Lab Practical 2 Diagrams PDF

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Dr. Moran...

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Sea Urchins: Tripneustes gratillia: ● Collector urchin ● Omnivorous grazers ● Dioecious ● Variation of colors ● Attains overall diameter of 10-15cm ● Hawaii and Indo-Pacific Life Cycle

Fertilization: ● Makes diploid zygote (2n) from 2 haploid gametes (1n) ● Contact of sperm to egg’s vitelline layer causes the acrosomal membrane of sperm to dissolve releasing enzymes used to break down vitelline layer ● Na+ concentration in egg changes ● Fast block to polyspermy ● Sperm’s acrosome goes through serious of chemical reactions moving toward egg’s plasma membrane ● Sperm binds to plasma membrane Process of Fertilization: ● Depolarization from Na+ changes Ca++ concentration in egg and fertilization envelope forms - slow block to polyspermy ● Sperm head enters cytoplasm - form male pronucleus ● Pronucleus fuses with egg nucleus, regenerating 2n chromosomes → zygote ● Mitosis (first cleavage) occurs

Polyspermy: ● When more than one sperm fertilizes a single egg ● Results in too many copies of chromosomes (3N+) ● Zygote inviable Blocks to Polyspermy: ● Slow Block - sperm binds to the egg's plasma membrane, changing ionic concentration in the egg. Cortical vesicles fuse to plasma membrane forming a visible fertilization envelope ● Fast Block - ionic concentrations in the egg change at 1st binding sperm to vitelline layer and release of acrosomal enzymes (Na+ concentration) Sea Urchin Development: ● Germinal vesicle ● Unfertilized eggs ● Pronucleus ● 1 Cell (zygotes) ● 2 cell (1st cleavage) ● 4 cell (2nd cleavage) ● 8 cell (3rd cleavage)

Q10 and Reaction Rates (temperature coefficient): ● Q10 measures temperature sensitivity of enzymatic reaction rate or physiological process due to increase by 10C ● Discontinuities indicate physiological perturbations ● Q10 values are around 2 and reflect doubling of molecules with energy higher than the activation energy required for an enzymatic reaction to occur ● Rate of reaction at 10C intervals ● Q10 = RT / RT-10 ● Doubles with each 10C → Q10=2 ● Usually Q10 is 2 or 3 ● Q10 = rate at higher temperature / rate at lower temperature

Q10 = (R2/R1) ^10C/(T2-T1) Temperatures to rise by 1-4C by 2100 Temperature impacts rate of development in marine invertebrates and success of developing larvae. Polyspermy: enr of multiple sperm nuclei into one egg Has both a fast and slow block to polyspermy Slow block: cortical granules around outside of a fertilized egg release contents into space around egg, forming fertilization envelope Thermal tolerance assays - temperature experiment ● 20C - 40C ● Incubated for 48 hours

Echinoderms: ● Deuterostomes - mouth second ● Bilateral symmetry in early development ● Later pentaradial symmetry ● Water vascular system ● Oral-aboral axis ● Radial cleavage in early embryo Water Vascular System: ● Madreporite - Regulates input of seawater into water vascular system ● Stone Canal - Cilia along the canal pumps water and maintains water pressure ● Ring Canal - Distributes water to all arms ● Polian Vesicle - Holds reserved water to maintain adequate water pressure ● Tiedemann’s Body - Filters incoming sea water to remove impurities ● Radial Canal - Distributes water to the tube feet ● Tube Feet - For walking and grasping

Echinoderm Classes: ● Asteroidea (sea stars) ● Echinoidea (urchins and sand dollars) ● Ophiuroidea (brittle stars) ● Holothuroidea (sea cucumbers) ● Crinoidea (crinoids) Asteroidea (sea stars): ● Distributed throughout the world’s oceans ● Generally carnivores or detritivores ● Flattened and pentaradially symmetrical ● Open ambulacral grooves, an aboral madreporite, and numerous pedicellariae in many species

Ophiuroidea (brittle stars): ● Found in most parts of the world, from Artic and Antartic to the tropics ● Carnivores, filter feeders, and scavengers ● Stomach does not extend into arms ● Digestion in folds of stomachs ● Burase: cilia-lined sacs responsible for gas exchange and secretion ● Madreporite on oral side ● Locomotion by bending and twisting of whip like arms - jointed ossicles ● No arms or anus ● Madreporite on oral side ● No pedicellariae and ambulacral grooves are closed

Echinoidea (sea urchins and sand dollars): ● Spherical body without arms ● Herbivores and nonselective grazers ● Rigid endoskeleton called a test ● Test - made of ossicles that cannot be moved independently ● Regular (urchins) and irregular (sand dollars and sea biscuits) ● Sand dollars have tertiary bilateral symmetry Holothuroidea (Sea cucumbers): ● Retain pentaradial symmetry with 5 rows of tube feet ● 10-30 tentacles (WVS) surrounding the mouth ● Breathe by pumping water through paired respiratory tree (cloaca) ● Skeletal plates are reduced to microscopic spicules, often shaped like wheels, bars, or anchors ● Tertiary bilateral symmetry

Paired respiratory trees make them bilateral as adults

Crinoidea (sea lilies and feather stars): ● Stalked sea lilies ● Free-living feather stars ● Abundant in Paleozoic seas, but today crinoids ● Declining group of only about 700 species ● Passive suspension feeders ● Mouth on the top surface surrounded by feeding arms ● U-shaped gut ● Most crinoids have many more than 5 arms

Dissections: ● Sea star - Asterias sp. ● 2 arms adjacent to madreporite - bivium ● 3 other arms - trivium ● Integument (epidermis and dermis)

Sea Star Larvae:

Blastula

Brittle Star Anatomy

Gastrula

Bipinnaria

Sea Urchins: Echinometra mathaei

Echinometra mathaei

Heterocentrotus mamillatus

Tripneustes gratilla

Sea Urchin - inter/ambulacra

Aristotle's Lantern - Echinoidea - scrape algae and food from rocks

Respiratory trees connected by cloaca, which leads to anus Internal madreporite opens into coelom

Feather star - stalked - columnal is disc shaped ossicles - Crinoidea Sea Star Development

Bipinnaria Larva

Sand Dollar Anatomy: Echinoidea - Clypeasteroida - Mellita quinquiesperforata

Seabiscuit - Echinoidea - Clypeasteroida - Clypeaster rosaceus

Phylum Hemichordata: ● Tripartite body plan ● 2 Classes - Pterobranchia (colonial filter-feeder) and Enteropneusta (large, solitary worms) Class Enteropneusta (acorn worms):

Acorn Worm

Tornaria - ring of cilia = telotroch

Phylum Chordata: ● Subphylum - Cephalochordata (sand lances and lancelets) ● Subphylum - Tunicata (Urochordata - ascidians, sea squirts, and salps) ● Acrania (without cranium) - contains tunicata and cephalochordata 4 Features of Chordates: 1. Dorsal notochord 2. Dorsal hollow (tubular) nerve chord 3. Postanal tail 4. Pharyngeal gill slits

Subphylum Cephalochordata: ● Filter - feed ● Best known and studied is Branchiostoma sp. (Amphioxus)

Tunicate Water Flow Tunicata - Class Ascidiacea

Tadpole Larvae - Ascidiacea - Tunicata

Tunicate - Siphons Anatomy

Salps - Class Thaliacea - Tunicata

Thaliacean -

Class Appendicularia: ● Solitary and pelagic lifestyle

Appendicularians / Larvaceans - mucous house - Class Appendicularia - Subphylum Tunicata

Pterobranchia

P. Chordata - SP. Cephalochordata - Amphioxus sp.

P. Chordata - SP. Cephalochordata - Amphioxus sp.

P. Chordata. SP. Tunicata. C. Ascidiacea. Phallusia sp. Siphons

BOTH - Tadpole larva - P. Chordata - SP. Tunicata - C. Ascidiacea - Metamorphosis

Solitary Tunicate Anatomy

Sea Urchin Dissection P. Echinodermata - C. Echinoidea - Arbacia punctulata

Star Fish Dissection...