How Do Scientists Identify and Classify New Species

How Do Scientists Identify and Classify New Species?

Carolus Linnaeus (1707 - 1778) ·Swedish botanist / physician that collected plants for their curative properties & needed to organize his collection. ·Contributed to the development of our modern system of taxonomy. ·Developed binomial nomenclature, a two-word naming system still used today. Each species is assigned a twopart scientific name

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What's My Name? Homo sapiens Human What's My Name? Pecari tejacu Javelina What's My Name? Canis lupus Dog What's My Name? Odocoileus virginianus White-tailed Deer

The three domains each contain at least one KIDomains Archaea and Bacteria kingdom. N C both contain Gall. Dthe prokaryotes and include organisms from O the kingdoms MEubacteria. Archaebacteria and The four S remaining kingdoms are all found within the Domain Eukarya. LI C K TH E CR OW N:

FIRST CELL Kingdom Plantae DOMAIN BACTERIA Kingdom Fungi Kingdom Eubacteria DOMAIN EUCARYA DOMAIN ARCHAEA Kingdom Archaebacteria Kingdom Protista Kingdom Animalia Erase the areas that each arrow is pointing to in order to reveal the information "hidden" below. . . Check for Understanding

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Identifying Organisms The names given to organisms often reveal: - The evolutionary history of their species - Ecological relationships with other species - Distinguishing characteristics of that species Common names are often confusing - Not all are fish: catfish, starfish, silverfish, jellyfish, crayfish In order to study this diversity: - Species are grouped into larger related classifications - A universal scientific name is given to every species A dichotomous key is a series of questions used to identify new or unknown species. (eg. flower)

1. Give three examples of flower characteristics used in the dichotomous key. 2. Which flower did you classify as a crucifer? Describe two flower characteristics you think may be useful in Identifying Organisms identifying flowers from other crucifer plants. Using a dichotomous key Question s 3. How do you think white cabbage butterfly larvae might With millions, and perhaps billions, of different identify crucifer species onplants? Earth, identifying organisms can be quite a challenge. Luckily, a simple set of questions, called a dichotomous key, can systematically lead a scientist from unknown to known. Try this dichotomous key activity to learn how this works. Then, answer the questions found in 1. Give three the tab examples of flower characteristics on the left. key. the dichotomous used in The three flower characteristics were the position of the ovary, the overall shape of the flower, and the pattern of symmetry. Answers 2. Which flower did you classify as a crucifer? Describe two flower characteristics you think may be useful in identifying flowers from other crucifer plants. The mustard flower is a crucifer. The flower was not cupshaped, and the top view of the lower showed radial symmetry with four petals arranged in a shape like a plus sign, +. 3. How do you think white cabbage butterfly larvae might identify crucifer plants? Probably by the number of petals, in the plus sign shape.

Creating a Dichotomous Key Question How can you create a dichotomous key to identify organisms? Figure A 3. 1 These students are using criteria to sort objects into groups like scientists use criteria to classify species into groups. Procedure Part 1: Everyday Objects 1. With a partner or group, empty your kit of items onto a desk or table. 2. Use the dichotomous key to organize the objects into groups. Start by choosing a major characteristic (e. g. , metal or plastic, tubular or nontubular) and divide the objects into two groups based on the characteristic. 3. On the key, record the defining characteristic of each group and the names of all the objects that belong in each group. 4. For each group, determine another characteristic that can be used to differentiate the objects into two groups. Then repeat step 3. 5. Repeat step 4 until you have 20 groups each with a single object. Inappropriat e Appropriate large greater than 60 kg short less than 150 cm light coloured many 10 or more beautiful more than 6 colours Table 1 6. Use the information recorded to create a dichotomous key. For each step in your dichotomous key, you need to create a pair of choices that focuses on a particular characteristic. Suppose the first characteristic recorded on your key is “presence of hair. ” Then for the first numbered step on your dichotomous key, you would write: 1 a hair is present 1 b hair is absent 7. At each characteristic such as those noted above, lead the reader to the next step to consider on your dichotomous key. What groups does each of the characteristics lead to? Write these groups as a step in your key and direct readers to go to the correct step for each outcome of step 1. Continue this process to construct the rest of your dichotomous key. 8. As you write each step on your dichotomous key, use the following guidelines: • avoid qualitative terms such as “large” or “many” • use quantifiable characteristics, such as exact measurements (see Table 1) • ensure each step has an outcome (identification of an object or a next step to go to) for both positive and negative responses

Analyzing and Interpreting Part 1: Everyday Objects 11. Give three examples of characteristics used in the dichotomous key. 12. Based on your dichotomous key, what characteristics do all the objects share? Part 2: Organisms from the Kingdoms 13. Did your partner successfully use your key? Explain why or why not. 14. Why is it important to use clear terms in a dichotomous key? 15. Why should qualitative terms be avoided in creating dichotomous keys? Skill Practice 16. List some characteristics that would be useless for a dichotomous key. Explain your choices. 17. Why are there always two choices at each step of a dichotomous key? Forming Conclusions 18. Is there a “right” and “wrong” dichotomous key? Justify your answer. 19. What improvements might be made to your key?

Attachments Biology. Source 2. flv Biological Classification Kingdoms - You. Tube. flv