ACTIVITY 1 DICHOTOMOUS KEY

TAXONOMIC KEYS Aid for rapid identification of unknown organism. Constitute important literature (manuals, monographs, floras, etc.) Key characters (diagnostic characters, important & conspicuous characters) Unknown organism must be carefully studied, described, and characterized before identification.

DICHOTOMOUS KEY - consist of a series of paired statements, termedcouplets, which describe some feature of the organism.

TYPES OF DICHOTOMOUS KEY1. Yoked or Intented1. Fruit an chene 1. Calyx differentiated from corolla ... 1. Ronunculus 2. Calyx not differentiated from corolla . 2. Clematis2. Couplet1. Animals with backbone Go to 21. Animals without backbone Go to 142. Vertebrates with feathers Go to 33. Branch

GUIDELINES FOR CONSTRUCTING DICHOTOMOUS KEYS1. Should be dichotomous (pair or 2)2. Two leads should of a couplet should be mutually exclusive3. Statements should not overlap4. Two leads should start with the same initial word5. Initial words should not be successive6. Vegetative and reproductive characters should be separate7. Avoid vague statements8. Male and female characteristics of dioucious plants should be separate9. Couplets should be divided into equal halves10. Leads should be prefixed by numbers or letters

ACTIVITY 2 PORIFERA

SPONGES or PORIFERANS Latin porus pore and ferre tc bear Animals of the phylum porifera Translates from Latin Pore-bearer Primitive, sessile, mostly marine, water dwelling, filter feeders Pump water through their bodies that filter out food particles Simplest animals Parazoa no true tissues Lack muscles, nerves, and internal organs Similarity to colonial choanoflagellates show probable evolution jump from unicellular to becoming multicellular

TYPES OF CELL IN PORIFERANS1. Choanocytesa. Collar cellsb. Functions as the sponges digestivec. Microvillis that are used to filter particlesd. Beating of flagellum creates sponges water current2. Porocytesa. Tubular cellsb. Make up the pores into the sponges body through the mesohyl3. Pinacocytesa. Pinacodermb. Outer epidermal layer of cells4. Archaeocytes or Amoebocytesa. Totipotent cellsb. Transforms into sclerocytes, spongocytes, or collencytes

5. Sclerocytesa. Secrete calcareous siliceous spicules which reside in the mesohyl6. Spongocytesa. Secerete spongin, collagen-like fibers which make up the mesohyl7. Collencytesa. Secrete collagen

SPICULES Stiffened rods or spikes Made of calcium carbonate or silica Used for structure and defense Arranged in a gelatinous mesohyl gelatinous non-ceullular matrix

THREE BODY TYPES OF SPONGES1. asconoid2. syconoid3. leuconoid

FOUR CLASSES OF SPONGES1. Calcarea bony2. Hexactenallida glass3. Demonspongiae sponging4. Sclerospongiae coralline sponges