Systematics Flashcards
State two justifications for the use of scientific names and classifications of organisms
Scientific names allow biologists to know with certainty that they are studying the same/different organisms. Classifications help by organizing the knowledge.
What is classification?
It is the process of arranging organisms into groups based on similarities that reflect evolutionary relationships
Arrange the Linnaean categories in hierarchical fashion.
Domain, kingdom, phylum, class, order, family, genus, species
Describe the binomial system of naming organisms.
The basic unit of classification is species; the name of each species has two parts: genus then followed by the specific epithet
What are the three domains?
The three-domain classification system assigns organisms to domains: Archaea, Bacteria, or Eukarya
What are the five kingdoms?
The kingdoms recognized are Archaea, Bacteria, Fungi, Plantae, and Animalia
What is a clade?
It is a group of organisms with a common ancestor
What is a node?
It is a branching point that represents the splitting of two or more new groups from a common ancestor
What is systematics?
It is the scientific study of the diversity of organisms and their evolutionary relationships
What is taxonomy?
It is the branch of systematics devoted to naming, describing, and classifying
What is a taxon?
It is each formal grouping at any given level
Interpret a cladogram.
By tracing along the branches back to the nodes, the cladogram indicates which taxa shared a recent common ancestor and how recently they shared that ancestor compared to other groups
What is homology?
It is the presence in two or more species of a trait derived from a recent common ancestor
What is convergent evolution?
The independent evolution of similar structures in distantly related organisms
What is reversal?
The reversion of a trait to its ancestral state
What is phylogeny?
The evolutionary history of a group of organisms from a common ancestor
What is homoplasy?
A characteristic that superficially appears homologous but is actually independently acquired by convergent evolution or reversal
How do molecular systematics contribute to the science of systematics?
Comparisons of nucleotide sequences in DNA and RNA, and of amino acid sequences in protein provide important information about how closely related organisms are
What is a monophyletic group?
Also known as a clade, it includes all the descendants of the most recent common ancestor
What is a paraphyletic group?
It consists of a common ancestor and some, but not all, of its descendants
What is a polyphyletic group?
It consists of organisms that evolved from different recent ancestors
How are cladistics and evolutionary systematists different in classifying?
Cladists use shared derived characters to determine relationships; evolutionary systematics is based on shared ancestral characters as well as shared derived characters
