Neo-Darwinism(modern synthetic theory)
Modern synthetic theory is the theory which is based on modern research and studies. It is based on modern branch of biology like genetics, population genetics, cytogenetic etc. this theory was given by a group of scientists. According to this theory, the causes of evolution are:
mutation
genetic recombination
gene flow
genetic drift
natural selection
reproductive isolation
Mutation:
Mutation, which is a sudden genetic change. Mutation may be change in a
single gene (genic mutation or point mutation) or affect many genes (chromosomal
mutation).
Genetic recombination:
Genetic recombination, which occurs in sexually reproducing organisms at
every reproduction. The chromosomes and thus genes of the parents mix at
random during zygote formation. That is why offspring of same parents are
different as they have different combinations of parental genes. Variation is also
brought about when gametes are formed after meiosis.
Gene flow:
Gene flow is when there is chance for mixing of genes of closely related species
through sexual reproduction.
Genetic drift:
Genetic drift occurs in small populations when it breaks off from a large
population only representative genes of the large population are present which
undergo change and the small population may evolve as a result.
Natural Selection:
Natural selection in the modern synthetic theory is considered to be
Responsible for “differential reproduction of genes” which means that more of
favorable genes get reproduced in a population.
Role of Reproductive Isolation:
Once new species arise from the parental species due to the effect of variation and
natural selection, reproductive barriers prevent the two species from exchanging
genes through reproduction.
Thus two related species cannot mate with each other and remain distinct. Isolation
means separation and reproductive isolation simply means that the two species are
prevented from successful reproduction and kept genetically distinct from each
other.
Modern synthetic theory is the theory which is based on modern research and studies. It is based on modern branch of biology like genetics, population genetics, cytogenetic etc. this theory was given by a group of scientists. According to this theory, the causes of evolution are:
mutation
genetic recombination
gene flow
genetic drift
natural selection
reproductive isolation
Mutation:
Mutation, which is a sudden genetic change. Mutation may be change in a
single gene (genic mutation or point mutation) or affect many genes (chromosomal
mutation).
Genetic recombination:
Genetic recombination, which occurs in sexually reproducing organisms at
every reproduction. The chromosomes and thus genes of the parents mix at
random during zygote formation. That is why offspring of same parents are
different as they have different combinations of parental genes. Variation is also
brought about when gametes are formed after meiosis.
Gene flow:
Gene flow is when there is chance for mixing of genes of closely related species
through sexual reproduction.
Genetic drift:
Genetic drift occurs in small populations when it breaks off from a large
population only representative genes of the large population are present which
undergo change and the small population may evolve as a result.
Natural Selection:
Natural selection in the modern synthetic theory is considered to be
Responsible for “differential reproduction of genes” which means that more of
favorable genes get reproduced in a population.
Role of Reproductive Isolation:
Once new species arise from the parental species due to the effect of variation and
natural selection, reproductive barriers prevent the two species from exchanging
genes through reproduction.
Thus two related species cannot mate with each other and remain distinct. Isolation
means separation and reproductive isolation simply means that the two species are
prevented from successful reproduction and kept genetically distinct from each
other.
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