Lecture Final Flashcards
What are Anapsids?
organisms with 0 temporal fenestrae. ex. turtles
What characterizes the dermis of mammals?
exceptionally thick dermis with presence of hair follicles
What are four types of chemoreception?
- Olfactory
- Gustatory
- Pheromones
- Unspecialized (ex. crying with onions)
What is the K-T boundary/ extinction?
65 million years ago (between the cenozoic and mesozoic eras).
The cretacious-tertiary boundary was a mass extinction where 80% of animals died (including the dinosaurs), but birds and crocodiles survived.
What are three strategies of increasing surface area of the intestine?
- Caeca (extensions)
- Spiral Valve: found in sharks and lungfish; increase path length
- Foldings: found in tetrapods.
What are placentals?
Mammals with placentas. I.e. humans.
Most widespread group of living mammals.
In the eye, what is the function of the Iris?
Controls entrance of light
What characterizes cynodonts?
- changes in jaw muscles allowing chewing
- Two occiptal condyles
- Semi-erect hindlimbs
- nasal turbinates
What are the four types of fenestrae?
- Anapsid
- Synapsids
- Diapsids
- Eurapsids
What two parts does the Rhobencephalon contain? What are they composed of?
Metencephalon: cerebellum, pons (exclusive to birds and mammals)
Myelencephalon: medulla oblongata
What are the components of the middle ear?
The incus, malleus, stapes
What are the three extra-embryonic membranes of the cleodoic egg?
- Chorion
- Amnion
- Allantois
What are the components of the outer ear?
Pinna, ear canal and tempanic membrane
What is the Rhombencephelon?
Hindbrain
What are the three membranes in the vertebrate ear?
Tectorial
Basilar
Vestibular
What two branches come from amniotes?
Sauropsids and Synapsids
What are pelycosaurs?
They are extinct “reptile- like” organisms with one occiptal condyle at the back of their skull (that rotates with the vertebrae).
What is the visceral nervous system?
Smooth muscles and glands (either sensory or motor fibres).
What are the three groups of extant mammals?
- monotremes
- marsupials
- placentals
What is aves? When did they radiate?
Birds. They radiated in the tertiary (cenozoic).
What characterizes a pronephric kidney?
- segmented, first 4 segments
- appear in all vertebrates (rudimentary
form) and quickly degenerate - functional in fish larvae, adult hagfish and some teleosts
What type of evolution do bird and mammal hearts represent?
Convergent evolution. 4-chambered with similar
design, but different origin.
The absence of cardiac shunt probably was an adaptation to allow
different arterial pressure in lungs vs body in active animals.
What are efferent nerves?
Motor nerves: Sends signals from the CNS to the organs (i.e. for movement).
What is a buccal pump?
Its a positive pressure used to push air into the lungs.
Found in fish and amphibians.
In the sensory organs, what are the macula and the neuromast? How do they compare?
The macula are found in the ear. They are patches of sensory cells sensing head position.
Neuromasts are found in lateral line systema and sense water movement.
They are similar in both structure and function.
What is the path of food through a ruminant stomach?
Esophagus –> rumin –> reticulum –>regurgitated and chewed –> swallowed –> Omasum –> abomasum –> intestines.
What mutation allowed mammals to produce milk?
Hox genes; during early stages of development in placental mammals, mutation
produces milk along the milk line.
What is an aspiration pump?
Uses negative pressure to pull air into the lungs.
Found in reptiles and mammals.
Uses the inter-costal muscles and either the diaphragmaticus (reptiles) or the diaphragm (mammals) to pull open lungs (sucking air in).
How did the cynodont jaw muscle change?
It went from a really simple abductor –> both the masseter and temporalis jaw muscles
Helped with chewing.
How many aortic arches do Tetrapods have? Which ones?
3 (carotid system to head derived from ventral aorta) and 4, 5, 6
What are three ways that horses increase the frequency of their stride (for speed)?
- Concentrate muscle for the legs in the trunk
- reduction of toes
- Use spring like tendons for leg movement (stores energy)
What is the Traditional View of early mammals and their radiation?
Early mammals were shrew like and radiated after teh extinction of dinosaurs
What is unguligrade limb differentiation?
Walking on a single digit (i.e. a specialized form of digitigrade). ex horses.
What are diapsids?
Organisms with 2 temporal fenestrae. Found in reptiles, birds and extinct groups.
What are archosaurs?
Subsection of diapsids including crocodiles and birds.
Also includes extinct dinosaurs.
How is the aspiration pump of birds adapted?
The aspiration pump is coupled with air sac system to create unidirectional air flow.
What did the malleus evolve from?
Meckel’s cartilage–> articular –> malleus
Do mammals have a cleodoic egg?
Yes, but there has been secondary loss of the chorion (i.e. shell) such that the uterus is used instead.
What kind of oral gland is exclusive to tetrapods?
salivary glands: multicellular glands with ducts, exclusive to tetrapods
These lubricate food.
Frogs, Anurans: Allows tongue to be sticky – prey capture
Some mammals: Digestion of starch to sugar
Snakes, lizards: poison glands – moved near orbits in marine reptile and birds:
salt excretion
In amphibians, what number is the systemic artery?
four
How many aortic arches do amphibians have? Which ones?
3 (carotid system) ,
4 (systemic arteries)
5
6 (pulmonary artery; or gills in salamanders with no lungs).
How many aortic arches do Teleosts have? Which ones?
They have four: 3,4,5,6
What type of lungs do reptiles and birds have?
Faveolar lung
What are specializations to the amphibian ear?
The second ear bone of amphibians (after the stapes) is the operculum. The operculum senses ow frequency sounds.
What is the Loop of Henle in the kidney?
It is a counter-current urine concentration system which transports urine to collecting
tubule (i.e. the ureter).
What are lepidosauria?
Lizards and snakes
What are the five principle ducts in vertebrates?
- Nephric ducts
- Muellarian (Paramesenephric) ducts (reduced in males)
- Opisthenephric/ mesenephric
- The Ureter (i.e. metenephric)
- Other accessory ducts
What are synapsids?
Mammals and mammal like reptiles
What is the functional unit of a mammalian kidney?
A Nephron
Which is a filter of blood in the kidney
What is hypsodonty and lophodonty in horses?
Hypsodonty: long teeth; as they get ground down
Lophodonty: rigid grinding surface.
What are the three types of dentition? What animals have them?
acrodont. ex. teleosts
pleurodont: ex. anurans, salamanders, lizards
thecodont: some fishes, crocodilians, fossil birds,
mammals
What is the latin term for Placentals?
Eutheria
What two types of integument glands do mammals have?
- Sebaceous glands: oily/waxy secretion (includes specializations such as mammary glands, and scent glands- these are also sweat glands).
- Sweat glands (secrete water/urea/salts)
What characterizes a metanephric kidney?
- Never segmented
- Functional in amniote
- Has dual origin - nephrogenic cord and metanephric duct (ureter)
Describe the turtle/ squamate heart.
Faculative heart; i.e. 3 interconnected compartments (divided atrium, undivided ventricle)
Both single circuit (when underwater)
and double-circuit pumping (when blood is flowing to the lungs)
What are two types of mechanoreceptors?
- The lateral line system
2. The ear
What is the chorion of the cleodoic egg?
It is the shell, which surrounds the embryo and yolk sac.
What are testudines?
Turtles!
What region of the temporal bar is missing in each squamate subdivision?
Lizards: missing lower temporal bar
Snakes: missing both lower and upper
This improves jaw mobility.
What did the stapes evolve from?
Hyomandibula–> collumella (i.e. the first middle ear bone in amphibians).
Compared to birds what kinds of glands do other reptiles have?
Other reptiles have fewer; all granular
What are the divisions of lepidosauria?
- Sphenodontians/ Tuatara (i.e. dent–> two rows of teeth in their upper jaw)
- squamates (i.e. lizards and snakes)
What is the autonomic nervous system?
It is a division of the peripheral nervous system.
It is involved in controlling visceral activity (i.e. thigs we don’t think about), such as cardiac control, respiratory function.
What is the fallacy of intermediate form?
The false belief that there are always intermediate forms in evolution
What is symmorphosis? What does it stipulate?
It’s the theory of economic design.
It stipulates that a structural design should be matched to, but not exceeding the functional demand.
i.e. it’s only as good as it needs to be.
What are specializations to the snake ear?
In some snakes, there is no middle ear, but the stapes is adapted into the jaw for vibration reception.
What is the skull-atlas joint for?
Vertical nodding
What is the procencephelon?
Forebrain.
Describe the cornea and lens’ structure in water vs. in air.
In water the cornea is flat (as there is no need to refract the light). The lens changes position to focus.
In air the cornea is rounded to refract light. The lens changes shape to focus.
What’s it called when teeth are different size/shape?
heterodont
What is the Mesencephelon? What does it involve?
Midbrain. Contains the optic lobe and auditory lobe (i.e. the superior and inferior colliculi)
In the eye, what is the pigment layer?
Prevents reflection.
What fibre in the spinal cord is myelinated?
White matter
What is the function of heterdont dentition in mammals?
Lateral and vertical chewing.
What are the two subdivisions of the autonomic nervous system in amniotes?
- Sympathetic: “fight or flight”
2. Parasympathetic: “feed and breed”
Why are small animals usually ectothermic?
They have a small volume to high surface area ration, and so they lose more heat than they can make.
When does the nephron need long tubule loops?
When the organism needs to have concentrated urine (i.e. when water is in short supply).
What is the function of a rigid backbone in modern birds?
To save energy, by reducing the muscles needed to maintain the streamlined body during flight.
What are two examples of simple reflex arcs of the spinal chord? Why are these considered simple?
- Somatic reflex arc– maintains posture
- Knee-jerk arc – functions in lower spinal chord.
Involve 2 neurons (1 sensory and 1 motor).
What are the regions of the mammalian vertebrae?
- Cervical: 7, characterized by absence of ribs; for rotation; two condyle, atlas-axial rotation
- Thoracic: ribs
- Lumbar: no ribs
- Sacral: articulate with pelvic girdle
- Caudal: presence of hemal arch
What are monotremes?
evolved in the Jurassic; lineage of platypus and achidnas
Suggests that early mammals laid eggs.
What are the two subdivisions of therapids?
- Cynodonts
2. Mammalia
How did the mammalian middle ear evolve?
When the quadrate and articular no longer hinged the jaw (as they did in reptiles) they were able to move back and evolve into the middle ear.
Why do horses have long skinny legs?
For speed, stamina and standing.
What are sauropsids?
Means “Lizard faces”; includes all the amniota except for synapsids.
What is suggested by the nasal turbinates of cynodonts?
Endothermy; as they warm and humidify air being breathed in and recover warmth from that being breathed out.
What’s it called when teeth are all the same size/shape?
homodont
In the eye, what is the sclera?
The rigid housing of the eye (outermost part).
What are the two locational divisions of the nervous system?
- Central Nervous System
2. Peripheral Nervous System
What is an open system in terms of urogenital ducts? Which sex has an open system?
This is a system where the gametes travel through the body cavity to the oviduct (instead being enclosed the entire time).
Female vertebrates have open systems.
What is the germ origin of olfactory organs?
Ectoderm
What is thecodont dentition?
thecodont – teeth occupy bony socket or alveoli; some fishes, crocodilians, fossil birds,
mammals
What are the trade offs between sprawled and pendulous limbs?
Sprawled limbs provide stability.
Pendulous limbs require less force for locomotion (i.e speedy)
Describe the mammalian heart.
4-chambered, double-circuit pump
What type of cervical vertebrae do birds have?
Heterocoelous cervical vertebrae.
These are saddleshaped for flexibility.
What is required for bipedalism? List five.
- sideways hip joint
- short distance between hip and head of femur
supports body weight, - strong gluteal muscle
- straight knee joint,
- longer leg bones
How do lungless amphibians respire?
Cutaneous respiration
What did the incus evolve from?
The palotoquadrate (later known as the quadrate) eventually evolved into the incus.
How are animals (ex. snakes) adapted to gravity?
- High blood pressure
- Hearts located far forward
- Slender body and tight skin
- Body muscles squeeze venous blood back to heart
- Vascular tissue of lung near heart/short vascular lung
Marine animals (marine snakes) would direct less energy towards specialization of these structures, ‘weightless’.
What are the five types of taste that humans can taste?
salty, sour, sweet, bitter, umami
What are crurotarsons?
They are extinct, competitors of dinosaurs; died out by chance.
What is historical contingency? What is it in terms of dinosaurs and crurotarsans?
It is the theory that the paths that life can evolve on are constrained by historical events that are often random.
Crurotarsans died out by chance.
What is a sensory receptor in terms of the sense organs?
Its a transducer that transforms a stimulus into an electric impulse (may amplify the signal).
List four ways that birds lungs are adapted to flying at high elevations?
- Unidirectional airflow
- Cross-current exchange
- Large exchange surface: 10 time more than mammals per volume
- Relatively fixed lung volume, using air sacs to ventilate air
Two cycles of inspiration and expiration to move the air mass through the system
What are three adaptations for dim light (i.e. nocturnal)?
- Large eyes (large lens, close to retina)
- Few cones, mostly rods (which are more sensitive to light)
- Tapetum lucidum (mirror; reflects light)
Where is the urine pathway in anamniotes vs. amniotes?
In anamniotes urine is carried in the opisthenephric duct, while in amniotes it’s carried in the ureter.
What is the evolutionary advantage of costal (i.e. rib) ventilation of the lungs ?
- more efficient than a buccal pump
- Lack of buccal pump muscles allows for longer neck
- Lack of buccal pump muscles allows for the elaboration of nerves that supply the forelimb.
What is the allantois of the cleodoic egg?
A sac that fills with waste as the yolk proteins are used.
Why do horses have a barrel shaped trunk?
Enlarged gut for fermentation. Specifically a large ascending colon and stomach.
What is the somatic nervous system?
Skin and voluntary muscles
How is the the bird’s sternum adapted to flight?
They have a keeled sternum which provides a larger surface area for pectoral muscles to attach (for flight).
In the eye, what is the function of the lens and cornea?
Forming an image
What are the three main lineages of tetrapods?
- Temnospondyls
- Lepospondyls
- Amniotes (stem branch anthracosaurs)
What are amniote’s key features?
- Amniotic egg (semi permeable membrane)
- Low skin permeability
- Costal (rib) ventilation of lungs
- Regionalization of the axial skeleton.
What are six adaptations of the skeleton of aves?
- Reduced and thin skull bones; no teeth
- Flexible neck
- Rigid backbone
- Pelvic girdle fused to synsacrum
- pelvic outlet (for eggs)
- Keeled sternum
What are therapsids?
Synapsids; more terrestrial than pelycosaurs.
Radiated in the late Permian and replaced pelycosaurs.
Some evidence of endothermy.
What are afrotherias?
They were the first placentals to evolve. ex. sea cow; elephants
In amphibians, what number is the carotid artery?
three
What is two-cycle breathing in birds?
Its breathing that takes two inhalations and two exhalations to cycle air through the lungs.
What is digitigrade limb differentiation?
Walk on their digits.
Here the metatarsals migrate upwards. ex. cats
What is the lateral line system?
A mechanoreceptor that detects water movement.
Is present in all fish and some amphibians.
Also includes an electroreceptor component.
What are the functional divisions of the nervous system?
- The somatic nervous system
2. The visceral nervous system
What is the function of the stomach?
evolved as storage place; breaking down food, little absorption
When did mammals radiate?
Mammals radiate slightly before and after the extinction of the dinosaurs.
What type of lungs do mammals have?
Alveolar lungs with lots of branching
What is the synsacrum in birds?
It is the fused extension of the sacral vertebrae (composed of some thoracic, lumbar and some caudal).
It is also fused with the pelvic girdle.
It allows for bipedalism.
What is the function of the ruminant mammal’s stomach structure? What are the four compartments of ruminant mammal’s stomachs?
Ruminant mammals have the differentiation of stomach to ferment plant
material and regurgitate
It has four compartments:
1. rumen – store and churn, symbiotic bacteria breaks down plant material
2. reticulum – receive food from rumen and form cud, regurgitate to chew
again
3. omasum – temporary holding site
4. abomasum – only site with gastric band
What are some Stratum Corneum derivatives of mammals?
claws
hoofs,
nails
hair
What carries the sperm from the testes to the nephric duct?
The efferent ductules
What are the two subdivisions of synapsids?
- “Pelycosaurs”
2. Therapsids
What are synapsids (skull fenestrae)?
1 lower temporal fenestra. Found in mammals
What is the germ origin of gustatory organs?
Endoderm
What is an exaptation?
A trait that has been co-opted for a use other than the one that natural selection has built it. ex. wings.
What is the functional kidney in amniotes?
In amniotes the functional kidney is the metanephric.
However the mesanephric duct in males does not degenerate and used to carry sperm.
Why is bird integument so thin?
Because it loosely attaches to the underlying muscle for mobility of wings.
Which of the two types of dinosaurs evolved into birds?
Saurischia.
What is the functional kidney of an anamniote?
In anamniotes the opisthenephric kidney is the functional kidney.
What are the two modifications of avian and crocodilian stomachs?
- proventriculus: between the esophagus and the stomach. Secretes digestive enzymes
- Muscular gizzard (ventriculus) – A tough horny layer inside that grinds and
mix food using small ingested rocks (no teeth in birds)
What was the Great Dying?
This was a mass extinction that occurred at the end of the Permian (250 million yeas ago). Killed off therapsids which then re-radiated.
What is involved in the Peripheral Nervous System?
Nerves and nervous system
What is the dentary?
The single lower jaw bone of mammals
What is the function of low skin permeability in amniotes?
To combat desiccation.
i.e. amniotes have more keratin.
What are the two hypotheses about the origin of flight (and one new idea)?
- The arboreal hypothesis: gliding from tree to tree.
- Cursorial hypothesis: the running start to jump for insects.
The new idea is that they may been used as an aid in scaling objects.
What characterizes a Opisthenephric/ Mesenephros kidney?
- reduced segmentation
- appear in late larval and adult anamniotes
Why might there have been such extensive radiation in mammals?
- Extended parental care
- Greater intelligence
- Versatile feeding mechanisms (dentition)
- Locomotory adaptations
Or it may have been some combination thereof to radiate into new terrestrial territory.
In the eye, what is the function of the ciliary apparatus?
Focuses image.
What characterizes the lungs of tetrapods?
-generally paired
-high SA to volume ratio
-trend towards increased compartmentalization associated with
increased body size and metabolic rate
What is “modularity of evolution”?
Embryos and adults are made up of modules which are each semi-independent units. Changing one module creates a radically new design. ex. it only takes 3 HOX mutations to go from a lizard to a snake.
What is involved in the Central Nervous System?
Brain and spinal cord
What are keratinized scales?
The scales of reptiles other than birds.
What is acrodont dentition?
acrodont – teeth attached to outer surface (summit) of jawbone; teleosts
What three characteristics must fossil mammals have?
- middle ear – malleus, incus, stapes
- lower jaw – single (dentary) bone
- jaw joint – dentary and squamosal bones
What are three ways that horses increase their stride length (for speed)?
- Loss of collar bone, raising the point of rotation
- lengthening of leg bones themselves.
- Changing foot posture to ungulagrade
What were the characteristics of early mammals?
- feed young milk excreted from mammary glands
- extended parental care of young
- large brain/body size ratio
- hair
- loss of nuclei in red blood cells.
What are the three tubes in the vertebrate ear?
Scala tympani
Scala media
Scala vestibule
What two parts does the procencephalon contain? What are they composed of?
- Telencephalon: Olfactory bulb, tract and lobes, cerebral hemispheres
- Diencephalon: Thalamus, hypothalamus, pituitary gland.
What characterized carnivorous pelycosaurs?
sprawled limbs
some had ‘sail’ of
neural spines (which may been used as a solar collector or for intraspecies
communication)
What are sauropterygia and ichtyosaurs?
Extinct marine reptiles (eurapsid skull).
In the eye, what is the choroid layer?
Nourishes the eye (i.e. blood)
What are the four layers of the gut wall?
- Serosa
- Muscularis externa (longtitudinal
muscle & circular muscle) - Submucosa
- Mucosa
What characterizes eurachontoglires (i.e. primates)?
agile in trees, opposable thumbs/toes, large brain to body ratio,
good binocular vision, enhance parental care
What is pleurodont dentition?
Pleurodont – attached to inner side; anurans, salamanders, lizards
What are the four types of limbless movement?
- Lateral undulations
- Concertina movement (used in narrow spaces)
- Side-winding (video of snake in sand)
- Rectilinear movement (caterpillar-esque)
What do filaments do?
They are in the olfactory organs and they serve to increase surface area for chemical reception.
In amphibians, what number is the pulmonary artery?
six
What are the differences between an amniotic egg and a cleodoic egg?
The cleodoic egg is hard shelled with 3 extra-embryonic membranes/
In terms of the evolution of the turtle body plan, what is the emergentist view?
More accepted.
Rapid evolution due to a change in the developmental regulation of the embryonic stage which causes the ribs to grow over the scapula (i.e. shoulder).
What are morganucodontids?
They are the best studied mesozoic mammal.
What are the four divisions of Eutheria (i.e. placentals)?
afrotheria: ex. sea cows
xenarthra: ex. armadillo
eurachontoglires ex. primates
laurasiatheria
What is the vestibular system?
Part of the ear; may have developed form the lateral line system. Registers head position and balance.
What are the adaptations to the mammalian ear?
Mammals have a cochlea and a pinna (i.e. an external ear).
What is the latin term for Marsupials?
Metatheria
What are epidermal scales?
They are the scales of birds. Found at the base of the beak and the feet.
Describe the anuran heart.
3-chambered heart (i.e. two distinct atria, one ventricle).
There is mixing of oxy/deoxy blood.
What is plantigrade limb differentiation?
Plants the entire foot on the ground.
What types of glands do birds have?
Large aveolar glands, including a specialized uropygial gland (at the tail) for oil secretions
What are the two types of dinosaurs?
Ornithischia
and Saurischia
This is based on pelvic structure.
What are the components of the auditory systems?
3 semi-circular canals (anterior, posterior, horizontal)
2 chambers: utricle and the saccule (which is extended into the cochlea in mammals)
In terms of the evolution of the turtle body plan, what is the classic transformationist view?
Gradual transformation with ossified bony plates.
What are afferent nerves?
Sensory nerves: sends signals from organs to CNS
What is regionalization of axial skeleton?
The differentiation of the vertebral column (i.e. into cervical and trunk for example)
What are the four types of mammal teeth?
incisors, canines, premolars, molars
What are marsupials?
Found mostly in oceania. Tiny young, lives in pouch as it grows.
ex. kangaroos
How many aortic arches do sharks have? Which ones?
They have five: 2,3,4,5,6
What are rods in the eye?
More sensitive; used at night; can’t see colour.
What are the five components of structure?
- Size
- Force
- Environment
- Strength of materials
- Diffusion and exchange.
What are euryapsids?
Organisms with 1 upper temporal fenestra. Found in extinct marine forms.
What are pendulent limbs?
Limbs that go under the body. Found post-amphibian.
What is the basilar papilla?
It’s the equivalent of the corti in a lizards, birds or amphibians ear.
Hair cell movements that transduce mechanical information.
Compare the sympathetic and the parasympathetic nervous systems.
The sympathetic nervous system is a stress response. It has a short preganglionic fiber and a long chain ganglia.
The parasympathetic is a rest response. It has a long preganglionic fiber and lots of post ganglionic neurons.
What are the cones in the eye?
Used for colour; three types.
What makes up a Nephron (i.e. the functional unit of a mammalian kidney)?
The nephric (renal) tube and the renal corpuscle
What are the two sources of the gonads, and what components do they develop?
- Mesomere genital ridges (form the sex cords/ supporting tissues)
- Primordial germ cells (become the gametes which migrate to the gonads)
What is the atlanto axial joint for?
Twisting movement
What is the amnion of the cleodoic egg?
The amnion surrounds the embryo with water.
What’s the squamosal and how’s it attached to the dentary?
The squamosal is part of the mammalian jaw. It is attached to the dentary through a jaw joint.
