Pre-Lab 1 Flashcards
What is a cladogram?
A cladogram is a diagram that shows the evolutionary relationships among various biological species based on shared characteristics.
True or False: Cladograms are based on morphological traits only.
False
What are the two main types of traits used in building cladograms?
Ancestral traits and derived traits.
Fill in the blank: Traits that are present in a common ancestor and all its descendants are called ______ traits.
Ancestral
What are derived traits?
Traits that are present in an organism but absent in its ancestors.
Multiple Choice: Which of the following is NOT a useful trait for building a cladogram? A) Morphological traits B) Genetic traits C) Behavioral traits D) Random traits
D) Random traits
What is the significance of homologous traits in cladograms?
Homologous traits indicate common ancestry and are essential for establishing evolutionary relationships.
True or False: Convergent evolution can complicate the interpretation of traits in cladograms.
True
What is the role of synapomorphies in cladistics?
Synapomorphies are shared derived traits that help to define clades and indicate common ancestry.
Fill in the blank: Traits that evolve independently in different lineages are called ______ traits.
Analogous
What is the principle of parsimony in constructing a cladogram?
The principle of parsimony states that the simplest explanation, or the least complex tree, is preferred when constructing a cladogram.
Multiple Choice: Which of the following traits is most useful for constructing a cladogram? A) Traits that change frequently B) Traits that are unique to one species C) Traits that are consistent across multiple species D) Traits that have no evolutionary significance
C) Traits that are consistent across multiple species
What is the importance of molecular data in cladistics?
Molecular data provides a more precise way to determine evolutionary relationships and can reveal traits not visible in morphology.
True or False: All traits are equally informative for constructing a cladogram.
False
What does a polytomy indicate in a cladogram?
A polytomy indicates an unresolved relationship where multiple lineages diverge from a single point.
Fill in the blank: The evolutionary history of a group of organisms is represented in a ______.
Phylogeny
What type of traits should be avoided when building a cladogram?
Traits that are subject to environmental influences and do not reflect evolutionary relationships.
Multiple Choice: Which of the following is a key feature of a cladogram? A) It shows the physical appearance of species B) It represents evolutionary relationships C) It lists species in alphabetical order D) It includes all known species
B) It represents evolutionary relationships
What is the difference between a cladogram and a phylogenetic tree?
A cladogram focuses on the branching patterns of evolution, while a phylogenetic tree includes branch lengths that represent evolutionary time or genetic change.
True or False: Cladograms can be constructed using both morphological and molecular data.
True
What is a clade?
A clade is a group of organisms that includes a common ancestor and all its descendants.
Fill in the blank: In cladistics, the goal is to identify ______ relationships among species.
Phylogenetic
What role do outgroups play in cladistic analysis?
Outgroups help to determine the ancestral states of traits and provide a reference for distinguishing between ancestral and derived traits.
What is the significance of trait polarity in cladistics?
Trait polarity determines whether a trait is ancestral or derived, which is crucial for constructing accurate cladograms.
