Class Tetrapod, Midsession quiz Flashcards
CLASS AMPHIBIA
What are the 3 orders of Amphibians?
- Order Gymnophiona
- Order Caudates
- Order Anura
GYMNOPHIONA
What are the Defining features of this order?
Micro and Macrohabitat?
Caecilians
Defining Features:
Burrowing Anuli
Internal Fertilisation
Limbless
Sensory tentacle
Eggs can be laid;
In Water: Gilled larvae, become terrestrial after metamorphing
Underground: Young hatch as small adults.
Microhabitat:
Moist, loose soil
Near Streams
tropical rainforests
Macrohabitat:
South America
CAUDATA
What are the defining features of this order?
Salamanders & Newts
Defining features:
Limb regeneration
Internal/external fertilisation
Entirely terrestrial
PAEDOMORPHIC
Breed in water; Larvae
Merge to land until ready to breed again
Skin is a respiratory organ
Alternate undulations (limbs)
Microhabitat:
Damp/Wet areas
Macrohabitat:
Northern Hemisphere
America, Europe Asia, Japan
Define Paedomorphic
Retaining juvenile characteristics as adults
ANURA
What are the defining features of this order?
Frogs
Defining features;
Bulging eyes aid swallowing
Buccal pump
Specialised skeleton for jumping, swimming
Oviparous - require water
Aestivation - torpor
freezing frogs
Metamorphosis;
1. tadpole structure break down, chemical constituents rebuild to adult structure
2. loss of gills/lung development
3. Hormonally controlled
Microhabitat
Moist
Macrohabitat
Globally excluding antartica
What are the 2 major groups of amniotes?
- Synapsids
- Sauraposids
SYNAPSID
SYNAPSID
- mammals
- Synapsid skull
- evolved earlier
- forelimbs more developed than hind
- DIAPHRAM
- Better Olfaction, poor Vision
** Synapsids were once more successful than Sauropsids until the Permian Mass extinction ~245 mya, called the ‘Triassic takeover’**
SAUROPSID
SAUROPSID
- Lizards, snakes, turtles, crocodiles, birds
- Diapsid Skull (NOT TURTLES)
- Better Vision, poor olfaction
- Hindlimbs are more developed than forelimbs
- GASTRALIA- rib-like structure on front of chest
What is the most defining feature of all Amniotes?
Amniotic egg
Amniotic sac in placental mammals
Double circulation
Name the important structures within the Amniotic egg
Allantois
Yolk
Chorion
Amnion
What is the function of the Yolk in the amniotic egg?
Provides nutrients and water for embryo
Fuel
When embryo uses up nutrients, the yolk shrinks
What is the function of the Allantois in the amniotic egg?
‘bladder’ storing nitrogenous waste
gas exchange
What is the function of the Chorion in the amniotic egg?
Encloses yolk, embryo and allantois
Facilitates gas exchange w/ exterior
What is the function of the Amnion in the amniotic egg?
Encloses embryo
provides cushion against mechanical shock
How has the amniotic egg allowed life on land?
- Doesn’t require a water source
- Self-sustaining environment
- Mammals, other than monotremes, develop the same amniotic layers but inside the womb
- Less pool competition - dispersal on terrestrial land
- Decreased predation
- Higher chance of survival off offspring (fewer in numbers though)
How do endotherms insulate themselves?
High MR
Insulation
Endothermy
Mammals and birds
internally thermoregulate
Ectothermy
Reptiles and Crocs
Rely on external heat sources
Evolution of Endothermy
Erect Gait, bipedal (upright posture) BIRDS
Jaw structure
Palate
Turbinates (humidity and breathing)
Why are amphibians vulnerable during metamorphosis?
Low immune competence due to the reorganising of essential molecular pathways (limbs)
High energetic cost of tissue reorganisation
Low nutrition - Don’t feed themselves during
*Tadpole structure breaks down, chemical constituents rebuild into adult structure *
What are the 5 abiotic challenges that tetrapods face?
- UV
- Gravity
- Desiccation
- Reproduction
- Temperature
Solutions to Abiotic factors:
- UV radiation
Behavioural avoidance
Protecting exposed surfaces
Scales, feathers, Fur
Skin pigmentation
Solutions to Abiotic factors:
- Gravity
Structural support & musculature
Endoskeleton
favours terrestrial locomotion
Joints and muscles
Solutions to Abiotic factors:
- Desiccation
Reptiles and birds can repackage ammonia
Concentrates urine in mammals
Rectal recovery of excretory fluids (dry faeces)
Salt excreting glands
Solutions to Abiotic factors:
- Reproduction
Amniotic Egg
Solutions to Abiotic factors:
- Temperature
Thermoregulation
Endo/Ectothermy
Behavioural Strategies
- Hibernation
- Torpor
- aestivation
Cold hardiness + freezing in frogs
What are the circulatory and respiratory adaptations of amphibians?
RESPIRATION
Buccal pump in frogs
Breathing through skin
Consequences:
Breathing through the skin can result in the inhalation of harmful chemicals in the air
CIRCULATION
3 cambers
Mixing
WHY?
Lower MR, don’t require much oxygen to be delivered to the body
What are the circulatory and respiratory adaptations of birds?
RESPIRATION
most efficient in the animal kingdom
Unidirectional (racetrack)
Negative pressure breathing
Rib + pelvic movements to inhale
9 air sacs in birds
Continuous flow of air through lungs, expells extra heat from the body
Makes flying possible
CIRCULATION
4 Chambers
Single aorta
High MR
Complete separation of Left and right heart
What are the circulatory and respiratory adaptations of crocodiles?
RESPIRATION
Unidirectional (racetrack)
Negative pressure breathing
Rib + pelvic movements to inhale
Fewer but still some air sacs in crocs
(posterior is main air sac)
CIRCULATION
4 Chambers
Crocs: cog tooth valve (diving) restricts blood flow to lungs
COG TOOTH lowers MR allowing for longer diving times
some mixing
2 aortas
Ectotherms, due to slight mixing and their sit-and-wait behaviour when hunting, does not require them to be warm-blooded.
What are the circulatory and respiratory adaptations of Mammals?
RESPIRATION
Bi-directional (waves at a beach)
Negative pressure breathing
Diaphram
Bi-pedal, erect gaits
Highly efficient
CIRCULATION
Same as Avian
1 Aorta
4 chambers
Complete separation of chambers
No mixing
Double circulation
What mechanisms have birds developed to fly?
LIFT: BERNOULLI PRINCIPLE
Side of wing with fast flow (above) has a lower pressure
The side of wing with slower airflow (below) has a higher pressure
Results in an uplifting force
Pressure is generally always higher below wings
pressure difference drives birds off the ground
THRUST:
Sweep air providing a forward motion
High powered downstroke
Low powered Upstroke
Defining features of Amphibians
Skin must always be wet to allow for skin respiration
Aquatic/require moist environments
Start off as larvae
Anapsid skull
