GENERAL BIOLOGY - Reproduction

• Reproduction


  A biological process in which different organisms can produce another of their kind
• Types of reproduction

  • Asexual reproduction
  • Sexual reproduction
• Asexual reproduction


  • Does not involve gametes or sex cells
  • Single parent
  • Faster and produces genetically identical to the parent
• Sexual reproduction


  • Involves the union of gametes (i.e., the sperm and the egg cell)
  • Two parents (male & female)
  • Slower but produces genetic variation
• Asexual reproduction methods

  1. Budding

  2. Fragmentation

  3. Regeneration

  4. Binary fission

  5. Vegetative reproduction

  6. Spore formation
• Vegetative reproduction

  1. Stolon

  2. Tuber

  3. Rhizome

  4. Bulbs
• Sexual reproduction in plants

  1. Pollination

  2. Fertilization

  3. Seed release
• Double fertilization in plants


  One sperm cell fuses with the egg cell, the other fuses with two polar nuclei
• Asexual and sexual reproduction in aphids

  • Parthenogenesis
• Reproductive traits in organisms

  • Color display
  • Sexual selection
• Phylogenetic evidence and evolutionary history


  • Primitive ancestor of plants and animals was likely a unicellular eukaryote
  • Not much similarity between the genes that make up the body plan of plants and of animals
• Plants vs Animals


  • Plants have cells that are positionally fixed and growth is highly regulated by the environment
  • Animals have motile cells and growth is determined by genes
• Life cycle


  n = haploid, 2n = diploid
• Molecular evidence from gene comparisons shows there is not much similarity between the genes that make up the body plan of plants and of animals
• Plant cells


  • Positionally fixed, not capable of movement
• Animal cells


  • Motile or capable of movement
• Plants have unicellular stages
• Animals have unicellular stages
• Plants


  • Highly regulated by the environment because plants cannot choose or change their growing locations
• Animals


  • Growth and development determined by its genes
• Plants undergo alternation of generations, with sexual and asexual life cycles, whereas the animal life cycle has only one continuous multicellular stage (after fertilization)
• During meiosis, plants produce spores first before forming the gametes, whereas in animals, the gametes are directly formed
• Plant growth and development


  • Develop by going through a longer period, just grow and develop continuously until they die
  • Grow by increasing their cell size
• Animal growth and development


  • Develop into a distinct and complete body shape
  • Grow by increasing the number of their cells
• Morphogenesis


  Change in shape
• Nutrition


  Process of providing or obtaining food necessary for health, survival, and growth of an organism
• Modes of Nutrition

  • Heterotrophic
  • Autotrophic
  • Saprophytic
  • Parasitic
  • Ectoparasitism
  • Endoparasitism
  • Holozoic
  • Herbivorous
  • Carnivorous
  • Omnivorous
  • Photoautotrophic
  • Chemoautotrophic
• Photoautotrophic


  Directly use the energy from the sun and other inorganic substances such as carbon dioxide and water to form organic food through photosynthesis
• Chemoautotrophic


  Organisms use chemicals to create simpler organic substances
• Photoautotrophic organisms

  • Red algae
  • Brown algae
• Chemoautotrophic organisms


  • Methanopryus kandleri
  • Haloquadra walsbyi
• Saprophytic


  Organisms obtain their nutrients from dead organic matter
• Saprophytic organisms

  • Oyster mushroom
  • Corallorhiza orchids
• Parasitic


  Organism takes food from another organism, the organism that takes food is called a parasite, and the organism from where the food is taken is called the host
• Parasitic organisms

  • Heartworm
  • Tick
  • Tongue eating louse
• Endoparasitism


  Involves parasites that live inside the body of the host
• Ectoparasitism


  Happens when the parasite is outside the body of the host
• Heterotrophic organisms

  • Herbivores
  • Carnivores
  • Omnivores
• Holozoic


  Organisms ingest solid or liquid food that is digested and absorbed by the body
• Food needs to be digested to convert complex food particles into simpler substances in the presence of enzymes and acids secreted by different digestive organs