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Reproduction

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Reproduction

• Production of new individuals is a fundamental characteristic of a living species.

• Genetic information is passed on from parental generation to their offspring

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Asexual Reproduction

• Involves:– Single individual– No gamate production– Inheritance of identical genetic info from the

parent– Mitotic divisions

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Sexual Reproduction

• Involves:– Formation of gametes by individuals– Meiosis which halves the number of

chromosomes– Fusion of a haploid male gamete with a

haploid female gamete to form a diploid zygote

– The growth of the zygote by mitotic divisions into a new individual

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Why undergo sexual reproduction?

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Meiosis

• In a diploid organism; – One set of chromosomes from father– One set from the mother

– 2 copies of each chromosome in a cell– These Chromosomes are homologous

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Meiosis

• Homologous chromosomes:– Are same length– Have centromere in same position– Have same number of genes– Genes are arranged in the same linear order

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Stages of Meiosis

See handout

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Significance of Meiosis

• Introduces some genetic variation• Maintains genetic stability• Each haploid (n) gamate carries only 1

gene for a particular characteristic• Crossing over leads to new combinations

of genes• Independent assortment of chromosomes

mixes up combinations of chromosomes

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