Chapter 24: Fishes Flashcards Preview

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Flashcards in Chapter 24: Fishes Deck (17):

What are the five classes of Fishes?

- Myxini
- Petromyzontida
- Chondrichthyes
- Actinopterygii
- Sacropterygii


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

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


Do fishes form a monophyletic group?

- no they do not
- in evolutionary terms, they can be defined as all vertebrates that are not tetrapods.


Fishes share a common ancestor with what?

land vertebrates


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

- 800


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

- salt
- water


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

- 1/20


What does their lateral line system detect?

- detects water currents and vibrations, a sense of "distant touch"


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

- it shaped and constrained its evolution


The term "fish(es)" refers to what?

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


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

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


What is the phylum and subphylum of these classes?

- Chordata
- Vertebrata


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

- Gnathostomes
- paired appendages and join tetrapods as a monophyletic lineage of 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?

- Silurian
- no
- Devonian


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.

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


Bony Fishes:
- What are the two distinct lineages? Describe them!

- 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.


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

- jaws, internal ossification, scales or paired fins.
- pore-like gill openings and an eel like body.

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