ASEXUAL REPRODUCTIONREPRODUCTION: biological process by which new individual organisms are produced. Fundamental to all life; may be sexual (requires two individuals

one of each sex) or asexual (by cell division).

Asexual reproduction occurs in many ways, the most common being:

Budding – the offspring grows out of the parent (Hydra’s)Gemmules – (internal buds) the parent releases a specialised mass of cells that can develop into offspring. (sponges)Fragmentation – the body of the parent breaks into distinct pieces, each of which can turn into an offspring. Regeneration – if a piece of a parent is detached, it can grow and develop into a completely new individual. (echinoderms – starfish example)Parthenogenesis – a complex reproduction process that involves the development of an egg that has not been fertilised into an individual (these organisms have no sex chromosones, animals such as bees, wasps, ants and some fish and reptiles can reproduce in this manner)

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Mitosis

The following slides provide an example of the unique feature of Asexual Reproduction which primarily distinguishes it from Sexual Reproduction.

Asexual Reproduction is a result of cell division. This is a process known as MITOSIS.

Sexual Reproduction is a result of cell fission. This process is know as MEIOSIS.

Asexual ReproductionAsexual Reproduction:ASEXUAL REPRODUCTION is an organism that reproduces by cell division. The

offspring produced by the organism is genetically identical to itself. The offspring is produced by a process call mitosis .

Image retrieved from: http://www.redbubble.com/people/ikshvaku/works/9986034-mitosis-somatic-cell-division

What does all of this mean?What does this all mean?Learning about the concept of Mitosis is quite complex, to make it easier to digest this

could be a preferable image to help engage the mind.

Image retrieved from: http://science.wonderhowto.com/inspiration/krispy-kreme-mitosis-0118283/ Who’s hungry now?

The PARENT DONUT

This first donut is called the “parent”.

PROPHASEThe second picture shows how the donut is undergoing changes. Prophase is when the

chromatin condenses into discrete chromosomes, the nuclear envelope changes and the centrioles form at opposite “poles” of the cell. The nuclear envelope dissolves and mitotic spindle forms. Spindle fibers from each centriole attach to each sister chromatid at the kinetochore.

In the donut example it can be seen that the white icing (nuclear envelope/membrane) that encases the sprinkles starts to break apart, this is an example of the nuclear envelope opening. The sprinkles that were once inside of the nuclear envelope have now duplicated, and the centrioles aka yellow sprinkles have headed to opposite ends of the cell (the donut).

METAPHASEIn the third picture the next process of Asexual Reproduction (Mitosis) can be seen by looking at how the

white icing and coloured sprinkles move and change within the cell. This process is called the METAPHASE. During the metaphase the duplicated chromosomes from the prophase prepare to SPLIT. Before the chromosomes split from each other most often they line up in the equator of the cell and are held in place by spindles. The spindles hold each chromosome opposite to its identical partner at the other end of the pole, the spindles will become the nuclear envelope upon cell separation. The Centrioles complete their migration to the poles.

By looking at the donut it is easy to see how the duplicated sprinkles (chromosomes) line up along the equator of the donut (cell) and are held there by the white icing (spindle) the yellow sprinkles (centrioles) have fixed themselves at polar opposites of the donut (cell).

ANAPHASEIn the next stage of the Mitosis process the spindles attached to kinetochores begin to

shorten. This exerts a force on the sister chromatids that pulls them apart. Spindle fibers continue to shorten, pulling chromatids to opposite poles. This ensures that each daughter cell gets identical sets of chromosomes.

In the donut example it is evident to see that each sister chromatid is opposing is identical sister by looking at the coloured sprinkles and their positions. The spindles (white icing) are shortening and the force of this pulls the chromatids (sprinkles) to opposite poles.

TELOPHASEThe final phase of mitosis is called TELOPHASE. It is where the chromosomes

decondense .The nuclear envelope forms. Cytokinesis reaches completion and once this process is complete the cell splits into two daughter cells.

By looking at the donut it is evident to see how the sprinkles (chromosomes) condense and the white icing (nuclear envelope) forms an envelope around them. Once this occurs, the donuts split into two daughter donuts. Identical to their parent.