Asexual vs. Sexual Reproduction. Part 1of 3

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Randall Crawford
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1 Asexual vs. Sexual Reproduction Part 1of 3

2 UNIT QUESTION: What new information has modern day biology been able to uncover about planarian stem cells and regeneration and what do these findings tell us about the human capacity for regeneration? Superhero Science - Limb Regeneration (2:18)

3 Objective To compare methods of sexual and asexual reproduction Reading - Two Methods of Reproduction

4 Asexual Reproduction vs. Sexual Reproduction Asexual Reproduction involves only 1 parent offspring genetically identical to parent involves regular body cells its quick Sexual Reproduction involves 2 parents offspring genetic mix of both parents involves specialized sex cells its slow

5 Asexual Reproduction Binary fission happens in bacteria, amoeba, some algae one parent cell splits into 2 identical daughter cells Budding happens in yeast, hydra, corals parent produces a bud bud gets detached and develops into offspring which is identical to parent

6 Types of Asexual Reproduction Binary Fission 1. Organism divides in half 2. 2 identical daughter cells produced 3. Daughter cells are half the parent s size 4. Daughter cells grow, then divide too 5. In bacteria (amoeba, paramecium)

7 Binary Fission - Asexual Reproduction 2 daughter cells are identical to parent Rod-Shaped Bacterium, hemorrhagic E. coli Bacteria reproducing video (45 sec)

8 Types of Asexual Reproduction Budding 1. Small bud grows out of parent cell 2. Two different sized cells made (with identical DNA) 3. Bud breaks off and grows 4. In yeast and hydra

9 Budding - Asexual Reproduction A hydra is a multi-cellular freshwater animal. Yeast is a single-celled fungi. There are over 1500 known species of fungi but that might only be 1 % of all fungal species. Yeast and Hydra - Budding video (2:47) Budding in a Hydra (1:27)

10 Types of Asexual Reproduction Regeneration (Fragmentation) 1. Repair/ grow lost body parts 2. Left over cells divide to make more cells 3. Lobsters, starfish, lizards, planarian

11 Fragmentation (Regeneration) Sea Star RegenerationBucket of Stars (2:07) Sea Star Regeneration (1:07) Planarian video (7:17) Sea-urchin Sand dollar

12 Parthenogenesis Parthenogenesis is a form of asexual reproduction where growth and development of embryos occur without fertilization. In plants, parthenogenesis means development of an embryo from an unfertilized egg cell. The word parthenogenesis comes from the Greek παρθένος, parthenos, meaning "virgin", and γένεσις, genesis, meaning "birth". The term is sometimes used inaccurately to describe reproduction modes in hermaphroditic species that can reproduce by themselves because they contain reproductive organs of both sexes in a single individual's body. Parthenogenesis occurs naturally in many plants, some invertebrate animal species (including nematodes, water fleas, some scorpions, aphids, some bees, some Phasmida, and parasitic wasps) and a few vertebrates (such as some fish,amphibians, reptiles,and very rarely birds). This type of reproduction has been induced artificially in a few species including fish and amphibians.

Parthenogenesis The three Whiptail Lizards on view in the Hall of Reptiles and Amphibians all play a part in one of the greatest mysteries of nature.

When the New Mexico Whiptail, as well as several other all-female species of whiptail lizard, does reproduce, and all of its offspring are female.

13 Parthenogenesis The three Whiptail Lizards on view in the Hall of Reptiles and Amphibians all play a part in one of the greatest mysteries of nature. The New Mexico Whiptail, pictured here, is an all-female species. When the New Mexico Whiptail, as well as several other all-female species of whiptail lizard, does reproduce, and all of its offspring are female. Moreover, it reproduces by parthenogenesis -- its eggs require no fertilization, and its offspring are exact and complete genetic duplicates of the mother. Scientists understand only partially how this reproductive mode developed, and it raises many questions. One of the most intriguing is how this cloning affects the lizard's ability to adapt to environmental changes. Since there is no genetic variation except that which occurs through mutation, the New Mexico Whiptail cannot evolve as other species do. The New Mexico Whiptail Lizard also offers an extraordinary opportunity to learn more about the role of sperm in fertilization, as well as about cloning.

14 Asexual Reproduction contd. Spore Formation happens in fungi, green algae, molds and non- flowering plants (e.g. ferns) spores are produced and each spore develops into offspring which are identical to parent Vegetative Reproduction does not involve seeds some offspring can grow from cuttings (e.g. coleus), runners (e.g. strawberries), tubers (e.g. potatoes) or bulbs (e.g. tulips) which are part of the parent plant

15 Fungi Spore Formation Fern Fungi (3:03) Mold and How it Affects Your Body (2:09) Bread mold (:25) Fern reproduction (1:30 )

16 Sugarcane - Vegetative Reproduction (:30) Can Grass Grow From Clippings? (1:01) What are Root Flower Bulbs? (2:40) Vegetative Reproduction Potato Sequence (:24) How to Grow Avocado Plants (2:38)

17 Asexual Ant - Females Only! Mycocepurus_smithii (1:30)

18 Asexual Reproduction - Review Asexual Reproduction 1. One parent 2. No sex cells 3. Offspring produced by cell division 4. Offspring identical to parent (same DNA) 5. Several types in plants and animals

Asexual Reproduction

Asexual Reproduction Only one parent is involved in asexual reproduction. The offspring is genetically identical to the parent. The offspring inherits all of its traits from one parent. Therefore, the