MitosisBinary FissionFragmentation

BuddingRegeneration

Is the formation of a new organism from a single parent resulting in 2 identical offspring

Examples :

Mitosis

Binary fission

Fragmentation

Budding

Reneration

Humans (multicellular eukaryotes)

body cells for growth and tissue repair

Amoeba (unicellular eukaryotes)

to form two new individuals

Results in two new identical cells

Bacteria

Unicellular prokaryotes

Parent cell divides to form two new identical cells.

Each new cell contains a single chromosome that carries DNA identical to the parent cell.

http://www.youtube.com/watch?v=3cD3U2pgb5w

Protists are also unicellular.

An example is the amoeba.

DNA is found in a true nucleus (eukaryote).

Mitosis is used to create two identical offspring.

Molds, mushrooms, and yeasts are made up of fine thread-like structures called hyphae.

The word hyphae comes from the Greek word hyphos, meaning web

Three types of asexual reproduction are possible…

Bread mold and mushrooms are multi-cellular organisms that can reproduce asexually by fragmentation

In fragmentation, a piece of the hyphae breaks off

The fragment then undergoes cell division by mitosis and an entire new organism develops

What structure must be present in the fragment to allow this to happen?

Molds and mushrooms can also use spores to reproduce asexually.

Spores are produced in a special case called the sporangium.

When released, each spore will germinate to form an entire new organism.

The spore itself is a reproductive cell that reproduces by mitosis.

Spores have been found in the atmosphere at altitudes of more than 160km!

Yeast cells are uni-cellular

In budding, a copy of the nucleus is made first.

Next a tiny bud forms on the cell wall of the parent cell.

The bud contains the new nucleus.

The bud grows and eventually breaks away from the parent to form a new yeast cell.

Humans are vertebrates which are multi-cellularorganisms

Human life begins with the union of male and female gametes (egg and sperm). This is sexual reproduction.

However, asexual reproduction or mitosis is vital to human growth and tissue repair.

In asexual reproduction, cells divide on their own to produce cells that are identical to each other.

Many invertebrates reproduce asexually.

Planaria, a multi-cellular organism, is a type of flatworm that reproduces asexually by dividing in two and reproducing the parts that are missing.

The new parts are formed by a process called regeneration.

Mitosis is the process used in regeneration.

Some animals, such as the hydra, use a form of budding to reproduce.

A cell near the base of the hydra undergoes mitosis over and over until a bud (a group of cells) forms.

Eventually the bud matures and detaches itself. The bud continues to undergo mitosis.

A new hydra is the result.