Unit 2: Fish, Amphibians, Reptiles

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)