1. Quick Questions
What are the two main criteria that all members of a species share?
Rana temporaria is a frog commonly found in Britain. Complete the table below by giving the most appropriate name for each of the numbers 1 – 7:
Kingdom
Animalia 1
Chordata 2
Amphibia 3
Anura 4
Ranidae
Genus 5 6 7

2. Answers Observable similar characteristics
ability to reproduce to create fertile offspring 2.
Kingdom
Animalia
Phylum
Chordata
Class
Amphibia
Order
Anura
Family
Ranidae
Genus
Rana
Species
temporaria

3. Difficulties in Defining a Species

6. What is phylogeny?

7. What is phylogeny?
The grouping of organisms to show the historical, evolutionary relationships between them.
From ‘phylum’
Drawn as a phylogenetic tree (cladogram) – closer the branches, the closer the evolutionary relationship

8. What is phylogeny? Comparative anatomy – look at homologous structures
Anatomical structures that have a similar evolutionary origin and development in the body
Indicates evolution from common ancestor

10. Drawing Cladograms Produces eggs 4 Opposite appendages
Placental mammal
4 chambered heart
Flippers
Sea Star X
Cow
Emus
Salamander
Blue Whale

16. Interpreting Cladograms
1.) The root of the phylogenetic tree is closest to which node?
2.) The common ancestor for species E and D can be found at which node?
3.) The common ancestor for species B and D can be found at which node?
4.) The common ancestor for species C and A can be found at which node?
5.) Which node represents the common ancestor of all species on the tree?
6.) Which two species share the most recent common ancestor (i.e. are most closely related)?

17. Interpreting Cladograms
1.) The root of the phylogenetic tree is closest to which node? 3
2.) The common ancestor for species E and D can be found at which node? 1
3.) The common ancestor for species B and D can be found at which node? 4
4. The common ancestor for species C and A can be found at which node? 3
5.) Which node represents the common ancestor of all species on the tree? 3
6.) Which two species share the most recent common ancestor (i.e. are most closely related)? C and B

18. Drawing a Cladogram
Use the information on the handout to complete the table by drawing a ‘x’ if an organism has a certain trait
Then draw a venn diagram to sort out the groups
If an animal only has one trait, it would be in the largest box. If it has all the traits, it would be in the smallest, centre box.
Then draw and label a cladogram of the organisms