Evolution of the Vertebrates Flashcards
1
Q
Vertebrates are animals that have?
A
Vertebral column or the backbone.
2
Q
Four key characters of chordates:
A
Muscular, post-anal tail
Notochord
Dorsal, hollow nerve cord
Pharyngeal slits or clefts
3
Q
a longitudinal, flexible rod between the digestive tube and nerve cord
A
Notochord
4
Q
Function of notocord
A
provides skeletal support
5
Q
In most vertebrates, a more complex,_________ skeleton develops
A
jointed
6
Q
Notochord:
In most vertebrates, the adult retains only remnants of the?
A
embryonic notochord
7
Q
Develops into the central nervous system in the adult stage.
A
Dorsal, Hollow Nerve Cord
8
Q
The nerve cord of a chordate embryo develops from a _________ that rolls into a _________ to the notochord
A
plate of ectoderm
tube dorsal
9
Q
In most chordates,__________ develop into slits that open to the outside of the body.
A
pharyngeal clefts
10
Q
Functions of pharyngeal slits:
A
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
11
Q
Chordates have a tail at what location to the anus?
A
posterior
12
Q
In many species of chordates, the tail is greatly reduced during?
A
embryonic development
13
Q
The chordate tail of chordates contains what?
A
skeletal elements and muscles
14
Q
It provides propelling force in many aquatic species
A
Muscular, Post-Anal Tail
15
Q
Early Chordate Evolution:
Ancestral chordates may have resembled?
A
lancelets
16
Q
Are named for their bladelike shape
A
Lancelets
17
Q
Marine suspension feeders. They retain characteristics of the chordate body plan as adults
A
Lancelets
18
Q
Genome sequencing of tunicates has identified genes shared by?
A
tunicates and vertebrates
19
Q
__________ in lancelets holds clues to the evolution of the vertebrate form
A
Gene expression
20
Q
Organisms more closely related to other chordates than lancelets
A
Tunicates
21
Q
Other name for tunicates
A
(Urochordata)
22
Q
Tunicates are marine suspension feeders commonly known as?
A
sea squirts
23
Q
At what stage does tunicate draws in water through an incurrent siphon to filter food particles?
A
Adult stage
24
Q
Tunicates most resemble chordates during what stage?, which may last only a few minutes
A
larval stage
25
These control the development of major regions of the vertebrate brain.
Hox Genes
26
The period where an immense variety of invertebrate animals inhabited Earth’s oceans.
Early Cambrian period(some 530 MYA)
27
Early Chordate Evolution:
Predators used ______ and ________ to skewer their prey.
sharp claws and mandibles
28
Early Chordate Evolution:
Give two main features. One of which enabled their bearers to filter food from the water
protective spikes or armour as well as modified mouthparts
29
This genus had ear capsules and eye capsules, parts of the skull that surround these organs
Myllokunmingia
30
paleontologists have identified Myllokunmingia as?
true craniate.
31
3 features of Myllokunmingia that made them true craniates
Ear capsule
eye capsule
parts of the skull
32
Research on _______ has also revealed important clues about the
evolution of the chordate brain.
lancelets
33
Lancelets have only a slightly _______ on the anterior end of their dorsal nerve cord
swollen tip
34
Their genome has been completely sequenced and can be used to identify genes likely to have been present in early chordates.
Tunicates
35
State three Hox genes and the major regions they control.
BF1 Otx and Hox3: Forebrain, Midbrain and Hindbrain
36
Craniates have how many clusters of Hox genes?
2
37
Lancelets and tunicates have how many cluster of hox genes?
1
38
A collection of cells near the dorsal margins of the closing neural tube in an embryo
Neural crest
39
Neural crest cells give rise to?
some of the
bones and cartilages of the skull.
40
In aquatic craniates, pharyngeal clefts evolved into?
gill slits
41
Compare Craniates to tunicates and lancelets
Has higher metabolism and are more muscular
42
At what year did paleontologists who were working in China discovered a vast supply of fossils of early chordates that
appear to straddle the transition to craniates?
1990s
43
Craniate fossils were formed during?, when many groups of animals were diversifying
cambrian explosion
44
Most primitive of the fossils are the 3-cm-long
_________.
Haikouella
45
Its mouth structure indicates that, like lancelets, it probably was a?
suspension feeder
46
Craniates: chordates with a head
The origin of a head opened up a completely new way of feeding...
Active Predation
47
Craniates share some characteristics: state four.
skull
brain
eyes
other sensory organs
48
What is one feature unique to craniates?
Neural crest
49
Gives rise to a variety of structures, including some of the bones and cartilage of the skull.
Neural Crest Cells
50
Skull bones and cartilage are derived from?
Neural crest Cells
51
What allowed some vertebrates to colonize the land?
Evolution of Limbs
52
more than 150MYA, vertebrates were restricted to the?
ocean
53
Approximately _____ species of vertebrates
52,000
54
In the vast oceans were the biggest animal ever to exist on Earth. Which is?
blue whale,
55
The period where a lineage of craniates evolved into vertebrates
Cambrian period
56
Vertebrates are craniates that have a?
backbone
57
Cambrian period
True or False
Vertebrates became more efficient at capturing food and avoiding being eaten.
True
58
The least derived surviving craniate lineage is?
Myxini, the hagfishes
59
Have a cartilaginous skull and axial rod of cartilage derived from the notochord, but lack jaws and vertebrae.
Myxini, the hagfishes
60
Organism with small brain, eyes, ears, and a nasal opening that connects with the pharynx
Myxini, the hagfishes
61
Myxini mouths contain tooth-like formations
made of?
keratin
62
Vertebrates have the following derived characters:
Vertebrae enclosing a spinal cord
An elaborate skull
Fin rays, in the aquatic forms
63
After vertebrates branched off from other craniates, they underwent another gene duplication transcription factor genes known as?
the Dlx family
64
Are little more than small prongs of cartilage arrayed dorsally along the notochord.
Vertebrae
65
Aquatic vertebrates also acquired dorsal, ventral, and anal fins stiffened by bony structures known as?
fin rays
65
Aquatic vertebrates also acquired dorsal, ventral, and anal fins stiffened by bony structures known as?
fin rays
66
The function of fin rays,
Provide thrust and steering control when swimming
67
Represent the oldest living lineage of vertebrates
Lampreys (Petromyzontida)
68
Jawless vertebrates inhabiting various
marine and freshwater habitats
Lampreys (Petromyzontida)
69
Lampreys (Petromyzontida) have ______surrounding the notochord and arching partly over the nerve cord
cartilaginous segments
70
Like lampreys, the early members of these lineages lacked THIS FEATURE, but the resemblance stopped there.
jaws
71
Fossils of Early Vertebrates
_______ were extremely abundant for over 300 million years.
Conodonts
72
They have been used for decades by petroleum geologists as guides to the age of rock layers in which they search for oil.
fossilized dental elements
73
Early vertebrates that lived from the late Cambrian until the late Triassic periods.
Conodonts
74
Conodonts are early vertebrates that lived from?
late Cambrian until the late Triassic periods
75
Unlike lampreys, conodonts had _________, which they used for either ______
mineralized mouthparts
predation or scavenging
76
Were the first vertebrates with mineralized skeletal elements
conodonts
77
Vertebrates with additional innovations emerged during the?
Ordovician, Silurian, and Devonian periods.
78
Fossils of Early Vertebrates four features. Not the derived characters
Paired fins
Inner ear
lacked jaws
muscular pharynx
79
Origins of Bone and Teeth
______ appears to have originated with vertebrate mouthparts
Mineralization
80
Origins of Bone and Teeth
The ______ became fully mineralized much later
vertebrate endoskeleton`
81
Named for their jaws, hinged structures that, especially with the help of teeth
Gnathostomes
82
According to one hypothesis:
gnathostome jaws evolved by modification of the _____ that had previously supported the anterior pharyngeal (gill) slits
The remaining gill slits remained as the major sites of respiratory gas exchange with the external environment.
skeletal rods
83
Hypothesis for the evolution of vertebrate jaws.
The skeleton of the jaws and their supports may have evolved from two pairs of ______ (red and green) located between gill slits near the mouth.
skeletal rods
84
Derived Characters of Gnathostomes
-Common ancestors of all gnathostomes underwent an additional duplication of ____, such that the single set present in early chordates became _____
-Their ____ is enlarged compared to that of other craniates, mainly associated with enhanced senses of _______
Hox genes, four
forebrain; smell and vision
85
Derived Characters of Gnathostomes
* Aquatic gnathostomes have a?
organs that form a row along each side of the body
sensitive to vibrations in the surrounding water
lateral line system
86
Gnathostomes appeared in the fossil record in the ______ period, about 450MYA, and steadily became more diverse.
late Ordovician
87
Evolution of the Gnathostomes:
Most _______ were less than a meter long, though some giant ones measured more than 10 m
placoderms
88
Collective term for other groups of jawed vertebrates
Acanthodians
89
Evolution of the Gnathostomes, by 420MYA, they had diverged into
the three lineages of jawed vertebrates that survive today:
Chondrichthyans, ray-finned fishes, and lobe-fins.
90
Today, jawed vertebrates, or gnathostomes, outnumber jawless
vertebrates
Gnathostomes have jaws that might have evolved from?
skeletal supports of the pharyngeal slits
91
Have a skeleton composed primarily of cartilage
Chondrichthyans
92
Chondrichthyans:
The cartilaginous skeleton evolved secondarily from _____
an ancestral mineralized skeleton
93
The largest and most diverse group of chondrichthyans includes the?
sharks, rays, and skates
94
–have a streamlined body and are swift swimmers
– carnivores
– have acute senses
–have a short digestive tract; a ridge called the _____ increases the
digestive surface area
Sharks
spiral valve
95
* Shark eggs are fertilized internally but embryos can develop in different ways:
_____: eggs hatch outside the mother’s body
_____: the embryo develops within the uterus and is nourished by the egg yolk
_____: the embryo develops within the uterus and is nourished through a yolk sac placenta from the mother’s blood
Oviparous
Ovoviviparous
Viviparous
96
Vast majority of vertebrates belong to a clade of gnathostomes known as Class?
Osteichthyes
97
This class includes the bony fish and tetrapods
Class Osteichthyes
97
Informally known as the fishes
Aquatic osteichthyans
98
Fishes control their buoyancy with an air sac known as?
swim bladder
99
Are gnathostomes that have limbs
Tetrapods
100
Tetrapods have some specific adaptations:
– Four limbs, and feet with digits
– Ears for detecting airborne sounds
101
The most significant character of tetrapods gives the group its
name, which means “_____” in Greek.
four feet
102
Terrestrial life brought numerous other changes to the tetrapod body plan.
head is separated from the body by a neck
originally had one vertebra on which the skull could move up and down.
origin of a second vertebra in the neck, allowed the head to swing from side to side
103
Terrestrial life
Bones of the ____ are fused to the _____
pelvic girdle, backbone
104
True or False
Adults of living tetrapods do not have gills
True
105
Except for some fully aquatic species:
During embryonic development, the _____ instead give rise to parts of the ears, certain glands, and other structures
pharyngeal clefts
106
The ______ were home to a wide range of lobe-fins.
Devonian coastal wetlands
107
Tetrapods that entered particularly shallow, oxygen-poor water could use their _____ to breathe air.
lungs
108
The tetrapod body plan did not evolve “out of nowhere” but was simply a ______of a pre-existing body plan.
modification
109
The Origin of Tetrapods
Recent discovery of a fossil known as ____ has provided new details on how this process occurred
Tiktaalik
110
Unlike a fish, Tiktaalik had a full set of ____ that would have helped it breathe air and support its body.
ribs
111
Tiktaalik had _____, allowing it to move its head about unlike fishes.
neck and shoulders
112
Fish characters vs Tetrapod characters
Fish: Scales, Fins, Gills, and lungs
Tetrapods: Neck, Ribs, Fin skeleton, Flat skull. eyes on top of skull
113
Are tetrapods that have a terrestrially adapted egg
Amniotes
114
Are a group of tetrapods whose living members are the reptiles, including birds, and mammals
Amniotes
115
The amphibians (class Amphibia) are represented today by about 6,150 species of?
salamanders(Order Urodela, “tailed ones”)
frogs (Order Anura, “tail-less ones”)
caecilians (Order Apoda, “legless ones”).
116
_____ is common among aquatic salamanders; the axolotl, for instance, retains larval features even when it is sexually mature
Paedomorphosis
117
Amniotes are named for the major derived character of the clade, the amniotic egg, which contains four specialized membranes:
– amnion
– chorion
– yolk sac
– allantois
118
Is a disposal sac for certain metabolic wastes produced by the embryo
Allantois
119
It protects the embryo in a fluid-filled cavity that cushions against mechanical shocks
Amnion
120
It enables the exchange of gas between the embryo and the air
Chorion
121
It contains a stockpile of nutrients that feed ths embryo
Yolk sac
122
Reptiles have scales that contain?
the protein keratin
123
Reptiles are_____, which means that they absorb external heat as their main source of body heat, however the reptile clade is not entirely ectothermic;
ectothermic
124
Birds are _____, capable of maintaining body temperature through metabolic activity.
endothermic
125
As reptiles diverged from their lizard- like ancestors, one of the first major groups to emerge were?
parareptiles
126
Mostly large, stocky, quadrupedal herbivores
parareptiles
127
Parareptiles died out by about 200MYA, at the end of the _____ period.
Triassic
128
As parareptiles were dwindling, another ancient clade of reptiles, the _____, was diversifying.
diapsids
129
Derived characters of the diapsids:
a pair of holes on each side of the skull, behind the eye socket
muscles pass through these holes and attach to the jaw, controlling jaw movement
130
Two lineages of the diapsids:
Lepidosaurs
Archosaurs,
131
This lineage also produced a number of marine reptiles, including the giant mososaurs.
Lepidosaurs,
132
Some of these marine species rivaled today’s whales in length; all of them are extinct
Lepidosaurs,
133
Lineage that produced the crocodilians, pterosaurs, and dinosaurs
Archosaurs,
134
originated in the late Triassic,
were the first tetrapods to exhibit flapping flight
The wing was completely different from the wings of birds and bats.
It consisted of a collagen-strengthened membrane that stretched between the trunk or hind leg and a very long digit on the foreleg.
Pterosaurs
135
Well-preserved fossils show evidence of muscles, blood vessels, and nerves in the wing membranes, suggesting that _____ could dynamically adjust their membranes to assist their flight.
pterosaurs
136
pterosaurs had become extinct when?
end of the Cretaceous period 65MYA
137
Three lineages of dinosaurs:
*Ornithischians,
*Saurischians,
*Theropods,
138
Were herbivores; they included many species with elaborate defenses against predators, such as tail clubs and horned crests.
*Ornithischians,
139
Included the long-necked reptiles
*Saurischians,
140
which were bipedal carnivores.
Included the famous Tyrannosaurus rex as well as the ancestors of birds.
*Theropods,
141
represented by two species of lizard- like reptiles known as tuataras
These organisms thrived on many continents well into the Cretaceous period, reaching up to a meter in length.
Lepidosaurs
142
Are found only on 30 islands off the coast of New Zealand.
tuataras
143
The other major living lineage of lepidosaurs consists of the lizards and snakes,
squamates,
144
are the most numerous and diverse reptiles alive today.
Lizards
145
are legless lepidosaurs that descended from lizards.
Snakes
146
Today, some species of snakes retain______, providing evidence of their ancestry.
vestigial pelvic and limb bones
147
Have a boxlike shell made of upper and lower shields that are fused to the vertebrae, clavicles (collarbones), and ribs.
Turtles
148
Alligators and Crocodiles are collectively known as?
crocodilians
149
Alligators and Crocodiles belong to a lineage that reaches back to the _____
Late Triassic period
150
Grew as long as 12 m and may have attacked dinosaurs and other prey at the water’s edge.
Mesozoic crocodilians
151
Like crocodilians, birds are _____, but almost every feature of their anatomy has been modified in their adaptation to flight.
archosaurs
152
Birds lack a_____, and the females of most species have only one ______.
urinary bladder,
ovary
153
Derived Characters of Birds,
The _____ of both females and males are usually small, except during the breeding season, when they increase in size.
gonads
154
Living birds are also _____, an adaptation that trims the weight of the head.
toothless
155
Chinese paleontologists have unearthed a spectacular trove of feathered _____ that are shedding light on the origin of birds
theropod fossils
155
Cladistic analyses of birds and reptilian fossilsindicate that birds belong to the?
theropods
156
Which was discovered in a German limestone quarry in 1861, remains the earliest known bird (Figure 34.31).
Archaeopteryx,
157
By 150 MYA,__________ had evolved into birds
feathered theropods
158
The clade that includes the 28 orders of living birds, can be found before the Cretaceous-Paleogene boundary 65.5MYA.
Neornithes,
159
The _____, which consist of the ostrich, rhea, kiwi, cassowary, and emu, are all flightless
ratites
160
a distinctive character of mammals
Presence of mammary glands
161
Derived Characters of Mammals:
* Presence of mammary glands a distinctive character of mammals
* presence of hair (fur) and a fat layer under the skin help the body retain heat
* generally have a larger brain than other vertebrates of equivalent size
* relatively long duration of parental care
* differentiated teeth
162
The three smallest bones of present-day mammals
Stapes
Incus
Malleus
163
Mammals belong to a group of amniotes known as
synapsids.
164
distinctive characteristic of synapsids
temporal fenestra
165
Evolved into large herbivores and carnivores and for a time they were the dominant tetrapods.
Synapsids
166
Events that gave a heavy toll on the synapsids
Permian-Triassic extinctions
167
Period when synapsid diversity fell
Triassic Period(251-200MYA)
168
Event when mammal-like synapsids emerged
While not true mammals, these synapsids had acquired a number of the derived characters that distinguish mammals from other amniotes.
End of the Triassic Period
169
Period when the first true mammals arose and diversified into many short-lived lineages
Jurassic (200–145MYA)
170
Periods where A diverse set of mammal species which measured less than 1m coexisted with dinosaurs
Jurassic and Cretaceous periods
171
When did the three major lineages of mammals emerge? State the three lineages
* – monotremes (egg-laying mammals)
* –marsupials (mammals with a pouch)
* –eutherians (placental mammals)
172
Period when extinction of large dinosaurs, pterosaurs and marine reptiles happen
late Cretaceous period
173
In late Cretaceous period, Mammals underwent an _______, giving rise to large predators and herbivores as well as flying and aquatic species.
adaptive radiation
174
found only in Australia and New Guinea
represented by one species of platypus and four species of echidnas (spiny anteaters)
lay eggs, a character that is ancestral for amniotes and retained in most reptiles
have hair and produce milk, but they lack nipples
Milk is secreted by glands on the belly of the mother.
After hatching, the baby sucks the milk from the mother’s fur.
Monotremes
175
lining of the uterus and the extra embryonic membranes that arise from the embryo
a structure in which nutrients diffuse into the embryo from the mother’s blood
Placenta
176
Include opossums, kangaroos and koalas
Both marsupials and eutherians share derived characters not found among monotremes.
They give birth to live young.
The embryo develops inside the uterus of the female’s reproductive tract.
Marsupials(mammals with pouch)
177
In most marsuppial species, the nursing young are held within a maternal pouch known as
marsupium.
178
During this era, Marsupials existed worldwide, however, are found in Australia and North and South America today.
Mesozoic era
179
Mesozoic era
* After the breakup of the supercontinent _____, South America and Australia became island continents, and their marsupials diversified in isolation from the eutherians that began an adaptive radiation on the northern continents.
Pangaea
180
Early Evolution of Mammals
* Australia
_______ has resulted in a diversity of marsupials that resemble eutherians in similar ecological roles in other parts of the world
convergent evolution
181
Early Evolution of Mammals
* South america
diverse marsupial fauna throughout the _______
it has experienced several immigrations of eutherians
Paleogene
182
About _______ MYA
North and South America joined at the ______and extensive two- way traffic of animals took place over the land bridge
3 MYA
Panamanian isthmus
183
Commonly known as placental mammals because their placentas are more complex
Eutherians (Placental Mammals)
