ASEXUAL REPRODUCTION    By V.L.

 

(in Bacteria, Protists, Fungi, and Animals)

 

 

 

 All living things go through a process called reproduction. Living things come from the result of this process. There are two kinds of reproduction processes. One is asexual reproduction and another is sexual reproduction. Asexual reproduction is the creation of a new individual that has the exact genetic information to its parent, meaning there are no gametes and different combinations on genes. Sexual reproduction on the other hand, the offspring are genetically different from both their parents.

 

 

 Asexual reproduction only happens in plants, bacteria, protists and fungi. Bacteria are unicellular organisms that don’t contain a ‘real’ nucleus. The actual type of asexual reproduction is binary fission. What happens is that a cell divides into two daughter cells that are identical to each other and to the original cell. Binary fission in bacteria only uses one chromosome to re copied and when division takes place, each cell only gets one chromosome, but the cells are still exactly the same, genetic wise.

 Because it doesn’t have a combination of genes, it only has one that is identical to the parent, it has a hard time adapting and adjusting to new environments.

 

 Unicellular cells like protists, are the most complex cells known. They mainly rely on asexual reproduction to reproduce themselves. The word protist is derived from the Greek word protos, meaning first. Unlike bacteria, the DNA of protists is contained within a true nucleus. The mitotic cell division in protists result in the form of two identical offspring. Protists  are important because they make the basis of many food chains

.

 Fungi (e.g., moulds, yeast and mushrooms),are composed of many thin filaments called hyphae. There are three types of asexual reproduction for fungi. Spores, fragmentation and budding. The simplest form is budding. First, a copy of the nucleus is made and then a small bud begins to form on the cell wall. This bud continues to grow larger, until it finally breaks away into an individual cell. Fragmentation happens when a small

 piece or fragment of the main cell breaks away to grow into a new individual cell. Spores by far, is the most important type of asexual reproduction. A spore is a reproductive cell that can grow into a new separate cell with mitotic cell division. When spores grow, they tend to take on a certain color.

 

 Asexual reproduction in animals can have a very high advantage. If an animal can only remain in one particular place they are unable to look for mates. Another advantage from asexual reproduction is that many offspring can be produced without the parent having to ‘waste’ time and energy. Environments can be a problem though. If the parent is able to

 stand certain environments then chances are the offspring will be able to live in those conditions too. They can use regeneration to reproduce parts of themselves that they’ve lost. They could also use budding as a form of asexual reproduction.

 

 

Definitions:

1) Protists : Any of the eukaryotic, unicellular organisms of the former kingdom Protista, which includes protozoans, slime molds, and certain algae. The protists now belong to the kingdom Protoctista, a new classification in most modern taxonomic systems.

 

2) Filaments :

    1. A fine wire heated electrically to incandescence in an electric lamp.
    2. Electronics. A high-resistance wire or ribbon forming the cathode in some thermionic tubes.

3) Eukaryotic: A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus.

 

4) Protozoans: Any of a large group of single-celled, usually microscopic, eukaryotic organisms, such as amoebas, ciliates, flagellates, and sporozoans.

 

5) Hyphae: The long, branching filaments of which the mycelium (and the greater part of the plant) of a fungus is formed. They are also found enveloping the gonidia of lichens, making up a large part of their structure.

 

6) Bacteria: A microscopic vegetable organism, belonging to the class Alg[ae], usually in the form of a jointed rodlike filament, and found in putrefying organic infusions. Bacteria are destitute of chlorophyll, and are the smallest of microscopic organisms. They are very widely diffused in nature, and multiply with marvelous rapidity, both by fission and by spores. Certain species are active agents in fermentation, while others appear to be the cause of certain infectious diseases.

 

7) Fungi: Any of numerous eukaryotic organisms of the kingdom Fungi, which lack chlorophyll and vascular tissue and range in form from a single cell to a body mass of branched filamentous hyphae that often produce specialized fruiting bodies. The kingdom includes the yeasts, molds, smuts, and mushrooms.

 

8) Chromosome: A threadlike body in the cell nucleus that carries the genes in a linear order.

 

9) Genes: A hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism. Genes undergo mutation when their DNA sequence changes

 

10) Nucleus: A part of the cell containing DNA and RNA and responsible for growth and reproduction.

 

 

 

Questions:

 

1)      What things does asexual reproduction happen in . Why does it only happen is them?

2)      What is a spore?

3)      Unlike bacteria, where does the DNA of protist ?

4)      What is asexual reproduction ?

5)      When spores grow what happens ?

 

Asexual Reproduction Word Search