W3 L5 - Archosauromorphia Flashcards
What orders belong to Archosauromorphias?
Crocodilia and Aves (Birds)
What are the different types of teeth Archosauromorphias can have?
Pleurodont: teeth on top of gums
Acrodont: teeth on top of gums, slightly into gums
Thecodont: teeth inside the gums completely
Order Crocodilia
- Closest extant relatives of birds
- Bony secondary palate
- Thecodont (tooth sockets)
- 4-chambered heart
- Semi-erect posture
- Gizzard
- Pressure and chemo-receptors
- Oviparous
- Temperature-dependent sex determination
How did Crocodilia’s adapt to living in water?
- Acute eyes raised on head
- Raised nostrils and ears
- Valves close ears and nose when diving
- Webbed feet
- Flap at back of mouth prevents water from getting in while they tear prey apart
Alligators and Caimans
- Teeth fit into pits in the upper jaw
- Dermal pressure receptors on jaws
- 2 species of alligator: American and Chinese
- 6 Caimans in South and Central America
Crocodiles
- 16 species
- Africa, Asia, Australia and Americas
- Salt glands on tongue
- Teeth do not slot into jaw
- Dermal pressure receptors on all scales
- Narrower jaw
Gharials
- 2 species
- India and Asia
- Thin snouts; reduced weight, but light-weight for catching fish
- “Ghara” = bulbous growth on male snout-tip; makes bubbles and resonant hum
Crocodile Heart
Has a Surface and Diving Mode
Surface:
- No mixing; complete separation of oxygenated and deoxygenated blood
- Cog-tooth-valve open
Diving:
- Low pressure in Pulmonary artery (to lung), so right ventricle pressure increases
- cog-tooth-valve closed
- Blood forced through left aortic valve into left aorta; blood mixes
- Possibly leads to low metabolism; extending dive period
Are dinosaurs apart of Archosauromorphias?
Yes, because their hip bones display a lizard-like or bird-like pattern
Class Aves
- ~150 mya
- ~10,000 species, >800 in Australia
- Highly diverse in:
- Diet, Locomotion, Habitat, and Appearance
Class Aves Defining Features
- Respiration
- Circulation
- Metabolism/-thermy
- Nitrogenous wastes
- Hearing
- Vision
- Olfaction
- Locomotion
- Foraging
- Reproduction
- Predator Avoidance
- Adaptations to extreme conditions
Class Aves, Breathing on Land
- Highly efficient
- One-way flow of air
- Bi-pedal, upright posture to avoid respiration-locomotion conflict
- Rib cage and muscles create negative pressure in the air sacs
How does Avian Unidirectional Flow of Respiration work?
- Fill posterior sacs
- Ventilate lung
- Fill anterior sacs
- Exhale
- Picture 1 - 4 going around in a circle kind of *
Class Aves, Metabolism/-thermy
- Endothermic
- High MR + insulation
- High Tb (38 - 42 C)
Class Aves, Nitrogenous Wastes
Act as uric acid
- Conserves H2O
- Insoluble waste product
- Pass little water in urine
Where did Avians get their evolution of flight from?
Theropod dinosaurs; clear evolutionary transition in fossil record
Class Aves, Structural Form
- Modified Diapsid skull
- Reversed first toe
- Digitigrade
- Lightweight, streamlined and rigid structures for flight
Class Aves, Bones
- Hollow and lightweight
- Caudal vertebrae fused to form a pygostyle
- Wing with bone fusion; 3 fingers
- ## Keel on sternum for flight muscles
What are the basic feathers?
Plumaceous and Pennaceous
Pennaceous Feathers
- Barbs hook like velcro to form tight sheets
Plumaceous Feathers
- No barbs; soft and loose
What are the six types of feathers?
Tail, Flight, Semiplume, Filoplume, Bristle, Downy
What do each of the feathers do?
- Tail and Flight: contour; large and stiff
- Semiplumes: intermediate stiffness; thermal insulation and shape the body
- Filoplumes: fine and hairlike; detect pressure and vibration, used to arrange other feathers
- Bristles: stiff and hairlike; near bill, eyes, nostrils, toes; screen out foreign particles, act as tactile sense organ
- Downy: entirely plumaceous; provides insulation for adults
How do birds fly?
Use their wings to generate:
- Lift; to counter gravity
- Thrust; to overcome drag
