ch 34 overview: half a billion years of backbones Flashcards
1
Q
What are Vertebrates and how many species are there?
A
They get their name from vertebrae, the series of bones that make up the backbone
There are about 52,000 species, including the largest organism ever to live on the earth.
2
Q
True or false: are Chordates bilaterian and from the clade of animals known as the Deuterostomia.
A
true
3
Q
chordates comprise all vertebrates and what two groups of invertebrates?
A
chordates comprise the urochordates and cephalochordates.
4
Q
true or false: all chordates share a set of derived characters.
A
true
5
Q
what are four key characters of chordates?
A
- notochord
- dorsal, hollow nerve cord
- pharyngeal slits or clefts
- muscular, post-anal tail
6
Q
what is a notochord?
A
the notochord is a longitudinal, flexible rod between the digestive tube and nerve cord.
7
Q
what kind of support does the notochord provide?
A
it provides skeletal support throughout most of the length of a chordate. in most vertebraes, a more complex, jointed skeleton develops, and the adult retains only remnants of the embryonic notochord.
8
Q
the nerve cord developes into what in the central nervous system?
A
the nerve cord develops into the central nervous system: the brain and the spinal cord
9
Q
how does the nerve cord of a chordate embryo develop?
A
the nerve cord of a chordate embryo develops from a plate of ectoderm that rolls into a tube dorsal to the notochord.
10
Q
what are pharyngeal clefts? what do they develop into?
A
in most chordates, grooves in the pharynx called pharyngeal clefts develop into slits that open to the outside of the body.
11
Q
what are the 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.
12
Q
true or false: chordates hace a tail anterior to the anus
A
false
13
Q
what are the characteristics of post-anal tail?
A
- in many species, the tail is greatly reduced during embryonic development
- the tail contains skeletal elements and muscles
- it provides propelling force in many aquatic species
14
Q
lancelets (cephalochordata)
A
they are marine suspension feeders that retain characteristics of the chordate body plan as adults. they are named for their bladelike shape.
15
Q
what do tunicates most resemble during their larvel stage?
A
tunicates most resemble chordates during their larvel stage, which may last only a few minutes.
16
Q
how does a tunicate draaw in water? what it do when it is attacked?
A
- as an adult, a tunicate draws in water through an incurrent siphon, filtering food particles
- when attacked, tunicates, or “sea squirts,” shoot water through their excurrent siphon
17
Q
what do ancestral chordates resemble? and how do they resemble?
A
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.
18
Q
what do genome sequencing suggest?
A
- genes associated with the heart and thyroid are common to all chordates
- genes associated with transmission of nerve impulses are unique to vertebrates
19
Q
what characteristics do craniates share with chordates?
A
-a skull, brain, eyes, and other sensory organs
20
Q
What are the derived characteristics of Craniates?
A
Craniates have two clusters of Hox genes; Lancelets and tunicates have only one cluster
- one unique feature to craniates is the neural crest
- In aquatic craniates the pharyngeal clefts evolved into gill slits
- Craniates have a higher metabolismand are more muscular than tunicates and lancelets
- craniates have a heart with at least two chambers, red blood cells with hemoglobin and kidneys
21
Q
A collection of cells near the dorsal margins of the closing neural tube in the embryo
A
Neural Crest
22
Q
What do neural crest cells give rise to?
A
A variety of structures, including some of the bones and cartilage of the skull bone
23
Q
Whats event documents the transition to craniates? and what is the fossils name?
A
The cambriaan explosion documents the transition to craniates
-Haikouella had a well formed brain, eyes, and muscular segments but not a skull
24
Q
What is the name of a more advanced chordate that had parts of a skull and was a true craniate?
A
Myllokunminga
25
Characteristics of Hagfishes
- are the most basal group of craniates (myxini)
- hagfishes have a cartilaginous skull and axial rod of cartilage derived from the notochord, but lack jaws and vertebrae
- They have a small brain, ears and tooth like formations
- they are marine and most are bottom dwelling scavengers
26
During what era did the craniates evolve into vertebrates? and what were they more efficient in?
During the cambrian period, they became more efficient at capturing food and avoiding being eaten
27
Characteristics of Lampreys
-are jawless vertebrates that feed by clamping their mouth onto a live fish
they inhabit various marine and freshwater habitats
they have cartilagenous segments surrounding the notochord and arching partly over the nerve cord
28
What species representd the oldest living lineage of vertebrates?
Lampreys (petromyzontida)
29
The first vertebrates with mineralized skeletal elements in their mouth and pharynx
Conodonts
-their fossilized dental elements are common in the fossil record
30
Where did mineralization appear from?
Mineralization appears to have originated with vertebrate mouthparts
-The vertebrate endoskeleton became fully mineralized much later
31
Give several examples of gnathostomes
gnathostomes include sharks and their relatives, ray-finned fishes, lobe finned fishes, amphibians, reptiles (including brds) and mammals
32
Characteristics of gnathostomes
- jawed vertebrates
- genome duplication including duplication of hox genes
- an enlarged forebrain associated with enhanced smell and vision
aquatic gnathostomes have lateral lines, which is sensitive to vibrations
33
What is the name of the earliestgnathostomes in the fossil record?
Placoderms-an extinct lineage of armored vertebrates
appeared in the ordovician
34
What are the three lineages of jawed vertebrates surviving today?
Chondrichthyans
ray finned fishes
lobe fins
35
What are chondrichthyans?and give two examples
- have sketetons composed primarily of cartilage
- The largests and most diverse group of chondrichthyans includes the sharks, rays and skates
36
Characteristics of sharks
- sharks have a strealined body and are swift swimmers
- the largest sharks are suspension feeders, but most are carnivores
- Sharks have a short digestive tract with a ridge called the spiral valve to increase the digestive surface area
- have acute senses including sight, smell, and the ability to detect electrical fields from nearby animals
- shark eggs are fertilized internally but can develop in different ways
-
37
Eggs hatch outside the mothers body
oviparous
38
The embryo develops within the uterus and is nourished by the egg yolk
Ovoviviparous
39
The embryo develops within the uterus and is nourished through a yolk sac placenta from the mothers blood
viviparous
40
The vast majority of vertebrates belong to a clade of gnathostomes called?
Osteichthyes
41
Characteristics of Osteichthyans
- nearly all living osteichthyans have a bony endoskeleton
- include bony fish and tetrapods
- aquatic osteichthyans are the vertebrates we call fish
- they have a laterline system
- most are oviparous, but some have internal fertilization and birthing
42
Operculum
Most fishes breathe by drawing water over gills protected by an operculum
43
How do fishes control their buoyancy?
With an air sac known as a swim bladder
44
Characteristics of ray finned fishes
Actinopterygii, include nearly all the familiar aquatic osteichthyans
- originated during the Silurian period
- the fins supported mainly by long , flexible rays, are modified for maneuvering, defense and other functions
45
Lobe fins
- have muscular pelvic and pectoral fins
- originated in the Silurian period
46
What are the three lineages of libe fins that still survive?
Coelacanths, lungfishes and tetrapods
(Coelacanths were thought to have become extinct but a living coelacanth was caught off the coast of south africa
47
What was one of the most signficant events in vertebrate history?
When the fins of some lobe fins evolved into the limbs and feet of tetrapods
48
Derived characters of Tetrapods
- four limbs and feet with digits
- a neck which allows seperate movement of the head
- fusion of the pelvis girdle to the backbone
- absence of gills (except aqutic species)
- ears for detecting airborne sounds
49
Tiktaalik nicknamed a "fishopod" shows which fish and tetrapod characteristics?
- fins, gills, lungs and scales
- ribs to breathe air and support its body
- a neck
- fins with the bone pattern of a tetrapod limb
- could most likely prop itself on its fins but not walk
50
How many species represent the class amphibia?
6,150 species
51
Amphibian characteristics
Amphibian means "both ways of life" referring to the metamorphosis of an aquatic larva into a terrestrial adult
-most amphibians have moist skin that complements the lungs in gas exchange
52
Felrtilization in amphibians
Fertilazation 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 mouths or in their stomach
53
Why have amphibian populations been declining?
A disease causing chytrid fungs, habitat loss, climate change and pollution
54
What are amniotes and give some examples
amniotes are a group of tetrapods whose living members are the reptiles, including birds and mammals
55
Derived characteristics of amniotes
- amniotes are named for the major derived character of the clade , the amniotic egg, which contains membranes that protect the embryo
- the extraembryonic membranes are the amnion, chorion, yolk sac and allantois
- the amniotic eggs of most reptiles and some mammals have a shell
- amniotes have other terrestrial adaptations such as relatively impermeable skin and the ability to use the rib cage to ventilate the lungs
56
How were early amniotes different from the amniotes of today?
- they were more tolerant of dry conditions than early tetrapods
- the earliest amniotes were small predators with sharp teeth and long jaws
57
What are some examples of reptiles?
the tautaras, lizards, snakes, turtles, crocodillians, birds and some extinct groups
58
Characteristics of reptiles
Reptiles have scales that create a waterproof barrier
-most reptiles lay shelled eggs on land
59
Ectothermic
Most reptiles are ectothermic, absorbing external heat as the main source of body heat
60
Capable of keeping the body warm through metabolism
Endothermic
ex-birds
61
What period does the oldest reptilian fossil date back to?
The carboniferous period
62
Parareptiles
The first major reptilian group to emerge, were mostly large, stocky quadrupedal herbivores
-were dwindling
63
Diapsids, What were the two main lineages?
- were diversifying
- the lepidosaurs and the archosaurs
64
Lepidosaurs
include tuataras, lizards, snakes and extinct mososaurs
65
Archosaur, what did they produce?
The archosaur lineage produced the crocodillians, pterosaurs, and dinosaurs
66
Pterosaurs
were the first tetrapods to exhibit flight
67
Dinosaurs
- diversified into a vast range of shaapes and sizes
- included bipedal carnin=vores called theropods
- debate continues about whether dinosaurs were endothermic or exothermic
conclusions have been made that dinosaurs were agile and fast moving
-signs of parental care
68
The group from which birds were descended from
Theropods
69
What are the two major species of the survivng lineage of lepidosaurs?
-lizard-like reptiles called tautaras and the squamates, the lizards and snakes
70
Apart from birds, what are the most numerous and diverse reptiles?
Lizards
71
Snakes
- snakes are legless lepidosaurs that evolved from lizards
- snakes are carnivorous; some are also venomous
72
Turtles
- all turtles have a boxlike shell made of upper and lower shileds that are fused to the vertebrae, clavicle and ribs
- some turtles have adapted to deserts and others live entirely in ponds and rivers
73
Crocodillians belong to what lineage? and date back to what age?
-they belong to an archosaur lineage that dates back to the triassic
74
What lineage represents birds?
Birds are archosaurs, but almost every feature of their reptilian anatomy has undergone modification in their adaptaion to flight
75
Derived characters of birds
- many characters are adaptations that facilitate flight
- the major adaptation is wings with keratin feathers
- others include lackof a urinary bladder, females with only one ovary, small gonads and loss of teeth
76
How did flight help with hunting? and what does it require?
- Flight enhances hunting and scavenging, escape from terrestrial predators, and migration
- flight requires a great expenditure of energy, acute vision, and fine muscle control
77
Why might have feathers evolved?
Early feathers might have evolved for insulation, camoflauge or courtship display
78
How could early feathers helped dinosaurs?
- Gain lift when they jumped
- gain traction runnig up hills
- glide from trees
79
What is the oldest bird known?
The Archaeopteryx
80
What clade do living birds belong to?
Neornithes
81
What are some of the groups of flightless birds?
- the ratites, orderstruthioniforms
- penguins, order sphenisciformes
- certain species of rails, ducks and pigeons
82
How many species represent the class mammilia?
more than 5,300 species
83
Derived characters of mammals
- mammary glands, which produce milk
- hair
- a high metabolic rate due to endothermy
- a larger brain than other vertebrates of equivalent size
- differentiated teeth
84
What did mammals evolve from?
Synapsids
85
What are synapsids?
Two bones that formerly made up the jaw joint were incorporated into the mammalian ear
86
By the early Cretaceous what thrw living lineages of mammals emerged?
monotremes, marsupials and eitherians
87
A small group of egg laying mammals consisting of echidnas and the platypus
Monotremes
88
Marsupials
Incude opossums, kangaroosand koalas
- the embryo develops within the placenta in the mothers uterus
- a marsupial is born very early in its development and completes its development while nursing in a maternal pouch called marsupium
- in some species such as the bandicoot, the marsupium opens to the rear of the mothers body
89
Eutherians
- have a more complexxx placenta than marsupials
- young eutherians complete thier embryonic development within the uterus, joined to the mother by the placenta
90
What does the mammilian order, Primates include?
Lemurs, tarsiers, monkeys and apes
-humans are members of the ape group
91
Derived characters of Primates
- most have hands and feet adapted for grasping and flat nails
- a large brain and short jaws
- forward looking eyes close together on the face, providing depth perception
- complex social behavior and parental care
- a fully opposable thumb (in monkeys and apes)
92
What are the three main groups of living primates ?
- Lemurs, lorises and pottos
- tarsiers
- anthropoids (monkeys and apes)
93
What are some examples of the group anthropoids, primates informely called apes?
gibbons,organgutans, gorillas, chimps, bonobos and humans
94
Derived characters of Humans
- upright posture and bipedal locomotion
- larger brains capable of language, symbolic though, artistc expression, the manufacture and use of complex tools
- reduced jawbones and jaw muscles
- shorter digestive tract
95
What percentage of human and chimpannzee genomes are identical?
99%
-changes in regulatory genes can have large effects
96
the study of human origin
Paleoanthropology
97
Hominins
(formely called hominids) are more closely relted to humans than to chimpanzees
- have discovered about 20 fossils of extinct hominins
- originated in africa
- early hominins show evidence of small brains and increasing bipedalism
98
True/False Early homonins were chimpanzees
False hominins and chimpanzees shared a common ancestor
99
True/ false Human evolutionis like the ladder leading directly to homo sapians
False hominin evolution included many branches or coexisting species, though only humans survive today
100
Australopiths
- are a paraphyletic assemblage of hominins
- some species such as Australopithecus afarensis walked fully erect
101
Homo habilis
The earliest fossils placed in our genus homo
-stone tools have been found with H. habilis giving this speces its name, which means "handy man"
102
Homo egaster
the first fully bipedal, large-brained hominid
-shows significan decrease in sexul dimorphism (a size difference between sexes) compred to its ancestors
103
Homo erectus
- originated in africa
- was the first homonis to leave africa
104
Neanderthals
Homo neanderthalensis, lived in europe and near east
- they were thick-boned with a larger brain, they buried their dead and made hunting tools
- debate is ongoing about the extent to which genetic material was exchanged between neanderthals and homo sapiens
105
Homo sapians
Homo sapiens appeared in africa
-all living humas=ns are descended from these african ancestors
homo sapians were the first group to show evidence of symbolic and sophisticated thought
106
