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Questions and Answers
What is the primary function of the enlarged pectoral fins in Batoidea?
What is the primary function of the enlarged pectoral fins in Batoidea?
All Batoidea species are known to be active hunters.
All Batoidea species are known to be active hunters.
False
What unique feature do sting rays possess for defense?
What unique feature do sting rays possess for defense?
Saw-toothed venomous spine
The largest rays, known as ___________, primarily filter feed on plankton.
The largest rays, known as ___________, primarily filter feed on plankton.
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Match the following terms related to Batoidea with their correct descriptions:
Match the following terms related to Batoidea with their correct descriptions:
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What is a key physical difference between skates and rays?
What is a key physical difference between skates and rays?
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Electric rays are primarily nocturnal hunters.
Electric rays are primarily nocturnal hunters.
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What type of reproductive strategy do skates use?
What type of reproductive strategy do skates use?
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Chimaeras have teeth that are modified into _______.
Chimaeras have teeth that are modified into _______.
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Match the following organisms with their characteristics:
Match the following organisms with their characteristics:
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What is the primary function of the nictitating membrane in sharks?
What is the primary function of the nictitating membrane in sharks?
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Mako sharks are known to grow larger than great white sharks.
Mako sharks are known to grow larger than great white sharks.
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What is the longest dorsal lobe in a shark's heterocercal tail called?
What is the longest dorsal lobe in a shark's heterocercal tail called?
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Sharks have a keen sense of smell that can detect 1 drop of blood in ____ drops of water.
Sharks have a keen sense of smell that can detect 1 drop of blood in ____ drops of water.
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Match the following types of sharks with their characteristics:
Match the following types of sharks with their characteristics:
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Which classification includes mostly smaller sharks?
Which classification includes mostly smaller sharks?
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All sharks have small olfactory lobes regardless of their habitat.
All sharks have small olfactory lobes regardless of their habitat.
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What sensory system do sharks use to detect turbulence and vibrations in the water?
What sensory system do sharks use to detect turbulence and vibrations in the water?
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What are the structures called that help sharks detect electric fields produced by other animals?
What are the structures called that help sharks detect electric fields produced by other animals?
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Sharks primarily rely on their vision in bright light conditions to locate prey.
Sharks primarily rely on their vision in bright light conditions to locate prey.
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What is the primary role of the tapetum lucidum in sharks?
What is the primary role of the tapetum lucidum in sharks?
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Sharks have more ______ than cones in their retinas.
Sharks have more ______ than cones in their retinas.
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What type of feeding behavior do sharks exhibit towards unfamiliar prey?
What type of feeding behavior do sharks exhibit towards unfamiliar prey?
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The inner ear of sharks helps them detect ______ and maintain balance.
The inner ear of sharks helps them detect ______ and maintain balance.
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Match the following shark sensory adaptations with their functions:
Match the following shark sensory adaptations with their functions:
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In what condition are sharks most likely to rely on their other senses, such as electroreception and smell, during an attack?
In what condition are sharks most likely to rely on their other senses, such as electroreception and smell, during an attack?
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Which of the following sharks are classified as homeothermic species?
Which of the following sharks are classified as homeothermic species?
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All sharks are poikilothermic.
All sharks are poikilothermic.
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What is the primary mechanism that allows regional heterothermy in mackerel sharks?
What is the primary mechanism that allows regional heterothermy in mackerel sharks?
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Sharks can replace up to ________ teeth in their lifetime.
Sharks can replace up to ________ teeth in their lifetime.
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Match the reproductive strategies with their definitions:
Match the reproductive strategies with their definitions:
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What types of feeding mechanisms do sharks utilize?
What types of feeding mechanisms do sharks utilize?
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Sharks are exclusively carnivorous and do not consume any other types of food.
Sharks are exclusively carnivorous and do not consume any other types of food.
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What is the gestation period range for sharks?
What is the gestation period range for sharks?
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Which of the following groups does not belong to Chondrichthyes?
Which of the following groups does not belong to Chondrichthyes?
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Megalodon was the largest bony fish ever recorded.
Megalodon was the largest bony fish ever recorded.
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What is the primary composition of the skeleton of Chondrichthyes?
What is the primary composition of the skeleton of Chondrichthyes?
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Chondrichthyans are known for their ability to replace their teeth in a _______.
Chondrichthyans are known for their ability to replace their teeth in a _______.
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Match the following features with the correct Chondrichthyan group:
Match the following features with the correct Chondrichthyan group:
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What mechanism do sharks use to stay neutrally buoyant?
What mechanism do sharks use to stay neutrally buoyant?
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Chondrichthyan skin is covered with placoid scales.
Chondrichthyan skin is covered with placoid scales.
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What are the functions of photopores in certain sharks?
What are the functions of photopores in certain sharks?
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The teeth of Chondrichthyans are primarily made of ______.
The teeth of Chondrichthyans are primarily made of ______.
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Which type of jaws is characterized by having the upper jaw fused to the cranium?
Which type of jaws is characterized by having the upper jaw fused to the cranium?
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All sharks and rays have swim bladders.
All sharks and rays have swim bladders.
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Name one characteristic feature of Holocephali.
Name one characteristic feature of Holocephali.
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The lateral line in Chondrichthyans is used to detect ______.
The lateral line in Chondrichthyans is used to detect ______.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Study Notes
Chondrichthyes: The Cartilaginous Fish
- Divided into two groups: Elasmobranchii and Holocephali
- Elasmobranchii have multiple gill openings on each side of the head.
- Have independently mobile upper jaws
- Includes sharks, rays, and skates
- Sharks are torpedo-shaped with 5-7 gill openings on each side of the head.
- Rays and skates are dorsoventrally flattened with 5 pairs of gill openings on the ventral surface
- Holocephali has an undivided head, due to a single external gill opening and gill slits covered by an operculum.
- Includes chimaeras, rabbitfishes, ratfishes, and ghost sharks
- Fishlike body with long, flexible tails
- Some have large eyes and broad tooth plates like a rabbit's.
Megalodon
- Largest shark
- Exhibits pre-birth cannibalism
Distinctive Characters of Chondrichthyes
- ~970 extant species
- Cartilaginous chondrocranium, jaws, gill arches, vertebrae, fin supports
- Bony tissues (fin spines, teeth, scales).
- Lost the plates seen in acanthodians, but have an exoskeleton of placoid scales.
- Male pelvic fins modified into claspers.
- Broad wing-like pectoral fins generate lift during swimming
- Large lipid-filled liver maintains neutral buoyancy.
- Retain nitrogenous compounds for osmotic regulation in marine environments
Phylogeny of Cartilaginous Fishes
- Chondrichthyes are divided into two main lineages: Elasmobranchii and Holocephali.
- Evolutionary relationships between different shark species are discussed.
- Shows a hierarchical tree of relationships highlighting species characteristics.
Shark Phylogenetic Relationships
- Galeomorphii (mostly large sharks) includes Great white sharks, Hammerhead sharks, Whale sharks, Basking sharks, Megamouth sharks, Mako sharks, and Horn sharks.
- Squalomorphii (usually smaller sharks) includes Cow sharks, Angel sharks, Spiny dogfish sharks, Green lantern sharks, and Cookie-cutter sharks.
Shark Vision
- Some sharks have a nictitating membrane (third eyelid) that protects it from abrasion.
- Sight likely plays an important role in feeding.
- Focusing is achieved by moving the entire lens.
- Vision is highly developed for low-light conditions.
- Most sharks feed at dusk or in deeper waters.
- Retinas have more rods than cones.
- Tapetum lucidum reflects light, enhancing vision in low light levels.
Electroreception
- Ampullae of Lorenzini are highly sensitive receptors in sharks and some other fish.
- Detectors in the head and face to detect electrical fields generated by other organisms
- Used to locate prey buried in sand or other hidden locations.
Membranous Labyrinth
- Part of the inner ear responsible for detecting water-borne vibrations
- Detects motion, and has specialized components (utriculus, semicircular canals and sacculus)
- Involved with balance and equilibrium
Predatory Behavior
- Usually attack familiar prey immediately, but circle unfamiliar prey
- Opportunistic feeders, eating dead or weakened animals
- During the final moments of attack, sharks often rely on touch, odor, electroreception and sound
- Lens shape can alter for focus and clarity.
Thermoregulation
- Most sharks are poikilothermic (body temperature changes with surrounding water).
- Some pelagic species (Mako shark) are homoeothermic.
- Heat exchange mechanisms in some shark species help regulate and maintain temperature.
- Blood vessels aid in temperature control.
Shark Ecology
- Apex predators maintaining marine food webs.
Regional Heterothermy
- Found in mackerel sharks (e.g., shortfin mako, great white).
- Countercurrent heat exchange throughout the body.
- Using a network of blood vessels, heat is captured to regulate internal temperature
- Warm and regulate temperature of the eyes.
- Helps sharks maintain stable body temperature in different water temperatures during swimming
Feeding
- Sharks have replaceable teeth, and many teeth will be replaced during a shark's lifetime.
- Sharks can be carnivorous (feeding on fish or mammals), or plantivorous (feeding on plants and plankton).
- Ingesting inorganic objects (plastics, metal).
Teeth Shapes and Functions
- Teeth mechanisms include biting, ramming, and suction.
- Teeth are held firmly in place by collagen.
- Different shapes are associated with different prey types.
Reproduction
- Pelvic fins modified into claspers (intromittent organ for internal fertilization).
- Oviparity: Eggs laid in sacs. Viviparity: Eggs hatched internally with nourishment.
- Lecithotrophy: A yolk supplies nourishment to the embryo. Matrotrophy: Mother supplies nourishment.
Copulation by Whitespotted Bamboo Shark
- The male's pelvic fins have siphon sacs inflated with sea water
- Male claspers interact with female cloaca.
- Process of copulation completed.
Batoidea
- 50% of elasmobranchs are made of rays and skates
- Features like sting rays, electric rays, and mantas
- Dorsoventrally flattened with expanded pectoral fins, used in locomotion.
- Ventral gill openings with spiracles.
- Whip-like tails have saw-toothed venomous spines in some species.
Batoidea (superorder of Elasmobranchii)
- Bottom-dwelling ambush hunters that rest on the ocean floor
- Protrusible mouths for prey capture.
- Teeth for crushing prey
- Large rays (manta, filter-feeding rays).
Skates vs. Rays
- Most skates have circular bodies, rays have kite-like shapes
- Skates have thick tails and no spines, rays have whiplike tails.
- Skates are oviparous and rays are viviparous.
- Electric rays employ specialized muscles to generate pulses that stun prey
Electric Rays
- Electric rays are ambush predators.
- Muscles on either side of their heads generate electric shocks for stunning prey
- Use pectoral fins to control movement in the water.
Subclass: Holocephali
- Includes chimaeras
- Bony plate covering gill arches - operculum
- Fusion of upper jaw to braincase, known as holostylic jaw.
- Some with a tentaculum (“clasper”) on the forehead
- Skin without scales.
- Teeth modified to crush prey
Chimaeras
- Live on the seafloor.
- Feed on bottom dwelling animals including sea anemones, jellyfish, small fish and mollusks.
- Relatively long life histories
- Reproduce once a year with multiple simultaneous eggs.
- Mostly lay eggs.
- Three main forms: Shortnose, Longnose and Plownose
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Description
Test your knowledge on the anatomy and behaviors of Batoidea species and sharks. This quiz covers topics such as physical adaptations, reproductive strategies, and unique defensive features. Perfect for marine biology enthusiasts!
