Taxonomy & Evolutionary Taxonomy & Evolutionary HistoryHistory

I.I. Taxonomic ConceptsTaxonomic ConceptsII.II. Taxonomic PrinciplesTaxonomic PrinciplesIII.III. Time ScaleTime ScaleIV.IV. Rate of Evolutionary ChangeRate of Evolutionary Change

I. Taxonomic ConceptsI. Taxonomic ConceptsA.A. Taxonomy – scientific system for Taxonomy – scientific system for

classification. Uses a set of rules to classification. Uses a set of rules to determine relationships among items determine relationships among items (organisms?) in a set.(organisms?) in a set.

B.B. Today, still based on Linnaeus’ seven level Today, still based on Linnaeus’ seven level system: Kingdom, Phylum, Class, Order, system: Kingdom, Phylum, Class, Order, Family, Genus, and Species.Family, Genus, and Species.

C.C. Remember as King Phillip Crossed Over Remember as King Phillip Crossed Over For Grape SodaFor Grape Soda

D.D. All organisms are referred to by their All organisms are referred to by their genus & species (binomial nomenclature).genus & species (binomial nomenclature).

II. Taxonomic II. Taxonomic PrinciplesPrinciplesA.A. Structures that are Structures that are

shared through descent shared through descent from a common ancestor from a common ancestor are called are called homologieshomologies..

B.B. HomoplasyHomoplasy is the is the process by which process by which similarities can similarities can develop in different develop in different groups of organisms. groups of organisms.Leads to analogous Leads to analogous structures.structures.

II. Taxonomic PrinciplesII. Taxonomic PrinciplesC. Structures in organisms C. Structures in organisms

that are used for the that are used for the same function, but have same function, but have developed developed independently and are independently and are not the result of not the result of common descent, are common descent, are called called analogiesanalogies..

D. Analogies are often the D. Analogies are often the result of result of convergent convergent evolutionevolution..

II. Taxonomic PrinciplesII. Taxonomic PrinciplesE. E. Cladistic Taxonomy Cladistic Taxonomy

An approach to taxonomy that groups species according An approach to taxonomy that groups species according to shared derived characteristics. to shared derived characteristics.

1.1. Traits that reflecting the ancestral condition of an Traits that reflecting the ancestral condition of an organism are organism are primitiveprimitive..

2.2. Traits shared by all members of a group, but not Traits shared by all members of a group, but not present before the group's appearance, are said to be present before the group's appearance, are said to be shared derivedshared derived characteristics (e.g nails in characteristics (e.g nails in primates)primates)..

II. Taxonomic PrinciplesII. Taxonomic PrinciplesE. Cladistic TaxonomyE. Cladistic Taxonomy

3.3. Related groups are thus in the same Related groups are thus in the same clade, or branch/level (genus, family, clade, or branch/level (genus, family, or whatever)or whatever)

4.4. At the finest levels, determining where At the finest levels, determining where one species starts or stops, however, is one species starts or stops, however, is sometimes a problem.sometimes a problem.

II. Taxonomic PrinciplesII. Taxonomic PrinciplesF. SpeciationF. Speciation1.1. Groups of organisms capable of breeding to create Groups of organisms capable of breeding to create

fertile offspring that COULD normally be expected fertile offspring that COULD normally be expected to contact one another.to contact one another.

2.2. Species are reproductively isolated from one Species are reproductively isolated from one another:another:

i.i. Biological – physical or genetic limitationsBiological – physical or genetic limitationsii.ii. Geographic – separation of the organisms on the Geographic – separation of the organisms on the

landscapelandscapeiii.iii. Behavioral – social separation of organisms (e.g. Behavioral – social separation of organisms (e.g.

nocturnal/diurnal)nocturnal/diurnal)

III. Time Scale: Geological III. Time Scale: Geological ErasEras

A.A. PaleozoicPaleozoic The first vertebrates appeared 500 mya The first vertebrates appeared 500 mya

B.B. Mesozoic Mesozoic Reptiles were dominant land vertebrates.Reptiles were dominant land vertebrates. Placental mammals appeared 70 mya Placental mammals appeared 70 mya

C.C. CenozoicCenozoic Divided into two periods: Tertiary and Divided into two periods: Tertiary and

Quaternary and 7 epochs.Quaternary and 7 epochs.

III. Time Scale: Cenozoic III. Time Scale: Cenozoic EpochsEpochs

Draw and leave space to fill this Draw and leave space to fill this chart:chart:

EpochEpoch TimeTime PrimatesPrimatesPaleocenePaleocene 65 mya65 myaEoceneEocene 55 mya55 myaOligoceneOligocene 34 mya34 myaMioceneMiocene 23 mya23 myaPliocenePliocene 5 mya 5 myaPleistocenePleistocene 1.8 mya1.8 myaHoloceneHolocene 0.01 mya 0.01 mya

III. Time Scale: Mammal III. Time Scale: Mammal EvolutionEvolution

A.A. The Cenozoic era is known as the Age of The Cenozoic era is known as the Age of Mammals.Mammals.

B.B. After dinosaurs became extinct at 65 mya, After dinosaurs became extinct at 65 mya, mammals underwent mammals underwent adaptive radiationadaptive radiation, , resulting in rapid expansion and resulting in rapid expansion and diversification. diversification.

C.C. One advantage was the larger One advantage was the larger neocortexneocortex, , which controls higher brain functions, which controls higher brain functions, comprised the majority of brain volume in comprised the majority of brain volume in mammals resulting in greater ability to learn.mammals resulting in greater ability to learn.

III. Time Scale: Mammal III. Time Scale: Mammal EvolutionEvolution

D.D. Another was the variety of diet mammals Another was the variety of diet mammals were capable of, due to their digestive and were capable of, due to their digestive and dental differentiation (dental differentiation (heterodontheterodont – having – having many types of teeth)many types of teeth)

E.E. Yet another was mammals’Yet another was mammals’ endothermy endothermy, or , or ability to easily self-regulate their body ability to easily self-regulate their body temperaturetemperature

F.F. Still another was mammals’ emergence of Still another was mammals’ emergence of marsupial marsupial and later and later placentalplacental birthing – birthing – keeping the developing embryo inside the keeping the developing embryo inside the mother for protection and greater mother for protection and greater developmentdevelopment

IV. Rate of EvolutionIV. Rate of EvolutionA.A. Punctuated EquilibriumPunctuated Equilibrium

– Long periods of no change Long periods of no change punctuated by rapid punctuated by rapid evolution and speciation (@ evolution and speciation (@ right)right)

– S. Gould and N. EldredgeS. Gould and N. Eldredge– Explains gaps in recordExplains gaps in record

B.B. Phyletic GradualismPhyletic GradualismDarwin’s idea of slow gradual Darwin’s idea of slow gradual change leading to eventual change leading to eventual speciationspeciation