Lesson 13 Flashcards
similarities between synapsids and sauropsids
- don’t need water to give birth ( because they are both amniotes)
- fast moving predators
- have or had powerful flight (synapsids - bats and birds for sauopsids)
- extensive parental care and complex social behavior
- endothermy
- these traits involved independently of the groups ^^^ traits evolved in paralle – not all features of amniotes
early on
- it was either lung ventilation or running – cannot do both
- retain a lot of lateral bending of the vetebrate axis as primary form of powering locomotion
- early tetrapods relied on parallel contraction not alternating contraction to compress the ribs and relax the ribs fro ventilation of the lungs
- air just gets shuttled back and forth (+ and -) but does not get filtered out
- instead of vertical — lateral bending
- rotating the limbs to be unerneath the body or becoming bipedal
- loss of lumbar ribs for derived froms
- bipedalism completely separates locomotion from ventilation
sauropsida
- both crocodiles and birds use pelvic movement to facilitate respirtation
- ancestral character trait to amniotes
- gastrallia – gave rise to a certain kind of breathing
how would gastrallia help in ventilation
when there is a contraction of the ishiotrunkus – it pulls down and the ridigity of dermal bones push outward of dermal bones
- body wall goes to relaxed state and air is pushed out
ROLE of gastrallia – to enable to eexpansion of the body wall enabling air to be taken in
how did the synapsid lung evolve
- branching of air chambers
- involve bronchi, alveoli
- ex: human alveoili is aboit 70 sq m
- the air exits in the same direction –> medium comes in in direction, stops, and leaves in the same diretion
TIDAL VENTILATION
how did sauropsid lungs evolve
- achieved also a great deal of SA for gas exchange but it doesn’t branch similar to a tree –> at leas some that we know of do not in fact have tidal ventilation (not the flow in and bout of the body of animal but the flow of the lungs)
– air for a bird flows through one way – really useful when you have aerobic demands
—– gastrallia get lost periodically
air sacs
- pump air through the bird’s lungs
- air flows unidirectionally though this^^^^^ even though it flows bidirectionally in the bird
- there are 2 cycles with separate inspiration and expiration phase
in cycle 1
- animal brings in air and air fills up in the lung
- then the animal expures and moves air across the lungs (lot of gas exchange occurs ) – but when the bird expires, it is not expiring that breath
—- in phase 2 ,
——– the animal inspires again and exhales the 1st breath
inhale - exhale (difference breath) - inhale - exhale (2nd breath)
blood flow
blood flow and air flow in different direciton
- gives rise to a gradient of concentration of hses between the parabronuhi and the capillaries
- concentration difference is maintained
speculation of dinos having air sacs
- thought of that they much have had air sacs due to their long neck
- gas exchange cannot occur with their long neck
- dead air and dead necks
- long necks are inefficient for gas exchange
- air sacs to overcome this inefficiency
lung ventilation requires greatly reduced blood pressure for systemic circulation in animal
- lung tissue is very delicate
— if there is too much blood pressure — it will destroy the thin tissue
– need to have 2 different kinds of tissues (found in both saurospids and synapsids)
KEY DIFFERENCES
- mammals lost one of their systemic arches
- ^^ may have enabled higher pressure and reduced turbulenxe
- we also find 1 systemic arch occuring in birds
– crocodiles retain systemic arches
what suggests that these 2 groups evolved independently
one lost the left systemic arch and the other lost the right systemic arch
both derived groups have a complete ventricular septum
- volume of blood must stay the same to achieve different pressures ^^ help of the septum to do this
- if there is a greater difference in pressure - then a group has a ventricular septuum
ex: mammals, crocodylians, birds
radiate heat (crocodylians)
- move blood that has been warmed (by the sun) on the surface of their skin to their core
- warming rates are more rapid than cooling rates
- blood flows differently depending on whether or not the animal is basking or not
- more rapid flow when animal is trying to warm up
similarities and differences in excretory products
nitrogenous waste mainly excreted in ammonia, urea, or uric acid
- urea is very soluble in water
- uric acid is basically unsoluble
- ammonia is about 1/2 as soluble as urea
- uric acid is the most efficient for water conservation
no kidney is as efficient in concentrating urine as the mamallian kidney is
- only mammals have this really long extension - loop of henley
– when an animal dehydrates, they produce very scant, concentrated urine
