Compound microscope allows you to view only very thin transparent objects thin slices or microscopic organisms made into slides Magnification M OO magnification ocular x objective lens o Ocular lens always 10x magnification Objective magnification is either 4x 10x 40x or 100x Magnification is always either 40x 100x 400x or 1000x Terminology eyepiece ocular ocular focus objective arm stage coarse focus knob fine adjustment iris diaphragm condenser Dissecting microscope enables you to see in 3D stereoscopically while viewing opaque objects eg Dissections entire small organisms and to view transparent objects large slides or whole mounts Terminology eyepiece ocular ocular focus objective arm stage coarse focus knob base plate magnification selector or zoom Porifera pore bearing animals Cellular level of organization Have unique flagellated collar cells called choanocytes that drive water through the canals and chambers Adults are sessile suspension feeders larval stages are motile Body wall consists of 3 components 1 epidermis with incurrent pores 2 mesohyl middle layer a non cellular protein matrix containing spicules sponging and amoebocytes archaeocytes Inner layer with choanocytes 3 Skeletal elements consist of spicules made from calcium carbonate or silicon dioxide and or spongin protein fibers Amoebocytes archaeocytes are totipotent can develop into all other sponge cell types There are 3 body types based on complexity degree of folding 1 asconoid syconoid 2 3 leuconoid C Calcarea o CaCO3 spicules C Hexactinellida o Six rayed SiO2 spicules C Demospongiae o SiO2 spicules and sponging Sexual reproduction o Monoecious hermaphroditic both sexes in one individual o Dioecious separate sexes Asexual reproduction o Budding o Fragmentation o Regeneration o Gemmules freshwater sponges only Spicules found in all 3 body types Asconoid body type o This is the simplest body type Note how much smaller these sponges are than the leuconoid body type sponges Why is there such a difference in sizes Hint SA o No folding of the spongocoel Syconoid body type o This is a sponge with a slightly more complex body type It has outpocketings of the spongocoel called radial canals o Can you find the spongocoel Where are the choanocytes located Leuconoid body type o The venus flower basket forms a symbiosis with a pair of bioluminescent shrimp The shrimp can clean the inside of the basket and the sponge provides food for the shrimp o Leuconoid sponges display the greatest degree of structural complexity They have a high degree of folding thereby increasing their internal surface area to volume ratio Has flagellated chambers instead of radial canals Cnidaria nettle bearing animals 3 classes o C Hydrozoa polyp is dominant but possesses a medusa at some point o C Scyphozoan medusa is dominant but possesses a polyp at some point o C Anthozoa polyp ONLY Tissue level of organization no organs Diploblastic 2 tissue layers 1 outer epidermis derived from the ectoderm 2 inner gastrodermis derived from the endoderm Mesoglea non cellular middle layer that provides support between the 2 tissue layers Have specialized stinging cells called cnidocytes that have unique organelles called Radially symmetrical and the primary body axis is oral aboral nematocysts within them These nematocysts are like mini harpoons that can be ejected and used for anchorage defense and prey capture The GVC gastrovascular cavity is saclike and has only one opening which serves as both mouth AND anus In addition to its role in digestion it also functions as a hydrostatic skeleton Respiration and excretion take place via diffusion Nervous system is a simple nerve net 2 body forms that can occur in the life cycle o Polyp sessile o Medusa motile o Which of these forms is dominant in the life cycle depends on the class Typically have planula larvae ciliated and motile C Hydrozoa o Polymorphism means having more than 1 form monomorphism having only one form Dimorphism having 2 forms o Cnidarians often form colonies that consist of many zooids polyps Thee zooids are often polymorphic and are specialized for certain functions Gastrozooid feeding zooid Gonozooid sexually reproductive zooids Dactylzooids defensive zooids o This hydrozoan secretes a calcareous skeleton The small pits you can see are where the polyp sticks out It is called fore coral because the many defensive polyps dactylzooids inflict a burning rash when touched o Note the asexual buds o Note the 2 tissue layers and the thin mesoglea layer in between o Note the gonads o Hydra is an atypical representative of the class hydrozoa Most hydrozoans are marine colonial and have a short medusoid stage BUT hydra is freshwater solitary and has no medusoid stage o Hydrozoa has a think mesoglea Scyphozoan has a thick mesoglea o This scyphozoan is called the cannonball jellyfish because the mesoglea is so thick To protect themselves from predators juvenile jacks a type of fish position themselves above the stinging tentacles of the jellyfish C Scyphozoa o Life cycle of the scyphozoan moon jellyfish 1 planula scyphistoma 2 3 strobila 4 ephyra Class Anthozoa zoanthids o Symbiosis sea anemone on a gastropoda shell symbiotic with a hermit crab o Members of this subclass include the sea anemones stony corals and o These are the skeletons of a variety of stony scleratinian corals They secrete skeletons of calcium carbonate that accumulate over time to form coral reefs o Members of this subclass include the pipe corals and the soft corals sea pens sea pansies sea fans sea whips They are colonial and always have 8 tentacles that are branching They secrete a skeleton of protein Platyhelminthes Acoelomates No coelom mesynchyme fills blastocoel Fate of blastocoel Acoelomate NOT taxonomic classification Triploblastic 3 germ layers 1 Germ layer ectoderm Tissue layer epidermis 2 Germ layer mesoderm Tissue layer mesenchyme 3 Germ layer endoderm Tissue layer gastrodermis Symmetry bilateral symmetry right and left sides Dorsal ventral anterior posterior Skeleton support hydrostatic skeleton Mesenchyme provides support Movement locomotion muscles work against hydrostatic skeleton Longitudinal circular transverse muscles Sensory nervous system cephalization 1 direction anterior mass of ganglia Sensory organs ocelli light sensing Auricles chemoreception Advanced forms ladder like nervous system Excretory system protonephridia flame cells removes waste water Circulatory system diffusion Respiratory system diffusion
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