Using and Making a Biological Key

Lab #1: Using a Biological Key Purpose: Classification is a way of separating a large group of closely related organisms into smaller subgroups. With a classification system, identification of an organism is easy. The scientific names of organisms are based on the classification systems of living organisms. To classify an organism, scientists often use a key. A key is a listing of specific characteristics, such as structure and behavior, in such a way that an organism can be identified. In this lab, we will: L study the method used in making statements of a key. 2. use a key to identify certain insect species. 3. use the key to identify fourteen shark families. . Materials: metric ruler insect key / insect diagrams shark key / shark diagrams Procedure: Part 1: Keying Sharks 1. Use Fig. 1 as a guide to the shark parts used in the key in Table 1. 2. Read sentences 1 A and IB of the key. Study Shark 1 in Fig. 2 for the characteristics referred to in 1A and IB. Follow the directions in these sentences and continue until a family name for Shark 1 is determined. 3. Continue this process with each shark until all animals have been identified. Label the family name on the line below each diagram . Part 2: Keying Insects 1. To identify insect A in Fig. 3, begin with paired descriptions la and lb in Table 2. One and only one of the descriptions should apply. If you find a number at the end of the description, is guides you to the next pair of descriptions. If you find a name at the end of the description, that should identify your insect. Of course, this key applies only to these specific kinds of insects. It will not identify any organisms not included in its construction. 2. Continues identifying until you have named and labeled all insects in Fig. 3 (A-M) 3. Study Fig. 4 and compare how the flow chart differs from the key. ' O' Table 1: Shark Identification Key 1. A. Body kitelike in shape ( if viewed from the top ] B. Body not kitelike in shape ( if viewed from the top ) Go to statement 12 Go to statement 2 Family Pristiophoridae ...Go to statement 3 - 2, A Pelvic fin absent and nose sawlike, B. Pelvic fin present . 3 A. Six gill slits present.. Family Hexanchidae ........Go to statement 4 B. Five gill slits present. , 4. A. Only one dorsal fin B. Two dorsal fins Family Scyliorhinidae Go to statement 5. A. Mouth at front of head rather than back along underside of head B. Mouth back along underside of head 5 Family Rhinocodontidae Go to statement 6 . Family Sphymidae ...Go to statement 7 . . Family Isuridae 6 A. Head expanded on side with eyes at end of expansion B. Head not expanded 7 A. Top half of caudal fin exactly same size and shape as bottom half .. B. Top half of caudal fin different in size and shape than bottom half , , .Go . to statement 10 Family Scapanorhynchidae Go to statement 11 10 A. A long needlelike point on end of nose, B. Nose without long point . Family Squalidae 11 A. Anal fin absent. B. Anal fin present ...... Family Carcharhinidae .. Family Rajidae . 12 A. Small dorsal fin present near tip of tail. B. No dorsal fin present near tip of tail Go to statement 13 Family Mobulidae Family Dasyatidae 13. A. Front of animal with two hornlike appendages B. No hornlike appendages Fig. 1: Guide to Shark Parts Dorsal ( top ) side first dorsal fin second dorsal fin caudal fin mouth back along underside 8 Family Alopiidae 9 A. Caudal fin very long, almost as long as entire body B. Caudal fin regular length . to statement Family Pseudotriakidae Go to statement 9 8. A. First dorsal fin very long, almost half total length of body B. First dorsal fin regular length. . Go anal fin pelvic fin gill slits pectoral fin Ventral ( bottom ) side ~ trvpl -vOp mip Q\pj*n * TTV , JJ t ' S' \SN simMSing; >JJBI|S : Z ÿ 35J Table 2: Identification Key of Certain Insects la. Insect with wings 2 lb. Insect without wings 2a. Wings all fully transparent with wings clearly visible 7 3 10 2b. Wings not all fully transparent 3a. Hind wings absent Housefly J 4 3b. Front and hind wings present 4a. Hind wings about the same size as front wings Dragonfly j 5 4b. Hind wings smaller than front wings Mayfly J 5a. Two or three long slender tails 6 5b. No long slender tails 6a. Wings at rest held like roof over body 6b. Wings at rest not held like roof over body . Cicada ^ . . . . Bee / 7a. Three long slender tails Silverfish J 8 7 b. No long slender tails Termite 8a. Head almost as wide as body 8b. Head much narrower than body Louse 9a. Head connected to body by a narrow neck / i . Flea S 9b. Neck not especially narrow 10a. Wings held against body when at rest 10b. Wings not held against body when at rest 11a. Hind legs enlarged for jumping ^ 9 11 . . Butterfly / Grasshopper j 12 lib. Hind legs not enlarged for jumping 12a. Front wings partly leathery ; tip transparent .. Stinkbug j 12b. Front wings fully shell-like Potato Beetle ^ D [-e-r »VM F PoirJ ^ S'i irv *f (v L £~ < Cc^ clc{ D ^ Fig. 4: Insect Identification Flowchart no hind housefly front, hind wings wings wings fully - trans same size front, hind parent wings hind —— p 2 or 3 long tails wings held like roof wings smaller no tails ^ ^ ^ wings not with jumping legs wings held wing tip trans against body no - parent mayfly cicada bee like roof wings dragonfly ^ ^ grasshopper stinkbug jumping legs wings not . fully - trans- these insects front wing shell like parent - ^ potato beetle ^ butterfly wings not against body 3 long tails no silverfish head wide as wings body no tails neck narrow ^ ^ termite louse head narrow neck not narrow flea Questions: 1. Is the presence of wings the only characteristic that could be used to divide the 13 insects into two groups? If no, what other characteristics in Fig. 2 could be used initially? /1 )n . dhuSfutri 2. Why is it easier to construct a flow chart, like Fig. 2, before creating an -ALOUJ Identification Key like Fig. 1? all baSrdl on JkA S/W nvr^ bjLf - Sno &t sjr& jML \ tevd~m.\ £ T/\ W - bor od - -KM ! S b> cxpg / 5^ : ^ ^ ' - “ Conclusion: Discuss why and how we classify living organisms (3 points). Explain why we use keys in identifying biological organisms (2 points). - L> r CjCu^ /o OLV ^ <, fZf 5 y-/ " ^ J C Qfjau^X c\ f 51 U $ c, ' ^ CA^O-M £ of ft , f -z. ) e.^4 f