13.2: Lab 13 Procedures
- Page ID
- 159741
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)PROCEDURE 1: BACKGROUND
- Answer the questions on the Answer Sheet to become acquainted with invertebrates.
PROCEDURE 2: SPECIMEN SURVEY
Equipment we’ll need:
- Various specimens of all eight phyla of invertebrates
- Move around the room to examine the specimens in each phylum. Complete Table 1 in the Answer Sheet using what we learned above and our observations of the specimens.
PROCEDURE 3: DICHOTOMOUS KEY
A dichotomous key is a useful tool for identifying organisms based on traits they do and don’t have. The key contains a series of questions that are typically yes or no, and the answer to one question leads us to another question. This video Using Dichotomous Keys by Science Sauce goes through a few examples to show how to use a dichotomous key. In the lab today, we are going to build a dichotomous key to identify the eight different invertebrate phyla.
For the Animal Kingdom, the first characteristic that divides groups is the presence of true tissues. Only animals in the Phylum Porifera (Sponges) are simple without true tissues. All other animals have true tissues with various levels of layer complexities. So, we can start our key there.
Next, animals are divided by their symmetry based on an imaginary bisection that goes through the middle of the body. Radial symmetry is found in animals that present two equal sides regardless of section direction (like a pizza). Bilateral symmetry is found in animals that can only be divided in equal left and right halves with a single line through the middle of the body. Figure 1 on the Answer Sheet has started the dichotomous key for us using information about the presence of tissue and symmetry.
Use the information we learned about the eight invertebrate phyla to complete the dichotomous key. Think about some of the major differences between the phyla. What major organ systems do they have, if any? Is the body cavity fully formed? Is their body segmented? Do they have limbs or are they tubular? How might they differ in embryonic development? Do they live in the water or on land or both?
- Figure 1 and Table 3 on the Answer Sheet show the two different ways to build a dichotomous key using the same information. Pick one of these methods to complete the dichotomous key for identifying the other six invertebrate phyla.
PROCEDURE 4: MYSTERY ANIMALS
Equipment we’ll need:
- Dichotomous key
- Identify the mystery invertebrates using the dichotomous key from Procedure 2 to complete Table 3 on the Answer Sheet