week 2

• What can major changes in body form result from?

  Changes in sequences and regulation of genes
• What is evolution not oriented towards?

  Goal
• What do phylogenies illustrate?

  Evolutionary relationships
• How are phylogenies inferred?

  From morphological and molecular data
• What are shared characters used to construct?

  Phylogenetic trees
• What does an organism's evolutionary history document?

  Its genome
• What continues to revise our understanding of the tree of life?

  New information
• What is a taxon?

  A named taxonomic unit
• What is a tetrapod?

  A vertebrate clade with limbs and digits
• What is a zygote?

  A fertilized egg
• What does the biological species concept emphasize?

  Reproductive isolation
• What may occur with or without geographic separation?

  Speciation
• How can speciation occur?

  Rapidly or slowly
• What made the origin of life possible on early Earth?

  Conditions
• What does the fossil record document?

  The history of life
• What key events in life’s history include the origins of organisms?

  Single-celled and multi-celled organisms
• What do the rise and fall of groups of organisms reflect?

  Differences in speciation and extinction rates
• What is ribosomal RNA (rRNA)?

  RNA that makes up ribosomes
• What does a rooted phylogenetic tree represent?

  The most recent common ancestor
• What is sexual selection?

  A form of selection for mating traits
• What is a shared ancestral character?

  A character from an ancestor not in the clade
• What is a shared derived character?

  An evolutionary novelty unique to a clade
• What is speciation?

  An evolutionary process of species splitting
• What are sister taxa?

  Groups sharing an immediate common ancestor
• What defines a species?

  A group that can interbreed and produce offspring
• What are stromatolites?

  Layered rock from prokaryotic activities
• What is sympatric speciation?

  Formation of new species in the same area
• What is systematics?

  A discipline classifying organisms and relationships
• What does a phylogenetic tree represent?

  A hypothesis about evolutionary history
• What is phylogeny?

  The evolutionary history of a species
• What is plate tectonics?

  The theory of Earth's crust movement
• What is a phylum?

  A taxonomic category above class
• What is a polyphyletic group?

  A group from two or more different ancestors
• What is polyploidy?

  A chromosomal alteration with extra sets
• What does a polytomy indicate?

  Unclear evolutionary relationships among taxa
• What is a protocell?

  An abiotic precursor of a living cell
• What are punctuated equilibria?

  Periods of stasis interrupted by sudden change
• What is radiometric dating?

  A method for determining absolute age
• What does reproductive isolation refer to?

  Barriers preventing viable offspring production
• What is molecular systematics?

  A discipline using nucleic acids for relationships