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What are the 3 subgroups of the lineage Chordata
- Two invertebrate groups (Urochordata and Cephalochordata).
- And Vertebrata.
Chordates are Deuterostomes with four unique characteristics that appear some time during the animals life. List those four characteristics
- A dorsal, hollow nerve cord
- Pharyngeal slits
- Muscular postanal tail
Define what a Notochord is
- A longitudinal, flexible rod located between the gut and nerve cord
- Composed of large, fluid filled cells encased in a stiff, fibrous tissue
- Extends through most of the length of the animals as a simple skeleton
True of false: A Notochord is present in most, but not all chordata embryos.
False: A notochord is present in all chordate embryos
True of False: The notochord does not persist to animal adulthood.
False: In some invertebrate chordates and primitive vertebrates, the notochord persists to support the adult
Where does the dorsal, hollow nerve cord develop, and from what does it develop?
- In the embryo
- From a plate of dorsal ectoderm that rolls into a tube located dorsal to the notochord
True or False: The dorsal, hollow nerve cord is unique to chordates
What develops from the dorsal, hollow nerve cord?
The brain and spinal cord
What do other animal clades have instead of the dorsal, hollow nerve cord?
Solid, usually ventral, nerve cords.
The pharynx is the region just ______ to the mouth and it opens to the _______ through several pairs of slits.
The presence of ______ permits water entering the mouth of chordates to exit without passing through the entire digestive system
pharyngeal gill slits
What was the original function of Pharyngeal Gill Slits?
For suspension feeding in invertebrates chordates
Explain the Muscular postanal tail.
A tail extending beyond the anus, found in most chordates and contains skeletal elements and muscles.
What is a Prehensile Tail, and what are examples of animals that have it?
- A prehensile tail is the tail of an animal that has adapted to be able to grasp or hold objects.
- New World Monkeys, Spider Monkeys, Boa Constrictor, and Opossum
What function does the muscular postanal tail serve for aquatic chordates?
Provides propulsive force
Species in the Urochordata are commonly called ________.
Lineage of Animals that is cloaked in a tunicate made of a cellulose like carbohydrate
- Lineage of Animals that is cloaked in a tunicate made of a cellulose like carbohydrate
- A. Cephalochordate
- B. Urochordata
- C. Notochord
- D. Vertebrata
Are most marine animals of Urochordates sessile or mobile?
Sessile. Most marine Urochordates are sessile and adhere to rocks, docks, and boats
True of False: Urochordates do not have planktonic or colonial species.
False: Some Urochordates are planktonic (floating), while others are colonial
True of False: Tunicates bare little resemblance to other chordates
What specifically separates Tunicates from other chordates?
- They lack a notochord, nerve cord, and tail
- They possess only pharyngeal gill slits
What special feature of Tunicate larvae makes them interesting?
Larval tunicates are free swimmers and possess all four chordate characteristics, but lose 3 during development.
Animals in the Cephalochordata are know as _______ due to their bladelike shape.
What kind of feeders are Cephalochordates
Marine filter feeders
Cephalochordates more closely resemble _________ than _________.
- Urochordate larva
- Adult urochordates
What are the 4 characteristics that define Vertebrates?
- Neural crest
- Pronounced cephalization
- Vertebral column
- Closed circulatory system
What did the unique Vertebrate structures probably evolve in association with?
Increased size and more active foraging for food.
Define Neural Crest
A group of embryonic cells found only in vertebrates, which contributes to the formation of certain skeletal components and many other structures distinguishing vertebrates from other chordates
True of False: Vertebrates show a much lesser degree of cephalization than cephalochordates.
False: Vertebrates show a much greater degree of cephalization than cephalochordates.
In Vertebrates, what parts of the skeleton make up the axis of the body, and what did it replace (think evolutionary)?
- Cranium and Vertebral column make up the axis of the body
- Replaces the notochord as the basic skeleton
What kind of circulatory system do vertebrates have, and what is it composed of?
- Closed circulatory system
- Ventral chambered heart (two to four chambers), arteries, capillaries, and veins
Vertebrates are divided in which two major groups?
- Agnatha (jaw-less vertebrates)
- Gnathostomata (jawed vertebrates)
What are the 8 lineages that Gnathostomes are divided into?
An animal possessing two pairs of limbs that support it on land
Which 4 Gnathostome lineages are tetrapods?
What are the adaptions (other than being tetrapods) reptiles, birds, and mammals have that are not found in amphibians?
- Amniotic egg (a shelled, water resistant egg)
- Most mammals do not lay eggs
True of False: Mammals are considered amniotes along with the birds and reptiles
Describe how the mouths of ancient Agnathans used to be.
Jawless with oval or slitlike mouths
Describe what ancient Agnathans used to lack, and where they (the animals) were often found.
Most lacked paired fins (Currently Lampreys and Hagfish lack paired fins), and were bottom dwellers.
True of False: All agnathans were sessile and lacked paired fins
False: Some agnathans were active and had paired fins
What are Ostracoderms considered to be?
One of the earliest invertebrates; were jaw-less and had "external armor"
What are the only extant (living) Agnathans?
What do they lack?
- Lampreys and hagfish
- Paired appendages (fins) and external armor
What is the shape of a Lamprey, and how does it feed
- Feed by clamping their round mouths onto live fish (They are ecto-parasitic of fish). Once attached, they use a rasping tongue to penetrate the skin and feed on the prey's blood.
Where do Lamprey's spend their larval development stage, and where do they migrate to.
- Freshwater streams
- Migrate to the sea or lakes as they mature
True of False: Hagfish are exclusively freshwater
False: Hagfish are exclusively marine
True of False: Hagfish are ecto-parasitic
False: They are scavengers without rasping mouthparts
Hagfish superficially resemble _______.
The agnathans were gradually replaced by _______
Vertebrates with jaws (Gnathostomes)
Early Gnathostomes included ancestors of the lineage _______ and _______, and a now extinct group of armored fishes called ______.
- Chondricthyes and Osteicthyes
The first jawed vertebrates were ______
Gnathostomes differed from Agnathans in which ways?
- Possessed paired fins
- Possessed hinged jaws
What are the advantages paired fins and hinged jaws allow?
- Paired fins - enhance swimming ability
- Hinged Jaw - allowed more varied feeding habits including predation
Vertebrate jaws evolved from ________.
Skeletal supports of the pharyngeal slits
Hinged jaws evolved as modifications of the _________ which previously supported the _______.
- Skeletal rods
- anterior pharyngeal (gill) slits
In vertebrates, while hinged jaws developed, the remaining gills slits retained which function?
Functioned as major gas exchange sites
The Devonian period is known as the ______.
Age of the Fishes
What two lineages radiated during the Devonian period?
Placoderms and Acanthodians (another group of jawed fishes)
What features are diagnostic of the lineage Chondricthyes
A cartilaginous endoskeleton reinforced by calcified granules
Species in the lineage Chondrichthyes have what 3 features
- Flexible skeletons composed or cartilage
- Well-develped jaws
- Paired fins
The ancestors of Chondricthyes had ______.
What kind of characteristic is the cartilaginous skeleton of Chondricthyes?
It is a derived characteristic, having evolved secondarily
Sharks lack a ______.
Describe the characteristics of the Sharks bodies:
1. The tail provides ______
2. The dorsal fins serve as ______
3. Pectoral and pelvic fins produce _______.
4. Some buoyancy is provided by ______, but most must _______.
- 1. propulsion
- 2. stabilizers
- 3. lift
- 4. Oil stored in the liver; swim continuously to remain in the water column
Which Chindricthyes are suspension feeders?
- Whale Sharks
- Basking Sharks
- Manta Rays
True of False: All sharks are carnivorous
False: Whale Sharks and Manta Rays are suspension feeders
Shark teeth evolved as _____.
How does the sharks digestive tract compare to other vertebrates?
It is proportionately shorter
What is present in the Sharks intestines?
It is a Spiral Valve, which increases the surface are and slows food movement
What special sensory adaptions are found in Sharks?
- Sharp vision (but cannot distinguish color)
- Olfactory senses (smell)
All fish have a ________
Lateral Line system
A Lateral Line System in sharks is _______, and is present where?
- composed of rows of microscopic organs sensitive to water pressure changes and detects vibrations
- Present along the flanks (sides)
How do sharks reproduce?
Sexually with internal fertilization
What are the 3 methods of birthing present in Sharks?
- Oviporous - Egg laying
- Ovoviviporous - Egg hatching inside the female
- Viviporous - Live birth
What is a Cloaca? What animal is it found in?
- a common chamber for reproductive, digestive and excretory glands
Rays are adapted to what lifestyle?
A bottom dwelling lifestyle
What are the hallmarks of Osteichthyes?
- A bony endoskeleton
- Swim bladder
How many lineages of Osctichthyes are recognized?
Describe the skeleton of Osteichthyes.
Bony skeleton, reinforced with a matrix of calcium phosphate
Where are Osteichthyes abundant?
Marine and Fresh Water
Describe the skin of Osteichthyes.
- Covered with flattened body scales
- Skin glands produce mucus that reduces drag when swimming
True of False: Osteichthyes have no lateral line system
False: Osteichthyes have a lateral line system present as a row of tine pits in the skin on both sides of the body
How does gas exchange occur in Osteichthyes?
By drawing water over the four or five pairs of gills located in the chambers covered by an operculum
What provides bouyancy for Osteichthyes?
A swim bladder
Most bony fish are ______ and utilize ______.
- Oviparous (egg laying)
- External fertilization
Give the genus/species of a special Osteichthyes, and explain what makes it stand out.
- Rivulus marmoratus
- It is a self-fertilizing hermaphrodite (essentially "Cloning" themselves). Also has Ovotestis.
True or False: All Osteichthyes are oviporous
False: Some are ovoviviporous or viviporous and utilize internal fertilization
Sharks arose ______, and bony fish probably arose from _______.
The swim bladder in Osteichthyes was modified from ______.
lungs of ancestral fishes which supplemented the gills for gas exchange in stagnant waters
The lineage ______ includes fish with fins supported mainly by flexible rays
The lineage _______ includes lobe-finned fishes (Coelacanths and Rhipidistans)
Coelacanths and rhipidistians are referred to as _______.
Give 2 descriptors of Coelacanths and rhipidistians
- 1. Their fins were flashy, muscular, and supported by extensions of the body skeleton
- 2. Many were large, bottom-dwelling forms that used their paired fins to walk on the substratum
Which is the only extant species: Coelacanths or rhipidistians
True or False: Coelacanths are marine and lungless
True of False: Not all rhipidistians are extinct
False: All rhipidistians are extinct
Three lineages of _______ exist only in the Southern Hemisphere
Where can lungfish be found?
Stagnant ponds and swamps where they surface to gulp air into lungs connected to the pharynx
What do lungfish do when ponds dry?
They burrow in the mud and aestivate (spending a hot or dry period in a prolonged state of torpor or dormancy)
Describe what was important of Lobe-Finned Fish of the Devonian period.
They were numerous and important in vertebrate genealogy because they probably gave rise to amphibians
_________ is an extinct tetrapod genus, among the first vertebrate to have recognizable limbs
Acanthostega is anatomically _______ and the first tetrapods (amphibians) fully capable of _______.
- Intermediate between lobe-finned fishes
- Coming onto land
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