* Meiosis – cell division for gamete production * In specialized tissues * Produces cells with the 1n chromosome number * Two Divisions * Meiosis I separates homologous chromosomes * Meiosis II separates sister chromisis * Asexual Reproduction * Mitotic division * Identical offspring * Sexual Reproduction * Fuse gametes from parents (syngamy) to produce a zygote * Each parent contributes half the genetic material * Increase the diversity of
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Main article: Evolution of sexual reproduction It is considered that sexual reproduction in eukaryotes first appeared about a billion years ago and evolved within ancestral single-celled eukaryotes.[2] The reason for the initial evolution of sex‚ and the reason(s) it has survived to the present‚ are still matters of debate. Some of the many plausible theories include: that sex creates variation among offspring‚ sex helps in the spread of advantageous traits‚ that sex helps in the removal of disadvantageous
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genetic copies of the parent. A more stringent definition is agamogenesis which is reproduction without the fusion of gametes. Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaea‚bacteria‚ and protists. Many plants and fungi reproduce asexually as well. While all prokaryotes reproduce asexually (without the formation and fusion of gametes)‚ mechanisms for lateral gene transfer such as conjugation‚ transformation and transduction are sometimes likened
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Introduction Codium‚ a genus of marine algae found in the order Bryopsidales‚ is found in most places worldwide‚ except for the Arctic and Antarctic. Like most members of Bryopsidales‚ Codium is siphonous and spreads quickly‚ often becoming a nuisance algae (Silva‚ 2008). There are many species within the genus Codium‚ but most of them are characterized by their spongy texture and the presence of utricles (Huisman et al. 2007). Species vary in color‚ sizes and shapes. They can be dark green to
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process of splitting the nucleus and it occurs hand in hand with the rest of the cell cycle and cytokenesis. Meiosis‚ on the other hand‚ is a process of taking a diploid cell (a cell with the full number of chromosomes) and producing haploid gametes
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generating genetic diversity: crossing over and independent assortment mixes up existing combinations of alleles of all genes to increase range of genotypes and therefore genetic diversity). Increase in genetic diversity of gametes results. Fertilization results in random fusion of gametes; this increases genetic diversity even further in the population. (4) Conclusion: Maintenance of genetic diversity
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the parent cell and grow to become mature haploid cells. Sexual reproduction among unicellular protists During environmental stress certain protists reproduce sexually - haploid cells divide by mitosis producing haploid gametes - a pair of gametes fuse to form a
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by non-motile spores Sexual reproduction- by non-motile heterogametes Male gametes- are spherical‚ non-motile‚ produced in antheridia. -Carried by water to female sex organ Carpognia- female sex organ of red algae‚ that‚ when fertilized‚ gives rise to carpospores. Trichogyne- the elongated tip of carpognium‚ to which a sperm may adhere. LIFE CYCLE OF RED ALGAE Consists of two alternating phases: 1.Haploid‚ gamete-bearing plants 2.Diploid‚ tetrasporic plants oTetrasporophyte-
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the cell and forms two completely separate cells that are exact duplicates of the parent cell. There are now two new daughter cells‚ each with its own nucleus. Meiosis Meiosis is a type of cell division where one body cell produces four gametes‚ each
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Class XII Question 1: Chapter 4 – Reproductive Health Biology What do you think is the significance of reproductive health in a society? Answer Reproductive health is the total well being in all aspects of reproduction. It includes physical‚ emotional‚ behavioural‚ and social well being. Sexually transmitted diseases such as AIDS‚ gonorrhoea‚ etc. are transferred from one individual to another through sexual contact. It can also lead to unwanted pregnancies. Hence‚ it is necessary to create
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