1. Producing Identical Offspring
Asexual Reproduction
Producing Identical Offspring

2. Asexual Reproduction
Unicellular organisms, many simple animals, and many plants reproduce asexually, at least during part of their life cycles.

3. Asexual Reproduction
Because asexual reproduction takes place only by mitotic cell division, every offspring has the same exact DNA as its parent.

4. Check for Understanding
Would you expect offspring produced asexually to show much variation? Why?

5. Asexual Reproduction
Usually rapid and often results in the production of large numbers of offspring.

6. Methods of Asexual Reproduction
There are several methods of asexual reproduction, including:
Binary Fission
Budding
Spore Formation
Regeneration
Vegetative Reproduction

7. Binary Fission
Binary fission is the simplest form of asexual reproduction.
Parent organism divides into two equal parts.

8. Binary Fission
Binary fission is the usual method of reproduction in one celled organisms, including bacteria, protozoa, and many algae.

9. Budding
Budding is a method of asexual reproduction in which the parent divides into two unequal parts.

10. Budding
The new individuals develop as small outgrowths, or buds, on the outer surface of the parent.

11. Budding
The buds may break off to live as an individual, or they may remain attached, eventually forming a colony.

12. Budding
Budding differs from binary fission in that the parent and offspring are not the same size.

13. Budding
Budding takes place in yeast and hydra, as well as in sponges and some worms.

14. Budding in Yeast and Hydra Video

15. Spore Formation
Spores are single, specialized cells that are produced by certain organisms.
Can be formed sexually or asexually.

16. Spores
Although spores can vary greatly in appearance, they all function as single units of reproduction.
Often surrounded with a thick hard outer wall.
May sometimes have a flagella.

17. Spores
Asexually formed spores are a common method of reproduction in many simple organisms, such as fungi, algae, and protozoa.

18. Spores These spores are produced through mitotic cell division.
They are formed within and released from a single cell structure that is the remains of the original parent cell from which they are formed.

19. Spore Formation in Bread Mold
Bread mold is a fungus, and can sometimes be seen growing as a dark mass on bread or other food.

20. Bread Mold
Spores are produced by mitotic cell division in spore cases on specialized stalks that grow upward from the surface.

21. Bread Mold Thousands of black spores develop within each spore case.
When fully grown, the walls break down, and the tiny light spores are swept away by air currents.

22. Spores
When a spore lands in a warm, moist environment, where nutrients are available, it germinates and grows to form a new mass of mold.

23. Bread Mold
Bread mold also reproduces sexually, which we will discuss later.
Bread Mold Video
(click photo above)

24. Bread Mold
In the space provided on your worksheet, draw and label a diagram showing the main structures of bread mold.

25. Regeneration
Regeneration is the ability of an organism to re-grow lost body parts.

26. Regeneration
Relatively simple animals can regenerate lost body parts. For example:
* Hydra
* Planaria
* Starfish
* Earthworm

27. Regeneration
The power of regeneration decreases in more complex organisms.
For example: While a crab can re-grow a lost claw, it cannot regenerate an entire animal from pieces.
Sea star regeneration
video
(click photo above)

28. Vegetative Reproduction
Although most plants reproduce sexually by means of seeds, asexual reproduction involving roots, stems, and leaves also occurs.

29. Vegetative Reproduction
Roots, stems, and leaves are called vegetative structures.
They normally play a role in the nutrition and growth of plants.

30. Vegetative Reproduction
When these structures give rise to new plants, the process is known as vegetative reproduction, or vegetative propogation.

31. Check for Understanding
Give three examples of vegetative structures.
Roots, stems, leaves
When these structures give rise to new plants, the process is known as what?
Vegetative Reproduction (propogation).

32. Vegetative Propagation
In vegetative reproduction, cells divide mitotically, then differentiate to produce another plant.
The new plant has the same hereditary characteristics as the parent plant.

33. Vegetative Propagation
Vegetative propagation occurs naturally and can be produced artificially.

34. Natural Vegetative Propagation
A bulb is a short underground stem surrounded by thick fleshy leaves that contain stored food.

35. Bulbs As the plant grows, small new bulbs sprout from the old one.
Each of the new bulbs can give rise to another plant.

36. Bulbs Examples of plants that reproduce with bulbs are: * Tulips
* Onions
* Lillies

37. Tubers
A tuber is an enlarged part of an underground stem that contains stored food.

38. Tubers White potatoes are tubers.
Along the surface of the tuber are indentations called “eyes”.

39. Tubers The eyes are tiny buds that grows into a shoot.
The young shoot uses food stored in the tuber until it can carry on photosynthesis.

40. Runners
A runner or stolen, is a stem that grows sideways and has buds.
Usually grows along the surface of the ground.

41. Runners
Where buds from the runner touch the ground, new plants develop.
These new plants will send out runners that will repeat the process.

42. Runners
Strawberry plants and many grasses that reproduce quickly use runners.

43. Rhizome A rhizome is a stem that grows sideways underground.
Usually thick and fleshy and contains stored food.

44. Rhizome Along the rhizome are enlarged portions called nodes.
Buds along the upper surface of the rhizome give rise to leaf-bearing branches.

45. Artificial Vegetative Propagation
Farmers and gardeners have developed ways to grow plants with desirable traits.
They do this through artificial vegetative propagation.

46. Cuttings
A cutting is any vegetative part of the plant used to produce a new individual.

47. Cuttings
Cuttings are usually placed in water and allowed to grow roots.
Once roots develop, the cutting is planted in soil and grows as a new plant.

48. Grafting
In grafting, a stem or bud is removed from one plant and permanently joined to the stem of a closely related plant.

49. Grafting The added piece is called the scion
Part of the combination providing the roots is known as the stock

50. Grafting
In the space provided on your worksheet, draw and label a typical grafting set up.

51. Advantages of Artificial Vegetative Propagation
Plants grown from seeds do not always show the same characteristics as the parent plant.
Vegetative propagation produces plants identical to the parent.

52. Advantages of Artificial Vegetative Propagation
Example 1:
Seedless fruit can only be grown through vegetative propagation.
Example 2:
Scions of a desirable plant can be grafted onto plants with a disease resistant root system.