Duncanrig Secondary School S3 Biology Elective Animal Reproduction Pupils Activity Booklet
Animal Reproduction 2 What you should know by the end of this unit: State that binary fission is a type of cell division carried out by single-celled organisms, such as Amoeba, so that they can reproduce. State that asexual reproduction is where a single parent reproduces to produce genetically identical offspring. State that genetically identical offspring are called clones. State that the nucleus of the cell controls cell division. Describe the main features of egg and sperm cells. Describe what is meant by the terms internal and external reproduction and be able to give examples of both. Explain the importance of internal reproduction to land living organisms. State that sperm are produced in the testes of animals. State that eggs are produced in the ovaries of animals. Able to compare fertilisation in trout (fish), frog (amphibian), chicken (bird) and human (mammal). State that young birds and mammals are dependent on the adult for care and protection. Explain how the number of eggs produced and the parental involvement in looking after their young can increase the chances of survival. Skills that you should be able to carry out by the end of this unit are: Calculate averages, ratios and percentages. Extract information from different sources. Present information in the form of a graph or a table. Work as part of a group and take responsibility to support the work of the group.
Topic 1: Asexual Reproduction 3 Asexual Reproduction in Single-celled Organisms All living things must reproduce in order to produce offspring similar to themselves. This is essential for their survival. If they were unable to reproduce they would decrease in number and become extinct. In single-celled animals, cell division allows them to reproduce. The cell simply divides into two identical, but smaller, cells when it is fully grown. growth cell division young cell mature cell This type of reproduction only requires one parent and is called asexual reproduction. All offspring produced by asexual reproduction are genetically identical to each other and are called clones. 1. Collect a copy of the resource sheet Asexual reproduction and cell division. 2. Watch the video clip about cell division. 3. Use paired reading to find out more about cell division from the background information on page 4. 4. Work with your partner to compete the resource sheet by describing what is happening at each stage as the single-celled animal divides, then stick the sheet into your jotter.
Topic 1: Asexual Reproduction 4 Background Information Asexual Reproduction and Cell Division In certain circumstances a cell, usually referred to as the parent cell, divides into two cells which are called daughter cells. It depends very much on the kind of organism and its age as to when and where cell division will take place. Single-celled organisms are able to reproduce by dividing into two. Amoeba is a singlecelled animal which lives in water and it reproduces in this way. This type of cell division is called binary fission. cytoplasm nucleus Amoeba The process of cell division is controlled by the nucleus in the cell. cell membrane Diagram showing cell division in an animal cell 1. The genetic material in the cell s nucleus is doubled. 2. The nucleus divides. Each half contains the same genetic information. 3. The cytoplasm divides in two. The two nuclei move apart. 4. Two new daughter cells are produced with identical genetic information to the parent cell.
Topic 1: Asexual Reproduction 5 Budding Hydra is a small aquatic animal related to jellyfish and sea anemones. It is able to reproduce asexually by budding. A small area of the body wall grows rapidly by cell division to form an outgrowth, the bud, on the body surface. The bud eventually develops tentacles and later the young Hydra detaches itself from the parent. older bud almost ready to separate from parent Hydra ball of cells forming a bud Each of the two daughter cells is an exact copy of its parent. Once a daughter cell has grown to full size, it divides too.
Topic 1: Asexual Reproduction 6? Key Questions (Answer in sentences) 1. What does the term asexual reproduction mean? 2. State one important way in which budding is different from binary fission. 3. What is meant by the term clone? 4. Suggest one advantage and one disadvantage of asexual reproduction.
Topic 2: Sexual Reproduction 7 Sexual Reproduction in Animals Most multicellular animals use sexual reproduction. This involves two parents, male and female, each producing special cells called gametes. In animals the male gametes are called sperm and are produced in the testes. The female gametes are called eggs and are produced in the ovaries. 1. Watch part of the Reproduction Biovideo entitled Introduction. 2. Copy the diagrams and the table below. Use what you have been able to find out to complete the table. Egg (Female gamete) cell membrane Sperm (Male gamete) head nucleus cytoplasm nucleus tail Produced by male or female? Relative size Small or big? Has it a tail used for swimming? Has it a large food store? Numbers produced Many or few? Egg Sperm
Topic 2: Sexual Reproduction 8? Key Questions (Answer in sentences)
Topic 2: Sexual Reproduction 9 1. What is meant by the term sexual reproduction? 2. Why do sperm cells have a tail? 3. Why does an egg cell have to be so much larger than a sperm cell? 4. (i) Place the following animals in order of the size of eggs they produce, smallest to largest: amphibians, birds and mammals. (ii) What is the significance of the differing amounts of yolk which they possess? Fertilisation Sperm and eggs simply die unless fertilisation occurs. Fertilisation is the fusion of the male and female nuclei when the egg and sperm join. The fertilised egg is now called the zygote. The zygote divides repeatedly forming a ball of millions of cells which form the new animal. 1. Collect a copy of the resource sheet Fertilisation and development of a fertilised egg. 2. Use the information on page 8 to complete the resource sheet by drawing a line to connect each statement with the matching picture to describe the stages in fertilisation and early development of the zygote.? Key Questions (Answer in sentences) 1. What does the word fertilisation mean? 2. What term is used to describe a fertilised egg?
Topic 2: Sexual Reproduction 10 Background Information Fertilisation and Development of a Fertilised Egg The diagram below shows what what happens during fertilisation and when the zygote divides to form the embryo. egg sperm one sperm penetrates the egg cell membrane nuclei fuse zygote formed cell of zygote divides to form the embryo cells divide repeatedly young animal (foetus) formed
Topic 2: Sexual Reproduction 11 Internal v External Reproduction A sperm must join with an egg for fertilisation to take place. There are two methods of fertilisation internal mainly used by land animals and external used by aquatic animals. Internal fertilisation involves the sperm and egg joining inside the female while in external fertilisation the sperm and eggs are released into the surrounding water where they join.
Topic 2: Sexual Reproduction 12 1. Watch the part of the Reproduction Biovideo entitled External and Internal Fertilisation. 2. Collect a copy of the resource sheet External and internal fertilisation and use the terms in the wordbank to label the diagrams. Stick the sheet into your jotter.? Key Questions (Answer in sentences) 1. Describe what is meant by external fertilisation, giving two examples. 2. Describe what is meant by internal fertilisation, giving two examples. 3. Why would internal fertilisation be so important to land-living animals? 4. Why do frogs have to return to ponds or streams in order to breed?
Topic 2: Sexual Reproduction 13 Survival Chances Animals which have external fertilisation, e.g. fish and amphibians, produce a great many more eggs than animals which fertilise internally, such as birds and mammals. How does this relate to their survival chances?
Topic 2: Sexual Reproduction 14 1. Collect a copy of the resource sheet Survival chances. 2. Complete the table on the resource sheet using the method given below. Total young surviving % survival = x 100 Eggs fertilised 1 Note: To calculate number of fertilised eggs or young perished = fertilised eggs diseased + fertilised eggs eaten + young eaten To calculate total young surviving = no. of eggs fertilised no. of fertilised eggs or young perished 3. Below the table, list the animals given in the table in order of the number of eggs they produce; starting with the animal which produces the least number of eggs. 4. List the animals given in the table in the order of the % survival of fertilised eggs; starting with the animal which has the highest % survival. 5. Complete the statement on the resource sheet and answer the question. 6. Copy and complete the following paragraph by selecting the correct word from each of the alternatives: necessitates avoids
Topic 2: Sexual Reproduction 15 Internal fertilisation land animals having to return to water to reproduce. With this type of fertilisation, disease- more causing germs are likely to reach and infect the gametes less more and the gametes are likely to drift away from each other less better that sperm will reach and fertilise the eggs are much. poorer internal For these reasons it can be seen that fertilisation has external many advantages over internal fertilisation and is essential external for land aquatic animals.
Topic 2: Sexual Reproduction 16 Sexual Reproduction in a Mammal As you have found out, mammals use internal fertilisation. In order for the sperm cells to meet the egg, copulation (intercourse) must occur. The male organ called the penis becomes erect due to increased blood flow. It can then be inserted into the female s vagina where the sperm, in a fluid (called semen), are expelled with force. The sperm then swim from the vagina up through the uterus (womb) to the oviducts (egg tubes). If the sperm meet an egg in one of the oviducts then fertilisation may take place.
Topic 2: Sexual Reproduction 17 1. Collect a copy of the series of resource sheets Human Male and Female Reproductive Systems. 2. Using the classroom resources, put the following labels on the diagram of the female reproductive system:- ovary uterus (womb) oviduct vagina Below each name write a brief description of its function. (If you need further help, see the clues given on page 15.) 3. On your diagram, mark with an F where fertilisation may take place. 4. Using the classroom resources, put the following labels on the diagram of the male reproductive system:- testis sperm duct urethra penis Below each name write a brief description of its function.. (If you need further help, see the clues given on page 15.)
Topic 2: Sexual Reproduction 18 Functions of the Parts of the Human Reproductive System The following information is given to help with the labelling exercise on page 10. Vagina This organ receives the penis and sperm during copulation. Sperm duct Tube which forces sperm from the testes to the penis. Ovary Where eggs (ova) are made. Urethra This tube normally carries urine but, during copulation, it carries sperm through the penis. Testes Where sperm are made. Penis This organ stiffens and during copulation is inserted into the vagina, where it deposits sperm. Oviduct Fertilisation occurs in this tube as it transports the egg to the uterus. Uterus (Womb) Where the fertilised egg stays while it develops into a baby.
Glossary of Terms 19 amniotic sac asexual reproduction binary fission budding clone embryo fertilisation foetus (or fetus) gametes ova (singular ovum) ovary oviduct penis The fluid-filled sac that surrounds and protects the embryo of reptiles, birds and mammals. Reproduction involving one parent, without the fusion of gametes. A type of asexual reproduction in which the organism, e.g. Amoeba, divides into two parts. A type of asexual reproduction in which offspring develop as outgrowths from the parent s body. A group of organisms which are genetically identical to one another (and their parent). The stage of development between the fertilised egg (zygote) and the newly formed organism. The fusion of the nucleus in a male gamete with the nucleus in a female gamete to form a zygote. The embryo of a mammal at the stage of development in which the main features are visible. Cells involved in sexual reproduction, e.g. eggs (ova) and sperm in animals. Female gametes (sex cells) of animals. An organ which produces female gametes. A tube leading from a funnel-shaped opening near an ovary to the uterus (womb). This organ stiffens and during copulation is inserted into the vagina, where it deposits sperm.
Glossary of Terms 20 placenta pregnancy semen sexual reproduction sperm sperm duct testis umbilical cord urethra zygote The organ through which the foetus of a mammal obtains food and oxygen from its mother s blood and passes waste substances into the mother s blood. The period during which a female mammal carries a developing embryo in her uterus (womb). Fluid produced by the testes of mammals. It is made up of sperm and chemicals which nourish them. Reproduction usually involving two parents, which produce gametes. The male gametes of animals. Tube that carries sperm from the testes to the urethra. Male reproductive organ of animals producing gametes called sperm. A tube containing blood vessels connecting a developing embryo with its placenta. In males, during copulation, the urethra carries sperm through the penis to the outside of the body. The cell which results from the fusion of a male and a female gamete (a fertilised egg).