Sarcoptergians Flashcards
Challenges to living on land?
Gravity
Movement- limbs
Eating
Breathing- lungs
Circulatory
Endothermy
Sensory- no lateral like
Conserving water
Modern Fish out of water examples
Walking catfish
Eels
Snakeheads
Gobies
Example of fish movement out of water
Climbing perch- use edges of gill plates, fins, and tails
Mudskipper- live in mudflaps
Purpose of amniotic eggs?
Allowed tetrapod to live independently of water for reproduction
Fingerlike projection adaptation example
Frogfish move along sea floor
Adaptations for movement out of water
Limbs with digits
Ankles/wrists
Pelvic girdle
Neck
Kidneys instead of gills
Choana
Opening between nasal cavity and nasopharynx creating upper throat
Features of tetrapodomorpha
Choana
1-2 bone pattern
Reduction and loss of cosmine in scales and dermal bones
Tetrapod limb consists of
Humerus
ulna
radius
carpals
phalanges
Eustenopteron, Pandericthys, and Tiktaalik are known as:
Basal Tetrapodomorphs
Tetrapods are derived from
Rhipidistians- boney fish
Eusthenopteron and earliest tetrapods share?
Skull bones- bones cover gills, snout bone elongated, and 6 appendicular bones
Did Eusthenopteron have lungs, why do we assume so, why do we not?
No fossils of lungs but sister group lungfish have lungs.
Difference between Eusthenopteron and Pandericthys
Body flatten
Upward eye
Straight tail
No anal/dorsal tail
Humerus- prop head up
The similarity between Eusthenopteron and Pandericthys (eating)
Labrinthodont teeth: folded sheet soft enamel
Tiktaalik fish like features
scales
lower jaw
fin rays
gills developed
pelvic girdle detached
Tiktaalik roseae tetrapod characteristics
No bony gills
ear structured to hear
pectoral girdle sep. from the skull
mobile neck
ribs thick
wrist & elbow& chest muscles ; pushups
Acanthostega and Icthyostega have:
Lost fin rays
Shoulder and hip bones
Sturdy limbs
Strong spine
Elongated snout
Eyes further in skull
digits
Two lineages of tetrapods
temnospondyls : non-amniotic
Reptiliomorpha: amniotic
Temnospondyls lead to..
Lissamphibia modern amphibians
Reptiliomorpha lead to
Amniotes: Reptiles, Birds, Mammals
Synapomorphies of Crown Tetrapods
Caecilians, Salamanders, Frogs, Amniotes
Tetrapod characteristics
Paired limbs - hindlimbs& forelimbs
Mobile necks - pectoral girdle
First vertebrate - atlas articulates with occipital condyles allowing skull to nod
Hypomandibular bone for jaws originally and then hearing
Temnospondyli closely related to
Lissamphibia
Two lineages of Temnospondyls
Stereospondyll & Dissorophoidea
Stereospondyli are
Caecelians - Gymnophiona
Dissorophoidea are
Salamander ( caudata) & Frogs (Anura)
Sauropsida lead to
Parareptilla & Reptile
Reptilia lead to
Tuatara& lizards (Lepidosauromorpha)
Turtle (testudines)
Crocodilians (Pseudosuchia)
Birds (Avemetatarsalia)
4 skeletal characters of amniotes
Lateral flange on pterygoid bones - origin of pterygoideus muscle used to close the jaw
2nd cervical vertebrate
Ankle bones- astragalus bone & Mesotarsal joint
2+ sacral vertebrate
amphibian 1
Reptile/bird 2
Mammal 3-5
Extraembryonic membrane
Amnion
Allantois- a storage place for nitrogenous waste
Chorion
Anapsids
Solid skull with no openings
Turtles and their ancestor
Synapsids
One pair of openings in the skull ass. with attachment of jaw muscles
Mammals & ancestors
Diapsids
Two pairs of openings in the skull roof
Lizards, Snakes, Crocodilians, Birds, and ancestor
Derived conditions for mammal
Fenestras merge with eye orbit
Derived conditions for Lizards & Snakes
bony bars lost
Derived conditions for Turtles
Diapsid condition lost as fenestra close
Adaptations to challenges (7)
locomotion
gravity
endothermy
water conservation
sensory
eating
breathing
blood uphill
Gravity adaptations- bone
Compact bone - dense and cancellous bone - light
Axial system vertebrae and ribs, zygopophysis resist twisting
Skelton- cranium, cervical, trunk, sacral, caudal
The synapsid conflict between locomotion and Respiration
Locomotion and Compresing rib cage for ventilation cannot occur simultaneously
The diaphragm separates body cavities & movements of the trunk
The saurapisd conflict between locomotion and Respiration
Bipedal locomotion using only limbs for locomotion and not trunk axial muscles
Lissamphibia
all 3 modern groups of amphibian
For amphibian : Kingdom, class, phylum, subphylum, subclass, order
Kingdom- Animalia
class- Amphibia
phylum- chordata
subphylum- vertebrata
subclass- Lissamphiibia
order
anura Frogs& Toads
caudata Tailed salamander
gymnophiona Naked snake- caecilians
Propel the frog into a jump and to support its landing
urostyle
What structure is used for hearing in the frog?
tympanic membrane
Urostyle
Fusion of the caudal vertebrae.
Important structure for jumping.
The last of the 10 vertebrae in a frog.
Selective forces from water to land?
escape drying pools of water?
– exploit new food sources on land?
– escape predators in the crowded waters?
– dispersal of juveniles?
– lay eggs in moist environments?
Advantages of terrestrial activity to tetrapodomprphs
More feeding opportunity
More movement
Acanthostega
8 digits
possessed gills - post branchial lamina on the fish-like shoulder girdle supports the opercular chamber
Ears- hear in water
Developed olecranon process - tricepe muscle
Ichthyostega
Smaller tail fin
Longer, large shoulders
7 digits
walk underwater
lateral line
salamander- like
Evolved muscles
Tiktaalik roseae- chest muscles
- Ball n socket rotate forearm
Hinge joint bends elbow
Bones evolved - first two tetrapods
Zygopophyses - interlocking
wrist bones
fin rays
supralittoral & opercular bones lost
Overlapping ribs
Ilium dorsally w/o sacral contact with vertebral column
Are amphibians monophyletic or paraphyletic?
monophyletic
Are reptiles monophyletic or paraphyletic?
paraphyletic of amniotes
What gave rise to amphibians
Temnospondyls
What gave rise to amniotes
Reptiliomorphs
Function of Fenestrations
Bigger and more complex jaw muscles
changes to adductor mandibularis muscle actions
changes to open/close of mouth
Reduce stress on skull
Astragulus
in ankle fused with 3 formerly independent proximal tarsal bones
Mesotarsal joint
Ankle joint of amniotes passed between the astragalus and calcaneus proximally and smaller distal tarsal bones for limb extension
Avemetatarsalian (dinosaurs & birds) adaptation
evolutionary changes in the ankle joints for bipedality and running
Examples of extinct reptiliomorphs outside Amniota
Archosauria- dinasours
Amniotic egg – structure, and membranes
Shell- protection
Albumin- water storage
Yolk- energy storage
Extraembryonic
Amnion - embryo develops
Allantois- nitrogenous waste storage
Allantois & Chorion- blood vessel, exchange gases
Theory of Development
-Earliest amniotes were probably
amphibious or semi-aquatic
- Inhabited humid environments and eggs
may have been laid out of water initially perhaps to reduce their risk of predation
Cladistic classification of amniotes
groups the amniotes on the basis of
common ancestry
Traditional classification
Based on clade features
Reptilia: reptiles – Aves: birds – Mammalia: mammals
Anapsids
– solid skull with no openings
– turtles and their ancestors
Bone adaptations
Compact bone - dense and is found on the outside of bone
Cancellous bone- light, spongy & found
in the inner tissue of bone and at the
joints.
Axial system - cranium, cervical, trunk vertebrate, ribs, zygophoysis, sacral, caudal
Allometry & effects
study of scaling
effect of gravity, SA, height, and weight
Eating adaptations on land
No suction feeding
Jaws, tongue, teeth, muscle
Bolus go into pharynx
Sticky Tongue
Salivary glands in terrestrial animals
Breathing air
Tital breathing (negative and positive pressure)
low viscosity
High oxygen
Lungs have more SA fro gas exchange
Lung evolution
Swim bladder in fish
Paired lungs in tetrapods
Ancestral forms: axial muscles of trunk had
two functions:
bend the trunk for locomotion
and compress the rib cage for ventilating the
lungs – These cannot occur simultaneously.
Synapsid modification
Diaphragm separates the body cavities and now
movements of the trunk (and internal organs)
now help with respiration.
Saurapsid modification:
bipedal locomotion using only limbs for locomotion
and not trunk axial muscles
Synapsids lung
Alveolar lung, Tree-like dichotomous branching patterns, Uses Tidal ventilation
Sauropsids
Faveolar lung, cuplike chambers (faveoli) line the walls of the lung or airways (parabronchi) for gas
exchange, 0-3 parabronchi, One directional flow of
air.
Pumping Blood Uphill water
Effects of gravity are negligible
The force of heart = only enough to overcome fluid
resistance traveling through vessels.
Pumping Blood Uphill- air
Evolution of the lymphatic system to collect leaked
fluids
more mass more resistance
Movement of heart location closer to lungs =
loss of sinus venosus and conus arteriosus
Circulatory System in fish
Sing: one atrium and one ventricle
inus venous and conous (or bulbus) arteriosus are
present in front and behind the heart respectfully.
heart is located close to the gills above the pectoral fins
Circulatory System in Tetrapods
db circuit: one path is deoxygenated and the other is oxygenated
heart moved posteriorly behind the shoulders
3-chamber and 4-chambers
Adaptations for diving tetrapods
Vision in water challenges
can be murky and refractive index of
cornea similar to water
Vision in air
The lens is flatter and focusing usually
By changing shape of lens eyelids
Protection tear ducts for lubricant production, nasolacrimal duct to drain tears
Hearing in water
sound waves pass freely from water into
animal tissues and hair cells can be directly
stimulated within lateral line system
Hearing in air & Sauropsids
Air: Not dense enough to move cilia of hair cells* Middle ear bones to amplify signals from tympanum and transmit to inner ear hair cells – Sauropsids = only have stapes & tympanum on head surface
Smell in water
chemical signals transmit more slowly
Smell in air
Scents deposited for territorial marking
Signals travel faster
- Ethomoturbinates = olfactory surfaces for location of odor receptors
- Nasoturbinates = moisten air
- Vomeronasal organ – unique organ in anterior roof of mouth used for chemosensory function esp. with pheromones
- Flehman response in ungulates (hoof stock) – flaring of lips to draw air into vomeronasal organ; usually males to detect females in hea
Tetrapods – emphasis on conserving water
-Descending loop of Henle, aquaporins in
collecting ducts to reclaim more water before
urine travels down ureter to collect in urinary
bladder
-Urinary bladder = urinate in specific locations for scent marking or avoid detection by predators
-Skin: keratin, lipids and oils in the skin help limit
evaporative water loss
1. Cutaneous water loss
2. Respiratory water loss
3. Excretory water loss
Body temperature- water
thermoconformers; some have
regional heterothermy using muscle
metabolism and countercurrent exchangers.
Heat capacity of water and heat conductivity
are both high
Body temperature- air
Thermoregulation more significant
Air is less stable for regulating temperature