Types of Asexual Reproduction

1. Types of Asexual Reproduction

2. Asexual Reproduction: • Asexual Reproduction is a type of reproduction by which offspring come from a single parent • Each offspring receives acopy of the parent’s genetic material.  Offspring are genetically identical to the parent and to each other.

3. Asexual Repro • https://www.youtube.com/watch?v=i9zj9V8OWRk

4. Video • Asexual Repro video: • https://www.youtube.com/watch?v=i9zj9V8OWRk • Amoeba Sisters • https://www.youtube.com/watch?v=fcGDUcGjcyk

5. Different forms of Asexual Reproduction • Binary Fission • Budding • Fragmentation • Spores • Vegetative propagation

6. Binary Fission • parent cell divides into two identical cells called daughter cells. • Eg.Bacteria

7. Doubling Time • Doubling time is the time for the number of bacteria to double its population • For bacterial it is about 20-30 minutes under optimal conditions • What conditions do you think affect bacterial growth, and how do they affect it?

8. Budding • Offspring begins as a small growth on the parent, called a bud. • Bud stays attached to the parent while it grows and develops • When the bud is fully developed, it breaks away from the parent cell and forms a new organism.  • Eg.Yeast Hydra https://www.youtube.com/watch?v=a5oHMjGqjyo

9. Fragmentation • A small part of the an animal breaks off and grow into a new organism. • A fragment can grow into a complete animal, depending on how much of the original parent is in the fragment. • Requires ability to regenerate (ability to regrow a body part, tissue, or organ).

10. Fragmentation • Eg.Flatworms, such as planaria • Eg.Sea stars • https://www.youtube.com/watch?v=AaN6uRvfPLY • Eg. hydra • Why can’t we regenerate? Scishow • https://www.youtube.com/watch?v=QFa6jP6WgzM

11. https://www.youtube.com/watch?v=GCNkbr6WBmQ

12. Salamander

13. Axolotls • Axolotls • https://www.youtube.com/watch?v=Eo50ctoOTWs

14. Check your understanding 1. What key piece of evidence tells you that bacteria reproduce asexually? 2. Define Binary Fission 3. In what ways is reproduction in yeast and bacteria similar? In what ways is it different? 4. Why is a daughter yeast cell identical to the parent cell?

15. Asexual Reproduction in Plants Vegetative Propagation

16. Spore Formation • Spores are the single-celled reproductive unit of nonflowering plants (such as ferns), fungi (such as moulds, puffballs, and mushrooms), and algae. • A spore is typically a cell surrounded by a tough, water proof cell wall, permitting the cell to survive unfavorable circumstances such as extremes of temperature and moisture.

17. Spore Formation • In Rhizopus numerous spores are produced within sacs called sporangia, knob like structures which are present at the top of the thread like structures calledhyphae.

18. VEGETATIVE PROPAGATION: • New plants grow from a portion of the roots, stems, or leaves of an existing plant. • Because the new plants are exacts copies of the parent, they are called clones.

19. Stolons/Runners • Horizontal stems that grow along the ground. • Eventually runners die, leaving independent, identical plants.  • Ex. Strawberries, spider plants

20. Bulbs • Roots grow out of the base of the bulb, and other bulbs from them. • Eg Camas, onions, and daffodils • Camas was used by First Peoples of Pacific Northwest as food.

21. Tubers (the potato) • Tubers are enlarged underground stems,  • Potatoes, Artichoke, yam, water chestnut, arrowroot • New roots and stems grow from the eyes of the potato

22. From leaves of parent plant • New plants develop a “piggyback” style off the parent leaf, forcing it to bend under the weight and touch the ground.  • The new piggyback will then develop roots and become a new separate plant. 

23. Artificial Vegetative Propagation Plants manipulated by people Splitting Cutting Grafting

24. Artificial Vegetative Propagation • usually done for quick production of new plants and to retain the qualities of the mother plant • Splitting Cutting Grafting

25. Splitting • A plant is split into two or more pieces, each containing intact shoots and roots. • Used with bulbs such as tulips and daffodils • Plants such as peonies and hostas

26. Cutting • Part of a leaf, stem or root is cut form a plant and placed in water with nutrients or potting soil. Cells near the cut surface develop into roots  or shoots. The new roots supply water and nutrients, and each shoot forma a new plant. Used on many houseplants.

27. Grafting • A bud, portion of the stem, or section of the root is cut from one plant and joined to another.  • Eg.Fruit trees such as apple and pear • Eg.Nut trees such as walnut and almond  • Eg. Grapevines

28. Layering • Simple Layering - A section of stem is bent to touch the ground, then a cut is made to promote growth of roots.  • Eg climbing roses, grapevines, honeysuckle, junipers, willows

29. Layering • Air Layering - a strip of outer bark is removed and moss is packed around the stem. Plastic is wrapped around the moss to prevent water loss. Once new root develops, stem is cut away form parent plant.  • Eg. magnolias, fruit trees, nut trees.

30. Characteristics of Asexual Reproduction • Only one organism is needed to reproduce • All offspring are genetically identical to each other and to the parent • A single organism can produce large numbers of offspring

31. Check your understanding • Describe an example of vegetative propagation. • Why are new strawberry plants that form from runners identical to the parent plant?

32. TEK (Traditional Ecological Knowledge) Includes sophisticated resource management methods that have been used for thousands of years. • Root plants such as camas, rice root, silverweed, and bitterroot were important sources of starches in the past. • First Peoples would manage camas meadows by replanting small, living sections of the harvested roots. • The bulb of the northern rice root, has small bulblets that look like rice. At the centre is a small sprout that can be replanted. The Kwakwaka’wakw word for it means “grandfather”

33. Check your understanding • What key piece of evidence tells you bacteria reproduce asexually? • In what ways is reproduction in yeasts and bacteria similar? • In what ways are they different? • Why is a daughter yeast cell identical to the parent cell? • Why is a spore considered a type of asexual reproduction? • Give an example of vegetative propagation. • CYU p60

34. ASEXUAL ADVANTAGES • Fast • Requires little energy • Successful gene combinations are maintained from generation to generation

35. ASEXUAL DISADVANTAGES • Parents and offspring may compete • Promotes uniformity (lack of diversity)

36. Compare • Binary fission occurs when a parent cell splits into two identical daughter cells of the same size.  • Fragmentation occurs when a parent organism breaks into fragments, or pieces, and each fragment develops into a new organism. ...  • Budding occurs when a parent cell forms a bubble-like bud

37. Some organisms can develop without fertilization Pathogenesis - reproduction from an ovum without fertilization, • some invertebrates particularly rotifers, aphids, ants, wasps, and bees