1. In order to begin, let´s review…
Systematics
Taxonomy
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Taxonomy limitations
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2. KEY CONCEPT Modern classification is based on evolutionary relationships.

3. Cladistics is classification based on common ancestry.
Phylogeny is the evolutionary history for a group of species.

4. Cladistics is classification based on common ancestry.
Phylogeny is the evolutionary history for a group of species.
evidence from living species, fossil record, and molecular data
shown with branching tree diagrams

5. Cladistics is a common method to make evolutionary trees.
classification based on common ancestry
species placed in order that they descended from common ancestor

6. A cladogram is an evolutionary tree made using cladistics.
A clade is a group of species that shares a common ancestor.
Each species in a clade shares some traits with the ancestor.
Each species in a clade has traits that have changed.
Algae bryophytes ferns gymnosperms angiosperms

7. Cladogram for tetrapods basis of arranging species in cladogram
Derived characters are traits shared in different degrees by clade members.
FOUR LIMBS WITH DIGITS
Tetrapoda clade 1
Amniota clade 2
Reptilia clade 3
Diapsida clade 4
Archosauria clade 5
EMBRYO PROTECTED BY AMNIOTIC FLUID
OPENING IN THE SIDE OF THE SKULL
SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW
FEATHERS & TOOTHLESS BEAKS.
SKULL OPENINGS BEHIND THE EYE
DERIVED CHARACTER
Cladogram for tetrapods
basis of arranging species in cladogram
more closely related species share more derived characters
represented on cladogram as hash marks

8. Cladogram for tetrapods
Nodes represent the most recent common ancestor of a clade.
FOUR LIMBS WITH DIGITS
CLADE
Tetrapoda clade 1
Amniota clade 2
Reptilia clade 3
Diapsida clade 4
Archosauria clade 5
Clades can be identified by snipping a branch under a node.
FEATHERS AND TOOTHLESS BEAKS.
SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW
OPENING IN THE SIDE OF THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
DERIVED CHARACTER
NODE

9. What type of taxonomic levels are not shown in this figure?
How could we include more taxa?
What would be some derived characters we might see if we add more general clades to this diagram?
FOUR LIMBS WITH DIGITS
Tetrapoda clade 1
Amniota clade 2
Reptilia clade 3
Diapsida clade 4
Archosauria clade 5
EMBRYO PROTECTED BY AMNIOTIC FLUID
OPENING IN THE SIDE OF THE SKULL
SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW
FEATHERS & TOOTHLESS BEAKS.
SKULL OPENINGS BEHIND THE EYE
DERIVED CHARACTER
Cladogram for tetrapods

10. Molecular evidence reveals species’ relatedness.
Molecular data may confirm classification based on physical similarities.
Molecular data may lead scientists to propose a new classification.
DNA is usually giving the last word to scientists.

11. Phylogenies
In the “before” diagram, which organisms are most related to mollusk?
In the “after” diagram, which organisms are most closely related to mollusk?

12. PHYLOGENIES REPRESENTED IN A CLADOGRAM

16. HOMEWORK:
Title: Classification based on evolutionary relationships background information.
Review/investigate about aminoacids: function, diversity (number of) and types.
In your notebook, bring information on cytochrome C oxidase´s location and its role in determining evolutionary relationships.

17. Homework
Aminoacids are monomers of proteins. They have a common molecular structure from which only the R group will differ, conferring them special properties such as being polar, non polar, acid or basic and many other properties. There are around 20 aminoacids that are useful for the humans.
Cytochrome C oxidase is a protein immersed in the mitochondrial membrane that aids in cellular respiration. It is present in all eukaryotic cells having almost the same molecular structure in them in closely related species. Because of this, its aminoacid sequence (primary structure) has been used to study evolutionary relationships.

18. Use of scientific terminology