SEXUAL AND ASEXUAL REPRODUCTION

By ABBAS 05

Briefing Asexual Reproduction

A change in the number of cells/individuals without achange in the genetic state of the cells

Cellular basis - Mitosis

Mitosis - process by which the number of cells is increased without changing the number of chromosomes in the cell

Types of Asexual Reproduction

1. Mitosis - is the exact duplication of the nucleus of a cell so as to form two identical nuclei during cell division.

Mitosis

(Figure 12.6 in your book)

Centrosomes

chromatin -uncondensedchromosomes

G2 of Interphase Prophase

-sister chromatids

- mitotic spindle

Prometaphase

-kinetochore

-kinetochoremicrotubule

-nuclear envelope

Metaphase

-metaphase plate

AnaphaseTelophase&

Cytokinesis

-daughter chromosomes

-cleavage furrow

-nuclear envelope

Mitosis

Prophase

Metaphase

Telophase

1.3 Asexual reproduction

- Parthenogenesis - Sporulation - Budding - Binary fission - Regeneration - Vegetative

SEXUAL AND ASEXUAL REPRODUCTION

1.3 ASEXUAL REPRODUCTION

BINARY FISSION

Definition Binary Fussion

•Binary Fussion = a single-celled organism divides into two cells of the same size.

•Each is identical to the Other

occurs in one-celled organisms such as the ameba and paramecium.

The nucleus divides by mitosis and the cytoplasm divides, forming 2 new daughter cells of equal size.

Binary Fission = is simplest form of

asexual reproduction. Parent organism divides into two

approximately equal parts. Each daughter cell becomes a new individual.

Binary Fission

1.3 ASEXUAL REPRODUCTION

REGENERATION

Regeneration = The ability to re-grow lost or damaged body parts.

Hydra, planaria, starfish, and earthworm More complex animals less able to re-grow parts. Crab can re-grow a claw. Some reptiles can re-grow a tail. Most mammals can repair damaged tissue but can not re-grow missing parts.

Definition

Refers to the replacement or regrowth of lost or damaged body parts

Regeneration

Vegetative Reproduction

1.3 ASEXUAL REPRODUCTION

Definition Vegetative

=fragments of the ‘parent’ can grow into new organisms

Occurs only in plants (vegetative). New plants develop from the roots, stems, or leaves of the parent plant.

New plants can be produced from sections of parent plants that are cut off.

New plants reproduced in this way are identical to the parent plant.

We see this in spider plants and willow trees, for example.

Runner or stolen = horizontal stem above the ground with buds. If a bud touches the ground it will form roots and stems and start a new plant. Strawberries.

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