• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Internal and External Fertilisation

Extracts from this document...


Internal and External Fertilisation Sexual reproduction > union of male and female gametes (sperm and ova)> two parents donate genes to the young > genes are donated through a process called fertilisation > offspring with a mix of inherited genes. Two mechanisms by which fertilisation can take place: External - (The eggs are fertilised outside of the body). Internal - (The eggs are fertilised within the female reproductive tract). External Fertilisation Characteristics: Gametes Large numbers of male and female gametes produced. Union Occurs in open water environments. Conception Mechanism Simultaneous release of gametes. Chance of fertilisation Low chance of fertilisation because male gametes are released into a large open area where there is less chance of successfully uniting with female gametes. ...read more.


Number of offspring/zygotes After many zygotes perish a smaller number of offspring survive; however, the number of offspring produced is usually larger compared to internal fertilisation. Breeding frequency Will breed more frequently compared to internal fertilisation due to the lower fertilisation success rate. * An advantage of external fertilisation is that it results in the production of a large number of offspring. * One disadvantage is that environmental hazards such as predators greatly reduce the chance of surviving into adulthood. Internal Fertilisation Characteristics: Gametes Large number of male gametes and fewer female gametes produced. Internal fertilisation is practiced by species that lay shelled eggs or have a period of internal embryonic development. ...read more.


Conception Mechanism Male needs to insert the sperm into the female's reproductive tract via penis or cloaca (copulation). Chance of fertilisation High chance of fertilisation because male gametes are released into a confined space where there is more chance of successfully uniting with female gametes. Environment for zygote Zygote usually develops in a very protected environment inside the female's body. Temperature is controlled there I less chance of predation, infection and loss of zygote from the area. Number of offspring/zygotes Smaller number of zygotes produced because very few perish (higher success rate), therefore, smaller numbers of offspring compared to external fertilisation. Breeding frequency Will breed seasonally and less frequently due to higher fertilisation success rate. * This extra protection increases the chances of survival because mom supplies everything that the embryo needs ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Exchange, Transport & Reproduction section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Human Reproductive System

    4 star(s)

    Suspensory ligament The suspensory ligament is a fold of peritoneum. It extends out from the ovary to the wall of the pelvis and conveys the ovarian artery, lymphatic vessels, vein and nerve plexuses. Uterus The uterus is a hollow, pear-shaped organ within which the fetus develops during gestation.

  2. Marked by a teacher

    Reproduction, Gamete formation and fertilisation

    4 star(s)

    The spermatids finally develop into ripe sperm with long tails. Thousands of sperm are produced every second, each taking about two months to mature. http://www.infertilitybooks.com/onlinebooks/malpani/images/04b_sperm_cell.jpg http://webanatomy.net/histology/reproductive/seminiferous_tubule.jpg Female Reproductive System Unlike the male, the female reproductive organs are sited entirely inside the body.

  1. Intracytoplasmic Sperm Injection

    glands (ovaries), and they are the largest cells in the human body. The growth of ovarian follicles is controlled by hormones from the Pituitary gland in the base of the brain. The egg lasts 28-30 days before they ovulate this is when one or more eggs are released from one of your ovaries.

  2. The Reproductive System of a Cow

    Estrogen levels are not at their highest during this 45 to 80 day rest period from birth to the cow's first estrus after calving, and so the cow doesn't go back into her normal cycling until after this period of time.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work