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16 terms

Genetics, Ecology & Evolution Final Vocabulary

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Hardy-Weinberg Equilibrium
1. Large population. The population must be large to minimize random sampling errors.
2.Random mating. There is no mating preference. For example an AA male does not prefer an aa female.
3.No mutation. The alleles must not change.
4.No migration. Exchange of genes between the population and another population must not occur.
5.No natural selection. Natural selection must not favor any particular individual.
Oscillating selection
The situation in which selection alternately favors one phenotype at one time, and a different phenotype at another time, depending on environmental factors.
Frequency-Dependent Selection
An evolutionary process where the fitness of a phenotype is dependent on its frequency relative to other phenotypes in a given population.
Heterozygote Superiority
When individuals who have a heterozygous genotype are more fit than individuals who have a homozygous genotype
Homologous Structures
Homologous structures or organs are those that share a common ancestry or origin.
Vestigial Structures
Vestigial structures are function-less structures that were functioning in an ancestral species.
Species
An individual belonging to a group of organisms having common characteristics and are capable of mating with one another to produce fertile offspring.
Allopatric Speciation
The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.
Sympatric Speciation
The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population (mutants) and the parent population. No geographic barrier is present.
Adaptive Radiation
the development of many different forms from an originally homogeneous group of organisms as they fill different ecological niches
Cephalization
the concentration of nerve tissue and sensory organs at the anterior end of an organism
Plesiomorphies
defined and grouped by the possession of one or more shared characteristics (called characters) that are derived from a common ancestor and that were not present in any ancestral group
Synamorphies
Derived traits that are shared among a group of organisms and are viewed as evidence of the common ancestry of the group
Apomorphies
derived characteristics; structures have undergone recent change; build phylogenies; Ex: Darwin's Finches
Clade Vs. Taxon
Clade: A group of organisms believed to have evolved from a common ancestor, according to the principles of cladistics.

Taxon: A taxonomic category or group, such as a phylum, order, family, genus, or species.
Monophyletic Vs. Polyphyletic
Monophyletic: Developed from a single common ancestral form.

Polyphyletic: Relating to or characterized by development from more than one ancestral type.