Reproduction

2013

Reproduction Sexual and Asexual

Yumkax Julio Fausto Iboy Hernรกndez AMANECER 12/04/2013

What is asexual reproduction?........................................... 1 Animals asexual? …………………………………………………………… 2 Plants asexual? ……………………………………………………………… 3 sexual reproduction ………………………………………………………. 4 animal sex …………………………………………………………………….. 5 sexual plants ……………………… ……… ……………………………….. 6

Whats is de reproduction asexual?

A vital function of all living things is reproduction, like nutrition and relationship. Leave offspring is a vital process to allow the species to continue to exist over time.

The type of reproduction without gametes is the most ancient, is called, asexual reproduction.

In the same genetic exchange does not occur.

One advantage of asexual reproduction is that no other agency is required to produce offspring, is fast and consumes few resources.

The biggest drawback to asexual reproduction is that it produces variability of individuals, because their genes do not vary over time. No gene exchange occurs between organisms to produce offspring with greater variability and adaptation to the environment in which they live.

Example of asexual reproduction in animals.

The more evolved beings have acquired the capacity of sexual reproduction allowing better adaptive response to their environment.

Animals Asexual.

Asexual reproduction occurs only in those animals whose cells still retain the embryonic tot potency, ie the ability to not only multiply, but also to differentiate into different cell types to achieve the reconstruction of parts of the body that might be missing. As embryonic tot potency is the more common is the simpler animal organization, it takes place in: - Porifera - Cnidarians - ANNELIDS - ECHINODERMS - PROTOZOA - Flatworms - Bryozoans

Most are seafood

Asexual reproduction in plants Reproduction by spores. Since a cell of an individual, whose nucleus divides repeatedly originate several daughter cells called spores. These cells, in favorable conditions, give rise to new individuals. It occurs in mosses and ferns.

Vegetative reproduction. It relies on the ability of plants to form new individuals from a fragment thereof, called yolk. We can distinguish four types: Stolons. Are of little height stems which grow parallel to the floor. Its buds emit roots.

Giving rise to new individuals become independent. Typical of strawberries and clover.

Rhizomes. They are underground stems that, every so often, produce roots and stems that rise to the surface. We find, for example, in the grass, reeds, ferns.

Tubers. They are underground stems and buds with food reserves, each of which can give rise to new roots and stems. They are, for example, in the potato.

Bulbs. They are underground stems with fleshy leaves that surround them. They buds can cause a new plant, like onions or tulip.

Features Sexual reproduction is Asexual.

Sexual reproduction is one in which involved specialized cells called gametes, which are formed in special organs called gonads and whose purpose is to form a variety of genetic combinations in the new bodies to improve the chances of survival.

The key process of sexual reproduction is meiosis, a special type of division that leads to a normal cell with a certain number of chromosomes (diploid) with the other half thereof (haploid), while generated multiple combinations of genes and organisms.

In addition to plants, animals, humans, other living things that reproduce sexually, such as: - Bacteria reproduce asexually by binary fission bipartition or Sexual and form through bacterial conjugation. Bacterial conjugation process is the transfer of genetic information from a donor cell to a receiver, promoted by certain types of plasmids that carry a set of genes whose products participate in the process, which requires direct contact between them, involving specialized surface structures and specific functions (Pili in Gram negative sexual and intimate contact in the Gram positive). Some of these plasmids behave as episomes, ie which can be integrated in the chromosome, in this case, if the conjugation occurs, it may transfer the plasmid itself over an adjacent segment of the chromosome, which in turn may recombine with sequences receptor homologous chromosome, resulting in a hybrid chromosome.

. The paramecium (protozoa) multiplies by simple division or excision (Asexual) and conjugation (Sexual). In sexual reproduction, two similar single-celled organisms fuse, exchange nuclear material and separate. Then each reproduced by excision. Sometimes, the participating agencies do not play and it seems that the revitalization process. Conjugation is the most primitive method of sexual reproduction in the bodies obtained with genetic features derived from two different cells. From time to time, paramecia are joined by their regions and exchange oral micronucleus substances. During conjugation, the macronucleus disintegrates and disappears. Enlarges and the micronucleus divides by mitosis into two.

Micronucleus both formed in each animal again divided and formed Micronucleus 4, of which 3 of them are absorbed and the remainder is divided again. In this instance each have two portions Paramecium Micronucleus and exchange portion thereof to each other. In each merge Paramecium micronucleus portion itself with the receiving portion of the other. At 2 fused portions are called zygote. Just then separated paramecia. In each Paramecium, the zygote, by division, giving rise first to 2, then 4, then to 8 Micronucleus. Of these 8 Micronucleus is 1 since become macrocores 4 and 3 are reabsorbed. Finally each Paramecium divides his Micronuclei and body 2 times giving rise to four new individuals.

Conjugation end results, the formation of 8 new paramecia.