Reptiles, Birds and Mammals Week 8 Flashcards
(158 cards)
1
Q
Evolution of reptilia
A
- Evolved from amphibian ancestor ~320 million years ago
- Majority of species to have evolved are now extinct
- Modern reptiles are derived from two lineages
2
Q
What are the two lineages that modern reptiles are derived from?
A
- Parareptilia
- Eureptilia
- Lepidosauromorpha
- Archosauromorpha
3
Q
What are the two groups of Eureptilia?
A
- Lepidosauromorpha
- Archosauromorpha
4
Q
Which animals are included in Parareptilia?
A
- Turtles & tortoises
5
Q
Which animals are included in Lepidosauromorpha?
A
- Snakes, lizards, Sphenodon (tuatara)
6
Q
Which animals are included in Archosauromorpha?
A
- Dinosaurs, crocodiles & birds
7
Q
What are the four extant orders of reptiles?
A
- Testudines
- Rhyncocephalia/Sphenodonta
- Squamata
- Crocodilia
8
Q
Which animals are included in Testudines?
A
- Turtles
- Tortoises
9
Q
Which animals are included in Rhyncocephalia/Sphenodonta?
A
- Tuatara (Sphenodon species)
10
Q
Which animals are included in Squamata?
A
- Lizards
- Snakes
11
Q
Which animals are included in Crocodilia?
A
- Crocodiles
- Alligators
- Caimans
- Gharials
12
Q
Evolutionary history of Testudines
A
Earliest turtle fossils date to 220 million years ago
13
Q
Testudines are grouped based on
A
How they withdraw their neck into shell
14
Q
Where do turtles inhabit?
A
Marine & freshwater habitats
15
Q
What are the two groups of testudines?
A
- Cryptodira: contract neck (marine turtles, most freshwater turtles, tortoises)
- Pleurodira: flex neck laterally
(some species of freshwater turtles)
16
Q
Where do tortoises inhabit?
A
Terrestrial environment
17
Q
What is the largest species of turtle and how much does it weigh?
A
- Leatherback (Dermochelys coriacea) - Shell can reach 2m in length
- Weigh up to 900kg
18
Q
What feature do all modern turtles and tortoises lack, and what do they have instead?
A
Teeth; keratinous ridges for grinding & slicing
19
Q
What is a unique feature of turtles?
A
- The position of limbs within shell
- Ribs encapsulate the scapulae rather than being outside the ribs like in other tetrapods
- Molecular genetics suggests this is due to an aberration in the turtle HOX gene
20
Q
Rhyncocephalia/Sphenodonta
A
- Native to New Zealand and surrounding islands
- Consist of two species
- Lifespan of ~100 years
- Have teeth
21
Q
What are the two species of Rhyncocephalia/Sphenodonta?
A
- Sphenodon punctatus
- Sphenodon guntheri
22
Q
What group did Rhyncocephalia/Sphenodonta diverge from and when?
A
Squamates (lizards & snakes); 250 mya
23
Q
Difference between lizard and Rhyncocephalia/Sphenodonta ear
A
- Lizards and others have a hole which is their external ear
- Sphenodonta have no outer aperture/hole, which is similar in turtles
- Sphenodonta have no eardrum
24
Q
Squamate evolutionary history
A
- Lizards evolved ~200 mya
- Snakes evolved from lizards ~100 mya
- Evolution of venom occurred early in squamate radiation
25
Squamate characteristics
- 60% of squamates venomous
- Predominantly snakes but also two species of lizard
- Movable quadrate bones that are particularly well developed in snakes
26
What are the two species of lizard in the squamate group?
1. The Gila monster (Heloderma suspectum) (USA)
2. Mexican beaded lizard (Heloderma horridum)
27
What do quadrate bones in squamates allow for?
- A greater range of motion of mandibles
- Can eat prey much larger than themselves
28
Crocodilia evolutionary history
- Appeared 84 million years ago
- The closest living relatives of birds
- Ancestors were bipedal
29
How many extant species of crocodilia are there?
22
30
What groups are included in crocodilia?
- Crocodiles
- Alligators
- Caimans
- Gharials
31
What is the largest crocodilia species?
- Australian saltwater crocodile
(*Crocodylus porosus*)
32
Characteristics of crocodilia
- Semi-sprawled posture which is a derived trait
- Sprawled belly-walk typical of lizards
- High walk where legs pulled underneath body
- Adaptated to semi-aquatic existence
33
What does the high walk of crocodilia allow for?
- Galloping (fast)
34
Dinosaurs evolutionary history
- Earliest dinosaur fossils date to the Triassic ~250 mya
- Came to dominate by the Jurassic 210 million years ag
35
What are the two main lineages of dinosaurs?
1. Ornithischia
2. Saurischia
36
What are the characteristics of Ornithischia dinosaurs?
- ‘bird hipped’
- herbivorous
- eg. Stegosaurus
37
What are the characteristics of Saurischia dinosaurs?
- ‘lizard hipped’
- Sauropods: herbivores
- Therapods: carnivores
- eg.Tyrannosaurus, birds
38
Oviraptor dinosaur significance
- Shows evidence of maternal care
39
Therapod dinosaur significance
- Embryos hatched from eggs in similar manner to modern birds
40
What was the significance of the dinosaur tail found trapped in amber in 2016?
- Shows that dinosaurs were, undoubtedly, feathered
41
Reptilia adaptations
- Most have adapted to drier environments
- Some have re-adapted to an aquatic environment
- All must return to land to lay eggs or live young (exception: sea snakes (viviparous))
42
What species is the exception for all reptilia returning to land to lay eggs?
Sea snakes (viviparous)
43
What limits the distribution of reptilia?
- Being ectothermic
- Body temperature determined by environment
- Excluded from subarctic & subantarctic habitats
44
Endothermic:
Body produces heat
45
Ectothermic
Heat absorbed from environment
46
Homeothermic
Body temperature constant
47
Poikilothermic
Body temperature varies
48
What did reptilian transition from water to land require?
- Waterproof skin to minimise loss of water
- Thick, heavily keratinised stratum corneum
- Epidermal scales
49
What are Epidermal scales?
- Keratin structures
- Scale morphology is species-specific
- Large, plate-like scales are called scutes
- Modified scales form horns, spikes & crests
50
What are scutes?
Large, plate-like scales
51
What do modified scales form?
Horns, spikes & crests
52
Which animals possess osteoderms?
Crocodilians, testudines & some lizards
53
What are osteoderms?
- Plates of bone (osteo-)
- Develop within the dermis (-derms)
- Provide additional support to epidermis
54
What is different about osteoderms in turtles?
- They are fused with ribs & vertebrae
- Ventral fusion of osteoderms
55
What is a carapace?
The hard upper shell of a tortoise, crustacean, or arachnid.
56
What is a plastron?
The nearly flat part of the shell structure of a turtle
57
What is a structural (bone) difference between amphibians and reptiles?
- Reptiles have a stronger skeleton than amphibians
58
Physical adaptations of reptiles for land:
- Well developed cervical vertebrae (Specialised atlas & axis)
- Thoracic & lumbar vertebrae not clearly distinguished
- Two sacral vertebrae
- Caudal vertebrae
59
What makes up the pectoral girdle in reptilia?
- Scapula, coracoid, clavicle
& inter-clavicle
- In some species the clavicle is lost
60
What makes up the pelvic girdle in reptilia?
- Ilium, ischium & pubis
- Arranged differently to mammals
- Small epipubic bones may be present that project from pubic symphysis (role unknown)
61
What makes up the limb bones in reptilia?
- Very similar to mammals
- 5 digits on each of manus & pes
62
What does the physical morphology of reptilia include?
1. Pectoral girdle
2. Pelvic girdle
3. Limb bones
4. Skull
63
What makes up the skull in reptilia?
- Temporal fenestrae which reflect differences in jaw musculature
64
What are the two reptilian tyles of skull?
1. Anapsid
2. Diapsid
65
What characterises an anapsid reptilian skull?
- Lacks fenestrae
- Ancestral reptiles, turtles & tortoises
66
What characterises a diapsid reptilian skull?
- Two fenestrae
- Ancestral form in dinosaurs & crocodilians; tuatara?
- Modified form in snakes, lizards & birds
67
Paired lungs in reptiles
- Many have a reduced left lung
- Snakes have long, thin lungs that extend the length of the body
68
What type of flow do Crocodilians have?
Unidirectional
69
True or false, reptilia have paired lungs
True
70
True or false, reptilia have a heart
True
71
What is true of the reptilian heart?
- Higher metabolic rate with greater oxygen demands
- Separate pulmonary & systemic circulations with some mixing in ventricles
72
Reptilian reproduction
- Sexual dimorphisms are minimal or non existent (hard to see), however there are different sexes
- Internal fertilisation
73
Oviparous reptiles
- Lay eggs
- Oviduct deposits albumin (not in snakes & lizards), shell membrane & shell
- In turtles & crocodilians: Ca2+ from shell used for calcification of embryonic skeleton
- Egg yolk is the source of food
74
Viviparous reptiles
- Birth live young
- 20% of extant snakes & lizards
- Fertilised eggs retained in oviduct
- Provides greater protection from predators & environment
75
Reptilian parthenogenesis
- Occurs in female lizards; fish, insects, & birds (v. rare: turkeys)
- The embryo derived solely from the fusion of 2 eggs
76
Parthenogenesis
Reproduction from an ovum without fertilisation
77
Significance of Pterosaurs
They are reptiles but not dinosaurs
78
What did birds evolve from?
Small, predatory dinosaurs
79
What evolutionary changes occurred to form birds?
- Loss of teeth
- Loss of tail
- Fusion & modification of skeletal elements
80
What are the three intermediate forms between dinosaurs & birds?
1. Archaeopteryx
2. Aurornis
3. Anchiornis
81
Characteristics of the bird ancestor Archaeopteryx
- Ancestral Reptilian Traits (clawed digits on forelimb, teeth (sharp), long, bony tail
- Derived Bird-like Traits (flight feathers, fused clavicles form, furcula strengthens, thorax for flight)
82
When, how and why did feathers likely first appear?
- In Compsognathids
- Short, hair-like on head, neck & body
- For insulation, different colours &
patterning, display, camouflage,
species recognition?
83
What type of feathers did Oviraptorosaurs likely have?
Tufted
84
Which intermediate dinosaur shared the feathers of modern birds?
Archaeopteryx
85
What other change accompanied the development of feathers in dinosaurs?
Changes in digits
- V --> IV --> III
86
Homologous features in the forelimb of 6 Vertebrates (Turtle, Bat, Bird, Human, Dolphin, Horse)
- Humerus
- Radius
- Ulna
- Carpals
- Metacarpals
- Phalanges
87
What characteristics did birds continue to evolve that are
uniquely adapted for flight?
- Gradual reduction, loss & fusion of many skeletal elements:
- Reduction in overall body size
88
What happened to the sternum as birds evolved?
It became larger, & evolved a central keel to anchor the flight muscles
89
What happened to the forelimbs as birds evolved?
Became longer than the hindlimbs, as the main form of locomotion switched from running to flight
90
What happened to the teeth as birds evolved?
Teeth were lost repeatedly in various lineages of early birds
91
Flightless birds:
a) Have lost this ability of flight secondarily
b) Never developed the ability of flight
A
92
What did amino acid analysis of collagen extracted from the
fossilised femur of T. rex reveal?
High homology to ostrich & chicken
93
How many *Australian* species of birds are there?
726
94
How many species of birds are there?
9,600
95
True or false; birds are the second largest class of vertebrates
True
96
What is the success of birds attributable to?
- Endothermy
- Flight
- Ability to adapt to a wide range of environments
97
Describe the beak of birds
- Keratinised structure derived from skin
- Grows continually to replace loss from wear
- May require clipping in caged birds
98
What is the Uropygial Gland of birds?
- Gland located on the dorsal surface of the tail
- Secrete lipoids
- Waterproofs & moisturises feathers, beak & scales
99
What are the three types of bird feathers?
1. Contour
2. Flight
3. Down
100
Describe contour feathers and their role:
- Cover most of the body
- Help with aerodynamics and
- Protection
101
Describe flight feathers and their role:
- Larger & stiffer than contour feathers
- Found on wings (remiges) - primaries: manus, secondaries: ulna (antebrachium)
- Tail (retrices)
102
Describe down feathers and their role:
- Positioned between contour & flight feathers
- Insulation
103
What characterises the bones of birds?
- Light, but very strong
- Greater content of CaPO4 than mammalian bone
104
What is pneumatisation in bird bones?
The presence of air sacs, making them large & strong, without being heavy
105
Which bones in birds are pneumatic?
Vertebrae, pelvis, sternum, costal bones, humerus & femur
106
Describe the evolution and modifications to the skull of birds
- Evolved from diapsid reptilian skull
- Enlarged cranium
- Jaws toothless & covered by keratinised sheaths (beak)
- Skull prokinetic (especially in parrots)
- Premaxilla & nasal bone form hinge with frontal
- Upper jaw can be raised as lower jaw depressed
107
Describe the structure and function of the sternum of birds
- Large, midventral keel in flying birds
- Attachment for flight muscles
108
In which bird species is the sternum absent?
Flightless species (except penguin)
109
Describe the structure and function of lungs of birds
- Relatively small, flattened & rectangular
- Unlobed
- Dense – 1/10 volume, similar weight
- Communicate with air sacs
110
Describe the structure and function of air sacs of bird lungs
- Blind-ending, thin walled extensions of bronchi
- Key role in respiration, minimal role in gas exchange
- Poorly vascularised walls
- Function as bellows
111
Describe the structure and function of the Heart & Circulatory System in birds
- Birds have a double circulation
- Heart is completely divided
- Birds have a higher metabolic rate and higher blood pressure than mammals
112
What are the two types of circulation birds have?
* Systemic
* Pulmonary
113
Explain reproduction in birds
- Males have a phallus consisting of a tubercle (bony structure) on the ventral wall that is everted during copulation and pressed to the female clocca
- Female birds usually only have a left ovary & left oviduct
- The ovary has very large, yolk-filled oocytes
- The oviduct is the site of fertilisation
114
Describe the structure and function of the brain in birds
- Proportionally small compared to body size
- Relatively large cerebellum that controls co-ordination of muscle
activity & balance in flight
- Very large optic lobes
115
What is the exception to birds having a proportionally small brain to their body size?
Corvids
116
Describe the intelligence of birds
- Varying degrees of cognitive ability
- Some bird species exceed abilities of some mammal species
117
Describe the intelligence of pigeons
Pigeons can memorise ~725 different visual patterns
118
Describe the intelligence of crows
Crows can make tools, problem solve and teach others
119
Describe the intelligence of parrots
- Parrots can learn human words and use them to communicate reciprocally.
- They can also understand numerical & relational concepts thought to be unique to humans, and make music
120
How is Australia unique in terms of mammals?
It has all three mammal subclasses
121
What are the 3 subclasses of mammals?
1. Eutheria
2. Prototheria
3. Metatheria (Marsupialia)
122
What are examples of subclass prototheria, order monotremata?
- Platypus
- Short-beaked echidna
123
What are examples of subclass Eutheria?
- Australian sea-lion, dingo
- Whales and dolphins
- Bats
- Native rats and mice
- Dugong
124
What are examples of subclass Metatheria (Marsupialia), order Diprotodontia?
Koala, wombats, possums, macropods (roos, wallabies)
125
What are examples of subclass Metatheria (Marsupialia), order Polyprotodontia?
- Dasyurids, numbat, Thylacine,
- Bandicoots, bilbies
- Marsupial mole
126
Which ancestor did all mammals evolve from?
All sub-classes evolved from a common reptilian ancestor
127
When did Monotremes diverge?
Approximately 170 mya
128
When did Marsupials diverge?
Approximately 100–150 mya
129
What is the oldest monotreme fossil?
- Opalised jaw from Lightning Ridge, NSW
- 110 million years old
- platypus-like
- *Steropodon galmani*
130
Where did monotremes originate?
Gondwana (supercontinent)
131
What reptilian characteristics do Monotremes retain?
- Oviparity
- Meroblastic cleavage of embryo
- Produce venom (platypus)
- Electroreception
132
What are the 5 extant species of Monotremes?
1. Platypus (Ornithorhynchus anatinus)
2. Short-beaked echidna (Tachyglossus aculeatus)
3. Western long-beaked echidna (Zaglossus bruijni)
4. Sir David’s long-beaked echidna (Zaglossus attenboroughi)
5. Eastern long-beaked echidna (Zaglossus bartoni)
133
What are the defining characteristics of monotremes?
1. Absence of calcified teeth
2. Electroreception
3. Reptile-like stance
4. Cloaca
5. Oviparity
6. No teats
7. Venom
134
How is electroreception used in monotremes?
To detect prey
135
What do monotremes have instead of calcified teeth?
- Adult monotremes have keratinised dental pads
- Nestling platypus develop premolars & molars
- These are lost just before leaving breeding burrow
136
How do monotremes deliver milk in absence of teats?
- Females produce milk secreted through pores in the skin
- Young lap milk from fur
137
Where is venom in monotremes?
Males secrete venom through spurs on hind limbs
138
Where are crural (venom) glands located in monotremes?
- Only in males
- In sharp keratinous spurs
139
Where are Electroreceptors located in monotremes?
- Within skin of bill/beak
- More extensive in the platypus than the echidna
- Platypus swing head side to side while swimming
140
Describe the structure and function of the monotreme skull
- Premaxilla
- Forms the rostral bill in platypus
- Rostral beak in echidna
141
Describe the structure and function of the monotreme pectoral girdle
- Possesses coracoids, epicoracoids & interclavicle which are reptilian features
- In eutherians, the coracoid is fused with scapula to become coracoid process
142
Describe the monotreme pelvic girdle
Epipubic bones (also marsupials)
143
Describe the structure and function of the monotreme limbs
- Right angles to body which is a reptilian feature, however, they rotate in sockets to give mammalian gait
- Platypus ‘knuckle-walks’ because of webbing
144
Describe reproduction in monotremes in terms of chromosomes
- Monotremes have multiple X & Y chromosomes
145
Describe sex determination in mammals
- In marsupials & eutherians sex is determined by SRY on Y
- Monotremes lack SRY
- Sex chromosomes share some similarities with bird Z & W
- Monotreme system is a link between bird & therian sex-determining mechanisms
146
Describe female reproduction in monotremes
- In platypus, only the right ovary is functional
- Both function in echidna
- Have large, yolky eggs
- Have mammary glands but no teats
147
What are marsupials named for?
Their pouch
148
How many species of marsupial are there, and how many are native to Aus?
270; 140 native
149
What do marsupials & eutherians have in common?
They diverged from a common ancestor
150
How are marsupials unique in their mode of reproduction?
Young are born in a very altricial state and depend on lactation rather than gestation
151
Compare marsupial chromosomes to eutherian chromosomes
- They are fewer and larger in marsupials
- XX is female, XY male
- Have SRY testis-determining
152
What are the 4 combinations of chromosomes in marsupials?
- XX = female reproductive tract & pouch
- XO = female reproductive tract & scrotum
- XY = male reproductive tract & scrotum
- XXY = male reproductive tract & pouch!
153
Describe the marsupial female reproductive tract
- Development of genital ducts & ureters unique
- In all mammals, embryo has ureters & Müllerian ducts
- Marsupials have oviducts, uterus & upper portion of vagina
154
Describe the differences between the eutherian and marsupial female reproductive tract
Eutherian:
- Ureters pass laterally to Müllerian ducts
- Distal end of Müllerian ducts fuse to form vagina
Marsupial:
- Ureters pass medially to Müllerian ducts
- Distal end of Müllerian ducts can’t fuse
- Two lateral vaginae from Müllerian ducts
- Median vagina of connective tissue
155
Define parturition
Giving birth
156
What is the marsupial pouch for?
- Encloses teats & young
- Marsupials have replaced role of gestation with increased role of lactation
157
What do the young of marsupials without a pouch do?
Hang on
158
Describe the Marsupial Neonate
- Majority of development occurs during lactation
- Hind limbs fetal paddles
- No hair or vibrissae
- Kidneys & gonads yet to differentiate
- Periderm covers eyes & ears
- At birth, the neonate climbs from urogenital sinus to pouch and attaches to the teat
