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Vertebrate Zoology LU > Exam 3 > Flashcards

Exam 3 Flashcards

Origin of Chondrichthyes, Origin of Osteichthyes Part 1 and 2, Origin of Tetrapods Part 1 and 2, The Mesozoic, Origin of Amniota, and Living on Land

1
Q

Where are Chondrichthyes placed phylogenetically?

A

Chondrichthyes occur within Acanthodii. Acanthodii is used primarily for extinct forms, as all extant forms are found within Chondrichthyes.

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2
Q

What are the extant members of Euchondrocephali and Elasmobranchii called?

A

Chimaeriformes refers to extant Euchondrocephalia, and Nesoselachii refers to Elasmobranchii.

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3
Q

What group refers to modern sharks within Neoselachii?

A

Selachii

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4
Q

What is a key feature of Chondrichthyes’ skin?

A

Placoid scales or tooth-like scales that make their skin rough and abrasive.

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5
Q

What is a defining characteristic of the Chondrichthyans skeleton?

A

Made of cartilage, which may display surface mineralization.

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6
Q

How are Chondrichthyans teeth arranged?

A

Teeth are arranged in whrorls, which may be a synapomorphy of all Eugnathostomes.

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7
Q

What type of reproduction is characteristic of Chondrichthyes?

A

Internal fertilization using a pelvic clasper as an intromittent organ.

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8
Q

How many extant species are there in Chimaeriformes?

A

56 species in 3 families

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9
Q

What is the reproductive mode of extant Chimaeriformes?

A

They are oviparous, laying eggs outside of the body.

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10
Q

What are common names for members of Chimaeriformes?

A

Chimaeras, ratfish, and ghost sharks

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11
Q

What are two sister clades within Neoselachii?

A

Selachii (Modern Sharks) and Batomorphi (Sawfishes, Skates, and Rays)

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12
Q

How does the mouth placement differ between basal Neoselachii and extant species?

A

Basal forms had terminal mouth placement, while Neoselachians have their mouths recessed under a protruding rostrum.

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13
Q

How do Batomorphs differ from Selachians in terms of pectoral fin attachment?

A

Batomorphi show fusion of the pectoral fins to the head, while Selachians do not.

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14
Q

What are the two main clades within Selachii?

A

Galeomorphi (includes famous sharks like white sharks and hammerhead) and Squalomorphi (which tend to be smaller and morphologically diverse).

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15
Q

What types of reproductive models are seen in Neoselachains?

A

Oviparity, viviparity, lecithotrophy, and matrotrophy.

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16
Q

Where are the fins on Batomorphs?

A

Fused pectoral fins and a ventral mouth.

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17
Q

What clade is Osteichthyes the sister group to?

A

Acanthodii

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18
Q

WHat are the two main sub-clades of Osteichthyes?

A

Sarcopterygii (lobbed-finned fish) and Actinopterygii (ray-finned fish)

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19
Q

Where is the diversity of Actinopterygii concentrated?

A

In Teleostei.

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20
Q

What accounts for less than 1% of Actinopterygii?

A

Basal Actinopterygian groups.

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21
Q

What happens to the lungs in less basal clades of Osteichthyes?

A

They become a gas bladder in Teleostei.

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22
Q

Name notable bones in the skill of Osteichthyes.

A

Dentary, opercle, maxilla, and premaxilla.

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23
Q

What composes the fin rays of Ostechthyes?

A

Lepidotrichia (segments)

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24
Q

What changed occured to the fins of Sarcopterygians?

A

The monobasic fin anatomy replaced the ancestral tribasic fin anatomy.

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25
Q

What fin type do gars and blowfish display?

A

Abbreviated heterocercal caudal fin.

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26
Q

What is the significance of reduced basal fin elements in Holostei?

A

They share this feature with Teleostei.

27
Q

What is the shape of the Teleostei caudal fin?

A

Homocercal

28
Q

Why are Teleost scales thinner than non-Teleosts?

A

To allow more flexibility during swimming.

29
Q

What special jaw feature do Teleosts have?

A

Mobile jaw elements with a flared oral cavity and a maxilla that rotates down and forward.

30
Q

What role does the gas bladder play in Teleosts?

A

It provides buoyancy, reducing the need for fin use in maintaining position.

31
Q

How do Teleost fins evolve?

A

Fins become more specialized for maneuvering.

32
Q

What are some key features of Teleostei?

A
  • Homocercal caudal fin for enhanced swimming efficiency.
  • Thinner scales allow more flexible body movement.
  • Mobile jaw elements allow for a wider oral cavity
  • Specialized gas bladder provides buoyancy, allowing fins to be used for maneuvering
  • Pharyngeal jaws complement the oral jaws, aiding in food processing
    Pelagic eggs are common, smaller, and buoyant, joining the plankton community as they develop
33
Q

Key Features of Osteichthyes

A
  • Lungs evolved into gas bladders in more derived clades like Teleostei
  • Skull contains multiple notable bones: dentary, opercle, maxilla and premaxilla
  • Fin rays are made of Lepidotrichia
  • Scales are covered in various forms of ancestral enamal
  • Fins shifted from a tribasic anatomy to monobasic in Sarcopterygians, while Teleosts reduced basal fin elements
34
Q

What are the three geologic periods of the Mesozoic era?

A

Triassic, Jurassic, and Cretaceous

35
Q

How long did the Mesozoic era last?

A

Almost 200 million years.

36
Q

What was the position of landmases at the start of the Triassic period?

A

Pangaea was fully formed, spanning from the north pole to the south pole.

37
Q

What land masses formed during the Jurassic period after Pangaea fragmented?

A

Gondwana and Laurasia

38
Q

During what period did modern continents begin moving toward their current postions?

A

During the Cretaceous period.

39
Q

Where was India located during thee Cretaceous period?

A

It was an island off the east coast of Africa.

40
Q

What caused the high global temperatures during the first half of the Mesozoic era?

A

Rising levels of atmospheric carbon dioxide.

41
Q

Was there any glaciation during the Mesozioc era?

A

No, there were no glaciers or icecaps, and forest occured in polar regions.

42
Q

What happened to sea levels during the Cretaceous period?

A

There was a significant sea level rise, with epicontinental seas extending into the interiors of some continents.

43
Q

Which group of amniotes was more diverse early in the Mesozoic era?

A

Synapsids were more diverse than Sauropsids early in this era.

44
Q

What happened to dinosaur diversity during the Jurassic period?

A

Dinosaurs became larger and more diverse

45
Q

When did dinosaur diversity peak?

A

During the Cretaceous period.

46
Q

What radiated in the water during the Mesozoic era?

A

Teleostei fishes and some tetrapods returned to water

47
Q

What evolutionary event occured between marine predators and their intervertebrate prey?

A

The Mesozoic Marine Revolution, an evolutionary arms race between predators with crushing jaws, and armored prey.

48
Q

What caused the End-Triassic period mass extinction?

A

Likely caused by intense volcanism and climate change due to the breakup of Pangaea.

49
Q

How many clades of terrestrial and aquatic tetrapods were lost in the End-Triassic mass extinction?

A

18 Clades

50
Q

What caused the End_Cretaceous (K-Pg) mass extinction?

A

The Chicxulub meteor strike and intense volcanism.

51
Q

What percentage of tetrapod families went extinct during the K-Pg extinction?

A

43% of Tetrapod families.

52
Q

Landmass Positions

A
  • The Triassic period began with Pangaea fully formed, spanning from pole to pole.
  • In the Jurassic period, Pangaea broke into Gondwana and Laurasia, separated by the Tethys Sea.
  • By the Cretaceous period, the modern continents began to move toward their current positions.
53
Q

Mesozoic Extinction Events

A
  • End-Triassic Extinction: Linked to volcanism and climate change caused by the breakup of Pangaea, 18 Clades of terrestrial and aquatic tetrapods were lost.
  • End-Cretaceous (K-Pg) Extinction: Caused by Chicxulub meteor strike and intense volcanism. 43% of Tetrapod families went extinct, affecting Archosaur and Mammalian clades.
54
Q

Osteichthyes

A

Bony Fishes

55
Q

Mammals

A

Synapsid

56
Q
A
57
Q

Lepidosauromorpha

A

Tuatara and Lizards (including snakes)

58
Q

Teleostei

A

Eels, Catfish, Tarpon, Tuna, Trout, Cod

59
Q

Elopomorpha

A

Eels

60
Q

Osteoglossomorpha

A

Bony-tongue fish

61
Q

Siluriformes

A

Catfish (apart of Teleostei)

62
Q

Zeiformes

A

Dories

63
Q

Selachii

A

Modern Sharks like white sharks and hammerheads

64
Q

Batomorphi

A

Skates and Rays

Vertebrate Zoology LU (1 decks)

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