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149 Cards in this Set
- Front
- Back
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What are the general characteristics of vertebrates? |
1) More than 57,000 living species 2) Live in almost all of earths habitats 3) Have diverse body forms and behaviors |
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What are the general characteristics of Non-Amniotes? |
- Embryos are enclosed by a membrane that comes from the mother as a component of an unfertilized egg, this is not considered a "true membrane" - Has a vitelline membrane which serves for protection, to protect against polyspermy, and for species specificity |
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What are the main groups of non-amniotes? |
1) Agnathans 2) chondrichthyes 3) Osteichthyes 4) Tetrapods |
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What are the two living groups of agnathans and what are there characteristics? -Living number of species? |
1) Hagfish (Myxinoidea) - 70 species, and they live on the seabed 2) Lamprey (Petromyzontoidea) -38 species, and they are migratory. They live in the ocean but spawn in rivers. -"Rock Suckers" They use suction to stick to rocks to resist current |
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What are the general characteristics of agnathans? |
Agnathans (Jawless) -Limbless and scaleless with no internal bone - does not have a complete vertebrae but has a cranium - scavengers and parasitic |
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What is the major defining characteristic of all chondrichthyes? |
cartilaginous skeleton |
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What are the two different groups of chondrichythyes? |
Neoselachii and Holocephalii |
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What two clades make up make up Neoselachii and what are their general characteristics? -How many species still living? |
1) Sharks -403 species -range in size 15 cm to 10 m 2) Rays -534 species -dorsoventrally flattened - bottom dwellers |
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What are some general characteristics of Holocephalii and how many living species are there? |
-Ratfish (looks like a rabbit) -33 species -long tails and buck teeth -lives on ocean floor and eats crustaceans and mollusks -single membrane covering the four gill openings |
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What are some general characteristics of osteichtyes and what are the two broad groups it is characterized in? |
-They are bony fish and they are too diverse to completely characterize 1)Ray finned ( actinopterygians) 2) Lobe finned (sarcopterygians) |
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What are some general characteristics of ray finned (actinopterygian)? |
- They are highly diverse -over 27,000 species and they are still discovering 150-200 new ones every year -generally they have scales |
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What two groups does ray finned osteichythyes get broken into? What are both groups general characteristics? |
1) Chondrostei -Made up of Birchirs, sturgeon, and paddlefish -few scales, cartilage, massive size 2) Neopterygii -Teleostei -Most of the ray finned fish fall into this category |
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What are the general chacteristics of sarcopterygians? |
-Lobe finned -Only 8 non tetrapod species still exist - most closely related to terrestrial vertebrates - Has bony structure of limbs |
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What are the general characteristics of tetrapods? |
-4 jointed appendages -Amphibians includes Urodela (tail/ salamander), anura (no tail/ frogs), and gymnophiona/ caecilians (legless burrowing) -Have a double life (aquatic larva, terrestrial adult) -Have bare skin (lacking scales, hair, or feathers) for the purpose of water, ion and gas exchange with the environment. |
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What are the general characteristics of amniotes? |
-Contains several Fetal membranes which are formed from the cells of a fertilized egg - Tend to be more terrestrial but have some secondary aquatic animals like sea turtles and whales |
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What is the purpose of the amnion in amniotes? |
Encloses the developing fetus in water |
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What is the purpose of chorion in amniotes? |
Facilitates nutrient/ gas exchange |
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What is the purpose of allantois in amniotes? |
Facilitates gas/waste exchange |
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What is the purpose of the yolk sac in amniotes? |
To enclose the nutrition |
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When were amniotes well established and what characteristics did the early versions share? |
-Established by the late Devonian period 416 million years ago - characteristics include; scales, dilute urine, simple lungs, and a single heart ventricle |
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What changed in the environment that affected amniotes? |
- Land masses moved and environments changed - amniotes evolved specialized physiologies to ensure oxygen extraction, temperature control, osmoregulation, and circulation |
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What are the two different groups of amniotes? |
Sauropsid amniotes and synapsid amniotes (dimetrodon) |
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What are the different lineages within the sauropsid amniotes? |
1) Testudinia 2) Lepidosauria 3) Archosauria |
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What are the general characteristics of Testudinia? |
-Turtles, tortoises and terrapins (both land and sea dwellers) - Has a hard shell made by putting its ribs outside of its body -most confusing of all because they are not similar to any other vertebrates |
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What are the general characteristics of lepidosauria and how many living species of each clade? |
-Lizards (5000), Snakes (3015), and Tuatara (2) - All have scales and similar skull morphologies -The skull is missing a piece to make them more flexible -Tuatara are only found in New Zealand |
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What are the two groups withing archosauria and what are their general characteristics? Living species? |
1) Crocodilia -Alligators and crocodiles (23 species) - vary in size up to 7 meters -Skin has tiny bones under the scales (osteoderms) -Socially interactive and attentive parents 2)Aves -Birds (over 9670 species) -Developed feathers before the ability to fly -Feathers are important for warmth, flight, and mating |
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What are the general characteristics of synapsid amniotes/ dimetrodon? |
-Mammalia - 4800 species traced back to the paleozoic era -all feed their young with maternal milk |
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What are the three mammalia groups and what are their general characteristics? |
1) Monotremes/prototherians -Platypus and echidna, young are hatched from eggs, found in australia and new guinea 2) Marsupials/ metatherians -Kangaroo and koala, have placentas but a short gestation (immature young), external pouch, found in australia and america 3) Placentals/ eutherians - placenta is extensive and gestation is long |
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In a human: What is the anatomical term for... a) Towards the head? b) Towards the feet? c) Towards the stomach d) Towards the back? |
a) Superior b) inferior c) Anterior d) posterior |
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In vertebrates: What is the anatomical term for a) Towards the head? b) Towards the feet? c) Towards the stomach? d) Towards the back? |
a) Cranial b) caudal c) ventral d) Dorsal |
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What is the standard position for humans? for Vertebrates? |
Humans: Standing straight up with palms facing forward Vertebrates: standing with spine in a straight line (example: Horse would have head down and out and tail out) |
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What are the subphylums of the phylum chordata? |
1) urochordata 2) cephalochordata 3)vertebrata |
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What doe early animals have in common? |
1) common cleavage patterns after fertilization 2) complex cellular reorganization (gastrulation) 3)Formation of germ layers |
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What are the characteristics of germ layers? |
-Germ layers decide the fate of cells associating with them - The give rise to the same structures in every species - there are three layers |
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What did Chistian pander discover about germ layers? Ernst Von Baer? |
Christian: - He noticed that all animals (except sponges) have 2 or 3 layers - He noted that communication between the layers drove induction Ernst Von Baer: - He notices that germ layers give rise to the same structures in every species |
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What is induction? |
The ability of one cell tissue to direct the development of neighboring cells or tissues |
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What are the three germ layers? |
Ectoderm, endoderm, and mesoderm |
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Why is the ecotoderm important, what does it give rise to? |
-The outermost germ layer -superficial layers of the skin - gives rise to nervous system and most of the sense organs |
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Why is the endoderm important, what does it give rise to? |
-The deepest germ layer - Gives rise to the majority of the digestive tract lining - Lining of digestive glands -respiratory surfaces - also gives rise to taste buds, throid, and thymus |
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Why is the mesoderm important, what does it give rise to? |
- The mesoderm is broken up into different parts - It is the middle layer and the last to appear in development and evolution - it forms the notochord - Givesrise to most muscles and most bone andthe circulatory and urogenital systems - Has a medial to lateral regionalization |
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What are the regions of the mesoderm? |
-Notochord is the centermost region - to the sides of the notochord is the paraxial region -then is the intermediate regions - lastly the lateral plate mesoderm |
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What is the importance of the paraxial region of the mesoderm? |
-it segments into somites - Forms bones and muscles of the trunk - forms muscles of the limbs - It is bilateral |
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What is the importance of the intermediate region of the mesoderm? |
-Forms kidneys and collecting systems - forms gonads and accessory genital organs |
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What is the importance of the lateral plate mesoderm? |
-Dorsal aspect contributes to limb bones while the ventral portion contributes to viscera - Example: A chicken embryo grows on top of a yolk sac and changes shape by taking up the nutrients from the sac |
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How does the coelom form? |
Forms from a splitting of the mesodermal layer |
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What type of symmetry do vertebrates show externally? Internally? |
External: Bilateral symmetry-generally mirror image Internal: asymmetric- organs are not mirror image |
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What side of the body is a Nodal protein secreted and what does it do?
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Secreted by cells on the left side of the body and it leads to paracrine signaling, autocrine signaling, and the expression of pitx2 |
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What classifies a deuterostome? |
-reflects the timing of mouth formation in the gut tube. -the gut tube has two openings and a deuterostome has the mouth forming second and the anus forming first |
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In vertebrates, what is the anus formed from? |
The blastopore |
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What are the two different types of embryologic patterns? |
Autonomous specification and conditional specification |
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What is autonomous specification? |
-invertebrate cellular differentiation is often pre determined - Mosaic development= each cell divides into daughter cells which will have the same structure no matter what, it wouldn't change even if isolated from the rest of the embryo - Factors are localized in the oovum |
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What is conditional specification? |
-vertebrate differentiation due to induction -commitment is driven by interactions between adjacent cells - regulated development- if cells are moved early enough their fate can be altered |
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What are the 5 defining characteristics that an organism must have at some point of development to be considered a chordate? |
1. Notochord 2. Dorsal hollow nerve tube 3. pharyngeal slits 4. Endostyle (secretes mucous) important in feeding 5.post-anal tail |
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What are the general characteristics of urochordates (Tunicates/ sea squirts)? What makes them unique? |
-They are marine filter feeders that are migratory as larva and sessile as adults - They are unique because the chordate characteristics are mostly in larval form due to their sessile adult life - They were originally thought to be ancestral but it seems their adult form is actually more derived |
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What are some general characteristics of celphalochordates (amphioxous)? |
- small and fish like with an active larval stage and a sessile burrowing adult life - They have V shaped myomers which help with movement - notochord extends all the way to head to give support when burrowing - Pharyngeal slits -external coelom (called atrium- ventrally located) - have an opening at the atriopore for water to flow out during filter feeding |
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In amphioxous, what are the pharyngeal slits used for? |
Feeding only- They are small enough to use diffusion through the body surface for gas exchange. Pharyngeal slits are NOT gills |
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What are some derived shared characteristics between cephalochordates and vertebrates? |
- They have a circulatory system with a dorsal aeorta, ventral pumping structure, pharyngeal vessel, and specialized excretory cells called podocytes which humans have in their kidneys - arteries between the slits come together to form a structure that functions like a heart |
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Between cephalochordates and urochordates, which is likely more ancestral? |
Adult cephalochordates have a more visible resemblance to verts where as urochordates relate to verts on a more molecular level. |
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What is control of AP patterning? What is AP patterning caused by? |
- Diversification of AP axis patterning -preceded by some alteration at a gene level -some organisms have more complex segmentation patterns but they all have; a defined head region, exact positioning of appendages, and aligned body regions. -all caused by hox genes |
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What are hox genes? Why are they important? |
-genes that bind to the homeobox and activate transcription factors -expressed in the early embryo to define the placement and morphology of a region |
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How many hox genes does radial patterning require? Does any species contain more than that? |
1-2 genes - early bilateral species contain more than that, such as drosophila -there are 8 genes in a drosophila cluster which arrange along the chromosome in the order of their anatomical expression |
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How many clusters do Amphioxus have? Jawless vertebrates? Jawed vertebrates? What does an increase in clusters do? |
Amphioxous= 1 cluster Jawless= 2 clusters jawed= 4 clusters - Once a gene is duplicated it will evolve separately, which means more clusters= more duplications= more usable genes = more diversity |
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What are the contributions of neural crest cells? |
- Forms the flat bones of the cranium - nerve ganglion sensory organs in the head and body - seed the pharyngeal arched to drive jaw formation - formation of the 4th heart chamber - Innervation of the GI tract to force directional movement of food/waste -pigmentation |
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Describe the evolution of Neural crest cells? |
First, in amphioxous cells they were found to be non migratory then, in some tunicates they noticed migration and pigmentation |
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Describe the vertebrae is vertebrates? |
- small, sequentially arranged units of hard bone and hard cartilage - encloses the spinal cord (dorsal hollow nerve tube) - Forms around the notochord -not found in all vertebrates |
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What do scientists say is a better name for vertebrates? Why? |
-Craniata Because all vertebrates have a... -developed brain -Distinct eyes - and a cranium that sits in front of the notochord anterior to the vertebral column |
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What do levers allow us to do? What are the three types of levers and an example of each? |
- Allow us to work easier, and involved a rigid bar moving around a fixed point -First class levers: fulcrum is between the load and the pull (seasaw/ looking up)- stability -Second class levers: Load lied between the fulcrum and the pull (wheelbarrow, standing on tippy toes) -**Third class levers: Pull lies between fulcrum and the load (lifting weights) |
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Which type of levers is most common in the body and why? |
Third class levers are the most common because it allows for insertion points close to the moving joint. It is very efficient |
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What functions as the Lever? Fulcrum? Pull? and Load? when speaking in terms of a body |
Lever: Bone Fulcrum: Joint Pull: contraction of muscle Load: resistance/ gravity, objects, body weight |
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What is the most common way fish adjust their buoyancy in water? |
They use a structure called a swim bladder. - They adjust the air in the swim bladder to adjust their placement in the water (This is not a respiratory structure) |
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Do bony fish need to swim to stay in a vertical position? |
No, They are most commonly neutrally buoyant and they stay in the same vertical position even at rest. - They move their fins slightly to counteract the motion of water going through their gills - Because of this they have a very developed swim bladder |
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What are the general characteristics of a swim bladder? |
- positioned in body cavity between gut and vertebral column - takes up 5-7 % of body volume (since sea water is denser, ocean fish need a smaller bladder for the same effect) - Walls of collagen are impermeable to gasses |
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How does a swim bladder work in general? |
- When gas is added to the swim bladder the fish raises its buoyancy -when gas is released from the swim bladder the fish decreases its buoyancy |
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How do fish such as minnows and goldfish, that live close to the surface of water adjust their buoyancy? |
- They retain a connection between the swim bladder and their gut. These fish are called physostomous and the pneumatic duct is what connects the bladder and gut - they gulp air at the surface to fill the bladder and burp to release air from the bladder |
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How do fish that live in deeper waters adjust buoyancy and what are they called? |
- physoclistic fish are the more derived form - they use a gas gland on the ventral floor of the bladder that are associated with a system of vessels called rete mirabile to extract gas from the blood and move it into the bladder |
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What is happening in the gas gland in physoclistic fish? |
- Cells in the gland acidify the blood in the vessels via glycolysis which separate the oxygen from the hydrogen in the hemoglobin, once build up is greater than the gland diffusion occurs, diffusion also occurs across the barrier of the vessels to have a positive feedback loop |
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How do physoclistic fish force oxygen out of their swim bladder? |
They use an ovale (muscular valve on the dorsal side) to increase pressure and force the oxygen back into the bloodstream
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What are some other methods fish use to adjust buoyancy if they do not have a swim bladder? |
-Increase body fats and oils -Reduce skeletal bone, (CaPO4 is a heavy salt, reducing that reduces the weight-- adding lipids to the bones is another way) - adjust internal ion concentrations |
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What are some other obstacles that fish experience when adjusting buoyancy? |
-Gravity: The downward push of water -Drag: the friction from water which gives the tendency for fish to pitch and yaw (pitch up and down, yaw side to side) |
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How is locomotion in water achieved? |
- A series of anterior to posterior contractions on one side - relaxation of opposite side and the bend travels posteriorly back - the water behind the bend is pushed which gives thrust forward - Lateral lift is negated by the side to side movement |
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What part of the fish is used in locomotion? What different types of locomotion are there? |
-Generally locomotion is confined to the posterior region of the fish Anguiliform: whole body undulations Carangiform: undulations in caudal half ostraciiform: hard bodies, only caudal fin moves |
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What are some adaptions that were made to locomotion is water instead of just flexing the body? |
-Some fish move fins in addition to the flex or replacing it in general |
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What is Amiiform motion? Gymnotiform? What movement do balistiform fish use? What is labriform motion? What is rajiform anterior? |
- dorsal fin oscillations - ventral anal fin oscillations - they use both dorsal and anal fins -uses rowing motion with pectoral fins -posterior undulations of pectoral fins |
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Which two types of aquatic locomotion types can increase the frequency of undulations? - What type is least beneficial? -What type is most beneficial? |
- Anguilliform and carangiform - Eels long body is a hindrance because it is too flexible - Tuna is shorter and less flecible which allows for more force concentrate in the back (faster) |
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What are the two types of drag? What are their characteristics? |
1) Viscous drag; fish body and water -constant over all speeds because the body doesnt change 2) Inertial drag; pressure differences due to water displacement -increases with speed |
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What type of drag is high for thin bodies? Thick bodies? -What form would improve thrust? |
- Thin bodies have a high viscous drag due to their surface area being to large in relation to their muscle mass -Thick bodies have to much inertial drag due to too much water being displaced -A tear drop shape would be the local minimum (thickness 25% of length, thickest part being 1/3 the length back from the anterior end) |
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What are some other aquatic locomotion adaptions seen in sharks and dolphins? |
they are long distance swimmers - We see dorso ventral axis narrowing for more movement. -focusing more on the force |
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What are some adaptions aquatic animals made in their tails to improve locomotion? |
-Sickle shaped caudal fin to retain the teardrop shape in the cross section -This reduces the drag across the surface |
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What specializations do they make to the peduncles of trout and minnows? |
-Deep thick peduncles -laterally compressed - burst swimmers with a startle reflex |
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What are the parts of the appendicular skeleton? |
-Girdle, links the fins to the trunk and is mostly for anchoring muscles -Proximal regions are the pterygiophores basal elements: Enlarged and close to girdle Radial elements: close to girdle - Distal regions are the ceratotrichia (keratinized rods) |
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What is the size difference between Cephalochordates (Ceph) and Vertebrates (Verts)? |
Ceph are very small (~1cm) compared to verts (smallest ~10 cm) |
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What is the function of solenocytes? |
Specialized cells located between coelom and atrium. They direct solute into the atrium so it can be flushed out of the body |
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How does waste excrete from the coelom in cephalochordates? |
By solenocytes via negative pressure
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What are the function of archinephric ducts and which system or process is it apart of? |
Help regulate and remove nitrogenous waste and is important in body excretions |
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Why did vertebrates get gills? |
The presence of gills increases the surface area to allow more gas exchange |
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Which structure is an infolding and outfolding (gills and lungs)? |
Gills are outfoldings caused by lamellae Lungs are infolding by septation and branching |
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What are the three chambers of the heart of early vertebrates? (in order of blood flow) |
Sinus Venosus -> Atrium -> Ventricle |
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Which chamber of the heart does the main job? |
Ventricle |
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Which heart chamber is the most muscular and which is the least muscular? |
Ventricle - muscular Sinus Venosus - thin |
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Which chamber is important in regulating blood volume? |
Sinus Venosus (therefore flexible/expandable) |
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Compare and contrast the structure of arteries and veins |
Arteries - thicker walls, muscular and elastic (need to withstand the pressure from ventricle and move blood to rest of the system) Veins - thin, sac-like and irregular shape (Deals w/ low pressure; need to be able to store blood) |
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What is venous compliance? |
Veins can alter it shape by shriveling up when there is low blood volume; the structure will open up when blood volume increases |
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True or false: all capillaries beds receives blood flow simultaneously and constantly |
False, there is not enough blood volume to provide blood to all capillary beds. Blood reaches the capillary beds when needed. |
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What structure acts as a shunt in blood flow to capillary beds? |
Arteriovenous Anastomoses (allow blood to bypass a capillary bed) |
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What are particular feeders? |
Organisms that eat by the mouthful |
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Did early vertebrates have specialized stomach and large intestines? |
No, they just had muscular gut |
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What is the cloaca? |
Where all waste products empties into and exit out of the body |
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Which germ layer does the kidney form from? |
Intermediate mesoderm |
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True or False: all vertebrates have similar filtration units |
True |
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What are podocytes? |
Cells that regulates what leaves the capillaries and into the kidney |
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Why is conditioned resorption and secretion beneficial in filtration? |
This allows the system to push out large volume into the kidney. Any foreign substance will be pushed out. Anything beneficial will be reclaim. Highly adjustable system of what remains and what leaves the body. |
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What is keratin made up of? |
Intermediate filaments and cytoskeletal proteins (which makes it very sturdy and high tensile strength) |
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Where is keratin found in vertebrates? |
On the outer skin of tetrapods, scales, horns, beaks, hair, and nails |
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How many percent of the total body mass does the integumentary system makes up? |
15% |
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What is the integumentary system evolved in? |
1- Osmotic and volume regulation 2- Protection 3- Gas exchange 4- Sensation 5- Metabolism 6- Energy Storage 7- Reproduction |
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What are the common features in reproduction seen in all vertebrates? |
- Paired gonadal tissues - Ovaries with follicular cells - Testes have seminiferous tubules |
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True or False: Neurulation is similar in all vertebrates |
True, and the notochord defines where the neurulation occurs |
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How does the neuroectoderm form a tube? |
The neuroectodem folds in on itself to form a tube |
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What are the three basic vesicles of the brain and what each vesicle controls? |
Forebrain - smell Midbrain - sight Hindbrain - balance and homeostasis |
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What are the secondary derivations of the brain? |
-Telencephalon - integration -Diencephalon - relay station and hormonal control -Cerebellum - motion coordination (only in jawed extant vertebrates) |
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What is the basic functional unit of the nervous system? |
Neuron |
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True or false: myelination of the neurons are seen in all vertebrates |
False, only in jawed vertebrates |
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What makes up the CNS and PNS? |
CNS - brain and spinal cord PNS - fibers serving distal structures (everything else) |
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Somatic Nervous system is ____A___ control, and visceral nervous system is ___B____ control. |
A = conscious control B= unconscious control (VNS aka autonomic nervous) |
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What are some senses that some vertebrates have? |
Sensation to -Chemosensory, electromagnetic radiation, pressure/gravity |
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What is the major molecule/component of ECM? |
Collagen |
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What material is vertebrate's skeleton made of? |
Hydroxyapatite, strong hard substance that can withstand acidic conditions. |
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What are the types of mineralized tissue found in vertebrates? |
- Cartilage - Bone - Enameloid -> in dermal scale - Enamel -> denses mineralized tissue; outer layer of the tooth - Dentine -> thick layer in tooth below the enamel - Cementum -> hold tooth in socket; only in some vertebrates |
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What are the two types of done found in vertebrates? |
Endochondral (forms from cartilage) and dermal (forms from connective tissue) |
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What is the most primitive mineralized tissue in vertebrates? |
Dermal Bone (forms the external armor in early verts) |
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What are the three components of vertebrates's cranial skeleton? |
1- chondrocranium 2- splanchnocranium 3- dermatocranium |
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Which components of the cranial skeleton forms into the jaw region? |
Splanchnocranium (also forms the pharyngeal arches) |
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If the chondrocranium does not become bone, what is that region called then? |
The neurocranium |
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What are the different structural components of the vertebrae? |
-Neural Arch: protect spinal cord -Centum: forms around notochord -Ribs -Hemal Arch: protects arteries in the caudal area |
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What are the two myomeres in jawed vertebrates? |
Epaxial - dorsal
Hypaxial - ventral |
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What are the basic fins in vertebrates and what motion do they control? |
All for propulsion Tail/caudal fin = thrust Dorsal & anal fin = control roll and yaw Pectoral fin = control pitch and braking |
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When did the earliest true vertebrates appear? (Name and vertebrate characteristics) |
-540 mya; cambrian explosion Myllokunmingia - 3cm - Cartilagenous cranium and skeleton - W shaped myomeres - Dorsal fin |
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What are the vertebrates characteristic in Hagfish? |
- Cranial structure
- Keratinized tooth plates - Muscular tongue w/ keratin plates - Ventral heart with neural control and 3 chambered |
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What are Hagfishes special defense mechanism? |
Produces slime/mucus |
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What are the primitive features of Hagfish? |
- No vertebral element - No true eye - Tentacle mount - Accessory hearts that are aneural located by the liver and tail. - Body fluid component similar to seawater |
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What are Lamprey's vertebrate characteristics? |
- Cranial cartilage - Vertebral structures = arcualia (homologous to neural arch) - Oral hood: big upper lip - Tongue similar to vertebrates w/ keratin spines - Large developed eyes - Dilute body fluid - Developed kidneys - Gills for ventilation |
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What are the earliest mineralized tissue made up of? |
Apatite (organisms with apatite are called conodonts) |
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What are the vertebrate features that the Conodonts have? |
- Mineralized their tissue (derive process) - Microfossils - Eyes - Nervous system - Can Ossify |
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How far do Ostracoderm's fossil date back? |
500-480 mya |
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What is the most distinct feature of Ostracoderm? |
Dermal body armor; important because of increase of predation |
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What are the vertebrates characteristics that the Ostracoderms possess? |
- Eyes - Sensory canals (lateral on its back) - Mineralized tissues: enameloid and dentin layered across a spongy acellular bone - Cerebellum (more derived than agnathans) - Respiratory gills - Dorsal fin - 1 paired fins seen in a group of ostracoderm (cephalaspids) |
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What are the gill arches involved in jaw formation? |
Mandibular (1st gill arch) - upper and lower jaw Hyoid (2nd gill arch) - muscle attachment |
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What is the name of the 4th chambered of the heart in Gnathostomes? |
Conus arterious (after the ventricle) |
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What are some of the distinct features of Gnathostomes? |
- Upper and Lower Jaw - 2 distinct nostril - 4 chambered heart - Defined epaxial and hypaxial - Vertebral around notochord |
