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National 5 Unit 2

National 5 Unit 2. Multicellular Organisms. Reproduction and Inheritance. Learning Outcomes. What is Reproduction?. All living things reproduce. Humans use sexual reproduction to produce their young.

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National 5 Unit 2

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  1. National 5 Unit 2 Multicellular Organisms Reproduction and Inheritance

  2. Learning Outcomes

  3. What is Reproduction? All living things reproduce. Humans use sexual reproduction to produce their young. In order to do this, the two parents (male and female) have different reproductive systems and organs that produce different sex cells.

  4. The female reproductive system

  5. The male reproductive system

  6. Roles of the reproductive system

  7. Sex cells – sperm In males, the sex cells are called sperm. tail middle piece head nucleus containing DNA cell membrane Sperm are produced in sex organs called testes.

  8. Sex cells – egg In females, the sex cells are called eggs. nucleus containing DNA cytoplasm membrane jelly coat Eggs are produced in sex organs called ovaries.

  9. Female egg / ovum does not move on its own large foodstore present made in ovaries Male sperm swims using tail very small no foodstore made in testes Sex cells - Gametes

  10. Ovulation and fertilisation In a female, one of the ovaries produces an egg approximately every 28 days. This is called ovulation. During sexual intercourse, millions of sperm are ejaculated into the vagina. If a sperm meets the egg, the sperm’s nucleus can join with the egg’s nucleus. The fusing of the two nuclei is called fertilisation.

  11. Fertilisation and implantation

  12. Fertilisation in Mammals • http://www.twigonglow.com/films/glossary/fertilisation-260/ • http://www.twigonglow.com/films/glossary/zygote-274/

  13. Sexual Intercourse and Fertilisation (3) Egg divides in two (2) Sperm fertilises egg (5) Embryo implants in uterus and grows (4) Ball of cells formed (1) Egg released from ovary

  14. Fertilisation in Mammals Day 3 Day 0 Egg released by ovary Day 4 Day 7

  15. Menstruation An important part of puberty for girls is the beginning of their monthly cycle. This is known as the menstrual cycle. The menstrual cycle involves the preparation of the uterus lining so that it can receive a fertilized egg. If an egg is fertilized, it can implant itself in the prepared uterus lining. If the egg is not fertilized, the lining of the uterus breaks down and is lost from the body. This is called menstruation,or a period.

  16. Asexual reproduction in plants • It is possible for plants to reproduce asexually i.e. without flowers or fertilisation. • It can occur naturally or as a result of propagation by growers • Sexual reproduction also occurs in plants • The FLOWER contains the both the male and female reproductive organs of a plant. • Flowers of different plants may not be exactly alike, but they are built to the same basic plan.

  17. Asexual Reproduction • Asexual reproduction only needs one parent, unlike sexual reproduction, which needs two parents. Since there is only one parent, there is no fusion of gametes and no mixing of genetic information. As a result, the offspring are genetically identical to the parent and to each other: in other words, they are clones. Runners

  18. Looking Inside a Flower

  19. Flower Show Petals Petals Stigma attract insects catches pollen grains Style Anther pollen tube grows down through this pollen made here Ovary Ovule contains ovules becomes a seed when joined with pollen

  20. Gamete formation in flowering plants Flowers are the organs of sexual reproduction in plants. Usually the male and female reproductive organs are both present in the same flower. Pollen grains contain the plant's male sex cells and are produced in the anthers. Ovules contain the plant's female sex cells and are produced in the ovary. http://www.twigonglow.com/films/glossary/ovule-427/ http://www.twigonglow.com/films/glossary/pollen-433/

  21. Insect Pollination These plants often have flowers that are brightly coloured and scented . The pollen from the anther sticks to the insect’s body while it is sucking nectar from the flower. The pollen gets brushed on to the style of the flower.

  22. Wind Pollination Feathery stigma The wind blows the smooth pollen off the antheronto the feathery stigmas, which hang outsidethe flower so they can easily catch the pollen. As these plants don’t rely on insects, the petals are in colour.

  23. Fertilisation Pollen grain Stigma Style Pollen tube Nucleus Ovary Ovule

  24. The zygote formed becomes an embryo which later grows into a plant containing genetic material from both the male and the female parents

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