Do Now & Announcements Turn in Life in a Raindrop lab if you did not do so last class period. Today: Dichotomous Keys Unit 1 Test MON 9/21, TUES 9/22 I will give you a review guide on Friday

What is a Dichotomous Key? The word dichotomous comes from Greek and English roots: dicho is Greek for “in two” tom means “to cut” The –ous ending is from the English, meaning “full of.” So dichotomous means “to cut in two” or to “divide in two.” And that’s what you do at each stage of deciphering a dichotomous key – divide in two.

Dichotomous Keys A dichotomous key is a grouping tool that scientists use to classify organisms based on observations. The key focuses on one feature or characteristic at a time. Usually, the key will list the presence or absence of something or maybe highlight opposites. When using a dichotomous key, you will only look at one characteristic at a time and divide your specimens into two groups until each living thing has been placed into a category all of its own.

Look at 1 animal at a time. Start with “1” Choose a or b Follow the directions

Pointed ears that stand up Pets Fur Carnivorous Pointed ears that stand up Cat Floppy ears that hang to sides Dog Herbivorous Guinea pig No Fur Feathers Bird No feathers Fish

Dichotomous Keys Lab You will need to get your materials from me Part 1: Jelly Belly Part 2: Alien Cards