Pre Midterm Lecture Notes Flashcards
what does diffusion require?
- large surface area between environmental medium and blood
- thin barrier
- effective ventilation
What is the fish gill designed for?
gas exchange in water
What are the closest relatives to the phylum chordata?
- phylum hemichordata (acorn worms)
- phylum echinodermata (star fish)
what makes up the deutrostoma?
chordata, hemichordata, echinodermata
why is the phylum hemichordata considered closely related to the chordata?
they share pharyngeal gills
what is the phylum echinodermata?
marine deuterostomes with radial symmetry as adults, bilateral symmetry as larvae
what are the 3 subphyla of the phylum chordata?
Urochordata, cephalochordata, vertebrata
5 characteristics of chordates
notochord dorsal, hollow nerve cord pharyngeal slits postanal tail endostyle/thyroid gland
describe the structure of the notochord
- fluid filled elastic rod
- dorsal to gut tube and ventral to the nerve cord
what is the function of the notochord?
- keeps body straight
- prevents collapse during muscle contractions
- promotes/organizes embryological development or nearby structures
what takes over the function of the notochord in more recently evolved species?
the vertebral column
how is the hollow nerve cord formed?
formed by invagination of the surface cells in embryo
true or false: the neural tube is dorsal to the gut tube
true
describe the structure and location of the pharyngeal slits
- located in pharyngeal area of digestive tract begin oral cavort
- slits form in wall of pharyngeal pouch
What is the function of pharyngeal slits in aquatic species
slits and pouches create water current between mouth and pharynx for feeding and respiration
What is the function of pharyngeal slits in terrestrial species
transient embryo structures and slits not opened in pouch all
describe the structure of the postanal tail
located posterior to anus
what is the function of the postanal tail?
swimming
describe the structure of the endostyle
granular groove on the floor of the pharynx
what is the function of the endostyle
- secretes mucous
- traps food particles
- involved in iodine metabolism
what is the endostyle an early version of
the thyroid gland
What era were the oldest vertebrates found?
early Cambrian (540 mya)
what are the 5 major innovations of vertebrates?
- vertebral column
- head: cranium & brain
- jaws
- paired limbs
- cleidoic egg
what is the head derived from?
neural crest cells and ectodermal placodes
what is the cleidoic egg?
new membranes isolate the embryo within a fluid filled compartment in the egg
provide gas/nutrient exchange
what is the process of development?
- cleavage
- gastrulation and neurulation
- differentiation and organogenesis
what is cleavage
single cell to multiple cells
what is gastrulation and neurulation?
cells organize into germ layers
formation of early gut
formation of neural tube
what is differentiation and organogenesis
cells organized into germ layers
primary tissue types generated from germ layers
3 germ layers
ectoderm
mesoderm
endoderm
4 primary tissues types from germ layers
epithelial
connective
muscle
nervous
what is the neural crest
“4th germ layer”
gives rise to variety of structures
arises from delamination from the neural tube and peripheral migration
what are ectodermal placodes
arise from thickenings of the surface ectoderm and cavitation
gives rise to sensory organs and receptors
what is an Agnatha?
a jawless fish
mouth present but no biting apparatus derived from pharyngeal arches
what are the 2 extant groups of agnathas?
hagfishes and lamprey (cyclostomes)
what are 2 extinct groups of Agnatha?
conodonts and ostracoderms
what are some characteristics of hagfishes?
-no jaws, fins, or image forming eyes
-multiple venous hearts
-single nostril
cartilaginous skull but rudimentary vertebrae
-large slime glands
what are some characteristics of lamprey?
- marine or fresh water
- cartilagenous skull and vertebrae
- no jaw
- single nostril
- dorsal unpaired fin
- image forming eyes
- parasitic
characteristics of conodonts
- extinct
- known originally from tooth-like elements
- marine and diverse
- chordate and vertebrae characteristics (notochord, myomeres, postanal tail)
characteristics of ostracoderms
small jawless
- lateral line system
- outer exoskeleton of dermal bone plates
when did jaws first begin evolving?
Devonian era (390 mya)
what did jaws evolve from?
the first branchial arch
- upper element: palatoquadrate
- lower element: Meckel’s cartilage
what are the 3 main groups of gnathostome fish?
placodermi (extinct)
Chondrichthyes
Osteichthyes
characteristics of placodermi
- heavy head, thoracic armour, naked body
- jaws with beak like plates
- paired pectoral and pelvic fins
- dominated Devonian
- extinct
characteristics of Chondrichthyes
- cartilaginous fishes - calcified skin
- placoid scales
- internal fertilization
- presence of spiracle
main types of chrondrichthyes
- chimaeras
- elasmobranchs (sharks, rays and skates)
characteristics of sharks
- jaws not attached to skull
- chemoreceptors and electroreceptors
- no swim bladder (liver and motion)
characteristics of stingray, electric ray, skates
- flattened body
- pectoral fins modified to become wing-like appendages
characteristics of Osteichthyes
- bony fish
- much more bone in endoskeleton
- swim bladder to control buoyancy
- swim with help of strengthened fins
what are the 2 main groups of Osteichthyes
actinopterygii (ray finned)
sarcopterygii (lobe finned)
what species are included in the actinopterygii?
- sturgeons and paddlefish
- garpike
- bowfins
- teleosts
characteristics of sarcopterygii
- lobe fin appendages
- internal bones and muscles
- fins have rays at the end
2 living groups of sarcopterygii
- lungfishes
- coelancanth
characteristics of lungfishes
- pair lungs - modified swim bladder
- dry sleep
what is the Tiktaalik?
-shows intermediate characteristics between fish and tetrapods
-limb like pectoral fins
function wrist joints and mobile neck
- no bony gill coverings
what is a skeleton
composed of bone, cartilage, ligaments, and tendons
what is the function of the skeleton?
- supports weight and protects soft parts
- anchors muscle movements
- stores minerals (Calcium)
what are the main components on the skeleton?
- head/ skull (cranium)
- axial skeleton (vertebral column, ribs, sternum)
- appendicular skeleton (girdles, fins/limbs)
what are the 3 components of the skull?
chondrocranium
splanchnocranium
dermatocranium
true or false: Agnatha species without armour have all 3 components of the skull
false: missing dermatocranium
true or false: Agnatha species with armour have all 3 components of the skull (ostrachoderm)
true
describe placoderm skull
- presence of jaw (Meckel’s cartilage and palatoquadrate)
- well developed dermatocranium
describe teleost skull
- all 3 components (neurocranium very small)
- increased # of bones, reduces connections
- increased manoeuvrability in jaw
- diverse bone size and number
diverse feeding mechanisms
what was a major innovation in teleost skull?
suction feeding
describe early gnathostomes mouths
- wide mouths
- hinge far back
- upper jaw fused with brain case
describe teleosts mouths
- narrow mouth
- hinge moved forward
- upper and lower jaws can move independently of brain-case
what is suction driven by?
volume change of orobranchial chamber
autostylic
- upper jaw braced against the brain case
- no hyomandibula role
- found in placoderms and lungfishes
amphistylic
- hyomandibula bone (2nd arch) acts as strut to help brace jaw along with brain case
- found in some shark and coelacanth
hyostylic
mandibular arch supported primarily by hyomandibula
-found in most bony fish and sharks
what is axial skeleton composed of?
- vertebral column
- centrum: body
- neural arch: protects spinal cord
- hemal arch: protects blood vessels
- processes
characteristics of fish axial skeleton
- fixed link between 1st vertebra and skull
- amphicoelous centra and no zyapophyses
-reginal differentiation
movement by lateral undulation
components of appendicular skeleton
appendages: paired fins or limbs
girdles: braces that support paired appendages
3 types of paired fins
lobe fins: fleshy, lungfish
fin fold fins: broad base, cartilaginous fish
ray fins: most bony fish
function of paired fins
stability, fine control when mobile
medial fins: where and function
dorsal fin, anal fin
keep body from rolling over
caudal fin function
add to propulsion in lateral undulation locomotion
fin characteristics
- membranes strengthened by bones and flexible rays
- rigid spines can also be present
elasmobranch fin rays
keratinized rods
bony fish fin rays
bone/cartilage elements and keratinized tips
pectoral girdle in sharks
- right and left halves fused in midline
- not joint to skull
pectoral girdle in teleosts
joint to skull via cleithrum bones
what is the basic structure of the integument?
- epidermis
- dermis
- hypodermis
true or false: all vertebrates have all 3 layers of skin
false: hypodermic may not be present
what did ectoderm become?
epidermis
what did mesoderm become?
dermis
what did neural crest become?
pigment cells
inside layer of epidermis name and function
stratus germinativum
makes new cells
outside layer of epidermis name and function
stratum corneum
keratinized for water proofing
middle layer of epidermis name and function
stratum granulosum
receives pushed up cells from inside layer
what are the 2 layers of dermis
vascular stratum spongiosum (pigment cells of chromophores)
thicker stratum compactum (lots of fibres)
what does the dermis include?
- A network of fibres (collagenous and elastic) for strength
- Small nerves, blood vessels
- Connective tissue to hold everything together
what does the hypodermic often contain?
fat cells for insulation and energy storage
functions of the integument
-protection
- osmotic regulation, excretion, respiration
- thermo regulation
colouring for defence/mating
-locomotion
what does mucous do?
- prevents entry of foreign materials
- reduces drag
- may include substances toxic to predators
stratum corneum function
provide protection against desiccation
stratum corner derivatives
scales, feathers, hair, claws, (keratin-based)
what are fish scales made of
- bone covered by the thin epidermis
- Sometimes coated with hard enamel (from epidermis)
- Deeper layer of dentin (from dermis)
what are teeth of modern tetrapods derived from?
ancient fish scales
true or false: enamel is epidermal in origin
true
true or false: dentine and bone is hemal in origin
true
what are placoid scales?
- Aka dermal denticles
- Protrude through epidermis
- Could organize water flow on skin to reduce drag (scales oriented posteriorly)
where are placoid scales found?
cartilagenousfishes (sharks and rays) so no bone
what are ganoid scales?
- Ganoin is a thick coat of enamel
- Dentin is lost
- Thick layer of lamellar bone
- Loss of vascular bone
- Entire structure covered by thin epidermis
where are ganoid scales found?
sturgeons,
paddlefish,
garpikes,
bowfins
what are elasmoid scales?
- Loss of enamel
- Made up of lamellar bone (relatively thin)
- Intermediate types exist
where are elasmoid scales found?
teleosts
where are cosmic scales found?
ancient fish (amour)
what was the first tetrapod?
Titaalik
who gave rise to modern amphibians?
- temnospondyls
temnospondyls characteristics
- extinct
- body robust
- flat skulls
- Occupied a wide range of ecological niches
- Some capable of excursions or life on land
lepospondyls characteristics
- Diverse small tetrapods
- Occupied specialized ecological niches
what did fins become in tetrapods?
chiridium
what 7 structural changes had to happen for fish to become tetrapods
- fin to chiridium
- evolution of true neck
- reinforced vertebral column and girdles
- Back part of the skull is shortened and hyomandibulais no longer attached to the oticcapsule
- Snout elongates and eyes move to top of the head
- reduction in skull bones
- Modification of dermal scales of fish into scutesor gastralia: cover only the belly in tetrapods
what is the chiridium?
muscular limb with well-defined joints and digits
true of false: there was a change in angle between humerus and radius between fish and tetrapods
true
what was involved in the evolution of a true neck?
- Loss of bones covering gill chamber in fishes
- Loss of bones that joined the shoulder to back of skull roof in fishes
- space between skull and shoulder
what change to the vertebrae happened when fish were evolving to tetrapods?
- Centra become more ossified
- Zygapophyses appear so that the vertebral column can help keep the body off the ground
tetrapod girdles vs. fish girdles
tighter binding between girdles and spine in tetrapod
how is brain case supposed in tetrapods?
supported by connection with room of mouth
what does the hyomandibula function become in tetrapods?
stapes (hearing)
are hyomandibula and stapes homologous or analogous
homologous
how do tetrapod skull bones change from fish skull bones?
- Fusion of small bones in nasal region (anterior)
- Loss of bones in opercular region (posterior)
what did dermal scales of fish become in tetrapods?
- scutes or gastrali
- cover only the belly
why don’t most tetrapods have scales on land?
- heavy
- cause issues with respiration
What structural changes might accompany improved locomotion on land?
- clavicle got bigger
- cleithrum shrunk
How did early tetrapods move?
- limbs and girdles were too small and poorly ossified for walking on land
- Limbs likely used as points of pivot to support lateral flexions of the body in shallow water
what challenges did transitioning vertebrates face
- Movement
- Respiration
- Sensing the environment
- Feeding, osmoregulation and reproduction
what fishes did tetrapods arise from?
sarcopterygian fishes
what is a tetrapod?
Vertebrates that possess a chiridium
what is the Acanthostega?
- a late Devonian early tetrapod
- have 8 fingers and 8 toes
- girdles designed to bear weight
- Tail with fin rays and internal gills suggest it was aquatic
what is a Ichthyostega?
- Late Devonian early tetrapod
- Lacked internal gill
what do fish require for good blood flow?
- Large surface area
- countercurrent exchange between blood and water
- thin water-to-blood barrier
what are the 3 types of internal gills?
- pouched gills of lamprey
- septal gills of shark
- opercular gills of teleost
what is unique about septal gills of shark?
Each individual septum protects each gill chamber
what is unique about pouched gills of lamprey
no gill covering
what is unique about opercular gills of teleost
- Reduction of number of gill bars and chambers
- Loss of spiracle and loss of septa
how do lamprey gill ventilate?
tidal ventilation through a compression/expansion of branchial cavity –mouth often attached to host
how do active fish gill ventilate?
- use ram ventilation –keep mouth open while swimming
- Most common is the dual pump
Gill ventilation: dual pump 2 phases
suction pump phase
pressure pump phase
explain the suction pump phase
- mouth open
- negative pressure
- opercular valve closed
explain the pressure pump phase
- mouth closed
- positive pressure
- opercular valve open
where do the gas bladder and lungs come from?
- Develop from out pocketings of pharynx
- Endodermal in origin
describe the gas bladder
- Single elongated sac that is dorsal to the gut
- Used for buoyancy –control position in water column
- Can also be used for respiration (respiratory gas bladder) as well as sound production and reception
where are the lungs located in fish?
ventral to the gut
gas bladder filling: physostomous
- connected to pharynx
- can be filled by gulping air in the digestive tract
gas bladder filling: physoclistous
- filled by gas gland, emptied at oval window
which is more efficient for respiration? unidirectional or bidirectional
unidirectional
describe the vertebrates circulatory system
- Closed system of connected ducts:
- Lots of individual/species variation
- system extremely adaptable - capacity for repair
- compensation for damage
- quick response
general components of the circulatory system
- cardiovascular system (heart, blood vessels, blood)
- lymphatic
4 chambers of the fish heart in order
- sinus venous
- atrium
- ventricle
- conus arteriosus/blubus arteriosus
how does the fish heart work?
- single circuit pump
- pumps deoxygenated blood in one direction
describe cartilaginous fishes hearts
- large conus arteriosus
- muscular and active as pumping organ
describe teleosts hearts
- highly elastic bulbus arteriosus in place of conus
- Keeps consistent flow to arches despite pressure generated by beating heart
how many pairs of aortic arches do lamprey have
8
how many pairs of aortic arches do hagfish have
15
how many pairs of aortic arches do Chondrichtyans and sarcopterygians have
5
how many pairs of aortic arches do Actinopterygians have
4
explain lungfish heart and aortic arches
- Partially divided atrium and ventricle (septa)
- Division extends into the conus by spiral fold valve
- Greatly reduces mixing of deoxygenated and oxygenated blood
- Deoxgenated blood to gills and then lungs
Which of the following is NOT one of the five characters of chordates? A. notochord, B. dorsal hollow nerve cord, C. vertebral column, D. gill pouches or slits, E. postanal tail
C. vertebral column,
Considering only extant species, which of the following groups has the highest species diversity? A. mammals, B. birds, C. squamates (lizards and snakes), D. actinopterygians, E. chondrichthyans
D. actinopterygians,
the selective advantage of the early jaws is likely:
A. improved respiration efficiency,
B. improved feeding efficiency,
C. expanded mandibular arch, D. strengthened muscles encircling the pharynx
A. improved respiration efficiency,
. Which of the following groupsis jawless? A. Ostracoderms, B. Chondrichthyans, C. Osteichthyans, D. Placoderm
A. Ostracoderms,
Sharks and rays are part of this group: A. Chondrichthyans, B. Osterichthyans, C. Actinopterygians, D. Sarcopterygians, E. Acanthodians
A. Chondrichthyans,
The majority of today’s fish species belong to this group: A. sturgeons, B. teleosts, C. sharks, D. Dipnoi
B. teleosts,
The common ancestor of chondrichthyans may have lost this part of its skull during the evolutionary processes: A. chondrocranium, B. dermatocranium, C. splanchnocranium, D. mandibular arch
B. dermatocranium,
From your understanding of the general composition of the vertebrateskull, a bone located on the outersurfaceof the skull is most likely developed from this part of the cranium:
A. chondrocranium,
B. splanchnocranium,
C. dermatocranium
C. dermatocranium
which of the following structures is part of the earliest jaw (in an evolutionary sense)? A. Meckel’s cartilage, B. hyomandibula, C. oral cartilage, D. cleithrum
A. Meckel’s cartilage,
Modern sharks have this type of jaw suspension, which allow sharks to have wide gape: A. hyostyly, B. amphistyly, C. autostyly, D. paleosty
A. hyostyly,
ancient fish scales contained four distinct layers: lamellar bone, vascular bone, dentin and enamel. Modern sharks and teleosts have evolved very different scales. Which layer do they share? A. lamellar bone, B. vascular bone, C. dentin, D. enamel, E. none
E. none
Fish integument systems generally have none or little of this component: A. stratum germinativum, B. stratum corneum, C. stratum spongiosum, D. stratum compact
B. stratum corneum,
fish scales are developed from this germ layer: A. endoderm, B. mesoderm, C. ectoderm, D. neural crest
B. mesoderm
Lampreys have this type of gills: A. pouched gills, B. septal gills, C. opercular gills, D. external gills
A. pouched gills
The fish heart is a single-circuit pump. The direction of blood flow through the heart chambers is: A. sinus venosus-atrium-ventricle-conus B. conus-atrium-ventricle-sinus venosus C. sinus venosus-ventricle-atrium-conus D. conus-ventricle-atrium-sinus venosus
A. sinus venosus-atrium-ventricle-conus
Which of the following groups uses adual pump to ventilate their gills? A. hagfishes, B. lampreys, C. teleosts, D. amphioxus
C. teleosts,
acanthostega is considered a well-developed tetrapod because it has \:A. well-developed joints and digits, B. fully terrestrial, C. well-developed vertebral column, D. lungs.
A. well-developed joints and digits,
from water to land represents a major transition in vertebrate evolutionary history, and many structural changes occurred during the transition. Which of the following structures is NOT part of these changes:
A. lung,
B. true neck,
C. chiridium,
D. zygapophysis,
E. joint between pelvic girdle and vertebral column
A. lung,
Tiktaalik represents a transitional form of vertebrates from water to land. It possesses this (these) structure(s) that resemble a tetrapod: A. a functional wrist joint, B. a mobile neck, C. lack of gill cover, D. all of above
D. all of above
Most of the vertebrate muscle tissues develop from this germ layer A. endoderm, B. mesoderm, C. ectoderm, D. Neural crest
B. mesoderm
Many vertebrate structures that are used for terrestrial life were first evolved in an aquatic environment. Which of the following structures was evolved on land? A.lungs, B. paired appendages, C. true neck, D. cleidoic egg
D. cleidoic egg
TV news reported a mammal-like living species from the Amazonian jungle, which has an endoskeletal vertebrate column, three girdles, and three pairs of paired limbs. Based from what you have learned in class, you would consider this report:
A. a major discovery,
B. doubtful but deserves a serious second look,
C. a hoax.
C. a hoax.
