Lec 3 Flashcards
What are the taxonomic categories?
Kingdom Phylum Class Order Family Genus Species
What are the six kingdoms? What are they based on?
Archaebacteria Eubacteria Protista Fungi Plantae Animalia
They are based on cell structure and nutrition.
What are the three domains? What are they based on?
Archae - lack simple RNA polymerase
Eubacteria - peptidoglycan in cell walls
Eukarya - eukaryotes
Based on molecular differences.
What do the three domains have in common?
The common ancestor of all living organisms.
What is Homoplasy?
Superficially homologous but independently acquired - e.g. Body form in sharks and dolphins.
What are Plesiomorphic characters?
Shared ancestral characters or a distant common ancestor.
What are Synapomorphic characters?
Shared derived characters or more recent common ancestor.
What does molecular systematics determine and how? Give an example.
The evolutionary relationships by comparing macromolecules.
E.g. - Ribosomal RNAs (5S, 16S and 23S)
-Transcribed from highly conserved DNA regions.
Also, Mitochondrial DNA.
What does the molecular clock do?
Measures the time since divergence from a common ancestor by the number of differences in nucleotide or protein sequences. The rate of change must be constant.
What is a monophyletic taxon?
All are descendants of most recent common ancestor.
E.g. Mammals.
-True evolutionary relationships
Otherwise known as Clade.
What is a Paraphyletic taxon?
Common ancestor but not all are descendants.
E.g. - Class Reptilia does not include birds, even though they share a recent common ancestor.
-Avoided by cladistic systematists.
What is a Polyphyletic group?
Does not share a recent common ancestor.
E.g. Protista.
They share homoplastic features.
This misrepresents evolutionary relationships.
What are the traits of Evolutionary Systematics?
Evolutionary branching. Structural and other changes is the extent of divergence.
The combination of shared ancestral characters and shared characters.
What are the traits of Cladistics?
This emphasizes common ancestry over phenotypic similarity. Only shared derived characteristics.
