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Echinoderms. Goals of the lab: to introduce general characteristics of the phylum Echinodermata to understand the embryological differences between protostomes.

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Presentation on theme: "Echinoderms. Goals of the lab: to introduce general characteristics of the phylum Echinodermata to understand the embryological differences between protostomes."— Presentation transcript:

1 Echinoderms

2 Goals of the lab: to introduce general characteristics of the phylum Echinodermata to understand the embryological differences between protostomes and deuterostomes to observe initial stages of embryo development, using prepared slides of starfish embryos to examine external and internal features of the starfish, as a representative of the phylum Echinodermata Echinoderms

3 Phylum Echinodermata eumetazoan (true tissues) bilaterally symmetrical larvae; radially symmetrical adults eucoelomate deuterostome

4 Phylum Echinodermata Class Astroidae Class Ophiuroidae Class Echinoidae Class Holothuroidae Class Crinoidae Sea starsBrittle stars Crinoids Sea urchinsSea cucumbers

5 Phylum Echinodermata No circulatory system No respiratory system Excretion (N elimination) by diffusion Simple nervous system, no brain Water-vascular system

6 A Comparison of Early Development in Protostomes and Deuterostomes

7 Early Embryonic Development

8 Unfertilized egg Starfish Development 2 blastomeres After fertilization & 1st cleavage 4 blastomeres 2nd cleavage 8 blastomeres 3rd cleavage 16 blastomeres 4th cleavage 32 blastomeres 6th cleavag e, next slide 5th cleavage

9 Starfish Development (continued) 64 blastomeres Non-motile blastula Ciliated blastula * blastula is same size as unfertilized egg Gastrula: Beginning invagination blastopore Gastrula: During invagination Gastrula: Archenteron, no mesenchyme Next slide

10 Starfish Development (continued) Gastrula: Archenteron with mesenchyme Late gastrula: lateral view Early bipinnaria larva, lateral view Brachiolaria larvaYoung starfish Late bipinnaria larva, lateral view blastopore becomes anus 2nd opening becomes mouth

11 Sea urchin larvae: pluteus Starfish larvae: Bipinnaria Sea cucumber & Crinoid: doliolaria larvae Brittle star larvae: pluteus

12 Phylum Echinodermata Tube feet & associated plumbing Used for walking, clinging to substrate & holding food Water Vascular System

13 Starfish water vascular system

14 Class Echinoidea: sea urchins Echinometra mathaei Collector urchin Echinothrix calamaris

15 Class Echinoidea: sea urchins Diadema

16 Class Echinoidea: sea urchins Slate pencil urchin

17 Colobocentrotus atratus Class Echinoidea: sea urchins

18 Class Holothuroidea: Sea Cucumbers Holothuria atra Polyplectana kerfersteninii

19 Class Holothuroidea: Sea Cucumbers Pearlfish in seacucumber

20 Linckia sp. Class Asteroidea: Sea Stars Pin cushion

21 Class Asteroidea: Sea Stars starfish/acanthaster-planci/video-00.html

22 Class Ophiuroidea: Brittle Stars Ophiocoma erinaceus

23 Class Crinoidea: Feather Stars

24 Starfish Dissection: Schematic View

25 Starfish: Oral View MouthAmbulacral grooveSpines Tube feet

26 Starfish Dissection: Skeleton Removed: Aboral View Stone canalDigestive glandsGonadsPyloric stomach Cardiac stomach

27 Starfish Arm: Digestive Glands Removed Ambulacral PlatesAmpullaeCardiac Stomach Gonads

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