Questions and Answers
How can organisms be classified?
On physical similarities.
What is the science of naming and classifying organisms?
Taxonomy.
What is a group of organisms in a classification system called?
Taxon.
What system gives each species a two-part scientific name using Latin words?
Signup and view all the answers
What includes one or more species that are thought to be closely related?
Signup and view all the answers
How does the Linnaean taxonomy classify organisms?
Signup and view all the answers
How does the Linnaean taxonomy name species?
Signup and view all the answers
How are the seven levels of the Linnaean classification system organized?
Signup and view all the answers
Describe the trend in the levels, or taxa, as you move down from kingdom to species.
Signup and view all the answers
List the seven levels of the Linnaean classification system.
Signup and view all the answers
Why did Linnaeus base his system of classification on physical similarities alone, as opposed to including molecular and genetic similarities?
Signup and view all the answers
Why are physical similarities among species not always the result of being closely related?
Signup and view all the answers
Why do scientists today rely on molecular and genetic similarities to classify organisms?
Signup and view all the answers
What is taxonomy the science of?
Signup and view all the answers
What is used in binomial nomenclature?
Signup and view all the answers
In the binomial nomenclature naming system, what is each species given?
Signup and view all the answers
What is modern classification based on?
Signup and view all the answers
What does the term phylogeny refer to?
Signup and view all the answers
What does cladistics classify organisms based on?
Signup and view all the answers
What is a cladogram?
Signup and view all the answers
What are traits that are shared by some species but not by others called?
Signup and view all the answers
What is phylogeny?
Signup and view all the answers
How can phylogeny be shown?
Signup and view all the answers
Describe the main goal of cladistics.
Signup and view all the answers
What is a clade?
Signup and view all the answers
How are derived characters used in marking a cladogram?
Signup and view all the answers
On a cladogram, what is a node and what does it represent?
Signup and view all the answers
Give two examples of molecular evidence that can be used to help determine species relatedness.
Signup and view all the answers
Why are evolutionary trees often changed?
Signup and view all the answers
What can be concluded if the genes of two species are found to be nearly identical?
Signup and view all the answers
What do the Greek roots of phylogeny mean?
Signup and view all the answers
Study Notes
Organism Classification
- Organisms are classified based on physical similarities.
- Taxonomy is the science of naming and classifying organisms.
- A taxon is a group of organisms in a classification system.
Naming Species
- Binomial nomenclature is a system that assigns each species a two-part scientific name using Latin words.
- Each species is identified by a genus name and a species descriptor.
Linnaean Taxonomy
- Linnaean taxonomy classifies organisms into groups called taxa based on traits.
- The seven levels of Linnaean classification are: kingdom, phylum, class, order, family, genus, and species.
Taxonomic Trends
- As you move from kingdom to species, the taxa groups get progressively smaller.
- Linnaeus focused on physical characteristics due to the lack of technology for molecular and genetic analysis.
Limitations of Physical Similarities
- Physical similarities don’t always indicate close relationships; traits may evolve similarly in different species due to environmental factors.
- Molecular and genetic similarities offer a more reliable classification, as physical differences do not separate molecular traits.
Modern Classification
- Modern classification prioritizes evolutionary relationships and phylogeny, which is the evolutionary history of a group of species.
- Cladistics classifies organisms based on evolutionary relationships and common ancestry.
Cladograms and Clades
- A cladogram is an evolutionary tree that suggests relationships among species.
- A clade is a group sharing derived traits from a common ancestor.
- Derived characters indicate shared evolutionary relationships and are used to construct cladograms.
- A node on a cladogram represents a point where a branch splits, indicating a common ancestor for the species above it.
Molecular Evidence in Classification
- Similar protein sequences and DNA sequences serve as molecular evidence to determine species relatedness.
- Evolutionary trees are adjusted when new evidence arises, reflecting updated understanding of relationships.
- Nearly identical genes between two species imply they have a similar DNA sequence.
Phylogeny Definition
- Phylogeny, derived from Greek meanings class (phylo-) and origin (geny), organizes organisms based on their historical backgrounds and relationships.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the Linnaean System of Classification through interactive flashcards. Learn about the key concepts such as taxonomy, taxons, and binomial nomenclature, which are essential for understanding how organisms are classified. Perfect for students and enthusiasts of biology.