Chapter 34: The Origin and Evolution of Vertebrates Flashcards Preview

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

What are the 4 characteristics of the phylum Chordata?

- notochord
- dorsal hollow nerve chord
- pharyngeal slits/clefts
- post anal muscular foot

2

What is the notochord?

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

How is the notochord adapted in humans?

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

4

What are pharyngeal slits?

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

In tetrapods, what do the pharyngeal slits form into?

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

6

True or false:

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

False

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

7

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

- Capture food
- Evade predators

8

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

- Vertebrae enclosing a spinal cord
- An elaborate skull
- Fin rays (aquatic)

9

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

- Jawless
- Vertebrates

E.g., hagfishes and lampreys

10

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

They have a presence of rudimentary (nonfunctional) vertebrae

11

Gnathostomes is a clade of animals that has what characteristics?

Jawed vertebrates

12

What are characteristics of hagfishes?

- jawless vertebrates
- notochord
- cartilaginous skull
- no backbone
- scavengers/decomposes
- slime glands (to repel predators)

13

What are characteristics of lampreys?

- parasites (latch onto a host)
- cartilaginous segments surround the notochord

14

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

d. 455 million years ago

15

The first tetrapods emerged:

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

b. 365 million years ago

16

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. 320 million years ago

17

How did jaws evolve?

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

18

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

Class chondrichythes: Sharks, skates, rays

In the clade gnathostomes, superclass tetrapoda

19

True or false:

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

True

20

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

- cartilaginous skeleton evolved secondarily from an ancestral mineralized skeleton
- largest and most diverse group include the sharks, rays and skates

21

What are the characteristics of sharks?

- 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

Osteichthyes is a superclass of what?

Bony fishes

Has two classes:
Ray finned fishes
Lobe-fins

23

Describe the characteristics of ray-finned fishes.

- named for bony rays that support their fins

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

24

Describe the characteristics of lobe-fins.

- muscular pelvic and pectoral fins
> for swimming and walking across substrates
- rod shaped bones

25

What are the 3 lineages of lobe-fins?

Coelacanths
Lungfishes
Tetrapods

26

What are some specific adaptations of tetrapods?

- 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

What are the classes of tetrapods?

Superclass Tetrapoda
- Class Amphibia
~ clade amniota
- Class Reptilia
- Class Aves
- Class Mammalia

28

What are characteristics of amphibians?

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

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