Bisc 316 Flashcards
Characteristic of Cartilage
- Chondrocytes (Mesenchyme cells) secrete chondromucoprotein
- Have less salt than bones - less rigid than bone
- Cells lack canaliculi
- Commonly found in embryos and young vertebrates
What are the type of Bones?
Dermal Bones
Replacement Bones
What is a Dermal Bone?
Bones of the skull is an example
Forms directly from mesenchyme (called osteoblast)
Thin plates of collagen matrix; salts is deposited
As the bone grows, the plate expand outer margin and thickens by adding new layers on inner & outer surface
What is the replacement bone?
Bone that replaces cartilage
Osteoblasts (Mesenchyme) enter along the blood vessels.
This is typical of long bones in vertebrates
Bone can also be added to the margins & outer surface end of bone cartilage & notochord.
What are the three types of Mineralized Tissues?
Bone
Dentine
Enamel
Dentine and Enamel don’t support the body
What is Dentine Tissue?
A mineralized tissue that defines the boundary between ectoderm and mesoderm.
Secreted by odontoblasts
It is internal to enamel and external to bone
It is harder than bone
Has inorganic salts of hydroxyapatite
What is Enamel?
Hardest tissue in the vertebrate body
Produced by ectoderm on top of dentine
No internal cells - so its a dead tissue
What are the 4 layers of dermal scales?
Lamellar bone - forms the base and contains a few blood vessels
Vascular layer - where the blood vessels go through
Dentine - Above the vascular layer
Enamel - Cap
What is the Super Class of Jaw Mouths called?
Gnathostomata
The 4 clades of Gnathosomes
Placoderms
Acanthodians
Chondrichthyes
Osteichthyes
Characteristics of Placoderms
Jaws but no true teeth Paired appendages with girdles Have neural and hemal arches (vertebrae) Gas bladder Heavy armor There are gaps in bony plates that allow for head articulation - allowing jaws to open wider and for jaw protrusion Have protrusible jaws
Characteristic of Modern Radiation
Hyostylic Jaw Suspension Teeth single cusp or flat crown Notochords are reduced to discs Complete pectoral and pelvic girdle Fins are narrow based Have claspers Full functioning vertebrae
What did the Elasmobranchii split into during the Jurassic?
Selachii
Batoidea
Characteristic of Holocephali
Has a subclass called Chimaeriformes Autostylic No teeth, but with plate to manipulate food Single gill opening Fnalike pectoral fins Oviparous
3 Major Radiation of Elasmobranchii
Paleozoic
Early Mesozoic
Extant Radiation (Jurassic)
Define Paleozoic Radiation
Early Sharks Notochord is continous Beginnings of the early centrum No pectoral girdle Amphistylic Jaw Suspension Teeth had 3 cusps No claspers Broad attachment to paired fins
Structure of the vertebrate
Centrum - The main supporting part of the vertebrate
Hema Arch - Only found in the tail
Neural and Hemal Spine - the function is to increase surface area for muscle attachment
Apophyses - Projection off the neural arch that help lock the vertebrate together
Advantages of the vertebrate
Stronger and more flexible than the notochord
Greater lateral movement then compared with a notochord
Prevents collapse during movement
Solid surface for muscle attachment
2 Subclasses of Chondrichthyes
Elasmobranchii
Holocephali
How many orders are there in Elasmobranchii
2 Living and 2 Extant
Characteristics of Chondrichthyes
Placoid Scales Cartilagenous Skeleton Spiracle Gill Openings No lung or gas bladder; liver for buoyancy Claspers that faciliate internal fertilization Teeth in replacement family Claspers
3 Major Radiation of Elasmobranchii
Paleozoic
Early Mesozoic
Extant Radiation (Triassic)
Define Paleozoic Radiation
Early Sharks Notochord is continous Beginnings of the early centrum No pectoral girdle Amphistylic Jaw Suspension Teeth had 3 cusps No claspers Broad attachment to paired fins
Define Early Mesozoic
Hemal Arch added Amphistylic Predatory Type Teeth Claspers Still no pectoral girdle Narrow based paird fins
Define modern/extant radiation
Hyoidstylic Jaw Suspension
Protrusible Jaw
Notochord constricted to form discs
Two types of drag
Viscous Drag
Inertial Drag
What is Viscous drag?
A boundary layer is created as layers of water (lamina) moves pass each other
Creates a shearing force where the faster the fish is moving, the thicker the boundary layers will be
Eddies created in boundary layer, and when the amount of eddies increase, it increases the amount of drag
What is Inertial drag?
Vacuum created as water is dispalced
Water flows in to replace the displaced water and creates inertial drag
Characteristic of Osteichthyes (Bony Fish)
Bony Skeleton Dermal Bone where the teeth is attached to bones of jaws Possession of three types of scales: Cosmoid Scales, Dermal Scales, and Elasmoid Scale Hyostylic Jaw Suspension Internal Support for the fins Primitive forms have hypercercal tails Modern ones have homocercal tail Diverticulum
What is diverticulum?
Lung or gas bladder that control the amount of gas inside the body which help it control its natural buoyancy
What are the three types of fish scales?
Cosmoid Scales
Ganoid Scales
Elasmoid Scales
What is a cosmoid scale?
Bone, dentine, and enamel
What is a ganoid scale?
Bone and enamel
What is a elasmoid scale
Bone and very thin layer of enamel
What class and subclass does ray fin fish belong to?
Class - Osteichthyes
Subclass - Actinopterygii
What class, subclass, and order does lobe-finned fish belong to?
Class - Osteichthyes
Subclass - Sarcopterygii
Order - Crossopterygii
What are the 3 major group of Actinopterygii?
Infraclass Chondrostei
Series Holostei
Series Telostei
What is the trend that we see in Actinopterygii?
Reduction in the amount of bone
Oversimplification of scales
Improvements in feeding mechanisms
Tail changes from hypercercal tail to homocercal tail
A ratio of 1:1 fin rays to radial fins
Increased flexibility and movement of fins
What order, class, and subclass does the lungfish belong in?
Order - Dipnoi
Subclass - Sarcopterygii
Class - Osteichthyes
Characteristics of the fossil form of dipnoi
Elongated bodies Thick cosmoid scales Hypercercal tails Unconstricted Notochord Amphistylic
Characteristics of the modern form of dipnoi
Decrease in ossification Autostylic Homocercal tail Lungs with diverticulum Aestivation Unconstricted notochord
Oldest fossil of Fish - The first known vertebrates
Myllokuminigia
Haikouichthyes
Characteristics of the first known fish
Jawless W-shaped myomeres No Bone No Mineralized Scales Ventralateral fins Cartilaginous Gill Supports
Characteristics of Cephalochordata
No paired fins - so most buried in mud
Notochord
No Cranium
No heart - Has contractile vessels
No respiratory pigment or blood cells
Stiffened cirri to filter out large food particles
Pharyngeal Slits for feeding and not for respiration
Characteristics of Urochordata
Sessile Closest to vertebrates Pharynx is an enlarged set of internal gill Inhalant and Exhalant siphons Notochord Pharyngeal Slits Dorsal Hollow Nerve Cord Muscular Post Anal
What is paedomorphosis
Process of being sexually mature while having larval characteristics
What are Hox genes?
Genes that are master regulators of development
Highly conserved in evolution where it is expressed in both embryo and adult
Number of Hox genes tend to increase with increased complexity
What are the two possible explanation as to why vertebrates are much more complex than invertebrates?
Hox Gene duplication
miRNA - where >50 families have evolved in vertebrates. Many of these families are associated with specific tissues
What is taxonomy?
The naming and classification of species
What are the two approaches to classification in phylogeny?
Phenetics
Cladistics
The 9 classes of vertebrates
Agnatha Placodermi Chondrichthyes Acanthodii Osteichthyes Amphibia Reptilia Aves Mammalia
What is a paleoclimate?
Condition, particularly the climate, under which organisms evolved
Who is Alfred Wegner?
The person who proposed the theory of continental drift
What are the 3 eons of the Precambrian?
Hadean, Archeon, Proterozoic
HArchPro
Phanerozoic Eon
Where fossil records were first visible
99% of all fossil records
Proterozoic Eon
First fossil record which were more complex than bacteria
Production of oxygen as waste product
Multicellular Organism
Large continental blocks
Soft-bodied organisms that were capable of secreting “articulating body parts” where it was fossilized and giving us a record
What is the earliest vertebrate?
Agnatha
What are the three major groups of Agnatha?
Cambrian Agnathans
Ostracoderms
Cyclostomata
What are the characteristics of Haikouichthys?
Vertebrate characteristic Cranium W-shaped myomeres Notochord with vertebral elements Sense organs clustered around the head region No bone or mineralized scales
What are the cambrian agnathans?
Haikouichthys
Myllokuniminigia
Conodonta
Characteristic of Conodonta?
Vertebrate Characteristic
Fin rays in caudal fins
Apatite in conodont elements
Muscular pharynx that are used for feeding and not for respiration
Characteristic of Ostracoderm?
Jawless Fish Possession of dermal bone Cerebellum No jaws Midline dorsal fin, and then a more derived feature of paired appendages arised based off of dermal armour Muscular Pharyngeal Pump Internal Gills 2 semi-circular canals
2 Classes of Ostracoderm?
Pteraspida
Which had 2 nasal openings
Cephalaspida
1 nasal opening
Characteristic of Pteraspida
Dorsal Spine Head shield of fused body plates Post-cranial exoskeleton No paired appendages/dorsal/anal fins Mouth bordered by 2 oral plates Hypocercal Tail
Evolutionary Significance of Pteraspida?
Improved moving efficiency
Increased feeding efficiency
Characteristic of Cephalaspida?
Heavily armored; head shield and smaller plates on body
Fusiform or flattened body
Hypocercal tail; some hypercercal tail
Stabilizing projection or fold
Adaptation of Ostracoderm
3 Different Tail Shape
Bony Flanges that are appendages
Branchial Basket - increase feeding ability and respiration
Evolved electric organs and lateral line system
Characteristic of Hagfish
Vertebrate rudiments in tail (Hemal Arch)
Scaleless
2 multicusped horny plates border on side of tongue-like structure
A primitive kidney
Blood osmotic concentration very similar to seawater
Only living vertebrate to have an accessory heart; aneural
Marine bottom feeding scavengers
Characteristic of Lampreys
Anadromus Parasitic 2 Semi-circular canals 7 pairs of gill pouches Primitive nervous system Reduced neural arch
What is the use of chlorine in kidneys and liver?
To regulate ions, water, and nitrogenous waste , enabling it to survive in a variety of salinities
Characteristic of Placoderm
Bony armor with gaps for articulation Paired appendage Gas bladder Neural and Hemal Arch Jaws (No True Teeth)
Characteristic of Acanthodii
Spiny Fish
Many fins
Large notochord
Difference between Acanthodii, Placodermi, and Ostracoderms
Jaws Paired fins with girdles Vertebrae Spiral Valve in Small Intestine Renal Portal System Oviducts and Mesenephric Ducts Pancreas with endocrine and exocrine functions Spleen
What is the breathe before you bite hypothesis?
It is important to get more oxygen as the jaws get bigger
With an enlarged arch, more oxygen is being sucked in
Stronger branchial muscles allow greater suction
Jaws arose from the splanchnocranium
Describe the evolution of jaws
First Gill Arch is incorporated into the cranium
2nd arch becomes the mandibular arch
Epibranchial forms the palatoquadrate
Ceratobranchial forms the Meckel’s cartilage
Hyoid Arch, the third visceral arch, is the site of articulation
3 Major Adaptation of Acanthodii and Placoderms
Jaws
Paired Fins
Vertebrae
Advantages of Paired Fin
Increased control of movement
Provided lift and descent
Improved drag for greater maneuverability
Defense
Visual Communication
Convert forward thrust to another direction
What are the 3 hypothesis to paired fin formation?
Gill Arch Hypothesis
Fin Fold Hypothesis
Fin Spine Hypothesis
What is the Gill Arch Hypothesis?
Paired fins and girdles arose from gill arches
Girdle from arches, and fin rays from gill rays
Presence of dermal bone in pectoral girdle
Appearance of posterior pelvic girdle
Embryological origin of girdle and gill arches
What is the fin-fold hypothesis?
A continuous fleshy fold stiffened by endoskeleton rays
Emrbyonic sharks develop pectoral and pelvic fin at the same time
What is the fin-spine hypothesis?
Acanthodii had a series of spines that had fleshy membrane along the trunk
Later had weak fin rays in the pelvic and pectoral fins only
Acanthodians lost all spines except 2 pairs containing fin rays
Subclasses of Osteichthyes?
Actinopterygii - Ray finned fish
Sarcopterygii - Flesh finned fish
Order Name for Lobe-finned fish?
Crossopterygii
