Sexual and Asexual Reproduction

Learning OutcomesBy 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.

There are two very different ways of reproducing:Asexual reproductionSexual reproduction

Types of Reproduction

Asexual Reproduction in Plants

BULBS

Onions Daffodils

Look at the examples of asexual reproduction.

Can you give a definition of the process?

TUBERS

Potatoes

RHIZOMES

Iris

RUNNERS

Strawberry Spider plant

Asexual ReproductionOnly 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.

Asexual reproduction in other organisms

Prokaryotes – binary fission

Describe in your own

words what is

happening in this

diagram.

1. Look at some other examples of asexual reproduction on pages 178-181.

2. Choose one example and draw and annotate a diagram to explain the process.

Sexual Reproduction

Sexual ReproductionSexual 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 GametesIn 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.

FertilisationFertilisation 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 ____________.

Sexual Reproduction in Plants

Flower StructureLabel the following structures on the diagram:

PetalOvaryStamenStyleStigmaSepalAntherFilamentOvuleCarpel

Flower Structure and FunctionComplete the card sort to match

the different floral structures with their functions.

Flower Structure and FunctionSTRUCTURE FUNCTIONPetals Brightly coloured and sometimes scented to attract

insects and other pollinators.Sepals Outer protective covering of the flower bud, can be

coloured like the petals.Anther Produces the pollen.Filament Holds up the anther.Stamen Male organs, consisting of the anther and filament.Stigma Sticky end of the carpel, which collects pollen.Style The sperm travels down the style from the stigma to the

ovary.Ovary Contains ovules.Ovule Contains the female nucleus which develops into seeds

once fertilised.Carpel Female organs, consists of the stigma, style and ovary.

Pollen grains

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?

Fruit or Vegetable?

VEGETABLE!ASEXUAL

FRUIT!SEXUAL

FRUIT!SEXUAL

VEGETABLE!ASEXUAL

FRUIT!SEXUAL

FRUIT!SEXUAL

VEGETABLE!ASEXUAL

Fruits always come from a ______.Fruits are made through ______

reproduction!

flowersexual

Now complete the ‘Sexual and Asexual Reproduction’

summary sheet.

Summary

Advantages and Disadvantages

Advantages Disadvantages

Asexual ReproductionSexual Reproduction

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.

Sexual Reproduction in Mammals

The Female Human Reproductive SystemLabel the following structures on the

female reproductive system diagram:CervixVaginaOviduct (fallopian tubes)OvariesUterus

Oviduct (fallopian tubes)

Ovaries

Uterus

Vagina

Cervix

The Male Human Reproductive SystemLabel the following structures on the male

reproductive system:Sperm duct (vas deferens)Seminal vesicleProstate glandEpididymisTestisScrotumPenisBladderUrethra

Vas deferens (sperm duct)

Seminal vesicleProstate gland

Bladder

Bladder Prostate glandVas deferensUrethra

UrethraPenis

Penis

Scrotum

ScrotumTestis

TestisEpididymis

FunctionsComplete 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 SystemUTERUS: 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