Reproduction

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Charli

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  • Sexual reproduction involves the fusion of gametes from two parents to produce offspring with genetic variation.
  • Bacteria

    • binary fission
  • Binary Fission
    1. The cell duplicates its DNA and then extends its cell membrane from the centre
    2. The cell elongates from the centre in each direction until it's long enough to cleave
    3. This is a very fast method of reproduction with the population of a colony sometimes doubling every 15-20 minutes
  • Parthenogenesis
    1. When an individual is produced from an unfertilised egg, known as the virgin birth
    2. Diploid = asexual reproduction
  • Types of asexual reproduction
    • Fission
    • Budding
    • Spores
    • Fragmentation
    • Parthenogenesis
    • Vegetative
  • Spores
    1. Single cells produced by an organism and released into the environment to propagate
    2. Rely on ideal environment conditions, wind & water to transport
  • An individual (or part of an individual) can reproduce an offspring that has identical genetic makeup to itself to grow and regenerate new tissue that is also genetically identical
  • Fungi, bacteria, and protists reproduction
    • Fungi - budding, spores
    • Bacteria - binary fission
    • Protists - binary fission, budding
  • Vegetative reproduction examples
    • Grafts - used commercially to produce desirable traits in flowers and fruit trees
    • Bulbs - daffodils, garlic
    • Tubers - potatoes (new plants can grow from the tuber)
    • Runners - strawberries; new roots grow from a runner to make a new plant
    • clovers
  • Protists

    • binary fission
    • budding
  • Creating a clone of the parent results in no genetic diversity
  • Vegetative reproduction (Propagation)
    1. Occurs when a new plant is produced from part of another plant
    2. Very quick reproduction
  • Fungi

    • budding
    • spores
  • Asexual reproduction

    A form of reproduction that does not involve the fusion of both male and female gametes (sex cells)
  • Fragmentation

    1. Organism breaks into 2 or more pieces
    2. A whole new organism is produced from each piece
    3. Must have those advantageous environments to survive
  • Fertilisation
    1. Occurs when the haploid nuclei of each gamete fuse, forming a diploid fertilised egg called a zygote
    2. Zygote continues to divide by mitosis as it travels through the oviduct towards the uterus
  • Plants: asexual and sexual reproduction

    • Sexual reproduction passes genetic information to the next generation, produces variation of offspring, requires 2 parents, offspring genetically related to both parents but different from each other, relatively long time taken
    • Asexual reproduction passes genetic information to the next generation, production of offspring, ability to quickly take advantage of favourable conditions, one parent required, offspring genetically identical to parent, relatively short time taken
  • Budding

    1. New organism formed from an outgrowth on parent
    2. When the outgrowth is large enough it frees itself from the parent
  • Implantation
    1. If a fertilised ovum implants into the uterine wall, pregnancy results and is maintained by secretion of various hormones
    2. Implantation occurs ~7 days after fertilisation (ovary → uterus)
  • Fertilisation
    1. Occur when the haploid nuclei of each gamete fuse, forming a diploid fertilised egg called a zygote
    2. Zygote continues to divide by mitosis as it travels through the oviduct towards the uterus
  • Hormonal control
    1. Endocrine glands regulate and control the menstrual cycle in a coordinated manner, synchronising the ovarian and uterine cycles to ensure fertility
    2. The result is an increase in the probability of successful reproduction, biological fitness, and therefore, the continuity of species
    3. The ovarian cycle refers to the decrease of changes in the ovary during which the follicle matures, the ovum is shed, and the corpus luteum develops
    4. The uterine cycle refers to the changes in the uterus, required for the preparation of the uterus for pregnancy
  • External fertilisation
    • Takes place in the external environment
    • Environment needs to be aquatic or moist terrestrial to prevent dehydration of gametes and allow gamete mobility
    • Involves a simultaneous release of gametes
    • Occurs in most invertebrates and some vertebrates (fish and amphibians)
    • A higher number of gametes and offspring than internal fertilisation due to:
    • A lower chance of fertilisation (less direct)
    • A lower survival rate of zygotes and offspring
    • Usually no parental care
  • Gametogenesis (production of gametes)
    1. Before birth:
    2. Oogenesis begins with a diploid cell. After growth and development, one oogonium forms one primary oocyte.
    3. Each ovarian cycle:
    4. From a primary oocyte - meiosis I forms a secondary oocyte and a primary polar body
    5. Meiosis II in the secondary oocyte produces an egg and polar body. This only occurs in eggs that have been fertilised.
    6. The egg survives, while all the polar bodies die.
    7. Only one functional egg cell comes from this process
    8. Spermatogenesis
    9. Process of male gametes (sperm) production in animals
    10. Occurs inside the walls of the seminiferous tubules within the testes
    11. Mature sperm are released into the lumen of seminiferous tubules
    12. Oogenesis
    13. Process of female gametes (ova) production in animals
    14. Begins at menarche
    15. Ends at menopause
    16. Females are born with all the eggs they will produce as primary (immature) oocytes
    17. Before birth:
    18. Oogenesis begins with a diploid cell. After growth and development, one oogonium forms one primary oocyte.
    19. Each ovarian cycle:
    20. From a primary oocyte - meiosis I forms a secondary oocyte and a primary polar body
    21. Meiosis II in the secondary oocyte produces an egg and polar body. This only occurs in eggs that have been fertilised.
    22. The egg survives, while all the polar bodies die.
    23. Only one functional egg cell comes from this process
  • Internal fertilisation
    • Takes place inside the body of the female
    • Involves male attraction and copulation
    • Requires energy investment
    • Puts the organism at risk of predation
    • Fewer eggs overall need to be produced
    • Occurs in some invertebrates (insects, snails) and most vertebrates (reptiles, mammals, and birds)
    • A smaller number of gametes and offspring than in external fertilisation due to:
    • A higher chance of fertilisation (more direct sperm to eggs)
    • A higher success rate of survival of young
    • Parental care of eggs and/or young is more common
  • Reproduction
    1. Fungi
    2. Budding
    3. Spores
    4. Bacteria
    5. Binary fission
    6. Protists
    7. Binary fission
    8. Budding
  • Sperm cells are produced by spermatogenesis in the seminiferous tubules within the testes.
  • The male reproductive system consists of the testes, epididymis, vas deferens, seminal vesicles, prostate gland, bulbourethral glands, penis, scrotum, and accessory ducts.
  • Fertilization involves the fusion of pollen and egg cells to produce seed.
  • Budding is a type of asexual reproduction where a new organism develops as an outgrowth or bud from the parent organism.
  • Regeneration is a type of asexual reproduction where a new organism grows from a fragment of the parent organism.
  • Asexual reproduction is when an organism produces genetically identical offspring without fusing gametes, such as budding or fragmentation.
  • The advantages of sexual reproduction include increased genetic variability, which can lead to better adaptation to changing environments, and the ability to avoid inbreeding depression by mating with unrelated individuals.
  • Egg cells are produced by oogenesis in the ovaries.