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Sexual and Asexual Reproduction. Learning Outcomes. By the end of this lesson, you should be able to: Define asexual and sexual reproduction. Describe systems of reproduction in unicellular and multicellular organisms.
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Learning Outcomes By the end of this lesson, you should be able to: • Define asexual and sexual reproduction. • Describe systems of reproduction in unicellular and multicellular organisms. • Describe mechanisms of reproduction in unicellular and multicellular organisms.
Types of Reproduction • There are two very different ways of reproducing: • Asexual reproduction • Sexual reproduction
Look at the examples of asexual reproduction. Can you give a definition of the process? BULBS Daffodils Onions
TUBERS Potatoes
Iris RHIZOMES
Strawberry Spider plant RUNNERS
Asexual Reproduction • Only involves one parent. • Offspring are completely identical to the parent – clones! • No gametes (sex cells) are needed. • Very safe and easy – no need to find a partner! • Common in small/simple animals, plants and bacteria. • Also happens in our body all the time – to replace worn out or dead cells. • It also happens in some bigger plants.
Prokaryotes – binary fission Describe in your own words what is happening in this diagram.
Look at some other examples of asexual reproduction on pages 178-181. Choose one example and draw and annotate a diagram to explain the process.
Sexual Reproduction • Sexual reproduction involves the production of sex cells called ____________. • The gametes are made in the _______________ _______. • The process of cell division that produces the gametes is called ___________. • In this process, each gamete only receives ___________ the amount of genetic material of the adult cell (haploid). • After ______________, this amount is restored to the full number of chromosomes in the fertilised cell (diploid).
The Gametes • In the animal kingdom, the male gametes are _________, and the female are _______. • In seed-bearing plants, the male gamete is a cell in the _________ ___________, and the female is a cell in the ____________. • Male gametes are usually very ___________ in size. They are usually ___________ - making their way to the ovum. • Female gametes are ____________ than the male, and are not ____________. • The male organism always produces a ____________ number of gametes than the female.
Fertilisation • Fertilisation occurs when the two ____________ of the ___________ and ___________ f_____. • This forms a new, single cell called a ____________. • This cell has a full set of chromosomes = ______. • This cell undergoes cell _____________ to develop into an ______________. • In plants, after fertilisation the ovule becomes the ___________ and the ovary becomes the ____________.
Flower Structure • Label the following structures on the diagram: • Petal • Ovary • Stamen • Style • Stigma • Sepal • Anther • Filament • Ovule • Carpel
Flower Structure and Function • Complete the card sort to match the different floral structures with their functions.
Fruit or Vegetable? • When the flower has been pollinated, the sperms meet the eggs, and seeds form (the offspring!) • The ovary turns into the fruit – with seeds inside ready for dispersal. Which of the following are fruits? Vegetables? Are they produced by sexual or asexual reproduction?
ASEXUAL VEGETABLE!
SEXUAL FRUIT!
SEXUAL FRUIT!
ASEXUAL VEGETABLE!
SEXUAL FRUIT!
SEXUAL FRUIT!
ASEXUAL VEGETABLE!
Summary flower • Fruits always come from a ______. • Fruits are made through ______ reproduction! sexual Now complete the ‘Sexual and Asexual Reproduction’ summary sheet.
Advantages and Disadvantages Create a table to show the advantages and disadvantages of asexual and sexual reproduction. Watch the video clip to help. Remember: The video is arguing the advantages of asexual reproduction. You will need to think up the advantages of sexual reproduction for yourselves.
The Female Human Reproductive System • Label the following structures on the female reproductive system diagram: • Cervix • Vagina • Oviduct (fallopian tubes) • Ovaries • Uterus
Oviduct (fallopian tubes) Ovaries Uterus Cervix Vagina
The Male Human Reproductive System • Label the following structures on the male reproductive system: • Sperm duct (vas deferens) • Seminal vesicle • Prostate gland • Epididymis • Testis • Scrotum • Penis • Bladder • Urethra
Vas deferens (sperm duct) Bladder Seminal vesicle Prostate gland Urethra Penis Epididymis Testis Scrotum Bladder Prostate gland Vas deferens Urethra Penis Testis Scrotum
Functions • Complete the functions table by sorting the functions with their correct structures. • Indicate whether the structure belongs to either the male or female reproductive system.
The Female Reproductive System • UTERUS: The foetus develops here during gestation. • OVARY: Produces ovum. • CERVIX: The shorter, narrow portion of the uterus where it joins with the vagina. • VAGINA: An elastic, muscular canal that extends from the cervix to the outside of the body. • OVIDUCT (FALLOPIAN TUBE): The passage from the ovaries to the uterus. Carries the ovum. • URETHRA: The tube which connects the bladder to the outside of the body. In females, it only carries urine. In males, it carries both the semen and the urine, at separate times.
The Male Reproductive System • SPERM DUCT (VAS DEFERENS): Transport sperm from the epididymis. • EPIDIDYMIS: A narrow, tightly-coiled tube where maturation of the sperms takes place. Connects the testes to the vas deferens. • PENIS: Passes either urine or sperms outside of the body. Consists of connective tissue, called erectile tissue, with many blood spaces in it. It allows sexual intercourse to take place. • TESTES: Produce sperm and the hormone testosterone. • SCROTUM: Sac containing testes. Keeps the testes at optimum temperature for sperm production. • SEMINAL VESICLE: Secretes a large proportion of the fluid that becomes semen. • PROSTATE GLAND: Stores and secretes a slightly alkaline fluid, which is a constituent of semen. • URETHRA