Bisc 102 vocab Flashcards
Convergent evolution
The evolution of similar features in independent evolutionary lineages
Fertilization/Syngamy
n+n->2n
Natural selection
The differential survival and reproduction of variant individuals within a population
Evolutionary fitness
The relative contribution each individual makes to the next and subsequent generations
Gene pool
The aggregate of all copies of every type of allele at all loci in every individual in a population, / In a more restricted sense, the aggregate of all alleles for just one or a few loci in a population
Heritability
The amount of phenotypic variation due to genotypic variation
Phenotypic variation
From genotype and the environment, variation in physical, physiological or behavioural trait.
Genome
The genetic material of an organism or virus; the complete complement of an organism’s or virus’s genes along with its noncoding nucleic acid sequences
Phenotype
The observable physical and physiological traits of an organism, which are determined by its genetic makeup
Episode of selection
Periods of strong selection pressure from a temporary environmental change or from a normal event in the life cycle of an organism
Directional selection
Favours individuals exhibiting one extreme of a phenotypic range, thereby shifting a population’s frequency curve in one direction or the other
Disruptive selection
Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes
Stabilizing selection
Natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes
Selection differential
Measures the selection pressure on a trait and can be calculated for an episode of selection as the difference between the mean value of a trait before and after the episode of selection
Sexual selection
A form of selection in which individuals with certain heritable traits are more successful in finding mates
Replication
The repetition of a scientific experiment sufficient times to ensure that differences in the results from different treatments are meaningful and not due to change events
The three condition that are necessary and sufficient for natural selection to produce evolutionary change in a given train in a population
- There must be phenotypic variation in the population; 2. The phenotypic variation within the population must have a heritable basis; 3. The heritable variation within the population must have fitness consequences
Trophic level
The level in the different feeding relationships in an ecosystem which determine the route of energy flow and the pattern of chemical cycling
Analogous
Having characteristics that are similar because of convergent evolution, not homology
Ancestral
Traits that are shared by a group of related organisms and their ancestor
Clade
A group of species that includes an ancestral species and all of its descendants
Derived
Traits that are shared by a group of related organisms that are not seen in the ancestor
Divergent evolution
The derivation of two or more lines of descent from a common ancestor, with the new derivatives becoming more dissimilar over time
Homologous
Characteristics that are similar because of common ancestry
Ingroup
A species whose evolutionary relationships we seek to determine
Monophyletic taxon
Equivalent to a clade; a group of taxa that consists of a common ancestor and all of its descendants
Outgroup
A species or a group of species from an evolutionary lineage that is known to have diverged before the lineage that contains the group being studied
Phylogeny
The evolutionary history of a species or group of related species
Phylogenetic tree
A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms
Paraphyletic group
A group of taxa that consists of a common ancestor and some, but not all, of its descendants
Polyphyletic group
A group of taxa derived from two or more different ancestors
Rooted
A phylogentic tree that has at its base the common ancestor of all taxa shown on that tree
Genotype
The genetic makeup or set of alleles of an organism
Phenotype
The observable physical and physiological traits of an organism which are determined by it’s genetic makeup
Locus
A specific place along the length of the chromosome where a given gene is located
Haploid
A cell containing only one set of chromosomes
Gene
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA. In eukaryotes the gene includes regulatory sequences as well as the region encoding the protein/functional RNA itself. In bacteria and archaea, it is just the coding region because multiple protein-coding genes are encoded in one operon under the control of one set of regulatory elements.
Homologous chromosomes
A pair of chromosomes of the same length, centromere position and staining pattern that posses genes controlling for the same character at corresponding loci. One is inherited from each parent
Allele
Any of the alternative versions of a gene that may produce distinguishable phenotypic effects
Homozygous
Having two identical alleles for a given gene
Heterozygous
Having two different alleles for a given gene
Dominant
An allele that is fully expressed in the phenotype of a heterozygote
Recessive
An allele whose phenotypic effect is not observed in a heterozygote
Incomplete dominance
The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele
Monohybrid cross
A cross between two organisms that are heterozygous for the character being followed (or the self pollination of a plant that is heterozygous for both characters)
Dihybrid cross
A cross between two organisms that are each heterozygous for both of the characters being followed (or the self pollination of a plant that is heterozygous for both characters)
Test cross
Breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ration of phenotypes in the offspring reveals the unknown genotype.
Autosomal
A chromosome that is not directly involved in determining sex; not a sex chromosome
Sex-linked
A gene located on either sex chromosome. Most sex linked genes are on the X chromosomes and show distinctive patterns of inheritance