Phylum ChordataPhylum Chordata

What Is A Chordate?What Is A Chordate?

4 characteristics present at some stage of life4 characteristics present at some stage of life

1.1. A dorsal, hollow A dorsal, hollow nerve cordnerve cord (called (called spinal cord in vertebrates)spinal cord in vertebrates)

2.2. NotochordNotochord – a supporting rod – a supporting rod (develops into a backbone in (develops into a backbone in vertebrates)vertebrates)

3.3. Pharyngeal pouchesPharyngeal pouches

4.4. TailTail that extends beyond the anus that extends beyond the anus

General Chordate StructureGeneral Chordate Structure

Notochord

MouthAnusTail

Pharyngeal Pouches

Hollow Nerve CordMuscle Segments

Nonvertebrate ChordatesNonvertebrate Chordates

• TunicatesTunicates - look nothing like - look nothing like other chordatesother chordates– The The larvallarval form has all the form has all the

chordate characteristicschordate characteristics– The adult tunicates have The adult tunicates have

neither a neither a notochordnotochord nor a nor a tailtail

• Lancelets Lancelets are more are more fishlikefishlike and have a definite and have a definite headhead containing a containing a mouthmouth

FishFish

Classes:Classes:

Agnatha – jawless fish Agnatha – jawless fish Chondrichthyes – cartilaginous fishChondrichthyes – cartilaginous fish

Osteichthyes – bony fishOsteichthyes – bony fish

Groups of fishGroups of fishFish are the first vertebrates to evolve

• Jawless Fish – have not true teeth or jaws; ex: lampreys & hagfish, parasitic

• Cartilage Fish – skeleton made of cartilage; ex: sharks, rays, skates

• Bony Fish – skeleton made of hard, calcified tissue bone; ex: perch, goldfish

CharacteristicsCharacteristics

• Integumentary– Scales & paired fins

• Skeletal/ Muscular– Endoskeleton - made of cartilage

or bone

• Circulation– 2-chambered heart; closed-single

loop circulation

• Reproductive– Internal or external; – Oviparous, Ovoviviparous, Viviparous

• Eggs house outside the mothers body• Born alive after developing eggs inside of

mother’s body• Bear live young that are nourished by

mother

• Nervous– Brain, lateral lines

• Respiratory– Gills

CharacteristicsCharacteristics

• Digestive– Variety in types of feeding;

complete digestive system

• Excretory– Remove ammonia from gills &

kidneys

CharacteristicsCharacteristics

• Body Temperature– Ectothermic

• Habitat– Marine & Fresh Water

CharacteristicsCharacteristics

Bony Fish Structures

Mouth

Eye

Operculum

Caudal fin

Lateral line

Dorsal Fins

Anal finPectoral

fin Pelvic fin

Swim Bladder

Gills

Brain

Spinal Cord

Heart

Liver

Reproductive organ

Anus

Intestine

StomachGallbladder

AmphibiansAmphibians

Class Amphibia

• Amphibians are tetrapod vertebrates (four footed)

• Include all tetrapod vertebrates that are not amniotes (lay eggs on land)

• Frogs, toads, salamanders, and newts

CharacteristicsCharacteristics

• Integumentary– Moist skin with mucus glands– Found near moist habitats to

keep skin damp

• Skeletal/Muscular– Endoskeleton– Adult: legs for walking or

jumping; no legs– Larva: swim

CharacteristicsCharacteristics

• Circulatory– Adult: 3 chambered heart,

closed-double loop– Larva: 2 chambered heart

• Reproductive– External fertilization; eggs must

stay moist (no shell)

CharacteristicsCharacteristics

• Nervous– Brain; eyes w/ nictitating

membrane; tympanic membrane (like a

drum) for hearing; lateral lines

• Respiratory– Adult: through lungs, skin, &

lining of the mouth– Larva: through skin and gills

CharacteristicsCharacteristics

• Digestive– Complete digestive system

(mouth --> anus)– Adult: carnivore– Larva: herbivore or filter feeder

• Excretory– Kidneys filter wastes from blood,

urine travels through ureters to urinary bladder and out through cloaca

CharacteristicsCharacteristics

• Body Temperature– Ectothermic (cold blooded, find

heat from an outside source like the sun)

• Habitat– Adult: live on land near water– Larva: live in water

Lifecycle of a FrogAdult FrogAdult Frog

Young Frog

Young Frog

Fertilized EggsFertilized Eggs

TadpolesTadpoles

Adults are typically ready tobreed in about one to two years.

Adults are typically ready tobreed in about one to two years.

Frog eggs are laid in water andundergo external fertilization.

Frog eggs are laid in water andundergo external fertilization.

The eggs hatch into tadpoles a

few days to several weeks

later.

The eggs hatch into tadpoles a

few days to several weeks

later.

Tadpoles gradually grow limbs, lose their tails and gills, andbecome meat-eaters as they develop into terrestrial adults.Tadpoles gradually grow limbs, lose their tails and gills, andbecome meat-eaters as they develop into terrestrial adults.

Evolution

• The first amphibians looked similar to lobe-finned fish

Groups of Amphibians

• Salamanders – have long bodies & tails, most have 4 legs, usually live in moist woods

Groups of Amphibians

• Frogs & toads – both jump & lack tails; frogs more closely tied to water

Groups of Amphibians

• Caecilians – legless animals; live in water or burrow in moist soil; many have fishlike scales,resemble earthworms or snakes