BIOS 173 
Lab 1 
Taxonomy / Porifera

 
 

Introduction

Bios 173 is a laboratory survey of the animal kingdom and the Bios 172 lecture you may also be enrolled in this quarter is an introduction to the study of evolution, animal behavior and ecology. Together these will complete the sequence of Introductory Zoology courses for science majors. Since the prerequisites Bios 170/171 serve as an introduction to molecules, cells, genetics and animal organ systems, animal development respectively, upon completion of Bios 172/173, you will have had an overview of all major zoological areas.

Each week in lab we will study a phylum within Kingdom Animalia. Our coverage will be limited to 11 of the 33 animal phyla. Whole animals will be observed, some live, some in the "museum display" and some to be dissected. Certain key structures and developmental stages will be further studied with the aid of the microscope and prepared slides. Film loops of representative groups, narrated by your instructor, will help to illustrate the feeding and reproductive behaviors described in the Buchsbaum lab text. Study the Buchsbaum text thoroughly before each lab meeting and bring it to every lab to use as a guide while you work. The labeled diagrams and the many photographs will aid in your identification of external anatomy and the internal structures you will be observing in the dissections and slides. Generally, your focus in lab each week will involve three areas:

  1. Taxonomy: For each phylum you will be responsible for the classes within and a few representative genera.
  2. Comparison of body plans: Each phylum is distinguished by characteristics that make it unique from other phyla. Likewise, each class within a phylum has both unifying and distinct traits that you will be asked to recognize.
  3. Phylogeny: The evolutionary history and the relatedness of each phylum will be studied based on evidence provided by the fossil record, developmental stages, molecular studies and morphology.

Science Magazine Tree of Life

As you work through lab, check off the objectives (gold handout) as you learn them. Use the lab time well. Be sure to study all the materials in lab and record what you see by sketching and taking notes--you may see it again on the practical exam. Even though Bios 172 lecture and 173 lab are separate courses, it may help you to keep a good perspective on all the material you are learning if you realize the information you receive in lecture may apply directly to many of the animals you are studying in lab, and also to those in your nature journal.
 

Getting Started

In this lab we will begin our study of the animal kingdom with Phylum Porifera, the sponges. First, however, it is necessary to set the stage for the existence of animal life on earth. Most scientists agree that animals likely evolved from protist ancestors. (And the eukaryotic protists likely developed from prokaryotic monerans.) Evidence for this and also the basis of our current taxonomic system is explained in Buchsbaum, pp. 2-13 and 532-541. An overview of the history of life on earth as evidenced by the fossil record is found on pp. 504-531. To better understand the evolution of complex life forms it is helpful to be familiar with the structure and function and behavior of the simpler forms. To this end, read Buchsbaum pp. 20-39. Also, study the four major groups (based on locomotion) within Kingdom Protista described on pp. 40-67. Keep in mind the presumed evolutionary significance, of these protozoans. Become familiar with the representative protists (see list below) demonstrated in lab by sketching each and using the diagrams in Chapter 4 to help you label your sketches.
   

KINGDOM ANIMALIA: Phylum Porifera


Class Calcarea (all marine)

Class Hexactinellida (all marine) Class Demospongiae

National Wildlife Federation, July/August 1999:  Sponges Get Respect

 

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