Key Terms for Exam 1 Flashcards
Any change in the inherited traits of a population that occurs from one generation to the next (over a period longer than the lifetime of an individual in the population)
Biological evolution
A process by which populations of organisms change over time
Evolution
A chain of ancestors and their descendants.
May be the successive generations of organisms in a single population, the members of an entire species during an interval of geological time, or a group of related species descending from a common ancestor
Lineage
A mechanism that can lead to evolution, whereby differential survival or reproduction of individuals causes some genetic types to replace (outcompete) others
Natural selection
The independent origin of similar traits in separate lineages
Convergent evolution
Characteristics are similar in two or more species because they are inherited from a common ancestor
Homologous
A derived form of a trait that is shared by a group of related species (i.e., one that evolved in the immediate common ancestor of the group and was inherited by all its descendants).
Synapomorphy
A visual representation of the evolutionary history of populations, genes or species
Phylogeny
Any change to the genomic sequence of an organism
Mutation
Occurs when genetic material from different strains get mixed into new combinations within a single individual
Viral reassortment
Evolution arising from random changes in the genetic composition of a population from one generation to the next
Genetic drift
A protein on the surface of the influenza virus that latches it to a host cell
Hemagglutinin
Measurable aspects of organisms, such as morphology (structure), physiology, and behavior. Genes interact with other genes and with the environment
Phenotypes
A group of organisms that a taxonomist judges to be a taxonomic unit, such as a species or order
Taxon (taxa)
The science of describing, naming, and classifying species of living or fossil organisms
Taxonomy
The study of layering in rock
Stratigraphy
The study of prehistoric life
Paleontology
The permanent loss of a population or species, arising with the death or failure to breed of the last individual
Extinction
The idea that the natural laws observable around us now are also responsible for events in the past.
Uniformitarianism
Traits are similar because they are inherited from a common ancestor
Homologous
Traits are similar because they have converged on a shared form. Not derived from a common ancestor
Analogous
A mechanism that can lead to evolution, whereby differential reproduction of individuals causes some genetic types to replace (outcompete) others
Natural selection
Inherited aspects of an individual that allow it to outcompete other members of a population that lack the trait (or that have slightly different version of the trait).
Adaptations
Arises when individuals of one sex (usually males) compete with each other over access to individuals of the other sex. It can lead to the evolution of traits like showy ornaments or weapons that improve an individual’s chances of mating
Sexual selection
A change in the frequency of traits or genetic variants that arises across generations due to random events. Most pronounced in small populations
Genetic drift
Terminal ends of an evolutionary tree, representing species, molecules, or populations being compared
Tips
Lineages evolving through time between successive speciation events
Branches
A point in a phylogeny where a lineage splits (a speciation event)
Node
Nodes within a phylogeny representing ancestral populations or species
Internal nodes
An organism and all of its descendants
Clade
A term used to describe a group of organisms that form a clade
Monophyletic
Heritable aspects of organisms that can be compared across taxa
Characters
Phylogenetic methods that construct trees by grouping taxa into nested hierarchies (clades) according to their shared derived characters (synapomorphies)
Cladistics
Character state similarity not due to shared descent (ex. produced by convergent evolution or evolutionary reversal)
Homoplasy
The reversion of a derived character state to its ancestral state
Evolutionary reversal
A trait that originates performing one function, and which is later co-opted for a new function
Exaptation
Members of the hominin genus Australopithecus
Australopithecines
Similar to natural selection, except that it results from human activity. When breeders nonrandomly choose individuals with economically favorable traits to use as breeding stock, they impose strong _____ on those traits.
Artificial selection
The transfer of alleles from one population to another. Occurs when organisms or their gametes move from one location to another
Gene flow
Structures constructed by organisms that can influence their performance or success. Although they are not part of the organism itself, their properties nevertheless reflect the genotype of each individual. Animal examples include the nests constructed by birds and the galls of flies.
Extended phenotypes
An antipredator strategy used by a potential prey item to signal danger or a lack of palatability. Ex. warning coloration
Aposematism
The physical proximity of alleles at different loci. Genetic loci that are physically close to one another on the same chromosome are less likely to be separated by recombination during meiosis, and are thus said to be….
Genetic linkage (genetically linked)
Strong selection can “sweep” a favorable allele to fixation within a population so fast that there is little opportunity for recombination.
Selective sweep
