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Dichotomous Keys 7.11A

Dichotomous Keys 7.11A. Middle School Science. The critters below are sketches of aliens that have just been discovered in Houston! They must be from a new, undiscovered planet. Let’s quickly name this planet. BUT we can not use any known word from earth to name it.

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Dichotomous Keys 7.11A

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  1. Dichotomous Keys 7.11A Middle School Science

  2. The critters below are sketches of aliens that have just been discovered in Houston! They must be from a new, undiscovered planet. Let’s quickly name this planet. BUT we can not use any known word from earth to name it. Name of Planet ______________________. Soon astronauts will travel through space in search of this planet. When they get there, however, they need to be able to identify these strange creatures. Today we are going to help them do that. Start by observing the aliens below. Underneath each one, list some observations you make.

  3. Now use your observations to make a list of all of the different characteristics observed.

  4. Alien CharacteristicsYour list might include these things: can we add any more? • Number of hairs • Number of legs • Belly button • Arms • Crooked smile • Small • Fat • Which of these characteristics are could change due to age, emotions, or eating habits? • Which of characteristics will stay the same regardless?

  5. Let’s use the list of unchanging characteristics: • Arms • Legs • Hair • Belly buttons

  6. Take each of these characteristics and divide them into 2 groups based on what you observe: Hair = One hair – two hairs Legs = Two legs – four legs BellyButton = Belly button – no belly button Arms = Arms – no arms

  7. Use this key to see if you can ID each of the Aliens. 1. Has one hair……………………………………………………… 2. Has two hairs…………………………………………………….. 4. 2. Has a belly button………………………………………………... BIP Has no belly button………………………………………………. 3. 3. Has two legs……………………………………………………… GLIP Has four legs……………………………………………………… FOOP 4. Has arms…………………………………………………………. GLOP Has no arms……………………………………………………… NOP

  8. Who is Who?

  9. You just followed a Dichotomous Key to identify these aliens! 1. What did the Dichotomous Key help you do? 2. What do you think they are used for?

  10. Dichotomous Key In science we use many helping aids to organize and easily retrieve information. A dichotomous key is a tool that scientists can use to help identify a particular specimen. The specimen could be a chemical that is identified by its physical properties, an insect identified by its markings and traits, or even a rock sample based on its different properties. The term dichotomous begins with the prefix of "di" which means two. The dichotomous key allows for the scientist to ask a series of questions with yes or no answers. Each question should be phrased so that the answer will either be yes or no. MAKE A VOCAB SQUARE FOR DICHOTOMOUS KEYS!

  11. Take a Walk Through the Forest and Identify Trees using a Dichotomous Key http://nationalzoo.si.edu/Education/ConservationCentral/walk/walk4.html

  12. 1a Leaves are needlelike go to 2 1b Leaves have flat blades go to 4 2a Needles attached singly go to 3 2b Needles attached in bunches White Pine 3a Needles on two sides of the stem Balsam Fir 3b Needles on all sides of the stem Red Spruce 4a Leaves are compound go to 5 4b Leaves are simple Silver Maple 5a 5-7 leaflets White Ash 5b 9 leaflets on each section Coffee Tree

  13. crenate - having rounded teeth.entire - having a smooth edge with neither teeth nor lobes.lobed - divided into rounded or pointed sections and the incisions (cuts) go less than halfway to the midrib.parted (or cleft) - the margins between the irregular teeth go more than halfway to the midrib.serrate (or toothed) - having small, pointy teeth that point toward the tip of the leaf. Describe Each Leaf

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