Lecture 3: What is a vert?

what is a vert?

contains a backbone, vertebral column

what is included in Metazoa? how many phyla? what phyla includes verts?

• metazoa = animal kingdom

• ~35 phyla including Chordata

what 3 subphylums are in Phylum Chordata?

• Urochordata = tunicates, salps (invert)

• Cephalochordata = lancelets (invert)

• Vertebrata = verts

what superphylum is Phylum Chordata part of?

Superphylum Deuterostomia

what are the 5 shared derived characteristics (synapomorphy) of Deuterostomia?

• notochord

• dorsal hollow nerve cord

• segments, muscular postanal tail

• pharynx w/ pharyngeal slits

• endostyle = glandular groove on floor of pharynx for mucus secretion to aid feeding

what are 2 traits that all Chordates have which are not a synapomorphy?

• all chordates have a structure that pumps blood

• bilaterally symmetrical

what 6 synapomorphies/characteristics distinguishes verts?

• vertebrae = form a centrum around notochord and eventually encircles nerve chord

• cranium = skull that surrounds the brain; can be made of bone, cartilage, or fibrous material

• head = prominent head that contains sense organs like eyes, ears, and nose

• tripartite brain = forebrain, midbrain, hind brain

• pituitary gland = produces and regulates hormones (i.e., testosterone, estrogen)

• mineralized tissues = creates structures (cartilage, bone) and surfaces w/ name different degree for resistance to abrasion (i.e., enamel, dentine)

what are the 3 distinct layers of the vert body called, and list and define each layer?

• germ layer = composed of 3 different tissue layers

• ectoderm = outermost layer; forms the skin, linings of digestive tract, majority of nervous system

• endoderm = innermost layer; forms some of the digestive tract, lining of glands associated w/ gut, forms respiratory surfaces of gills, lungs, taste buds, and glands

• mesoderm = middle layer; forms muscles, skeleton, connective tissues, and urogenital systems

what are the 4 main unique developmental features of verts?

• duplication of Hox gene complex

• MicroRNAs

• Neural crest

• epidermal placodes

what is the purpose of duplication of the Hox gene complex?

• controls development along body axis (y-axis)

• allows for increased complexity in body structures

define purpose of MicroRNAs

non-coding RNA sequences that regulate the synthesis of proteins by binding to mRNA and regulate the development of derived vert. structures (i.e., liver, kidneys, etc.)

Neural crest cells

• when are these present in the development of a vert?

• define

• what type of tissue is it found in?

• why are these cells important?

• seen ONLY during the development of a vert.

• neural crest cells = cells that are migratory and multipotent so they have the ability to differentiate into different types of cells

• found in embryonic tissue

• important innovation in origin of vert. body plan

define the purpose of epidermal placodes

thickening of embryonic epidermis gives rise to complex sensory organs (i.e., nose, eyes, inner ear), contributes to lateral line (and cranial nerves innervate it)

what are the 4 main vert. adult tissue types?

• epithelial tissues

• muscle tissues

• neural tissues

• connective tissues

define epithelial tissues

sheets of tightly connected cells that form boundaries b/w the inside and the outside of the body

define muscle tissues

contain filamentous proteins actin and myosin which cause muscles to contract

define neural tissues

includes neurons and glial cells

connective tissues

• what are the 3 functions it provides

• what type of tissues does it include

• what 4 structures are connective tissues found in?

• provide structural support, protection, strength

• includes mineralized tissues = bone, teeth, cartilage

• adipose, blood, tendons, ligaments

what 3 types of bones do verts have

• dermal bone

• endochondral bone

• perichondral bone

• define dermal bone

• provide 2 examples of dermal bone

• formed in skin, but no cartilaginous precursor

• Ex: dermal armour (i.e., exoskeleton), skull bones (dermal in origin) to form shell around brain

• define endochondral bone

• what organisms are these found in?

• made up of osteocytes that form a cartilaginous precursor

• unique to bony fishes and tetrapods (forms internal skeleton)

define perichondral bone

formed deep w/in the body, forms around cartilage or bone

describe the endo and exoskeleton of primitive verts

primitive verts have both bony exoskeletons and cartilaginous endoskeleton

describe how bony fishes and tetrapods skeletons developed?

skeleton laid down in cartilage, and bone replaces later in development

describe how shark skeletons evolved?

sharks secondarily lost bony skeleton, deposits in base of teeth, scales, and in some spp. vertebrae surfaces

define odontodes

• original tooth-like components of ancestral vertebrate dermal armour, homologous w/ teeth

• shark scales have similar structure

compare teeth to bone

harder that bone, more resistant to wear bc they are composed dentine (inner layer) and enamel/enameloid (outer layer)

order in evolution of features for the skeletomuscular system

notochord => gill skeleton => cranium => dermal skeleton => appendicular skeleton

define notochord

act as a dorsal stiffening rod

define gill skeleton

keeps the gill slits open

define cranium

surrounds brain

define dermal skeleton

external plates and axial skeleton (vert., ribs, and median fin supports)

define appendicular skeleton

limbs and limb girdles

in the cranial skeleton, what cell forms the skull and what are the 3 types?

neural crest cells including chondrocranium, splanchnocranium, and dermatocranium

where is the chondrocranium found?

surrounds the brain

what does splanchnocranium form?

forms the gill arches

define dermatocranium

outer covering forming in skin

what are the 3 parts of the brain?

forebrain, midbrain, hindbrain

what are the 2 parts of the forebrain and what is their position?

telencephalon (anterior region) and diencephalon (posterior region)

describe 3 traits that are part of Telencephalon

• olfactory capsules

• enlarges in cerebrum

• neocortex = sensory integration and nervous control (region of cerebrum)

describe 2 traits of the diencephalon

• pituitary gland, hypothalamus (floor) = neural-hormonal coordination and integration

• pineal organ = photoreceptor, hole in skull admit light (pineal eye) like a sky light

what type of nerve is found in the midbrain?

optic nerve (non-mammals)

what are 2 parts of the hindbrain?

• medulla oblongata (myelencephalon) = respiration, relay station for inner ear

• cerebellum = coordinates and regulates motor activities

what type of muscles can be found attached to the notochord/vertebrae

segmental muscles and connective tissue

• describe segmentation of axial musculature

• describe the locomotion of axial musculature

• describe the limbs used for axial musculature

• segmented myomeres, segmented in W pattern

• locomotion via serial contractions of segmented muscle bands and tail fin swimming

• paired fins for steering, braking, and lift

what are the 4 basic vert systems?

alimentary system, cardiovascular system, excretory and reproductive systems, sense organs

what is the alimentary system used for?

feeding and digestion

what is the cardiovascular system used for?

what is the type of circulatory system in verts?

blood carries oxygen and nutrients through vessels to the cells of the body, removes CO2 and waste products, stabilizes the internal environment

• circulatory systems are CLOSED in verts

what 2 structures are included in the excretory and reproductive systems?

includes kidneys and gonads

what are the 7 parts of the vert sense organs?

• gustation - taste

• olfaction - smell

• vision - similar eye type in all verts

• electroreception - perceive electrical impulses generated by muscles of other organisms (only works in waters: fishes, monotremes)

• mechanoreception - lateral line system

• balance and orientation - inner ear

• tetrapod hearing - inner are associated w/ the evolution of vocalization

what is the ancestral form of vert. respiration and ventilation

O2 absorption and CO2 diffusion across skin

what is the aquatic and terrestrial form of vert respiration and ventilation

gills (aquatic) and lungs (terrestrial)

what respiration structures did Early Osteichthyes have?

had lungs to supplement gill respiration

where did swim bladders evolved?

swim bladders evolved from lung

how do surface areas affect vert respiration?

surface areas large enough to allow O2 diffusion from air into blood

what is the relationship b/w arteries and capillaries?

arteries are connected by capillaries

define arteries

carry blood away from heart

define veins

return blood to the heart

list and define the 3 chambers of the heart?

1. sinus venosus = thin walled sac

2. atrium = blood sucked intro from sinus venosus

3. ventricle = thick muscular walls in which contraction forces blood into ventral aorta

what organism has a 4 chambered heart and what is the 4th chamber?

Gnathostomes have a 4th chambered heart = conus arteriosus

define aorta

primary artery that receives blood pumped from the heart (ventral aorta) and shunts to gills

what are the 2 main things capillary beds are composed of?

what is its purpose?

composed of a net of arterioles and venules - exchange nutrients b/w blood and tissues

define portal vessels

blood vessels b/w 2 capillary beds

compare the pump of a human heart to a fish heart

fish hearts are 1 pump which goes directly to the body while in humans have a double pump system in which ½ of the pump goes to the lungs while the other ½ goes to the body

what organ is part of the excretory system

kidney

what is the function of kidneys

dispose of nitrogenous waste via urea, uric acid, and urine from protein metabolism (aka breakdown of proteins) and regulates body’s water and minerals (i.e., sodium, chloride, calcium, etc.)

why do we need to get rid of nitrogenous waste?

bc very TOXIC

list and define the important structure in kidneys?

Nephrons = specialized structures that allow for ultrafiltration in which high blood pressure forces water, ions, and small molecules through a tiny gap in capillary walls

what is the function of gonads?

make haploid gametes including eggs from ovaries and sperm from testes

describe the transportation of gametes, describe the specifics for transports sperm and eggs

gametes are transported to cloaca via specialized ducts

• sperm is directly released into archinephric ducts (from kidneys) to cloaca

• egg is released into coelom but then transported to oviducts

list and define the 3 types of major reproductive life history w/ organism examples

1. ovipary = release eggs that develop and hatch externally (i.e., most fish, reptiles, birds, and monotremes)

2. ovovivipary = producing eggs that are hatched w/in the body so that the young are born alive but w/out placental attachment (certain reptiles or fishes)

3. vivipary = giving birth to live young rather than eggs (most mammals and some reptiles and fish)

what is the system for smell?

somatic sensory system = senses chemicals at a distance, sensations received in forebrain

what is the system for taste?

visceral sensory system = sensing items upon direct contact w/ sensations received initially in hindbrain

what is the system structure for vision?

• retina = hemispherical sheet

• light sensitive cells = cones and rod which differ in concentrations across animals

for the hearing system

• function of inner ear?

• what organisms have a cochlea? what organisms have a lagena?

• what does the cochlea and vestibular apparatus form?

• how do sound waves travel in the inner ear?

  • structure in whales and dolphins that aid in this?

• the inner ear receives sound waves

• cochlea is found in tetrapods only; lagena is found in non-mammalian tetrapods

• the cochlea and vestibular apparatus form a membranous labyrinth

• sound waves create waves of compression inside the cochlea that passes through the endolymph

  • in whales and dolphin (bc do not have external ear), the sound waves travel to the pan bone which is an acoustic window on the jaw allowing sound to get to the inner ear

what are the 4 main sensory structures for balance and orientation?

inner ear, hair cells, sacculus and utriculus, semicircular canals

how does the inner ear contribute to balance and orientation?

contains the vestibular apparatus which detects the animal’s position in space

how do hair cells contribute to balance and orientation?

basic sensory structure - detects movement of fluid (endolymph) either from change in position or impact of sound waves

how does the sacculus and utriculus contribute to balance and orientation:

• what are their structures and where are they located?

• what do they contain?

• what do they detect?

• both are fluid filled sacs in ears

• contain maculae and crystals of calcium carbonate resting on hair cells and otoliths

• detects which way is up and linear acceleration

how do semicircular canals contribute to balance and orientation?

swellings (Ampullae) detect angular acceleration through cristae (hair cells embedded in jellylike substances)

what are 2 types of extra sensory organs?

electroreception and mechanoreception

Electroreception

• where does it occur?

• what is it used for?

• what is the main structure?

• electroreception is only used in aquatic environments

• used for distance reception

• structure = Ampullae of Lorenzini (for Chondrichthyes)

Mechanoreception

• what is its use?

• what is the main structure?

• mechanoreceptions detects the vibration of water to aid in spatial awareness, predator avoidance, and schooling behavior

• main structure = lateral line = contains hair cells which aggregate into neuromast organs to detect water displacement which enters into the body through small external openings along the lateral line