101 terms

Bio of Vert Exam 2

fish locomotion
- lateral undulation of the body
- most are streamlined and coated in mucous
- swimming in water is energetically cheaper than walking on land
tightly packed skeletal muscles of the trunk of fish, one muscle contraction causes a wave of contractions
Basic vert plan for integument
- 2 layers of skin
- epidermis: outer layer, thinner, protection
- dermis: inner layer, thicker, connective tissue, vessels, and capillary beds
- hypodermis: not technically part of the skin, cushioning layer
Myxini and Cephalospidomorphi integument
- cuticle on outside of skin (mucous)
- epidermis is thicker than dermis, contains a large number of mucous cells
- extra fat tissue below dermis
Chondrichthyes integument
- epidermis is thinner than dermis, less mucous
- placoid scales (tooth shaped) around sensitive areas
Osteichthyes integument
- epidermis is thinner than dermis
- most have scales over whole body
- scales are covered by dermal and epidermal tissue
ganoid scales
thick, heavy non-overlapping
cycloid scales
thin, lightweight, overlapping, smooth margin
ctenoid scales
thin, lightweight, overlapping, spiny posterior margin
fish feeding
- early fish were likely filter feeders
- jawless fish: filter feeders some parasitic
- jaws mean larger mouths and larger prey
- fish suck prey in with vacuum from the buccal cavity
basic vert plan for digestive system
- alimentary canal: tube within a tube, opening at each end, tube is lined with epithelial tissue and smooth muscle in wall
- breakdown of large molecules into smaller molecules
- accessory digestion organs: liver, pancreas, gallbladder, they excrete chemicals into the alimentary canal
- there are five regions of the alimentary canal
5 regions of alimentary canal
1. receiving region: mouth and accessory structures
2. conducting region: esophagus (back of mouth to stomach), muscular contractions move food to stomach
3. storage region: stomach temporarily stores food, chemical digestions occurs here
4. region of terminal digestion and absorption: small intestine, most nutrient absorption, walls have extensions called villi which increase absorptive area
5. region of waste formation and water absorption: large intestine, anything that wasn't broken down or absorbed is formed into waste, empties to cloacal or anal opening
Fish digestive system
- shortest esophagus of verts.
- no real distinction btw small and large intestines
- have a gizzard: lower portion of the stomach for grinding food
- pyloric ceca: blind pouches at junction of the stomach and small intestine that contain microorganisms to help digestion
- hepatopancreas: liver and pancreas fused into one organ
Basic vert plan for circulatory system
- closed system: blood mostly kept inside vessels (can sometimes escape through capillaries)
- blood contains erythrocytes with hemoglobin for oxygen binding
- vessels: arteries, arterioles, capillaries, venules, veins
- heart pumps the blood
Fish circulatory system
- 2 chambered heart (one atrium, one ventricle)
- 2 pseudo-chambers (sinus venosus and conus arteriosus)
- blood is carried to gills for gas exchange
- heart is 2.5% of weight
- blood is <5% of weight
- lungfish have gills and saclike lungs, 4 gill arches where one pair leads to the lungs, atrium and ventricle are partially divided
fish blood flow
blood from body > sinus venosus > atrium > ventricle> conus arteriosus > vetral aorta > 5 afferent arterioles > 5 gill arches > capillary beds of gills > 5 efferent arterioles > dorsal aorta > to body and head
fish respiratory system
- ram ventilation: swimming with mouth open to force water over gills. Fish with reduced or absent operculum, or that have a spiracle
- operculum opens and closes to force water over gills
- gas exchange occurs via counter current exchange mechanism
- lungfish have simple sacs that are connected to the esophagus, they gulp air
- swim bladder can either be connected to the esophagus or it can be filled via gas exchange (rete mirable)
gill cover with pharyngeal muscles, fish with these do not need to move to force water over their gills
gas exchange
- the exchange of O2 and CO2 between an organism and its environment
- needs a thin, moist surface with lots of capillary beds
gill structure
- gill arches, filaments, and lamellae
- lamallae: epithelial sacs with capillary beds (most important for gas exchange)
- arch is for structural support
- fish either have 4 or 5 arches
movement of molecules from high to low concentration over a gradient
counter current exchange (in fish)
- blood and water flow in opposite directions which allows for a constant O2/CO2 gradient over the entire gill region
- water moves front to back
- blood moves back to front
- might be most efficient mechanism for gas exchange
Basic vert plan for nervous system
- enlarged mass of nervous tissue (brain) at anterior end of the dorsal hollow nerve cord
- increases in size as organisms are more evolutionarily developed
Fish nervous system
- 2:1 brain to spinal cord ration
- smallest ratio of all verts
- have sensory receptors throughout whole body
fish olfaction
- external nares, olfactory sacs in back of nasal cavity
- most developed in migratory species
fish vision
- no eyelids
- round lens
- focus by moving lens forward and backward
- likely to have good sense of color vision
fish hearing/equilibrium
- inner ear primarily for picking up vibrations through the skull and webberian apparatus
- inner ear with endolymph and lined with cilia with sensors allows for good balance
Acoutico lateralis system
- in fish
- series of pores/canals covering the body with sensory receptors within the canals
- cupula
- neuromast region
- concentration of pores around head region
- picks up vibrations in water
basic vert. plan for excretory system
- kidney: typically a pari, main urinary organ
- nephron: structure in kidney, what balances water and ion concentrations
Excretory 3 step process
1. filtration: blood is filtered in glomerulus to form glomerular filtrate
2. reabsorption: removing good things from the filtrate to keep in the body, most of it happens in the proximal tubule
3. secretion: secreting waste products found outside the nephron and intracellular fluid back into the filtrate (mostly happens in distal tubule)
fish excretory system
- gills can release ions into the water, water can also be taken in through the gills
- marine and freshwater fish have differences
freshwater fish vs. environment
- env. ion conc. < body ion conc.
- env. H2O conc. > body H2O conc.
- constant intake of H2O
- do not need to drink
- large glomerulus
- short nephric tubule
- dilute waste product (ammonia)
marine fish vs. environment
- env. ion conc. > body ion conc.
- env. H2O conc. < body H2O conc.
- constant loss of H2O
- constantly drinking
- small glomerulus
- long nephric tubule
- concentrated waste product (urea) can be stored in tissue
basic vert plan for reproduction
- goal is to perpetuate the species by producing offspring
- involves meiosis to produce 1N gametes and syngamy to produce 2N zygotes
fish reproduction
- mostly oviparous, some are ovoviviparous
- most are dioecious
- some are monoecious (contain both sex organs, some exhibit reversal)
- few are parthenogenic ( can develop egg without fertilization)
- external fertilization
- produce eggs in large numbers
- parental care is variable
amphibian integument
- thinnest of all vertebrates, no protective structures
- major function is protection
- mucous secretion, can also secrete toxins
- can regulate temp, absorb water, and do gas exchange
amphibian locomotion/support
- in water they are supported by water
- on land limbs fight gravity and muscles provide support
amphibian skeleton
- skull is flattened and has fewer bones than fish
- hindlimbs have similar structure to Crossopterygii fish
- salamanders have short limbs that support the long body
- frogs have larger hindlimbs than their forelimbs
- joints have increased flexibility and agility
- pelvic girdle is attached to lower vertebral column
- pectoral girdle is attached to vertebral column
- vertebral column is more flexible than fish with smaller processes to prevent too much twisting
- have an atlas (#1 cervical vert) to support skull (nodding)
- sternum is reduced in frogs
- in frogs
- supporting rod within the pelvic girdle composed of fused caudal vertebrae
- allows simultaneous movement of hindlimbs
amphibian digestive system
- have a cloaca with a vent to the outside
- prey is variable, mostly carnivorous
- have a true tongue
- sit and wait predators
true tongue
- well supported by muscle
- assists in capturing and swallowing prey
- sticky tongue in amphibians
amphibian circulatory system
- separation btw pulmonary and systemic circuits
- 3 chambered heart ( 2 atria, 1 ventricle)
- 2 pseudo-chambers (sinus venosus off of right atrium, conus arteriosus off of ventricle)
- spiral valve: within CA, O2 sensor shunts blood to proper aortic arch based on O2 levels
amphibian blood flow
venous system > sinus venosus > right atrium > ventricle > conus arteriosus (low O2) > pulmonary arteries > aortic arch > lungs > pulmonary veins > left atrium > ventricle > conus arteriosus (high O2) > aortic arches > carotid to head and systemic to body
amphibian respiratory system
in water
- larvae and some aquatic adults
- 3 pairs of gill arches
- same counter current exchange mechanism as fish
on land
- surface must remain moist
- all gas exchange through air
- cutaneous respiration: gas exchange through the skin
- buccopharyngeal respiration: gas exchange through thin lining of the mouth cavity
- buccal pump with lungs: lungs are simple sacs, must gulp/swallow air
amphibian temperature regulation
- ectothermic
- in water body temp is near water temp
- on land body temp fluctuates depending on conditions
- regulation is behavioral
- cooling: stay moist, in shady areas, nocturnal
- warming: basking, more common in water than on land
amphibian nervous system
- 8-12:1 brain to spinal cord ratio
- numerous skin receptors for chemoreception (skin is thin so chemicals can penetrate easily)
- have acoustico lateralis system, but reduced compared to fish (no canals, only pores)
amphibian vision
important sense, large eyes relative to body size, large round lens, good color vision
amphibian auditory sense
- vibrations from substrate pass from limbs to skull. frogs have tympanum to pick up sound waves
- frogs have 1 middle ear ossicle and inner ear, can pick up high frequency sounds
amphibian excretory system
- ammonia is the primary waste product for aquatic amphibians
- urea is the primary waste product for land amphibians
- some pond frogs can excrete both
- in water, same ion conc. problems as freshwater fish
- on land they must conserve water, mucous glands keep skin moist
- water can be absorbed through skin and stored in lymph sacs and bladder
- most don't drink, and kidneys are not very advanced to conserve H2O, so they modify behavior to conserve water
amphibian reproductive system
- non-amniotic eggs
- eggs must be laid in water or moist area to prevent desiccation
- mostly have external fertilization
- all dioecious
- few are parthenogenic
- larval stage is aquatic, but not all have larval stage
- timing is important, time it with wet/rainy season
- degree of parental care is variable
condition to remain in a larval stage but reach sexual maturity. species as a whole are not neotonic, but individuals can be on their own. usually aquatic salamanders
reptile integument
- thicker skin with scales
- skin is dry
- more advantages to living on land as compared to amphibians
shedding os skin, in response to growth
reptile support/movement
- highly ossified skeleton
- denser, larger bones than amphibians
- skull is elongate with larger orbits and nasal cavity
- more cervical vertebrae ( atlas and axis, nodding and rotation)
- ribs are larger and more protective than amphibians (for turtles they are enclosed in the carapace, snakes have a muscular connection between the ribs and ventral scales for movement)
- limbs are bigger and have better joints and more muscle support
reptile digestive system
- most carnivorous, some herbivorous and omnivorous
- true tongue, protrusible in many
- size of prey based on gape size of mouth
- digestive tube is normal to basic plan
- only modification is venom glands
venom glands
- modified salivary glands in reptiles
- in snakes fangs house the glands
- in lizards grooved teeth dispense the venom
- venom is a modified digestive enzyme for breaking down cells and tissues
- in heloderm lizards and venomous snakes
reptile circulatory system
- similar to amphibians but heart is larger, they have a higher metabolism, higher blood pressure, and higher O2 need
- 3 chambered heart, ventricle is partially divided
- no pseudo-chambers, except turtles which have an SV
- 3 pairs of aortic arches
1. pulmonary
2. dorsal systemic (to body)
3. ventral systemic (to head)
- muscular ridge in the wall of ventricle sections off the ventricle when it contracts, separating oxygen rich and poor blood
- crocs have a completely separated ventricle (4 chambered)
reptile blood flow
right atrium > pulmonary arteries > lungs > pulmonary veins > left atrium > ventricle > systemic arteries > body and head
reptile respiratory system
- no gas exchange through skin
- larger and more complex than amphibians, more surface area for gas exchange
- negative pressure mechanism
negative pressure mechanism
- contraction of internal organs and rib cage/body wall musculature to pull air into lungs
- posterior movement and expansion of wall, pulls air in
- relaxation of muscles of organs and body wall squeezes, forces air out
reptile temperature regulation
- all ectothermic
- cannot contain metabolic heat
- metabolic activity and muscle contractions generate heat
- use behavioral and physiological means to regulate temp
- warming: sunning/basking, pigment cell dispersion
- cooling: shading, panting, blood diversion, torpor
generation of heat
seasonal dormancy, decrease in activity, not the same as hibernation.
site where reptiles spend winter below freeze line in a torpid condition
reptile nervous system
- 25-30: 1 brain to spinal cord ratio
- increased cerebrum, optic lobes, and cerebellum
reptile vision
- increased optic lobes, larger lens, larger orbits, upper and lower eyelids, and nictitating membrane in most
- good color vision
- blood sinus in some lizards
blood sinus
- near eye in lizards, squirts blood on lens to clear it, also used as a defense mechanism
parietal eye
- in reptiles, not an actual eye
- photoreceptor at top of the head to to monitor day length
- thin spot on top of head, with pineal gland just below it
- tuataras have an actual lens on the parietal eye
- for lizards, it helps them orient to the sun
reptile auditory sense
- has a similar inner ear to amphibian
- most have 1 inner ear ossicle
- some have a tympanum
- snakes have no ear opening or tympanum or inner ear ossicle
- vibrations travel from the forelimbs to the skull
- snakes can sense vibrations from the ground through the skull and can pick up high pitch frequencies
reptile olfaction
- larger snout than amphibians, potential for better sense of smell
- squamates have protrusible tongues that pick up chemicals, and jaconsens organ in back of mouth
- tuatara and turtles have tongues with taste/smell center
- pit organs in some snakes
pit organs
- present in pit vipers
- special opening btw the eyes and nostrils, lined with sensory epithelium
- pick up minimal changes in temperature
reptile excretory system
- higher blood pressure, higher metabolism, more blood to filter, and larger body size then amphibians
- still must conserve water
- embryonic reptiles have similar design to fish and amphibians
- have a metanephric kidney
- waste product is uric acid (paste) packaged with feces in cloaca
- salt glands below the eyes secrete ions
- lymphatic sacs in pelvic region and bladder can store water
metanephric kidney
- more advanced and larger then fish and amphibian kidneys
- filters at a higher pressure
- has many more nephrons, so can filter more blood
- drained by ureter
- present in reptiles, birds, and mammals
- longer nephric tubule, can reabsorb more H2O and secrete more waste ions
reptile reproductive system
- oviparous, ovoviviparous, or viviparous
- produce amniotic egg (truly terrestrial egg)
- amniotic egg requires internal fertilization
- all males (except tuatara) have a copulatory organ
- squamates have a hemipene
- crocs have a single shaft
- turtles have a singular lobed shaft
- sperm can be stored 10 yrs or more in females
- some lizards and a few snakes are parthenogenic
- egg shells are leathery for most
- parental care varies
adaptations for flight
endothermy, feathers, acute senses, long flexible neck, lightweight bones, flight muscles, enhanced chest
bird integument
- relatively thin integument
- feathers are the insulatory material (trap the heat produced by flight)
- feathers also act as flight surface and steering apparatus
- feathers form within dermis
- vessels within the feather provide color and nutrients to feather
- keratin gives feather their strength
grooming of feathers with use of preen gland located next to cloaca (used to oil the feathers)
bird skeleton
- skull is lightweight, thin, and has fewer plates
- lack teeth, have a beak instead
- bones are lightweight and strong with air spaces btw bony bars
- pygostyle
- synsacrum and furcula
- sternum is keeled, providing more attachment area for the flight muscles
- appendages are highly modified
- upper arm bones are extended as wings
hardened, keratinized sheath over the jaws and nasal cavity. shape and size of beak and tongue is specialized for that birds diet
fused caudal vertebrae forming a bump at posterior portion of the bone, creating more attachment area for tail feathers
- bird flight muscle
- top, larger muscle 15% of mass of bird
- powers downstroke of wings
- bird flight muscle
- bottom, smaller muscle 10% of mass of bird
- powers upstroke of wings
bird digestive system
- high metabolic rate, endothermy, and flight require a lot of food
- diet is highly varied
- birds have a cloaca
- crop: enlarged lower portion of esophagus (extra storage)
- stomach is in two sections (proventriculus and gizzard)
- cecum: at junction of stomach and small intestine, houses microorganisms
ontogenic shift
in diet of birds. Chicks mainly eat soft bodied vertebrates, no matter what adults of that species eat
bird circulatory system
- similar to crocs
- 4 chambered heart (2 atria, 2 ventricles)
- distinct pulmonary and systemic circuits
- sinous venosus is reduced to a small patch of cells in the right atrium (pacemaker cells)
- heart makes up 4% of body weight
- rapid heart rate b/c of endothermy and high metabolism
bird blood flow
vena cava > right atrium > right ventricle > pulmonary arteries > lungs > pulmonary veins > left atrium > left ventricle > aorta > body
bird respiratory system
- more O2 required for birds
- bird lungs are less than half the volume of mammal lungs but potential air volume is 3x that of mammals
- bird lungs are not blind sacs, it is a flow through system so 25-30% of air is replenished with each breath
- lungs have parabronchi
- air sacs provide extra space to temporarily hold air
- require two ventilation cycles to move a given volume through
- ventilation is aided by the furcula
bird air pathway
external nares > nasal cavity > mouth > pharynx > trachea > syrinx > split of trachea > 2 bronchi > posterior air sacs > lungs > anterior air sacs > trachea > out of mouth/nares
voice box of birds
bird ventilation cycle
inhale 1: air into posterior air sacs
exhale 1: air into lungs
inhale 2: air into anterior air sacs
exhale 2: air out trachea
- constant flow of air through lungs
bird thermoregulation
- endothermic, body temp is around 38 to 45 C
- shivering can produce heat
- moving blood through flight muscles, hormonal stimulation, panting, and arrangement of vessels in legs can generate heat
- counter current heat exchange in hindlimbs
counter current heat exchange in birds
- veins are inside coiled arteries
- arteries carry warm blood from the heart
- veins carry cool blood from the feet
- heat dissipates from arteries into veins to warm the blood moving from the feet to the heart
- very important in cold environments
bird nervous system
- 35:1 brain to spinal cord ratio
- enlarged cerebrum
- well developed pineal gland for photoreception
bird vision
- very large orbits, largest eye to body size ratio of verts
- possibly best color vision of all verts (more cones than rods)
- have nictitating membrane and moveable eye lids
bird olfaction
- probably poorly developed due to less surface area
- can detect heat currents
bird auditory senses
- well developed outer ear opening, middle ear, and ossicle
- inner ear cavity with mass of auditory epithelium
- bird calls are an integral part of breeding so hearing is advanced
bird excretory system
- metanephric kidney, more advanced than reptiles
- birds have higher bp and metabolic rate than reptiles so kidneys have to work harder
- waste product is uric acid (water is reabsorbed and uric acid is packaged with feces for release from cloacal vent)
- supraorbital salt glands release waste ions through nasal openings, important in marine birds
bird reproduction
- all are oviparous
- most males lack copulatory organs
- parthenogenesis has been observed in birds
- in females only one of the two ovaries matures and produces eggs
- egg is fertilized in the upper 1/3 of the oviduct
- zygote is surrounded by albumen as it moves down the oviduct
- shell gland near lower reaches of oviduct secrete shell around egg, albumen, and yolk
- oviduct empties into cloaca
- egg is released out of the cloacal vent
bird breeding
- most birds are monogamous (90%)
- the other 10% are polygamous
one female mates with multiple males
one male mates with multiple females, more birds are polygynous than polyandrous