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Learning Objectives Know that asexual reproduction involves: • one parent, and does not require sex cells or gametes • New organism is exactly the same as the parent (clone), as there is no genetic variation. Be able to name examples of living things that can reproduce asexually. Describe different methods of asexual reproduction. ASEXUAL REPRODUCTION • No fusion of gametes (sex cells) • Genes from only one parent • Offspring show NO variation • Genetically identical offspring (clones) • Asexual reproduction is where ONE parent can produce NEW LIFE • Very often this happens in BACTERIA or FUNGI. • One CELL simply divides into TWO to make a new offspring. • EVERY new cell is IDENTICAL to the parent that made it. • A cell that is identical is called a CLONE. • All the GENES in every cell are the SAME. Asexual Reproduction Fill in the blank spaces with the missing words Some organisms can reproduce a_______. Only one parent is needed and.... • there are no g________ • there is no mixing of g_________ information from two p_________ • there is no genetic v_________ among the offspring • the o________ are genetically i_________ to each other and to the parent • these genetically identical offspring are called c_____ KEYWORDS offspring, parents, clones, gametes, asexually, genetic, variation, identical Twig Video Click on the link to watch a short video on asexual reproduction http://bit.ly/LFHNmP Asexual reproduction • Gardeners use asexual reproduction to create new plants that are identical to the parent plants. • Cloning allows growers to mass produce plants that may be difficult to grow from seed. • All the plants are genetically identical, which is useful because you can be sure of their characteristics. • They cannot create new varieties this way. • But they can produce required plants much quicker than growing them from seeds produced in sexual reproduction. • On the other hand, the lack of genetic variation means that if the plants become exposed to disease or to changes in environmental conditions, all of them will be affected. How can we make copies of organisms? Cloning Cuttings Some plants can reproduce asexually. Cuttings from the stem are taken and then planted. These grow into new plants which are clones because they are genetically identical to each other and to the single parent plant. The most common way for gardeners to create new plants asexually is by taking cuttings and growing them These cuttings will develop their own roots and grow into an identical new plant. Other methods can also be used. Layering: Some plants produce offshoots or plantlets. These plantlets can be grown in the soil still attached to the parent plant. Once they have established a root system they can be detached from the parent plant to grow on their own. Runners Strawberries reproduce asexually They send out runners over the ground These runners sprout roots at various intervals and new plants grow Once the plants are established, the runners die and rot away Potatoes use tubers to reproduce. They send out underground stems that swell out at the end into tubers These are young potatoes and contain stores of food (starch) Each tuber can then grow into an entire new plant Bacteria, amoeba and some other single-celled organisms can reproduce asexually by a process of cell division in which two daughter cells are produced from the one parent cell. Hydra Sponge Yeast Some multi-celled organisms, like hydra and some species of sponge, can reproduce asexually by budding. Yeast also reproduce by this method. Buds form in the body wall which grow into miniature adults, eventually breaking away to become independent. They are clones of the single parent. • Aphids, otherwise known as GREENFLY can reproduce ASEXUALLY. • This means that they do not need a partner. • A a single female aphid could produce 600 billion descendants in one season. This is not very common but some animals such as star fish and sea anemone can reproduce asexually. Mammals cannot reproduce asexually. However, scientists have found a way to clone animals in the lab. The first cloned mammal was Dolly the sheep. Dolly is an exact genetic duplicate of the animal from which a single cell was taken to clone her. This is a picture of Dolly and her lamb Bonnie. Dolly lived to the age of 6 years old. Though sheep have a life span of 11-12 years Dolly developed arthritis. This was possibly because she was cloned from a 6 year old sheep. Today we will make clones of 2 different plants. • I will show you how to make a clone of a spider plant using the layering technique. • In your groups you will take a cutting from a geranium plant.