STAGES OF SEXUAL REPRODUCTION Animal Biology Ben Cherry

STAGES OF SEXUAL REPRODUCTION Animal Biology Ben Cherry & Amanda Harrison

LESSON AIMS Aim: To develop an understanding of the stages of sexual reproduction Obj: Describe the different stages of sexual reproduction in mammals Obj: Identify the difference in gestation lengths in various mammal species Obj: Describe advantages and disadvantages of external and internal fertilisation

RECAP Q – Name two parts of the male reproductive system A – Testes, glands, sperm duct, urethra, penis Q – What do the testes produce? A – Sperm cells Q – Name two parts of the male reproductive system A – ovaries, egg tubes, uterus, cervix, vagina Q – What is the Uterus also known as? A – The Womb

TASK – GROUPS (3 MINS) Put these in word in order of when they occur…. Fertilization, Parturition, ovulation, Gestation, Copulation and Implantation

STAGES OF SEXUAL REPRODUCTION Sexual reproduction is a natural way of reproduction in humans, animals and the majority of plants also choose to reproduce sexually. Sexual reproduction consists of a set of events and can be divided into five stages: Copulation, Fertilization, Implantation, Gestation and Parturition.

OVULATION Ovulation is the release of eggs from the ovaries. In humans, this event occurs when the follicles rupture and release the secondary oocyte ovarian cells. https: //www. youtube. com/watch? v=n. Lmg 4 w. SHd

COPULATION Copulation the sexual behavior in which a male introduces sperm into the female's body, especially directly into her reproductive tract EGG CELL Organisms have sex cells called gamet es The male gamete is called sperm whereas female gamete is called ovum or egg. In every organism, these gametes are formed within special structures. Since female gamete is immobile, male gametes need to be transferred for fertilization.

FERTILISATION Sexual reproduction happens when a male gamete and a female gamete join. This fusion of gametes is called fertilisation. Sexual reproduction allows some of the genetic information from each parent to mix, producing offspring that resemble their parents, but are not identical to them. Sperm cells travel in semen from the penis and into the top of the vagina. They enter the uterus through the cervix and travel to the egg tubes. If a sperm cell meets with an egg cell there, fertilisation can happen.

IMPLANTATION Implantation is the stage of pregnancy at which the already fertilized egg adheres to the wall of the uterus so that the egg may have a suitable environment for growth and development into a new offspring. The uterus has thick walls suitable for egg attachment and growth. A female hormone increases the blood supply in the wall, water content, and secretion of glycogen, a nutrient for the surrounding tissue and developing egg.

GESTATION The foetus relies upon its mother as it develops. These are some of the things it needs: - protection The placenta is - oxygen responsible for providing oxygen and - nutrients (food and water) nutrients, and - It also needs its waste substances removing waste removing substances. It grows into the wall of the uterus and is joined to The foetus is protected by the foetus by the uterus and the umbilical cord the amniotic fluid, a liquid contained in a bag called the amnion The mother's blood does not mix with the foetus's blood The placenta lets oxygen, nutrients and waste pass between the two blood supplies

PARTURITION The cervix relaxes and muscles in the wall of the uterus contract. Waves of muscle contraction push the baby out of the mother's body through the vagina.

http: //www. bing. com/videos/search? q=TED+ANIMALS+BIRTH&&view=detail&mid=A 4 DEDF 8 EF 6286 B 9 E 5752&&FORM=VRDGAR

ADVANTAGES AND DISADVANTAGES OF INTERNAL AND EXTERNAL FERTILISATION What is internal fertilisation? Can you name examples? What is external fertilisation? Can you name examples? With the person sitting next to you, discuss and write down the advantages and disadvantages of internal and external fertilisation

ADVANTAGES AND DISADVANTAGES OF INTERNAL FERTILISATION Internal Advantage s More protection against outside environments and predators Greater change of successful fertilisation More selective of their mates Increase chance gametes meet Reproduction Harder to bring both male and female into intimate contact Less chance of desiccation of gametes Limited amount of offspring being produced at any given time. Disadvantage s Higher risk of sexually transmitted diseases being passed on

ADVANTAGES AND DISADVANTAGES OF EXTERNAL FERTILISATION External Reproduction Advantage s Results in the production of a large number of offspring More genetic variation Easier to find mates as the gametes released can drift (wind, water etc). Environmental hazards such as predators reduce the change of surviving into adulthood. Not guaranteed that sperm will come in contact with eggs Disadvantage s Large amounts of gametes go unfertilised and wasted. Greater chance of desiccation of gametes/zygotes.