Classification and taxonomy

• The binomial system uses two parts to name an organism: the genus and the species.
• In binomial nomenclature, the genus name is always capitalized, while the species name is not.
• The binomial system helps scientists determine how closely related organisms are by examining their genus and species names.
• Why is the binomial system considered universal?

  It is used by all scientists
• Two species may look similar due to similar environmental conditions and selective pressures.
• Natural selection can lead to similar traits in unrelated species living in similar environments.
• The broadest category in the taxonomic hierarchy is the domain.
• In the taxonomic hierarchy, smaller groups are arranged within larger groups.
• Each group in the taxonomic hierarchy is called a taxa.
• There is overlap between groups in the taxonomic hierarchy.

  False
• What is the purpose of classifying organisms?

  To understand relationships between organisms
• The Linnaeus system is a universal method for classifying organisms.
• Organisms are classified based solely on visible similarities and differences.

  False
• Match the classification method with its description:

  DNA base sequences ↔️ Compares genetic material

  mRNA base sequences ↔️ Compares RNA structure

  Amino acid sequences ↔️ Compares protein structure

  Immunological comparisons ↔️ Compares antigens and antibodies
• Immunological comparisons use the similarity of antigens on cell surfaces to determine relatedness.
• Organisms with more similar DNA base sequences are more closely related.
• Phylogenetic classification focuses on evolutionary relationships and origins.
• What do branches in a phylogenetic tree represent?

  Common ancestors
• The most recent common ancestor of humans and chimpanzees is represented at a branch in their phylogenetic tree.
• In a phylogenetic tree, going further to the left indicates moving backward in time.