Chapter 34: The Origin and Evolution of Vertebrates Flashcards Preview

Bio 94: Exam 3 > Chapter 34: The Origin and Evolution of Vertebrates > Flashcards

Flashcards in Chapter 34: The Origin and Evolution of Vertebrates Deck (28)
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1
Q

What are the 4 characteristics of the phylum Chordata?

A
  • notochord
  • dorsal hollow nerve chord
  • pharyngeal slits/clefts
  • post anal muscular foot
2
Q

What is the notochord?

A

A longitudinal, flexible rod located between the digestive tube and the nerve cord.
- provides skeletal support throughout most of the length of a chordate

3
Q

How is the notochord adapted in humans?

A

It is reduced and forms part of the gelatinous disks sandwiched between the vertebrae

4
Q

What are pharyngeal slits?

A

Slits that allow water to enter into the mouth and exit without having to go through the digestive tract

  • in vertebrates these have been modified for gas exchange and are called gills
  • in invertebrates these are used for suspension feeding
5
Q

In tetrapods, what do the pharyngeal slits form into?

A

Parts of the ear and other structures around the head and neck

6
Q

True or false:

In most vertebrates, a more complex, jointed skeleton develops, and the adult fully retains the notochord.

A

False

In most vertebrates, a more complex, jointed skeleton develops, and the adult retains only remnants of the embryonic notochord.

7
Q

Vertebrates have a skeletal system and a complex nervous system. What have these two features allowed animals to do?

A
  • Capture food

- Evade predators

8
Q

What are the characteristics of the subphylum vertebrata in the phylum chordata?

A
  • Vertebrae enclosing a spinal cord
  • An elaborate skull
  • Fin rays (aquatic)
9
Q

Cyclostomes is a clade of chordates that have two characteristics, what are they?

A
  • Jawless
  • Vertebrates

E.g., hagfishes and lampreys

10
Q

Hagfish and lampreys lack a backbone but are still considered vertebrates. Why?

A

They have a presence of rudimentary (nonfunctional) vertebrae

11
Q

Gnathostomes is a clade of animals that has what characteristics?

A

Jawed vertebrates

12
Q

What are characteristics of hagfishes?

A
  • jawless vertebrates
  • notochord
  • cartilaginous skull
  • no backbone
  • scavengers/decomposes
  • slime glands (to repel predators)
13
Q

What are characteristics of lampreys?

A
  • parasites (latch onto a host)

- cartilaginous segments surround the notochord

14
Q

The first cartilaginous fishes emerged:

a. 250 billion years ago
b. 250 million years ago
c. 455 billion years ago
d. 455 million years ago

A

d. 455 million years ago

15
Q

The first tetrapods emerged:

a. 365 billion years ago
b. 365 million years ago
c. 420 billion years ago
d. 420 million years ago

A

b. 365 million years ago

16
Q

The first amniotes emerged:

a. 320 million years ago
b. 320 billion years ago
c. 365 million years ago
d. 365 billion years ago

A

a. 320 million years ago

17
Q

How did jaws evolve?

A

By modification of skeletal rods that supported the pharyngeal (gill) slits

18
Q

Who have been the dominant predators in the ocean for 320 million years?

A

Class chondrichythes: Sharks, skates, rays

In the clade gnathostomes, superclass tetrapoda

19
Q

True or false:

Sharks need to continuously swim so that water moves across their gills

A

True

20
Q

What are the characteristics of the class chondrichythes in the subphylum vertebrata?

A
  • cartilaginous skeleton evolved secondarily from an ancestral mineralized skeleton
  • largest and most diverse group include the sharks, rays and skates
21
Q

What are the characteristics of sharks?

A
  • streamlined body, swift swimmers
  • carnivores
  • short digestive tract with a ridge called the spiral valve that increases the digestive surface area
  • acute senses
  • males have clasper fins
22
Q

Osteichthyes is a superclass of what?

A

Bony fishes

Has two classes:
Ray finned fishes
Lobe-fins

23
Q

Describe the characteristics of ray-finned fishes.

A
  • named for bony rays that support their fins

E.g., tuna, trout, clownfish, ocean sunfish, oarfish, sea horse

24
Q

Describe the characteristics of lobe-fins.

A
  • muscular pelvic and pectoral fins
    > for swimming and walking across substrates
  • rod shaped bones
25
Q

What are the 3 lineages of lobe-fins?

A

Coelacanths
Lungfishes
Tetrapods

26
Q

What are some specific adaptations of tetrapods?

A
  • 4 limbs, feet with digits
  • ears for detecting airborne sounds
  • neck (movement of head)
  • fusion of the pelvic girdle to the backbone
  • no gills (except some aquatic species)
27
Q

What are the classes of tetrapods?

A
Superclass Tetrapoda 
- Class Amphibia
   ~ clade amniota 
        - Class Reptilia 
             - Class Aves
        - Class Mammalia
28
Q

What are characteristics of amphibians?

A
  • eggs require aquatic environment
  • moist skin that complements the lungs in has exchange

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