In order to begin, let´s review… Systematics Taxonomy Contrast / Facts Compare Class Taxonomy limitations How to improve?

KEY CONCEPT Modern classification is based on evolutionary relationships.

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

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

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

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

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

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

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

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.

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

PHYLOGENIES REPRESENTED IN A CLADOGRAM

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.

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.

Use of scientific terminology