Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Genetically modified food wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Molecular cloning wikipedia , lookup
Point mutation wikipedia , lookup
Koinophilia wikipedia , lookup
Genetic engineering wikipedia , lookup
History of genetic engineering wikipedia , lookup
By Dr Adrian Mascia (Ph.D Biology, Education. M, 2009, teacher of the year TYPES OF REPRODUCTION Reproduction: The creation of a new generation of single cells, single celled organisms or multi-cellular organisms. The production of new organisms will always begin with the division of a single cell. A–sexual: Reproduction without the assistance of another organism Sexual: Requires two organisms of the same species to combine gametes to form a zygote A-SEXUAL REPRODUCTION There are several methods of A-sexual reproduction 1. 2. 3. 4. 5. Fission Spore formation Budding Fragmentation Vegetative reproduction A-sexual reproduction is very rapid, however does not provide genetic diversity, this can put at species at risk of extinction should conditions change Fission • Fission involves the replication of chromosomal DNA • Once replication occurs, the DNA strands are attached at opposing ends of a cell membrane, and cell division occurs (giving rise to 2 identical cells) • This is a very rapid process (exponential) • E.G Amoeba Spore Formation • Spores are hardy, self contained capsules containing DNA • Spores are generally mass produced, and are very effective as they will only leave their dormant state when conditions become suitable (increasing chance of survial) • E.G ferns, mosses, some prokaryotes and protists Budding • Budding involves the development of a new organism from the out growth of a parent organism. • The new organism may detach at some point and become a stand alone organism • E.G Hydra, some flat worms, yeast cells Fragmentation • Some organisms such as sponges have the ability to fragment as well as reconstruct themselves • A sponge can be broken into many pieces, forming many new organisms • Can also reform a new organism from fragments Vegetative Propagation • There are some species of plants from which you can regrow a clone of the original plant by planting cuttings • This process also allows for a process called grafting, where two different plant cuttings (root and shoot) can be combined to produce a new plant SEXUAL REPRODUCTION • Basic process of Meiosis (two gamete cells fusing to form a zygote) • Creates genetic diversity (essential for the survival of a species) • Not as fast as A-sexual reproduction Sexual reproduction in Uni Cellular organisms • Common misunderstanding that single celled organisms reproduce only A-sexually • If this were the case we would not see the amazing diversity of single celled organisms • Several protozoan have the ability to produce gametes • Generally one gamete is larger and sedentary and one is smaller and mobile (much like in humans) • Paramecium does not involve gamete production, rather an exchange of genetic material whilst lined up along side one another. This process is called CONJUGATION