Deuterostomes

• First embryonic opening becomes the anus• Includes the phyla Echinodermata and Chordata

Echinodermata• Marine animals• Bilateral symmetry (larvae)• Three tissue layers• Coelomates• Hard exoskeleton

– Name means “spiny skinned”• Movement: water vascular

system– Tube feet that create or release

suction• Today: Dissect starfish

Examples of bilateral larvae

Chordata

• Not all chordates are vertebrates• Chordates have the following characteristics as

embryos:• Dorsal (back) tubular nerve cord• A notochord

– Supportive rod

• A post anal tail• Pharyngeal pouches that become gill slits

Visual of chordate characteristi cs

Tunicates (Urochordates)

• Invertebrate chordates• Adults maintain gill slits• Observe pictures and

models in lab

Cephalochordates

• Invertebrates• Lancelet example• Adult has all 4

characteristics• Observe pictures and

models in lab

Vertebrate Innovations• Vertebral column• Segementation and

specialization• Complex brain and cephalization• Jaws• Paired fins, gave rise to limbs• Gills, evolved into lungs

Today: Frog

•Amphibian•First vertebrate able to live on land• Important external

structures:– Tympanum: internal

ear/eardrum– Nares:

nostril/breathing hole

Frog Mouth• Eustacian tube: leads to

ears• Maxillary and vomerine

teeth• Glottis: opens to larnyx,

vocal cords• Esophogus: leads to

stomach

Internal Frog

• If female, find ovaries with eggs• Identify two lungs (partially hidden by liver)

Internal Frog Conti nued

• Liver and gallbladder

• Esophagus and stomach

• Small and large intestines

Internal Frog Conti nued

• Pancreas and spleen• Fat bodies: store fat

Internal Frog Conti nued

• Heart covered by pericardium– Three chambers (1 ventricle, 2 atria)

Internal Frog Conti nued•Kidneys (long and narrow)• Testes (yellow and oval)• Mesonephric ducts: carry urine•Cloaca: opening to outside