spontaneous generation

generation /gen·er·a·tion/ (jen″ĕ-ra´shun)

1. reproduction (1).

2. a class composed of all individuals removed by the same number of successive ancestors from a common predecessor, or occupying positions on the same level in a genealogical (pedigree) chart.

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alternate generation  reproduction by alternate asexual and sexual means in an animal or plant species.

asexual generation  production of a new organism not originating from union of gametes.

first filial generation  the first-generation offspring of two parents; symbol F1.

parental generation  the generation with which a particular genetic study is begun; symbol P1.

second filial generation  all of the offspring produced by two individuals of the first filial generation; symbol F2.

sexual generation  production of a new organism from the zygote formed by the union of gametes.

spontaneous generation  the discredited concept of continuous generation of living organisms from nonliving matter.

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spontaneous generation.

See abiogenesis.

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generation

1. the process of reproduction.

2. a class composed of all individuals removed by the same number of successive ancestors from a common predecessor, or occupying positions on the same level in a genealogical (pedigree) chart. Said also of antibiotics or other chemicals derived from parent compounds.

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alternate generation

reproduction by alternate asexual and sexual means in an animal or plant species.

asexual generation

production of a new organism not originating from union of gametes. Called also direct generation.

direct generation

see asexual generation (above).

filial generation (first)

the first generation offspring of two parents; symbol F₁.

filial generation (second)

all of the offspring produced by two individuals of the first filial generation; symbol F₂.

generation interval

the mean age of the parents when the animals that are to replace them are born.

parental generation

the generation with which a particular genetic study is begun; symbol P₁.

sexual generation

production of a new organism from the zygote formed by the union of gametes.

spontaneous generation

the discredited concept of continuous generation of living organisms from nonliving matter.

generation time

1. in epidemiological terms the time required between infection occurring and the patient reaching full infectivity.

2. in histological terms the time required to complete one full cell cycle; average of 20 hours for mammalian cells.