Biology 5C Midterm Vocab

Evolutionary biology

the scientific study of the evolutionary processes that produced the diversity of life on Earth

Evolution

the process of biological change by which species of different organisms change over time

Microevolution

gradual, short-term adaptation of a species to its environment; evolution of traits within a single population of interbreeding individuals

Macroevolution

long-term evolution across entire taxonomic group (taxa), including the evolution of one taxon into one or more new taxa

DNA

basic building block of gene consisting of nucleotides: adenine, cytosine, guanine, thymine

Gene

segment of DNA that encode a specific protein and control a trait

Allele

an alternate or variant form of a gene

Chromosome

larger unit of hereditary consisting of DNA and proteins

Locus

location of a gene on the chromosome

Genotype

the genetic makeup of an individual

Phenotype

the physical appearance of a trait

Dominant allele

expressed every time even alone

Recessive allele

only expressed when in pair

Transcription

making of RNA from DNA

Translation

make of protein from RNA

Epigenetics

study of gene function that do not involve a change in DNA sequence, but DNA methylation

True-breeding

referring to an organism that produces offspring of the same variety over many generations of self pollination

Character

an observable heritable feature that may vary among individuals

Trait

one of two or more detectable variants in a genetic character

Gene

a discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA

Locus (loci)

a specific place along the length of a chromosome where a given gene is located

Allele

any of the alternative versions of a gene that may produce distinguishable phenotypic effects

Genotype

the genetic makeup, or set of allele, of an organism

Phenotype

the observable physical and physiological traits of an organism, which are determined by its genetic makeup

Homozygous

having two identical alleles for a given gene

Heterzygous

having two different alleles for a given gene

Dominant

an allele that is fully expressed in the phenotype of a heterzygote

Recessive

an allele whose phenotypic effect is not observed in a heterozygote

Monohybrid cross

a cross between two organisms that are heterozygous for the character (self pollination of a heterozygous plant)

Dihybrid cross

a cross between two organisms that are each heterozygous for both of the characters being followed (self pollination of a plant that is heterozygous for both characters)

Non-coding elements

sequences/regions in the genome that do not code for protein or RNA

Mutation

a change in the DNA sequence relative to some standard or previously existing sequence

Mutant

an individual whose genome contains a mutation at some location of interest (in a specific gene)

Phenotypic variation

variation in phenotypes such as morphology, behavior, physiology among members of a group of organisms

Genetic (genotypic) variation

variation in mutations/alleles among members of a group of organisms

Somatic mutations

mutations that occur in the body tissues of an organism, and are not transmitted to the next generation

Germline mutations

mutations that occur in the gametes (sperm or egg) and are transmitted to the offspring

Mutagen

a substance or environmental factor that increases the rate at which mutations occur

Error correction mechanisms

cellular/molecular mechanisms that correct most errors in DNA replication/meiosis

Non-disjunction

the failure of chromosomes to correctly separate during meiosis

Deleterious/beneficial/neutral mutations

mutations that cause a decrease/increase/no change in fitness (respectively)

Population

a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring

Gene Pool

the aggregate of all copies of every type of allele at all loci in every individual in a population. The term is also used in a more restricted sense as the aggregate of alleles for just one or a few loci in a population

Polymorphic

occurring in several different forms, in a particular with reference to species or genetic variation

Monomorphic

having or existing in only one form

Allele Frequency

the proportion of a specific allele in a gene pool

Genotype Frequency

the proportion of individuals in a population with a specific genotype

Random mating

Mating with no regard to the genotype or phenotype of a mate, so that any sperm had an equal chance of fertilizing any egg

Hardy-Weinberg Equilibrium

the state of population in which frequencies of alleles and genotypes remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work (random mating and no evolution)

Null Model

a model that give expected outcomes if the thing you are interested in doesn't happen

Genetic Drift

the random change of allele frequencies from one generation to the next due to random sampling

Population Size

the number of organisms in a population

The Founder Effect

the acceleration of genetic drift that occurs when a small number of individuals become isolated from a larger population

The Bottleneck Effect (genetic bottleneck)

the acceleration of genetic drift that occurs when a population decreases in size