![Page 1: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/1.jpg)
U N I T Y & D I V E R S I T Y: W H AT ’ S T H E R E L AT I O N S H I P ?
CLADISTICS
![Page 2: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/2.jpg)
WHAT ARE CLADISTICS & TAXONOMY?
• Cladistics: Method of hypothesizing how one organism is related to another. • Taxonomy: system of naming/classifying species• Taxon: the name of a group or a single organism
![Page 3: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/3.jpg)
WHAT’S A CLADOGRAM?
• Cladogram: a graphic organizer showing the relationship between organisms
![Page 4: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/4.jpg)
WHAT’S THE EVIDENCE?
• Scientists base their hypotheses on shared characteristics, called a homologous feature
Ex. Forelimbs of four-legged animals
![Page 5: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/5.jpg)
3 BASIC ASSUMPTIONS
1. All organisms are related by a common ancestor
![Page 6: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/6.jpg)
3 BASIC ASSUMPTIONS
2. There is a branching (splitting in two) pattern of relationships
![Page 7: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/7.jpg)
3 BASIC ASSUMPTIONS
3. Change in characteristics occurs over time
![Page 8: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/8.jpg)
METHODOLOGY“HOW-TO” OF CLADISTICS
![Page 9: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/9.jpg)
1. SAME CLADE
• The organisms you are organizing must all be part of the same clade, or “branch”
• Which color represents a clade?
![Page 10: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/10.jpg)
2. DETERMINE THE FEATURES
• Taxa do not overlap • Decide if each taxon has the characteristics or
not
vertebra + + + + + + +
Boney skeleton - + + + + + +
4 limbs - - + + + + +
Amniotic egg- - - + + + +
hair - - - + + + +
Egg w/ shell - - - - - + +
![Page 11: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/11.jpg)
3. GROUP BY FEATURES
• Species go on the ends of branches
• Nodes are common ancestors
• Features are labeled
![Page 12: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/12.jpg)
VOCABULARY
• Shared (primitive) trait: a characteristic that was present in the common ancestor• Derived trait: a characteristic that is different
from the common ancestor• Outgroup: shares a common ancestor, but is the
least related in the clade
![Page 13: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/13.jpg)
• What is an example of a shared trait?
• What is an example of a derived trait?
• Which is the outgroup?
![Page 14: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/14.jpg)
4. RULE OF PARSIMONY
• If there are multiple possible cladograms, the simplest one (with the least number of changes) is best.
![Page 15: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/15.jpg)
READING TREESHOW TO READ A CLADOGRAM
![Page 16: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/16.jpg)
STRATEGY
• Look for the most recent common ancestor (nodes) • More recent ancestors will be “higher”• Older ancestors will be “lower”• Don’t read “along the tips”
![Page 17: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/17.jpg)
PRACTICE WITH CLADOGRAMS
![Page 18: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/18.jpg)
PRACTICE WITH CLADOGRAMS
![Page 19: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/19.jpg)
PRACTICE WITH CLADOGRAMS
![Page 20: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/20.jpg)
PRACTICE WITH CLADOGRAMS
![Page 21: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/21.jpg)
MORE PRACTICE
![Page 22: UNITY & DIVERSITY: WHAT’S THE RELATIONSHIP? CLADISTICS](https://reader035.vdocuments.us/reader035/viewer/2022062314/56649e865503460f94b89cad/html5/thumbnails/22.jpg)
FINALLY!!!