Date post: | 18-Aug-2015 |
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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