devonian

Question 14

Cartilaginous Fishes:

• Lost ____ and adopted ___.
• Flourished during the ___ and ___ periods
• They almost became extinct at what period?
• They increased in numbers in the early ___ and diversified to form a modern ___ assemblage.

Answer 14

• heavy dermal armour, skeleton of cartilage
• Devonian, Carboniferous
• end of the Paleozoic
• Mesozoic
• Sharks

Question 15

Bony Fishes:

- What are the two distinct lineages? Describe them!

Answer 15

• Ray-Finned lineages: radiated to form modern bony fishes

- Lobed- finned fishes: relict group with few species today they include the sister group of the tetrapods.

Question 16

Members of Lampreys and Hagfishes lack what structures?BUT both groups share what?

Answer 16

• jaws, internal ossification, scales or paired fins.

- pore-like gill openings and an eel like body.