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Unit 2: Fish, Amphibians, Reptiles
8 days
September 10th: Chordata and Vertebrata
• Chordates are animals that have internal notochords.
• Most are vertebrates, but a few are invertebrates
• The 2 types of invertebrate chordates are the lancelets and tunicates
General Characteristics
• Marine
• Called Urochordates
• Lancelets superficially resemble fish
• Tunicates superficially resemble sponges
Lancelet Anatomy
Tunicate Anatomy
Classification
Kingdom: AnimalPhylum: Chordata
Class: Ascidiacea
Sea Squirts:~2,000 spAttached to coastal rocks and the sea bedBag-like tunicatesSome predatory, most filter feedersOften colonialLarva resemble tadpoles
Classification
Kingdom: AnimalPhylum: Chordata
Class: Thaliacea
Pelagic Tunicates:~70 spPlanktonic in oceanLarge perforated pharynx, used for filter feedingIndividuals up to 10in and colonies up to 46ft
Classification
Kingdom: AnimalPhylum: Chordata
Class: Leptocardia
Lancelets:~24 spShallow sand or gravelTropical or temperateSexualExternal fertilization
Vertebrates
• What is a vertebrate?
• Less than 3% of animals are vertebrates
General Characteristics• Subphylum: Vertebrata
• ~64,000 sp
• Vertebral column
• Gills
• CNS
ClassificationKingdom: Animal
Phylum: ChordataSubphylum: Vertebrata
Class: Mammalia Class: AvesClass: Reptilia Class: AmphibiaClass: Myxini (Hagfish) Class: Cephalaspidomorphi (Lampreys)Class: Chondrichthyes (Cartilaginous Fish)Class: Osteichthyes (Bony Fish)
September 11th and 15th: Fish
• What are fish?
• Informal collection of diverse animals• 4 classes
General Characteristics• Largest group of vertebrates
• Has gills
• Has scales
• Ectothermic (Cold-blooded)
• Maneuvers using fins (median and/or paired)
General Characteristics• Internal skeleton (material varies)
• Vision varies
• Hearing typically good, utilize swim bladder
• Taste and smell often linked
• Lateral line system, pressure
General Characteristics• Some can detect electrical signals:– Cartilagionous fish receive impulses by structures
called the ampullae of Lorenzini– Located in pores at surface of skin– Contain a conductive gel– Some species can produce electrical currents
Evolution• First appeared more than 500 mya
• Originally jawless
• Jaws eventually evolved from front gill arches
• Cartilaginous fishes appeared around 370 mya
• Typically have 2 chambered heart
Fish Anatomy
Types of Scales
Gill Physiology
Lungfish
• Can breathe air using primitive lung-like organs:
Oxygen Diffusion
• Some fish can diffuse oxygen and CO2 through their skin:
Marine vs. Freshwater
• Salt concentration is different inside the fish vs. outside environment:– Marine need to keep water in– Freshwater need to keep water out– Osmosis
Marine vs. Freshwater
• Salmon, lampreys, sharks, and rays– Same concentration inside and out
• Able to transfer salt in and out of their bodies
Temperature Control• Seek sun and/or shade
• Alter pigments
• Change depth
• Blood contains antifreeze-like protein (Icefish)
• Conserve heat generated by large swimming muscles (GW shark, tuna, etc.)
Reproduction• Sexual
• Usually external fertilization
• Timing is varied
• Location is varied
• Sperm = milt; eggs = roe
Parental Care
• None
• Nest guarding
• Mouthbrooding
• Ex. Sea Horses
Class: Myxini and Cephalaspidomorphi
• What are jawless fishes?
• ~90 sp
General Characteristics• Elongated bodies
• Smooth, scaleless skin
• Jawless mouth
• Varied habitats
• Can be parasitic
Lamprey Anatomy
• Moderate vision• Breed in freshwater, adults typically marine• Pass through several larval stages
Hagfish Anatomy
Can secrete slime Totally marine
Virtually blind No larval stages
Class: Chondrichthyes
• What are cartilaginous fish?
• ~810 sp• Sharks, skates, rays
General Characteristics
• Skeleton made from cartilage
• Specialized teeth, replaced continuously
• Skin covered in toothlike scales
• Mostly marine
General Characteristics
• No swim bladder
• Carnivorous
• Oil-rich liver increases buoyancy
• Mostly negatively buoyant, much keep swimming
General Characteristics
• All have ampullae of Lorenzini
• Most have lateral line systems
• Good sense of smell
• Internal fertilization
Reproduction• 3 process of producing young:– Release leathery egg cases (mermaid pouches)– Young hatch from egg inside female’s body– Young develop inside a placentalike structure
No larval stage
Sharks• Frilled Shark:
ovoviviparous, 6.5ft
• Spotted Wobbegong: viviparous, 6ft
Sharks
• Basking Shark: ovoviviparous, 33ft
• Tiger Shark: ovoviviparous, 20ft
Sharks
• Bull Shark: viviparous, 11ft
• Shortfin Mako: ovoviviparous, 13ft
Sharks
• Whale Shark: viviparous, 39ft
• Great White Shark: viviparous, 20ft
Skates and Rays
• Smalltooth Sawfish: viviparous, 20ft
• Manta Ray: viviparous, 20ft
Skates and Rays
• Eagle Ray: viviparous, 8.5ft
• Blue-spotted Stingray: viviparous, 6.5ft
Class: Osteichthyes
• What is a bony fish?
• ~23,500 sp• 2 subclasses: Lobe finned and Ray finned
General Characteristics
• Skeleton made from bone
• Most have swim bladder
• Varied aquatic habitats
• Often good vision and hearing
General Characteristics• Typically external fertilization
• Some hermaphroditic species– Both sequential and simultaneous
• Schooling
• Most pass through larval phases
Subclass: Sarcopterygii
Lobe-finned fishes:
Lobe Fin Anatomy
Coelacanth
• Thought extinct for 65 million years
Subclass: Actinopterygii
Ray-finned fishes:
Ray-finned Fishes
• European Sturgeon: 11ft
• Snipe Eel: 30in
Ray-finned Fishes
• Gulper Eel: 39in
• Atlantic Herring: 16in
Ray-finned Fishes
• Red Piranha: 13in
• Wels: 16ft
Ray-finned Fishes
• Candiru: 1in
• Electric Eel: 8.5ft
Ray-finned Fishes
• Sockeye Salmon: 33in
• Sloane’s Viperfish: 14in
Ray-finned Fishes
• Bearded Angler: 4in
• Oarfish: 26ft
Ray-finned Fishes
• Weedy Seadragon: 18in
• Giant Grouper: 8.5ft
Ray-finned Fishes
• Blue Marlin: 14ft
• Oceanic Sunfish: 13ft
September 23rd and 24th: Amphibians
• What is an amphibian?
• ~5,000 sp
General Characteristics• Wet skinned
• Often terrestrial as adults
• Require water to reproduce
• Usually have 4 limbs
• Ectothermic
Skeleton
• Amphibians have very simplistic skeletons, with far fewer bones than other vertebrates, including fish
Skin• Naked, smooth, no hair or scales
• Permeable to air and water
• All have mucous glands
• All have poison glands
• Can be highly pigmented
Reproduction
• Sexual• External• Requires water
Amphibian Life Cycle
Devonian Park
• During the Triassic and Cretaceous many amphibians were apex predators
Labyrinthodontia
Circulatory System
• Typically have a 3 chambered heart
Respiration• Most have lungs
as adults
• Also exchange gases through their skin
• This requires them to stay moist
• Very few live in dry terrestrial biomes
Classification
Kingdom: AnimalPhylum: Chordata
Class: AmphibiaOrder: Caudata
Newts and Salamanders:~470All have larval stagesInternal fertilizationSperm transferred by spermatophoresMany brightly colored, toxic species3 different life cycle types: amphibious, terrestrial, aquatic
Caudata Pictures
Classification
Kingdom: AnimalPhylum: Chordata
Class: AmphibiaOrder: Gymnophiona
Caecilians:~170 spLive in burrows in soil or underwaterOviparous or ovoviviparousSuperficially resemble worms of snakesFeeding tentacle below eye, sharp teeth
Gymnophiona Pictures
Classification
Kingdom: AnimalPhylum: Chordata
Class: AmphibiaOrder: Anura
Frogs and Toads:~4,380 spPredatory as adults, herbivores as larvaWalk, run, hop, swimVaried feet adaptations for lifestyleAmplexus = breeding ‘embrace’
Anura Pictures
Indicator Species
Amphibians in Danger
Panama’s Golden Frog
October 2nd, 6th, and 8th: Reptiles
• What is a reptile?
• 7,984 named species
General Characteristics• Amniotes
• Epidermal scales
• Paired feet with 5 toes
• Lungs
• 4 or 3 chambered heart, closed system
General Characteristics
• Internal fertilization
• Eggs have hard shell
• Ectothermic
• No larval stage
• Can be viviparous
General Characteristics• Typically sexual, some species undergo
parthenogenesis– All offspring are haploid and male
• Can be totally terrestrial
• First appeared ~340 mya
• Dominant land animals during Mesozoic
Living Fossils
• Crocodiles
• Tuataras
Classification
Kingdom: AnimalPhylum: Chordata
Class: ReptiliaOrder: Chelonia
Tortoises and Turtles:~294 spFirst appeared ~200mya, evolved very little sinceHard shell, not removable4 limbsMany undergo vast migrations
Vocabulary
• Then:– Tortoise = terrestrial– Terrapin = freshwater– Turtle = marine
• Now:– Turtle = all of the above
Chelonia Anatomy
Chelonia Shell Types
Chelonia Pictures
Classification
Kingdom: AnimalPhylum: Chordata
Class: ReptiliaOrder: Rhynchocephalia
Tuataras:2 spOn 2 group of New Zealand IslandsVery cold tolerantLive in burrowsGrow slowly, breed infrequently, live long (~100 yrs)
Rhynchocephalia Pictures
Classification
Kingdom: AnimalPhylum: Chordata
Class: ReptiliaOrder: Squamata
Suborder: SerpentesSnakes:~2,900 spNo ears, no eyelidsUsually only 1 functional lungNo limbsCarnivorous
Classification
Suborder: SerpentesSuperfamily: Henophidia
Boas, Pythons, and Relatives~149 sp
Classification
Suborder: SerpentesSuperfamily: Caenophidia
Family: Colubridae
Colubrids (typical snakes)~1,858 sp
Classification
Suborder: SerpentesSuperfamily: Caenophidia
Family: Elapidae
Elapsids (100% venomous)~291 sp
Classification
Suborder: SerpentesSuperfamily: Caenophidia
Family: Viperidae
Vipers(highly evolved fangs)~228 sp
Classification
Kingdom: AnimalPhylum: Chordata
Class: ReptiliaOrder: Squamata
Suborder: LacertiliaLizards:~4,500 sp
Classification
Suborder: LacertiliaSuperfamily: Iguania
Iguanas, Chameleons~1,412 sp
Classification
Suborder: LacertiliaSuperfamily: Gekkota
Geckos~1,054 sp
Classification
Suborder: LacertiliaSuperfamily: Scincomorpha
Skinks~1,890 sp
Classification
Suborder: LacertiliaSuperfamily: Anguimorpha
Monitors, Glass Lizards~173 spIntelligent (can count)
Anguimorpha• Ancestors of snakes
• Contains both poisonous lizards– Gila Monster– Mexican Bearded Lizard
• Contains largest lizards– Komodo Dragon
• 155lbs• Up to 9 ft long
Classification
Kingdom: AnimalPhylum: Chordata
Class: ReptiliaOrder: Squamata
Suborder: Amphisbaenia
Amphisbaenians:158 sp
Amphisbaenians• Superficially resemble worms
• 3 species have front limbs
• Live underground
• Concentric rings of scales
• Pelvic girdle remnant
Classification
Kingdom: AnimalPhylum: Chordata
Class: ReptiliaOrder: Crocodilia
Crocodiles and Alligators:23 spApex predatorsAmbush attacksParental careHunt large prey, store in underwater larders
General Characteristics• Teeth in sockets, hollow, regrow
• Glands on tongue eliminate salt
• Erect posture, modified ankles
• Can reach 16 km/hr through forest
• Closest living relative to birds
Crocodilia Pictures
Extinct Monsters
CaimanCrocodileAlligatorCrocodileGharialCrocodileSaltwaterCrocodile (largest living reptile)