Lecture 9 DA Flashcards
Are amphibians limited to aquatic environments despite being terrestrial?
They are, as they are not fully terrestrial.
Where is the hollow nerve cord found in arthropods and annelids?
On the ventral side.
What lines the pharyngeal slits? What is its purpose?
Endostyle lines the slits, and secretes mucus for filter feeding.
How are vertebrates distinguished?
Presence of a cranium.
What are the 8 classes of subphylum vertebra, and their common names?
Myxini - hagfish Petromyzontida - lamprey Chondrichthyes - sharks/rays Actinopterygii - ray finned fish Sarcopterygii - lobe finned fish Amphibia - amphibians Reptilia - reptiles/birds Mammalia - mammals
what gave rise to the amphibians?
Early tetrapods, a lobe finned fish that developed legs.
Is the tetrapod clade paraphyletic or monophyletic?
Mono
What do all vertebrates have embryonically?
Th 5 chordate traits.
What 3 features were involved in the transition to land?
Evolution of lungs.
Evolution of tetrapod limbs.
Protection from drying out - feathers, skin, scales etc.
What are the advantages of transitioning to land?
Safe, free of predators at that point.
What were the first animals to colonise land (2)?
Arthropods, and some molluscs.
Sarcopterygii and tetrapod taxa are what to each other?
Sister taxa.
What do all tetrapods have? Does this include amphibians?
All have lungs, including amphibians.
Can fish breathe air? Explain.
Some fish breathe air by leaping, and storing it in the oesophagus.
What are lungs, in terms of the oesophagus?
An enlarged pocket of the oesophagus.
What do lungs form in fish?
Swim bladder in many fish, which is also an outpocket of the oesophagus.
What are the four steps of limb development?
- Bones similar to humerus, radius, and ulna, ray fins still present.
- Wrist bones develop, ray fins replaced with 8 bony digits.
- Limbs capable of walking on land develop, digit number decreases.
- Fully formed tetrapod limb with 5 digits.
Are tetrapod limb structures analogous or homologous?
Homologous.
What is the keel of amphibians like?
Strong bony keel.
How many limbs and digits do amphibians usually have?
4 limbs, and 4 digits.
What is the skin of amphibians like?
Smooth, and moist.
How do amphibians usually respire (3)?
By lungs, skin or gills.
What kind of -therms are amphibians (2)?
Ectothermic and poikilothermic.
Where does fertilisation take place in amphibians?
Most often externally in frogs/toads, internally in salamanders.
Do amphibians have a urinary hole/anus or a cloaca?
Cloaca.
Are amphibians adapted for terrestrial life?
Only partially.
Are amphibians more terrestrial or more aquatic?
Most are aquatic, living close to water for its lifecycle.
Do frog/toad eggs have shells?
No.
How do amphibian aquatic larva respire?
Tadpoles have gills.
How do frogs/toads respire in the adult stage? What is needed for this?
Respire across their skin, must be kept moist.
How many chambers do fish heart have?
2, one atria, one ventricle.
How many chambers do amphibian hearts have?
3 chambered, 2 atria, one ventricle.
What are anurans?
Frogs.
How do amphibians fill their lungs?
Use positive pressure - croaking.
What are the 3 orders of amphibia?
Gymnophiona
Urodela
Anura
Is amphibia para or monophyletic?
Mono
What is meant by apoda? Are gymnophiona apoda?
Apoda means no limbs. Gymnophiona are apoda.
What are caecilians?
Gymnophiona.
Do gymnophiona have eyes? Do they have scales?
Small or no eyes. Some have mesodermal scales in skin.
Where do gymnophiona live?
They burrow.
Where does fertilisation occur in gymnophiona? Are they ovi or viviparous?
Internal fertilisation, some lay eggs, some viviparous.
What is the common name for order urodela?
Salamanders, newts
What angle are urodela limbs from their body?
Their limbs are at right angles to their body.
Where does fertilisation occur in urodela? Do they lay eggs or direct development? (hint - aquatic vs terrestrial)
Internally. Aquatic have eggs, while terrestrial have direct development.
What is paedomorphosis?
An evolutionary change in which larval features of an ancestor are retained to adulthood by descendants.
What is paedomorphosis believed to be a mechanism of?
Believed to be a mechanism for evolutionary changes via changes to evelopmental regulatory genes.
What are vertebrates believed to have evolved from? (hint - paedomorphosis)
From paedomorphosis of larval stages of urochordates.
What is the common name of order anura?
Frogs/toads
Do anura have a head, trunk and tail?
They have a fused head and trunk, but no tail.
Do urodela have a head, tail and trunk?
Yes.
Name 3 differences between frogs and toads.
Toads have thicker skin.
Toads have shorter legs.
Toads are more terrestrial.
where does fertilisation occur in anura?
Externally.
What do anura eggs hatch into?
Aquatic larva.
What are the eating habits of tadpoles vs adults?
Tadpoles are herbivorous, while adults are carnivorous.
Do frogs have pouches?
Some do, and brood eggs there.
What were the first land based tetrapods?
Amphibians.
Which groups are amniotes?
Reptiles, birds and mammals, but not amphibians.
Are amniotes monophyletic? What clade are they within?
They are monophyletic. Are within tetrapods.
What are amniotes evolved for?
Full terrestrial life.
What first colonised the air?
Insects.
Where does fertilisation take place in amniotes?
Internally.
What is the amniotic egg, and what is its purpose?
Prevents the egg/embryo from drying out.
What are 6 amniote adaptations?
Thicker, more waterproof skin. Rib ventilation of lungs. Stronger jaws High pressure cardiovascular system. Water conserving, nitrogen excretion. Expanded brain and sensory organs.
What are the 4 membranes of the amniotic egg?
Chorion
amnion
Allantois
Yolk sac
What is the purpose of the chorion?
Allows gas exchange with the environment.
What is the purpose of the amnion?
Surrounds and cushions the embryo with fluid.
What is the purpose of the allantois?
Stores waste, and allows gas exchange.
What is the purpose of the yolk sac?
Storage of nutrients for the embryo.
Does the tough shell of an amniotic egg allow for gas exchange? Explain.
Yes, it has pores.
What is the outermost membrane of the amniotic egg?
Chorion.
When are the amniotic egg membranes formed?
After fertilisation.
How many digits do reptiles have mostly? Do all reptiles have digits?
Mostly 5. Limbs absent in snakes and some lizards.
Where does fertilisation occur in reptiles?
Internally.
What kind of egg do reptiles have?
Calcareous or leathery shelled eggs.
Do reptiles have a larval stage?
No.
How do reptiles respire?
By lungs.
Do reptiles have gills?
No.
Do reptiles need moist skin to respire?
No.
Do reptiles have a cloaca or seperate tracts?
Cloaca.
What kind of -therms are reptiles? Does this apply to all reptiles?
Reptiles are ectothermic and poikilothermic, except for birds.
They are endothermic and homeothermic.
What does the epidermis of reptiles form?
Keratinised scales, and feathers in birds.
How many occipital condyles do reptiles have? What about mammals?
Reptiles - 1
Mammals - 2
Are reptile scales homologous to fish scales? Why/why not?
No, because reptile scales come from the epidermis. Fish scales come from the dermis.
What is the purpose of scales in reptiles?
Provides physical protection, prevents dessication.
Aside from sclaes, what else can be found in the dermis in some reptiles?
Bony dermal plates, ie shell of a turtle.
Regarding their heart, what do all reptiles have?
All have a septum between their right and left atria.
Do reptiles have a septum between their ventricles?
Most have a partial septum.
Crocodilians have a complete one.
How do reptiles inflate their lungs? What kind of pressure is involved?
Rhythmically inflate lungs by expanding thoracic cavity. They use negative pressure.
Do reptiles have a diaphragm?
No.
How do turtles, lizards and crocs respire?
Turtles ventilate by expanding/pulling visceral organs, which press on lungs.
Lizards by compressing/expanding ribs.
Crocs, same as lizards, but pull their liver back, and twist their pubic bone.
How did the ancestral form of reptiles locomote? What is a disadvantage of this?
Lateral undulations of the trunk, as in lizards. Compresses lungs and limits respiration for endurance.
How have modern forms of reptiles improved locomotion?
Bipedal locomotion, as in birds and dinosaurs, and movement of ribs, pelvis and organs.
What are the advantages of ectothermy (3)?
High efficiency in converting food to biomass, as none used for maintaining temperature.
Can thrive on little food, and poor producibility ecosystems (deserts).
Can survive with a low metabolism rate.
What are the disadvantages of ectothermy (4)?
Activity is limited by external temperature.
Requires behavioural adaptations for finding its thermal microenvironment (basking).
Become inactive for part of the year.
Limited on latitudinal range.
What are the three amniote skulls?
Anapsid
Synapsid
Diapsid
What are anapsid skulls like? what organisms have them?
No temporal holes posterior to orbits.
Earliest reptiles had them.
What are synapsid skulls like? What organisms have them?
One pair of temporal holes posterior to orbits, for jaw muscle attachments.
Gave rise to therapsid reptiles, and mammals.
What are diapsid skulls like? What organisms have them?
Two pairs of temporal holes posterior to orbits for jaw muscle attahments.
Gave rise to all other reptiles including dinosaurs and birds.
What kind of skull does a turtle have? Explain.
Begins with a diapsid skull, but secondarily loses the two temporal holes. Is therefor considered anapsid.
What subclass can be found in reptilia?
Diapsida
What two superorders are found in diapsida?
Lepidosauria
Archosauria
What order can be found in diapsida? What is the common name?
Testudines. Turtles/tortoises.
What two orders are found in superorder lepidosauria? Common names for both?
Squamata and sphenodonta
Are snakes/lizards and tuataras respectively.
What order is found within superorder archosauria?
Crocadilia, and also includes dinosaurs and birds.
What is the carapace of order testudines (turtles) like?
Shell carapace fused to ribs, and vertebra of thorax.
How do testudines ventilate?
Muscle contractions of thorax, abdomen and limbs.
What are tortoises?
Terrestrial turtles.
Where are testudine eggs laid?
Buried into the ground, sea turtles return to water.
What is the sex of a testudines determined by?
Nest temperature, as in crocs and some lizards.
What order has the most recently evolved reptiles?
Squamata
What do order squamata have that allows large mouth opening?
Kinetic skull with movable quadrate bone, that can hinge.
Do squamata shed their skin?
Yes.
Are all squamata viviparous or oviparous?
Mostly oviparous. Can be viviparous by retaining egg in oviduct until hatched.
What are sauria? Common name?
Suborder within order squamata. Lizards, iguanas, geckos. Primitive forms of squamates.
What is characteristic of sauria?
4 limbs and a tail thar can automise at predetermined points.
Do sauria have moveable eyelids? What about snakes? what is their vision like?
Sauria can moveable eyelids, unlike snakes. They have good eye vision.
What is serpenta? Common name?
Suborder wthin order squamata. Snakes.
What are the olfactory and vibration senses of serpenta like?
Very good.
How do serpenta detect odour molecules?
Tongue licking carries the odour to the roof of their mouth, where the sensory organ is.
Do serpenta have eyelids?
They have fused, transparent eyelids.
Do serpenta have ear openings?
No.
Are serpenta all carnivorous? Are there exceptions?
Yes, no exceptions.
Are all serpenta vivi or oviparous?
Mostly oviparous, can be viviparous.
When do order sphenodonta feed? Where do they live?
Theyre nocturnal. Live in burrows.
What are the most primitive living reptiles?
Order sphenodonta.
What do sphenodonta have that allows sun exposure regulation?
Primitive third eye on their head.
What surviving lineage gave rise to dinosaurs/birds?
Order crocodilia.
What did crocodilia evolve from?
Fully terrestrial ancestors.
What is the difference between an aligator and a crocodile?
Aligator - broad snout, upper teeth visible when mouth is closed.
Corocodile - narrow snout, upper and lower teeth visible when mouth is closed.
What are the largest crocodiles?
Saltwater.
