genbio unit 4 & 5

• Reproduction


  One of the characteristics of life, biological process in which new individual organisms are produced, can be sexual or asexual
• Types of Reproduction


  • Sexual
  • Asexual
• Sexual Reproduction


  Involves the union of gametes (egg cell and sperm cell) through fertilization
• Asexual Reproduction


  Involves the creation of cloned offspring from a parent organism
• Main Parts of a Flower

  • Reproductive (Stamen and Pistil/Carpel)
  • Sterile (Petals/corolla and Sepals/calyx)
• Stamen


  Male parts, pollen generator, includes anther (production site of pollen) and filament (supports anther)
• Pistil/Carpel


  Female parts, pollen acceptor, includes stigma (pollen's receiving site), style (supports stigma), ovary (fertilization site), ovule (becomes seed)
• Petals/corolla


  Bright in colour to attract pollinators such as insects
• Sepals/calyx


  Small, leaf-like parts growing at the base of the petals, protect the flower before it blossoms
• Types of Flowers


  • Perfect (have both pistil and stamen parts)
  • Imperfect (either only have the pistil or stamen)
  • Complete (contains all four main parts)
  • Incomplete (lacks at least one of the four main parts)
• Pollination


  Transferring pollen from an anther to a stigma, can happen within same flower (self-pollination) or different flowers
• Pollination Strategies


  • Bee pollination
  • Moth on yucca flower
  • Blowfly on carrion flower
  • Long-nosed bat feeding on cactus flower at night
  • Hummingbird drinking nectar of columbine flower
• Pollination Agents


  • Biotic (bees, moths, flies, bats, hummingbirds)
  • Abiotic (wind, water)
• Haplontic Life Cycle


  Dominant stage is a multicellular haploid stage which produces gametes that fuse to form unicellular zygotes
• Haplodiplontic Life Cycle


  Has a multicellular haploid (gametophyte) stage that produces gametes, and a multicellular sporophyte stage
• Diplontic Life Cycle


  Life cycle dominated by the diploid stage, as seen in flowers
• Usual Life Cycle of Angiosperms

  Seed > mitosis > main plant > mitosis > flower where meiosis occurs (produces haploid sperm and egg in pollen) > pollen reaches egg > fertilizes egg > fruit with seed
• Double Fertilization


  Pollen tube discharges two sperm, one fertilizes the egg and the other fertilizes the polar nuclei to form the triploid endosperm
• Parts of a Seed

  • Seed coat
  • Embryo (radicle, hypocotyl, epicotyl, plumule)
  • Endosperm
• Types of Seed Germination

  • Epigeous (hypocotyl connects radicle then epicotyl arises from cotyledon, cotyledon goes up with shoot system)
  • Hypogeous (cotyledon inside seed stays underground, radicle root goes down, hypocotyl attaches to cotyledon, epicotyl goes up)

  
• Types of Fruit


  • Simple (single or several fused carpels)
  • Aggregate (single flower with multiple separate carpels)
  • Multiple (group of flowers called an inflorescence)
  • Accessory (contains other floral parts in addition to ovaries)
• Parts of a Fruit

  • Pericarp (epicarp, mesocarp, endocarp)
  • Accessory parts (petals, sepals)
  • Seed (embryo, endosperm, seed coat)

  
• Seed and fruit dispersal is aided by different agents like wind, water, and animals
• Asexual Reproduction in Plants

  Produces individuals genetically identical to parent plant, can occur through fragmentation, apomixis, or vegetative propagation
• Methods of Vegetative Propagation

  • Stems (runners, nodes)
  • Roots (tubers)
  • Leaves (succulent)
  • Bulbs

  
• Artificial Propagation


  Includes grafting, layering, and cutting
• Ways Animals Reproduce


  • Asexual (budding, fission, fragmentation & regeneration, parthenogenesis)
  • Sexual
• Sexual Reproduction in Animals

  Creation of offspring with the fusion of egg and sperm, results in genetic recombination and increased variation
• Reproductive Cycles


  Includes ovulation, where mature eggs are released at the midpoint of a female's cycle
• Budding


  1. Individuals arise throughout the outgrowths from a parent

  2. Create a colony of individuals attached to a parent

  3. Ex. corals
• Fission


  1. Separation/division of an organism to form individuals of same size

  2. Ex. animal-like protists, Amoeba
• Fragmentation & Regeneration


  1. Animal's body breaks into different parts, which regenerate

  2. Ex. Sponges, annelids, cnidarians and tunicates
• Parthenogenesis


  1. Apomixes in plants, where the egg cell develops without fertilization

  2. Ex. Mama Mary gave birth to Jesus

  3. Ex. bees, wasps, lizards, sharks
• Sexual Reproduction


  1. Creation of offspring with the fusion of egg and sperm

  2. Results in genetic recombination, leading to: increase in variation in offspring, providing an increase in the reproductive success of parents in changing environments, an increase in the rate of adaptation, a shuffling of genes, elimination of harmful genes from a population

  
• Reproductive Cycles


  1. Ovulation: release of mature eggs at the midpoint of a female cycle

  2. Most animals exhibit reproductive cycles related to changing seasons

  3. Reproductive cycles are controlled by hormones and environmental cues

  4. Animals may reproduce asexually or sexually, or they may alternate these methods

  5. Sexual reproduction is a special problem for organisms that seldom encounter a mate, solution is hermaphroditism (intersexual) = each individual has BOTH male and female reproductive systems, some hermaphrodites can self-fertilize

  6. Individuals of some species undergo sex reversals, some species exhibit male to female reversal (for example, certain oysters), while others exhibit female to male reversal (ex. a coral reef fish)
• Fertilization & Fusion of Gametes


  The mechanisms of fertilization, the union of egg and sperm, play an important part in sexual reproduction
• Types of Fertilization


  • External
  • Internal
• Types of Union of Gametes

  • Isogamy
  • Heterogamy
• Chlamydomonas Life Cycle (Chlamydia)

  1. Zygote opposite to egg is diploid > produce gametes via meiosis > germinate > instead of sperm and egg, they form + and - kasi magkakamukha sila > progenitor cells undergo asexual reproduction to produce plus and minus gametes > flagellar adhesion > fuse their gametes > activated according to structure > fuse cells forming +/- organism (zygote) > maturation

  2. Male and female gametes are not discernable
• Female Reproductive System


  • Ovary creates follicle which houses the egg > when follicle matures the egg will go to oviduct and wait for the sperm to reach it
  • Menstrual and ovarian cycle happen collectively
  • The secretion of hormones and the reproductive events they regulate are cyclic
  • Before ovulation, the endometrium (uterine lining) thickens with blood vessels in preparation for embryo implantation
  • Thick lining is needed to protect and accommodate the baby and uterus; if lining is thin, the baby won't survive
  • If an embryo doesn't implant, the endometrium is shed in a process called menstruation
  • When the endometrium sheds, so do the blood vessels and the blood inside of it
  • Hormones are closely linked to the uterine cycle (changes in the uterine lining) and ovarian cycle (changes in the ovaries, follicles, egg chamber)