BIO C04

• Reproduction is the biological process by which new individuals of the same species are produced, ensuring the continuation and survival of that species
• Asexual reproduction


  A single parent produces offspring without the involvement of gametes or fertilization. The offspring is genetically identical or nearly identical to the parent, as there is no genetic recombination
• Sexual reproduction


  Two parents contribute genetic material to produce offspring. Specialized cells called gametes, which are produced by the reproductive organs, combine to form a new organism. The offspring inherits a combination of genetic material from both parents, resulting in genetic diversity
• Hydrilla (Hydrilla verticillata) reproduces asexually
• Humans reproduce sexually
• Alternation of generations in plant reproduction


  • Sporophyte generation (diploid, 2n)
  • Gametophyte generation (haploid, n)
• Flower structure


  • Complete flower structure: sepals, petals, stamens, carpels
  • Incomplete flower structure: absence of one or more of the above structures
• In flowering plants, the diploid sporophyte generation is dominant
• Gametophyte formation


  1. Microspore (male gametophyte, pollen grains)

  2. Megaspore (female gametophyte, embryo sac within ovule)
• Double fertilization in angiosperms


  1. Sperm cell fertilizes egg cell

  2. Sperm cell fertilizes central cell
• Vegetative propagation


  Generation of new individuals without the involvement of seeds, from stems, roots and leaves
• Vegetative propagation structures


  • Runners and stolons
  • Rhizomes
  • Tubers
  • Bulbs
  • Cuttings, marcotting, grafting
• Most animals reproduce sexually
• Parthenogenesis


  Modification of sexual reproduction where an unfertilized egg develops into a complete individual
• Monoecious


  Contain both male and female sex organs in a single body
• Dioecious


  Separate sexes, egg of one parent is fertilized by sperm of another
• External fertilization


  Gametes are released and unite outside the bodies of reproducing animals
• Internal fertilization


  Gametes unite inside the bodies of reproducing animals, copulation facilitates sperm transfer
• Developmental strategies with internal fertilization


  • Oviparity (eggs deposited outside mother's body)
  • Ovoviviparity (eggs kept within mother, young obtain food from egg yolk)
  • Viviparity (young develop within mother, obtain nourishment from her blood)
• Budding


  Formation of a new individual as an outgrowth or "bud" on the parent organism, bud detaches and becomes independent
• Fragmentation


  Animals can regenerate from fragments of their bodies, each fragment has potential to develop into a complete organism
• Reproductive organs of angiosperms differ from animals in two ways: 1) male and female structures usually occur together in the same individual, 2) reproductive structures are not permanent parts of the adult individual
• Autotrophs are organisms that use energy from the sun to produce food, while heterotrophs are organisms that cannot make their own food and must obtain energy from outside sources
• Functions of soil


  • Physical support
  • Water reservoir
  • Nutrient reservoir
  • Mineral absorption
  • Cation exchange
  • pH regulation
  • Microbial activity
  • Decomposition of organic matter
• Photosynthesis is the major source of plant nutrition via the fixation of CO2 into sugar using solar energy
• Plant macronutrients


  • C, O, H, N, K, Ca, Mg, P, S
• Plant micronutrients


  • Cl, Fe, Mn, Zn, B, Cu, Mo
• Deficiency of any one plant nutrient can have severe effects on plant growth
• Nutrients

  Utilized for various functions such as growth, reproduction, and defense
• Functions of soil


  • Physical Support
  • Water Reservoir
  • Nutrient Reservoir
  • Mineral Absorption
  • Cation Exchange
  • pH Regulation
  • Microbial Activity
  • Decomposition of Organic Matter
• Photosynthesis is major source of plant nutrition via the fixation of CO2 into sugar using solar energy
• Macronutrients


  • C, O, H, N, K, Ca, Mg, P, and S
• Micronutrients


  • Cl, Fe, Mn, Zn, B, Cu, and Mo
• Deficiency of any one macronutrient or micronutrient can have severe effects on plant growth
• Macronutrients


  Used in relatively large amounts
• Micronutrients


  Used in minute amounts
• Mineral deficiencies may be expressed as differences in color of plant leaves
• Hydroponics


  A method of growing plants without soil, where nutrient-rich water is used to deliver essential minerals and nutrients directly to the plant roots
• Rhizobium


  Nitrogen-fixing bacteria that form symbiotic relationships with plants, especially legumes, to provide them with ammonia or nitrate
• Mycorrhizae


  Symbiotic associations between plants and mycorrhizal fungi that substantially expand the surface area available for nutrient uptake and enhance phosphate transfer