Summary Biology

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ISBN-13 9789463760232
112 Flashcards & Notes
1 Students
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This is the summary of the book "Biology". The author(s) of the book is/are Karlijn Moeskops. The ISBN of the book is 9789463760232. This summary is written by students who study efficient with the Study Tool of Study Smart With Chris.

Summary - Biology

  • 2.1 Reproduction

  • Reproduction
    The process of making new individuals of the same species
  • 2 types of reproduction
    1. Asexual reproduction
    2. Sexual reproduction
  • Asexual reproduction
    Reproduction without the fusion of egg and sperm. It requires only ONE parent.
    1. The offspring are exact copies of this one parent
    2. All offspring are identical to the parent
    3. No variety in the population
    4. Make the population vulnerable (eg. When environment changes, all individuals might be affected in a negative way)
    5. Allow organisms to reproduce quickly
      - don't have to find a mate
      - no time OR energy is lost in mating behaviours
  • Sexual reproduction
    1. Requires two parent
    2. Both parents produce sex cells and the cells HAVE TO fuse to create a new individual
    3. The new individual is a mixture of the two parents
    4. The offspring is unique, one of a kind
  • Animal that reproduces asexually and sexually
    Sea anemone
  • FISSION METHOD
    Asexually reproduction, the body of the animal splits into two separate individuals (e.g. Sea anemone).
    It occurs when the animal reaches a certain size.
  • HERMAPHRODITE
    The animal is both male and female.
    It can make sperm and egg cells.
    The sperm and egg cells are released into the water.
    When they fuse together, a larvae will grow and eventually a new sea anemone can develop.
  • 2.2 The human reproductive system

  • Sexual anatomy between men and women is different.
    Reproductive organs grow from the same tissues when they develop.
    The only difference is the type of hormones that these tissues are exposed to while they grow.
  • The male reproductive system
    A male has both internal and external reproductive organs.
  • Male external reproductive organs
    1. Penis
    2. Scrotum
  • A scrotum is a skin pouch which contains 2 organs called testes.
    The testes starts to produce sperm cells when a boy reaches puberty.
  • Healthy sperm cells require a temperature slightly lower than 37 degrees celcius.
    That's why the testes hang outside the body where it is several degrees cooler.
  • See figures on page 37 (figure 2.3)
  • Newly produced sperm cells only live for 3 days, after which they are broken down again.

     A male produces 100-200 sperm cells per day.
  • A sperm cell has a head and a tail.
  • The head of the sperm cell
    Contains hereditary information which will be transmitted to the next generation.
  • The tail of the sperm cell
    Moves the sperm along.
  • Sperm cells are specialised cells, but like any cell they have some basic structures.
  • Animal cells
    • Enclosed by a cell membrane
    • filled with a liquid called cytoplasm
    • Have a nucleus that stores the genetic information
  • Cytoplasm
    A liquid that fills the cell membrane that encloses an animal cell
  • Nucleus
    Stores the genetic information
  • Ejaculation
    1. When semen passes out of the body (Produces semen) 
    2. contains 500 million sperm cells 
  • Seminiferous tubules
    Are where sperm cells are developed in the testes
  • Epididymis
    Cap-like structure
    Located on top of each testis
    Where sperm cells are stored TEMPORARILY
  • Sperm ducts
    Where the sperm cells have to travel through before they can leave the body
    There are 2 of these sperm ducts, one for each testis
    They lead away from the testes and towards the internal male reproductive organs
  • Sperm cells need fluids to swim in and nutrients for energy.
    They draw their nutrients from the fluids in which they swim.
  • Seminal vesicles
    Produce some of these fluids that give nutrients to the sperm cells
  • Prostate gland
    Produces the rest of the fluids that give nutrients to the sperm cells
  • Semen
    Sperm cells and fluids together
  • Urethra
    1. A tube inside the penis that transports both semen urine out of the body, but not at the same time.
    2. The end where the 2 sperm ducts join together
  • A muscle inside the urethra prevents semen and urine going out at the same time.
  • Erectile tissue
    A spongy-like structure inside the penis where the blood is pumped into, so that the penis can become erect for the semen to pass out of the body
  • Circumcision
    Removal of the foreskin of the tip of the penis. (Usually a common practice in some religions)
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