BIO 203 1st Edition Lecture 13 Outline of Last Lecture I. 3 Features Define and Animal’s Body PlanA. The number of tissue types in embryosB. The type of body symmetryC. The way in which the earliest events of embryo development proceed.II. About FungiIII. Characteristics of FungiIV. ChytridiomycotaV. ZygomycotaVI. GlomeromycotaVII. BasidiomycotaVIII. AscomycotaOutline of Current Lecture I. Cost of sexual reproductionII. Red-Queen hypothesis for the maintenance of sexIII. Advantages: Asexual vs. Sexual ReproductionIV. Disadvantages: Asexual vs. Sexual ReproductionV. Types of Asexual ReproductionVI. Sexual ReproductionCurrent LectureI. Cost of sexual reproductiona. Sex results in recombination – good for populations, potentially bad for individuals. Very advantageous combinations of genes in the parent may get splitup in the offspringb. Sex requires extra energy expenditure – finding a mate can be costly and riskyII. Red-Queen hypothesis for the maintenance of sexa. Proposed by Van Valen in 1973.b. In Alice in Wonderland, Alice runs as fast as she can to stay in the same place.c. The analogy to nature is that organisms evolve as fast as they can, just to keep pace with their co-evolving competitors, parasites, predators, and pathogens.d. Evolution requires genetic variation, which can arise through sexual recombination.III. Advantages: Asexual vs. Sexual reproductionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Sexuali. Generates novel gene combinationsii. Advantage in the face of antagonistic biotic interactions (competition, predation, parasitism)iii. It reduces the expression of potentially harmful genesb. Asexuali. Fast! Simple mitotic nuclear division followed by cytokinesis. Meiosis takes time.ii. All cells can reproduceiii. Favorable gene combinations are maintainedIV. Disadvantages: Asexual vs. Sexual Reproductiona. Sexuali. The production of males is a cost to the rate of reproduction relative to rates by asexual populationsii. Recombination breaks up favorable gene combinationsiii. Male and female gametes must be brought into contactb. Asexuali. In a changing environment, adaptation is severely restricted by asexual reproductionii. Risk of extinction by biotic interactionsV. Types of Asexual Reproductiona. Mitotic Parthenogenesis (apomixes): reproduction by single cells that are derivedby mitosisi. Offspring are clonesii. Parthenogenesis is widespread among animalsiii. Obligate parthenogenesis (only asexual reproduction) is found in the bdelloid rotifers and darwinulid ostracodsb. Fission or ‘Vegetative’ reproduction: reproduction by detachment and subsequent differentiation of groups of mitotically derived cells or tissuesi. Production of offspring without recombination of genetic materialii. Takes place by subdividing an existing body into 2 or more multicellular parts (‘budding’ or ‘fission’)c. Incomplete fission can give rise to colonial organismsVI. Sexual Reproductiona. Reproductive processes in which the recombination of genetic material derived from more than one parent is possible.b. In animals sexual reproduction always involves meiosis and the formation of a gametesc. Sexual reproduction with fertilization: processes of reproduction in which meiotically derived haploid eggs and sperm fuse to create a diploid zygoted. Gonochorism (dioecy): sexes are separated and individuals are either exclusively male or femalee. Hermaphroditism - Both reproductive tissues in an