MODULE 3 LESSON 2: Taxonomic Characters and Sources of Data

taxonomic/systematic

• Morphological

• Chemical

• Genetic

• animal sounds

In establishing classification schemes and phylogenetic reconstructions, ______________ evidence must be gathered from a variety of sources.

Evidences can come from:

• __________________ characteristics

• __________________ characteristics

• __________________ characteristics

• Other characteristics (e.g. ____________)

Morphological sources of data.

Various sources of data used in classification

_________________________

• External features of an organism. Most common source of taxonomic data.

Morphological sources of data.

Various sources of data used in classification

_________________________

• Species descriptions and taxonomic keys use morphological characters all the time

Morphological sources of data.

Various sources of data used in classification

_________________________

• 
  

  

• evolutionary

Various sources of data used in classification

• An ideal taxonomic key should be ____________ in format.

• evolutionary

Various sources of data used in classification

• Characters in a couple must not merely differentiate one organism from another.

• The character must have an ______________ significance.

• phylogenetic; similarity

Various sources of data used in classification - In Evolutionary Systematics

• The sources of data for _____________ reconstruction - not merely based on _____________.

• plesiomorphic; apomorphic

Various sources of data used in classification - In Evolutionary Systematics

• Character states may be evaluated as _______________ (primitive character) or ________________ (advanced or derived character).

• homologous

• common ancestry

• homoplasy

Various sources of data used in classification - In Evolutionary Systematics

• Character evaluation only applies to _______________ characters,

  • similarity is based on ____________ ______________

  • not as a result of convergent evolution (_____________)

• outgroup

• outgroup; plesiomorphic

• apomorphic

How do you determine if a character is plesiomorphic or apomorphic?

• The most common method used is the ____________ method.

• An ____________ taxon is a representative ancestral clade hence assumed to be more primitive or more like the original (__________________).

• Any modification in the character state from the outgroup will be considered an advanced or derived character (______________).

Chromosomes; Cytosystematics

Various sources of data used in classification

______________ as sources of data (________________)

• Deals with relationships and classification of organisms using comparative studies of chromosomes.

1. Chromosome number

2. Chromosome size

3. Chromosome morphology

Various sources of data used in classification - Chromosome characteristics useful in systematics

What are all the characterisitcs?

• _______________________

• _______________________

• _______________________

Chromosome number

• Constant

• Aneuploid series

• Euploid series

Various sources of data used in classification - Chromosome characteristics useful in systematics

__________________-. Usually uniform within a species but may sometimes varies (e.g. mutants).

• ___________ (e.g., Quercus alba, Q. macrocarpa, and Q. prinus: all 2n=12)

• ____________________ - chromosome numbers not in exact multiples (e.g., Crepis pulchra 2n=8, C. schachtii 2n=10, C. paludosa 2n=12)

• ____________________ - chromosome numbers in exact multiples (e.g., five series in Fuertesimalva spp.: F. chilensis 2n=10, F. echinata 2n=20, F. limensis 2n=30) Crepis pulchra Crepis schachtii Crepis palud

Chromosome size

Various sources of data used in classification - Chromosome characteristics useful in systematics

______________. For comparing closely related species with the same chromosome number. Chromosome length can be used in size characterization.

Chromosome morphology

Various sources of data used in classification - Chromosome characteristics useful in systematics

____________________________. For comparing closely related species with the same chromosome number. This characteristic is best observed in the metaphase stage of mitosis.

Chromosome morphology

Various sources of data used in classification - Chromosome characteristics useful in systematics

_____________________

• Parameters include relative arm length, centromere position, and presence of satellites.

Behavioral sources of data

Various sources of data used in classification

________________________

• Mating calls is one of the most common behaviors used in identifying individuals from its closely related species

Behavioral sources of data

Various sources of data used in classification

________________________

• Flash patterns in fireflies is also another behavior used to differentiate firefly species from one another.

Behavioral sources of data

Various sources of data used in classification

________________________

• 
  

  

Behavioral sources of data

Various sources of data used in classification

________________________

• 
  

  

Physiological sources of data

• chemosystematics

Various sources of data used in classification

________________________

• E.g. In plant ________________

• An interdisciplinary field that uses secondary metabolites such as flavonoids, terpenes, and alkaloids as characters for establishing relationships among and within plant taxa.

Phenols

Various sources of data used in classification

• Group of organic compounds with hydroxylated benzene rings

Phenols

Various sources of data used in classification

• It is ubiquitous in the plant kingdom, but specific compounds vary among taxonomic groups.

Flavonoids

Various sources of data used in classification

• Reliable markers in chemosystematics due to their chemical stability and widespread distribution in the plant kingdom.

• Hornworts

Various sources of data used in classification

• __________ (a group of bryophytes) are the only plants that do not possess flavonoids.

Molecular sources of data (or Molecular Systematics )

• macromolecules

Various sources of data used in classification

_______________________

• refers to the use of data from ________________ (nucleic acids and proteins) to infer phylogenetic relationships among organisms.

Molecular sources of data (or Molecular Systematics )

Various sources of data used in classification

_______________________

• Sequence data:

  • (1) nuclear DNA- nDNA,

  • (2) Chloroplast- cpDNA,

  • (3) Mitochondrial DNA- mtDNA

• Nuclear DNA (nDNA)

Various sources of data used in classification - Sources of DNA sequence data

• _____________________

  • transmitted from parent(s) to offspring by nuclear division (meiosis or mitosis) via sexual or asexual reproduction.

• Chloroplast DNA (cpDNA)

Various sources of data used in classification - Sources of DNA sequence data

• _________________________

  • transmitted sexually from egg. In conifers, it is transmitted from sperm.

• Mitochondrial DNA (mtDNA)

Various sources of data used in classification - Sources of DNA sequence data

• ______________________

  • Usually transmitted sexually from egg

Molecular evolution

• substitution

• Fewer

The Rationale of using DNA in molecular systematics

_____________________

• sequence of nucleic acids and proteins changes across generations.

  • identify the number of nucleotide or amino acid undergoing _______________.

  • ________ substitution implies closer ancestry.

• Homologous genes

Types of Genes (in speciation)

• ___________________

  • Genes that originated from the same pre-existing gene

• Orthologous genes

Types of Genes (in speciation)

• _________________

  • Homologous genes resulting from speciation, and they have identical functions in different organisms.

• Paralogous genes

Types of Genes (in speciation)

• ____________________

  • Homologous genes resulting from duplication usually having the same or similar functions.

• Orthologs

• Paralogs

• Homologs

Types of Genes (in speciation)

• ___________ - A gene that has diverged as a result of a speciation event (many species)

• ___________ - two genes diverge as a result of a gene duplication event (same species)

• ___________ - genes are evolutionarily related

Types of Genes (in speciation)

Molecular Clocks

_________________

• Using mutation rates for deduction of the time when two different taxa diverged.

• fossil records

• geologic events

Calibrations of Molecular Clocks

• Molecular clocks must be calibrated based on:

  • (1) _________________

  • (2) _________________
    
    

  • = to produce trees that provide more or less accurate date of divergence of branches from a recent common ancestor

• Allozymes

• Isozymes

• Microsatellites

• Restriction Fragment Length Polymorphism (RFLP)

• Random Amplified Polymorphic DNA (RAPD)

• Amplified Fragment Length Polymorphism (AFLP)

Other techniques and markers used in molecular systematics

• __________________

• __________________

• __________________

• __________________

• __________________

• __________________

ALLOZYMES

Other techniques and markers used in molecular systematics

• Different molecular forms of an enzyme that correspond to different alleles of a common gene (locus).

ALLOZYMES

Other techniques and markers used in molecular systematics

• They are usually detected through electrophoresis. Different allozymes of an enzyme migrate differentially due to slight difference in amino acid composition.

ALLOZYMES

Other techniques and markers used in molecular systematics

• Traditionally, they are used for assessing genetic variation within a population.

ISOZYMES

Other techniques and markers used in molecular systematics

• Refer to each of two or more enzymes with identical function but different structure.

ISOZYMES

Other techniques and markers used in molecular systematics

• They are encoded by genes of different loci, but they process or catalyse same or similar reactions.

ISOZYMES

Other techniques and markers used in molecular systematics

• Analyzing them can determine presence or absence of certain alleles.

Other techniques and markers used in molecular systematics

• Regions of DNA containing short (usually 2-5) repeats of nucleotides (e.g., TGTGTG) (tandem repeats).

Other techniques and markers used in molecular systematics

• They are identified by constructing primers that flank the tandem repeats.

• microsatellites

Other techniques and markers used in molecular systematics

• Using primers in tandem repeats to identify _____________