Chapter 17 Animals Part II

Chapter 17 Animals Part II - BIOS 1063 Chapter 17 Evolution...

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BIOS 1063 Chapter 17 Evolution of Animals Part II II. Echinoderms Phylum: Echinodermata (Sea stars, brittle stars,sea urchins). The name means Spiny skin- Echinoderms are Deuterostomes and so are all vertebrates. All the animals with a complete digestive system that we have discussed thus far (from roundworms to arthropods) are protostomes. This means that the opening of their digestive tract that they form first during embryonic development is the mouth. (protostomes). Deuterostomes form the anus opening first during development. (Deutero means the end; and stomes means opening ergo the end opening). Endoskeleton- endoskeleton (inside skeleton) spines stick through a thin epidermis-which is where they get their name meaning spiny skin. Echinoderms best characterized by their water vascular system. Water Vascular system: gas exchange, waste disposal, and extend tube feet for locomotion. Sea Stars (star fish) Brittle stars Sea Urchins Sand dollars III. Phylum Chordata . During embryonic development, all chordates including humans share these characteristics: 1. Dorsal hollow nerve cord (this forms the chordate brain and spinal cord) 2. Notochord: flexible longitudinal rod located between the digestive tract and the nerve cord (This forms the back bone, as human adults. Our notochord is reduced to just the cartilaginous disks between the vertebra) 3. Pharyngeal Gill Slits -gill structures in the pharynx ( (these will close before birth in humans and other mammals, however some humans are born with gills). We also have webbed fingers and toes during embryonic development. 4. Post-anal tail : We lose the tail before birth, however on occasion, humans are born with a tail, which they surgically remove. These characteristics are found in all chordate embryos and may carry over to adult forms. There are 3 Sub-Phylums of Chordates, but we will concentrate on only the third subphylum-Vertebrates. 1. Tunicates (found only in aquatic environments)
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2. Lancelets (found only in aquatic environments) 3. Vertebrates (found in both aquatic and terrestrial environments) Vertebrates: Unique characteristics of vertebrates: We have a cranium (skull for our brain) and a backbone-as vertebra Fishes: Two Super Classes of Vertebrates A. Agnathans- (without jaws)
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This note was uploaded on 06/02/2011 for the course BIO 1083 taught by Professor Williamson during the Spring '08 term at University of New Orleans.

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Chapter 17 Animals Part II - BIOS 1063 Chapter 17 Evolution...

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