Chapter 34

Question 1

The animals called ________ get their name from vertebrae, the series of bones that make up the backbone

Answer 1

vertebrates

Question 2

Vertebrates have great_________, a wide range of differences within the group

Answer 2

disparity

Question 3

_________ are bilaterian animals that belong to the clade of animals known as ____________

Answer 3

Chordates: Deuterostomia

Question 4

Chordates comprise all vertebrates and two groups of invertebrates, the ________ and ____________

Answer 4

urochordates and cephalochordates

Question 5

All chordates share a set of derived characters.

Four key characters of chordates:

Answer 5

Notochord (provides skeletal support)
Dorsal, hollow nerve cord
Pharyngeal slits or clefts
Muscular, post-anal tail

Question 6

The _________is a longitudinal, flexible rod between the digestive tube and nerve cord. It provides skeletal support throughout most of the length of a chordate

Answer 6

notochord

Question 7

The ______of a chordate embryo develops from a plate of ectoderm that rolls into a tube dorsal to the notochord

Answer 7

nerve cord

Question 8

The nerve cord develops into the central nervous system: _______

Answer 8

the brain and the spinal cord

Question 9

In most chordates, grooves in the pharynx called ____________ develop into slits that open to the outside of the body

Answer 9

pharyngeal clefts

Question 10

Functions of pharyngeal slits

Answer 10

Suspension-feeding structures in many invertebrate chordates
Gas exchange in vertebrates (except vertebrates with limbs, the tetrapods)
Develop into parts of the ear, head, and neck in tetrapods

Question 11

Chordates have a ______ posterior to the anus. Contains skeletal elements and muscles
It provides propelling force in many aquatic species

Answer 11

tail

Question 12

________ are named for their bladelike shape

They are marine suspension feeders that retain characteristics of the chordate body plan as adults

Answer 12

Lancelets

Question 13

________are more closely related to other chordates than are lancelets. As an adult, a _______ draws in water through an incurrent siphon, filtering food particles
When attacked, _________ or “sea squirts,” shoot water through their excurrent siphon
________ are highly derived and have fewer Hox genes than other vertebrates

Answer 13

Tunicates

Question 14

Ancestral chordates may have resembled lancelets
The same Hox genes that organize the vertebrate brain are expressed in the lancelet’s simple nerve cord tip
Genome sequencing suggests that:

Answer 14

Genes associated with the heart and thyroid are common to all chordates
Genes associated with transmission of nerve impulses are unique to vertebrates

Question 15

The origin of a head enabled chordates to coordinate more complex movement and feeding behaviors
_________ share some characteristics: a skull, brain, eyes, and other sensory organs

Answer 15

Craniates

Question 16

Craniates have _______ clusters of Hox genes; lancelets and tunicates have only _______ cluster

Answer 16

two: one

Question 17

One feature unique to craniates is the _________, a collection of cells near the dorsal margins of the closing neural tube in an embryo

Answer 17

neural crest

Question 18

Neural crest cells give rise to a variety of structures, including ____________

Answer 18

some of the bones and cartilage of the skull

Question 19

In aquatic craniates the_____________ evolved into gill slits

Answer 19

pharyngeal clefts

Question 20

Craniates have a higher ______ and are more _______ than tunicates and lancelets

Answer 20

metabolism: muscular

Question 21

Craniates have a heart with at least ____ chambers, red blood cells with ________, and kidneys

Answer 21

two: hemoglobin

Question 22

Fossils from the ________ document the transition to craniates

Answer 22

Cambrian explosion

Question 23

The most primitive of the fossils are those of the 3-cm-long ________

Answer 23

Haikouella

Question 24

_________ had a well-formed brain, eyes, and muscular segments, but not a skull

Answer 24

Haikouella

Question 25

The most basal group of craniates is Myxini, the _______, have a cartilaginous skull and axial rod of cartilage derived from the notochord, but lack jaws and vertebrae.

Answer 25

hagfishes

Question 26

During the Cambrian period (~500 mya), a lineage of craniates evolved into ________.
________ became more efficient at capturing food and avoiding being eaten

Answer 26

vertebrates: Vertebrates

Question 27

Vertebrates underwent a second gene duplication involving the Dlx family of transcription factors
Vertebrates have the following derived characters:

Answer 27

Vertebrae enclosing a spinal cord
An elaborate skull
Fin rays, in the aquatic forms

Question 28

Lampreys represent the __________ of vertebrates. Are jawless vertebrates that feed by clamping their mouth onto a live fish
Inhabit various marine and freshwater habitats
They have cartilaginous segments surrounding the notochord and arching partly over the nerve cord

Answer 28

oldest living lineage

Question 29

________ were the first vertebrates with mineralized skeletal elements in their mouth and pharynx. Their fossilized dental elements are common in the fossil record

Answer 29

Conodonts

Question 30

______ appears to have originated with vertebrate mouthparts, much later in vertebrate endoskeleton.

Answer 30

Mineralization

Question 31

Today, jawed vertebrates, or ________, outnumber jawless vertebrates. Include sharks and their relatives, ray-finned fishes, lobe-finned fishes, amphibians, reptiles (including birds), and mammals. _______ have jaws that might have evolved from skeletal supports of the pharyngeal slits

Answer 31

gnathostomes: Gnathostomes

Question 32

Other characters common to gnathostomes
Genome duplication, including duplication of Hox genes
An enlarged forebrain associated with enhanced smell and vision
In aquatic gnathostomes, the _________, which is sensitive to vibrations

Answer 32

lateral line system

Question 33

The earliest gnathostomes in the fossil record are an extinct lineage of armored vertebrates called __________.
They appeared in the Ordovician, about 450 million years ago

Answer 33

placoderms

Question 34

Another group of jawed vertebrates called _______ radiated during the Silurian and Devonian periods

Answer 34

acanthodians

Question 35

Three lineages of jawed vertebrates survive today:

Answer 35

chondrichthyans, ray-finned fishes, and lobe-fins

Question 36

__________have a skeleton composed primarily of cartilage
The largest and most diverse group of ________ includes the sharks and rays, while a second smaller group includes ratfishes

Answer 36

Chondrichthyans (Chondrichthyes)

Question 37

The reproductive tract, excretory system, and digestive tract empty into a common ______ (opening) found in many nonmammalian vertebrates

Answer 37

cloaca

Question 38

Shark eggs are fertilized internally but embryos can develop in different ways

Answer 38

Oviparous: Eggs hatch outside the mother’s body
Ovoviviparous: The embryo develops within the uterus and is nourished by the egg yolk
Viviparous: The embryo develops within the uterus and is nourished through a yolk sac placenta from the mother’s blood

Question 39

Most rays are bottom-dwellers that feed on ____ and _______

Some rays cruise in open water and scoop food into their gaping mouth

Answer 39

molluscs and crustaceans.

Question 40

________ typically live at depths greater than 80m and feed on shrimp, molluscs, and sea urchins. Second subclass of chondrichthyans.

Answer 40

Ratfishes

Question 41

The vast majority of jawed vertebrates belong to a clade of gnathostomes called ______. Aquatic _____ are the vertebrates we informally call fishes

Answer 41

Osteichthyes

Question 42

Most fishes breathe by drawing water over gills protected by an________ (bony flap)

Answer 42

operculum

Question 43

Most species of ray-finned fish are ________ (lay eggs outside mother’s body), but some have internal fertilization and birthing

Answer 43

oviparous

Question 44

One of the most significant events in vertebrate history was when

Answer 44

the fins of some lobe-fins evolved into the limbs and feet of tetrapods

Question 45

Tetrapods have some specific adaptations

Answer 45

Four limbs, and feet with digits
A neck, which allows separate movement of the head
Fusion of the pelvic girdle to the backbone
The absence of gills (except some aquatic species)
Ears for detecting airborne sounds

Question 46

Tiktaalik, nicknamed a “fishapod,” shows both fish and tetrapod characteristics
It had:

Answer 46

Fins, gills, lungs, and scales
Ribs to breathe air and support its body
A neck
Fins with the bone pattern of a tetrapod limb

Question 47

_________ are represented by about 6,150 species
Order _________ includes salamanders, which have tails. Order _______ includes frogs and toads, which lack tails. Order ______ includes caecilians, which are legless and resemble worms

Answer 47

Amphibians (class Amphibia): Urodela: Anura: Apoda

Question 48

__________is external in most species, and the eggs require a moist environment. In some species, males or females care for the eggs on their back, in their mouth, or in their stomach

Answer 48

Fertilization

Question 49

Amphibian populations have been declining in recent decades

The causes include :

Answer 49

A disease-causing chytrid fungus, habitat loss, climate change, and pollution

Question 50

_________ are a group of tetrapods whose living members are the reptiles, including birds, and mammals

Answer 50

Amniotes

Question 51

Amniotes are named for the major derived character of the clade, _________, which contains membranes that protect the embryo
The extraembryonic membranes are the_____, _________, ___________, and _________

Answer 51

the amniotic egg: amnion, chorion, yolk sac, and allantois

Question 52

Most reptiles are ___________, absorbing external heat as the main source of body heat
Birds are _________, capable of keeping the body warm through metabolism

Answer 52

ectothermic: endothermic

Question 53

The first major group to emerge were __________, which were mostly large, stocky quadrupedal herbivores

Answer 53

parareptiles