|
Geog 215: Introduction to Biogeography |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Morphology and variation | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Premise: Members of a taxonomic species are characterised by their morphology, which commonly displays variation between individuals and populations. Botanists and zoologists commonly use 'keys' to assign an unknown plant or animal to a family, genus and species. The key may be based on the overall morphology of the specimen or the morphology of critical parts of the organism. You are provided with samples of material from six conifers growing on campus. Three of them are native to Burnaby Mountain; three are introduced from other areas. You are set the tasks of: i) identifying the samples; ii) comparing the range of the three native trees in the sample group; and iii) assessing the degree of variation within one native species and other members of this genus in North America. TASKS 1. Use the key provided to identify the genus to which each sample belongs. Identify your decision pathway for each sample by drawing a coloured line on the key. (6) 2. Use your answers to fill in the table below. Identify the three native trees (samples 1, 2, and 3) to species. Identify the authority for each of these three species names, and list any synonyms. (6)
3. The accompanying maps show the biogeographic ranges of the native species. Briefly describe each. (3) 4. What do you conclude about the ranges of the three species from these range maps? Be brief; this topic is dealt with in detail in a later assignment. (3) Use the accompanying descriptions from the "Flora of North America" (=FNA) to answer the following questions. 6. What is its range? (2) 7. According to the FNA descriptions, how much variation is there in these species in terms of such characteristics as the length of seed cones or seeds? Express the variation as a percentage about a mean (8).
8. The FNA gives estimates of the range of sizes of leaves, buds, cones, seed scales, etc. in the species to which sample #1 belongs. On the basis of your limited sample, where does the Burnaby Mountain population lie in these range estimates? Are they close to the midpoint, or extreme? (2)? 9. The descriptions in the FNA and other sources indicates that there are other kinds of natural variation in these species. List two examples of natural variation (2) 10. Has this natural variation been exploited for any particular purpose? Give examples (2). |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||