Phylum: ChordataPhylum: ChordataVertebratesVertebrates

Fish and AmphibiansFish and Amphibians

Vertebrate CharacteristicsVertebrate Characteristics

To be in the phylum Chordata you must To be in the phylum Chordata you must have these four characteristics at some have these four characteristics at some point in your developmentpoint in your development

1. dorsal, hollow nerve cord 1. dorsal, hollow nerve cord (backbone)(backbone)

2. a notochord (most when embryos)2. a notochord (most when embryos) 3. pharyngeal pouches (turn into gills)3. pharyngeal pouches (turn into gills) 4. tail that extends beyond the anus4. tail that extends beyond the anus

FishesFishes Fishes are aquatic Fishes are aquatic

vertebrates which vertebrates which havehave Paired fins - movementPaired fins - movement Scales – protection Scales – protection

(can tell age of some (can tell age of some fish by counting the fish by counting the rings)rings)

Gills – exchanging Gills – exchanging oxygen and carbon oxygen and carbon dioxidedioxide

Groups of Groups of FishFish

1. Jawless Fish 1. Jawless Fish no teeth or jawsno teeth or jaws Keep notochord as adultsKeep notochord as adults Many are parasites, no Many are parasites, no

swim bladderswim bladder Examples – Examples –

hagfish hagfish

and and

lampreyslampreys

Groups of FishGroups of Fish 2. Cartilaginous Fish2. Cartilaginous Fish

Skeleton made of cartilageSkeleton made of cartilage Tooth-like scales covering skinTooth-like scales covering skin 350 species – most are under 3 feet350 species – most are under 3 feet Teeth are replaced when worn out – Teeth are replaced when worn out –

20,000 in lifetime20,000 in lifetime Examples: sharks, rays, skatesExamples: sharks, rays, skates

Groups of FishGroups of Fish 3. Bony Fish – called ray-finned fish3. Bony Fish – called ray-finned fish

Very diverse groupVery diverse group Most have a swim bladderMost have a swim bladder Anadromous fish can move from salt to Anadromous fish can move from salt to

fresh waterfresh water

AmphibiansAmphibians Amphibian means double Amphibian means double

life –water and landlife –water and land Larvae- use gills- live in Larvae- use gills- live in

waterwater Adults – use Adults – use lungslungs – –

live on landlive on land Moist skinMoist skin No scalesNo scales No clawsNo claws Tympanic membrane Tympanic membrane

behind eye (earbehind eye (ear))

Surinam FrogAfter the female lays her pea-sized eggs, the male places them on her back and pushes them into her spongy skin. The eggs incubate as mom's new skin slowly develops and covers them, keeping them safe and out of sight. They then hatch out of her back.

Life cycle of FrogsLife cycle of Frogs

Groups of Groups of AmphibiansAmphibians

1. Salamanders1. Salamanders Long bodies and tailsLong bodies and tails Four legsFour legs CarnivoresCarnivores Live in moist woods Live in moist woods Some keep gills their entire Some keep gills their entire

liveslives

Groups of AmphibiansGroups of Amphibians2.Frogs and Toads

Frogs – long legs for jumping and they are closely tied to water.

Toads – short legs and often live in moist woods or even deserts.

Groups of AmphibiansGroups of Amphibians

3. Caecilians – legless animals that 3. Caecilians – legless animals that live in water or burrow in moist soil. live in water or burrow in moist soil. Some feed on termites. Fish like scales Some feed on termites. Fish like scales in their skin.in their skin.