Sexual Reproduction

Usually occurs in plants, animals, and most multicellular organisms Sexual Reproduction Offspring are formed when genetic information is passed from more than one parent and shares the characteristics of both parents– a male and female; the offspring is unique The female sex cell is the egg (ova) and the male sex cell is the sperm Usually occurs in plants, animals, and most multicellular organisms

What do you remember about mitosis? Sexual Reproduction What do you remember about mitosis? Mitosis – asexual reproduction of cells; two exact copies of the parent cell Contain 46 chromosomes Also known as diploid cells (diploid = duplicate) Examples include skin, muscle, and blood cells

Sexual Reproduction Meiosis – sexual reproduction of cells; contains only half the number of chromosomes Contain 23 chromosomes each; when joined there is a total of 46 chromosomes Chromosomes that carry the same set of genes are homologous Also known as haploid cells (haploid = half) Examples include sperm and egg/ova (gametes) Chromosomes are copied once, but the nucleus divides twice!

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Create a T-chart in your comp book. diploid haploid Two sets of chromosomes One set of chromosomes Mitosis division Meiosis division 2 daughter cells 4 daughter cells 46 chromosomes 23 chromosomes Skin, muscle, and blood cells Gamete (sperm and ova cells) Asexual reproduction Sexual reproduction

Important Terms Gamete – a mature haploid cell (sperm or ova) that is able to join with the opposite haploid cell, and produce a zygote Zygote –a cell formed by the union of two gametes (sex cells; sperm and ova/egg) Genes – set of instructions for an inherited trait; located on chromosomes.

Advantage of Sexual Reproduction Produce offspring with genetic material from both parents which creates a greater variety in the species More adaptations in species allow for greater adaptation to changes in the environment In species where males help raise the offspring, it is possible to produce more offspring with a greater chance of survival

Organisms reproduce more slowly and take longer to colonize Disadvantages of Sexual Reproduction Organisms reproduce more slowly and take longer to colonize Sexual population grows twice as slowly as the asexually producing one If a mate is not found, the female’s egg is wasted Parents often have to raise the offspring/offspring are not self-sufficient