Bot350 Exam1

Native

  • Taxa that evolved locally

Non-native synonyms

  • Naturalized, exotic, invasive, introduced

Endemic

  • Taxa restricted to a single place

Introduced taxa

  • Taxa introduced by human interference

4 major components of taxonomy 

  • Description, identification, nomenclature, classification

Description

  • The assignment of morphological characteristics to a taxon

Identification

  • The process of associating an organism with a taxon name

Nomenclature

  • The naming of taxa based on a standardized system

Binomials

  • Genus + specific epithet

Deficiences with the current taxonomic system

  • Eurocentric, unfriendly to non-roman alphabet, TEK ignored

Classification

  • The arrangement of taxa in hierarchical order

Hierarchy of taxa

  • Order, family, genus, species

Artificial classification

  • Classifications based on morphological similarities, not based on evolutionary relatedness, before the theory of evolution

What is Cal Linnaeus’s legacy?

  • Standardized binomial name, and fundamental system of classification (phylum, order, family, etc)

What were two other classification systems

  • Jussie and De Candolle

Natural classification

  • Classification representing evolutionary history

How do we classify today

  • Starting in the 90s DNA replaced morphology

Phylogeny

  • A diagram depicting evolutionary relatedness

Nodes/branching points on a phylogeny tree are

  • Speciation events

Evolution = 

  • Change + speciation + conservatism

Conservatism 

  • Keeping ancestral traits

Sister taxa

  • Taxa that share an immediate common ancestor

Monophyletic group/clade

  • Includes an ancestor and all its descendants

Rules for taxonomic groups

  • A single element or monophyletic set of elements

Synapomorphy

  • Derived shared characteristics

Apomorphy

  • Derived characteristic

Denote the change from hair to no hair

  • Hair > no hair

Symplesiomorphy

  • An ancestral shared characteristic

Convergent evolution

  • Homoplasy

Monophyletic

  • An ancestor and all of its descendants

Polyphyletic

  • Organisms with no recent common ancestor, based on homoplasy

Paraphyletic 

  • An ancestor and some of its descendants, based on symplesiomorphy

Monocot synapomorphy

  • One cotyledon

Eudicot _____morphy

  • Two cotyledons is a symplesiomorphy

Dicotyledons are ____phyletic

  • Paraphyletic

Eudicots are ____phyletic

  • Monophyletic 

Monocots are ___phyletic

  • Monophyletic

Basal Angiosperms are ___phyletic

  • Paraphyletic

Polytomy

  • An unresolved node (a node with more than 2 immediate descendants)

Parsimony

  • The simplest explanation is usually correct, the fewer transitions the more likely the event

Phylogeny chart ancestral and derived symbols

  • 0 = ancestral, 1 = derived

Autoapomorphy

  • Derived trait exclusive to a taxon

Where is DNA in a plant cell?

  • Nucleus, chloroplast, mitochondrion

Nucleus DNA

  • Two versions of each chromosom, >1Gb

Chloroplast DNA

  • Single and circular molecule of DNA, 150Kb

Mitochondria DNA

  • Single and circular molecule of DNA, 500Kb

Mutation types

  • Point mutation, base or gene insertion, whole gene duplication

Why is DNA more reliable than morphology for phylogenies

  • More characters, characters are discrete from one another, character states are unambiguous, some neutral genes have no selective impacts

Are DNA traits immune to homology?

  • NO

Single markers

  • A marker is a contiguous sequences of DNA used for phylogenetic/genetic analysis, < 2000 base pairs, obtained by DNA amplification and sequencing

The first phylogenies of flowering plants were inferred from a single chloroplast gene:

  • Rbcl

Single markers can be _______ to obtain larger matrices

  • Concatenated (linked)