Asexual vs Sexual Reproduction LESSON POWERPOINT

Asexual vs Sexual Reproduction

1. Sexual vs. Asexual Reproduction

2. QUESTION: How does a parent organisms produces a new organisms or offspring? PARENTS AND THEIR OFFSPRINGS

3. REPRODUCTION Process by which living organisms like humans, plants and animals form new individual of the same kind.

4. REPRODUCTION ASEXUAL SEXUAL

5. Sexual Reproduction A type of reproduction in which the genetic materials from two different cells combine, producing an offspring The cells that combine are called sex cells Female – egg Male – sperm Fertilization : an egg cell and a sperm cell join together A new cell is formed and is called a zygote

6. Advantages: Sexual Reproduction Diverse offspring : genetic variation among offspring Half of the DNA comes from mom Half of the DNA comes from dad Due to genetic variation, individuals within a population have slight differences Plants – resist diseases Traits can develop to resist harsh environments that allows an organism survive

7. Advantages: Sexual Reproduction Selective Breeding Used to develop many types of plants and animals that have desirable traits Agriculture/Farming: better plants, larger animals Desirable pets

8. Disadvantages : Sexual Reproduction Time and Energy Organisms have to grow and develop until they are old enough to produce sex cells Search and find a mate Searching can expose individuals to predators, diseases, or harsh environmental conditions Fertilization cannot take place during pregnancy , which can last as long as 2 years for some mammals.

9. Examples: Sexual Reproduction

10. Sexual Reproduction in Plants (Pistil) Male Parts Female Parts pollen (male) + ovule (female) → single-celled zygote → multi-celled embryo (contained in a seed) → new individual

11. Pollen is produced in the male organs of the flowers - anthers . Pollinatio n occurs when pollen is transferred from the anthers to the female organs by wind or by animals. If the female stigma is receptive to a pollen grain, the pollen produces a pollen tube , which grows through the female tissue to the egg , where fertilization takes place by the sperm nucleus.  Sexual Reproduction in Flowering Plants

12. Pollination flowers are designed to lure insects to help with the pollination process also wind, animals, birds can transport pollen

13. External Fertilization External fertilization usually requires a medium such as water, which the sperms can use to swim towards the egg cell. External fertilization usually occur in fish and amphibians. The females lay the eggs in the water and the male squirts the sperm in the same area.

14. Internal Fertilization Fertilization occurs within the female. Internal fertilization occurs in mammals, insects, birds, reptiles. Mammals (gorillas, lions, elephants, rats, zebras, and dolphins have live births) Insects, birds, reptiles lay eggs

15. Sexual Reproduction Summary Male Gamete Female Gamete Type of Union Result of Union Final Result Plants pollen ovule (egg) pollination single cell zygote multi-cell embryo (in seed) Animals sperm egg fertilization single cell zygote multi-cell embryo

16. Asexual Reproduction One parent: organism produces offspring without fertilization Uniform offspring : Because offspring inherit all of their DNA from one parent, they are genetically identical to each other and to their parent

17. Fission : Asexual Reproduction Fission : Cell division in prokaryotes that forms two genetically identical cells DNA is copied The cell begins to grow longer, pulling the two copies apart The cell membrane pinches inward in the middle of the cell Cell splits to form two new uniform , identical offspring Examples : bacteria, Ecoli, pond critters

18. When conditions are good, such as plenty of water, food, right temperatures, etc., binary fission is a very effective way of producing many, many offspring. For example, the cell of a Paramecium can divide, grow, and divide again in the space of 8 hours. Fission : Asexual Reproduction

19. Budding : Asexual Reproduction Budding : a new organism grows by mitosis and cell division on the body of its parent The bud , or offspring is identical to the parent The bud, when large enough, can break off of the parent and live on its own Offspring may remain attached and form a colony Examples : Yeast, Hydra, cactus

20. Regeneration : Asexual Reproduction Regeneration : occurs when an offspring grows from a piece of its parent. Producing new organisms : Sea Stars Sea urchins, sea cucumber, sponges, and planarians Producing new body parts : Gecko Newts, tadpoles, crabs, hydra, and zebra fish

21. Parthenogenesis involves the development of an egg that has not been fertilized into an individual. Animals like most kinds of wasps, bees, and ants that have no sex chromosomes reproduce by this process. Some reptiles and fish are also capable of reproducing in this manner. Parthenogenesis : Asexual Reproduction

22. SPORE FORMATION SPORES- single specialized cells that when released from PARENT CELLS can GERMINATE to form new individuals Some spores have hard outer covering and some have flagella Ex: fungi, algae and protozoans fern, mosses

23. FRAGMENTATION Organisms split into fragments each of which develop into mature clones Sometimes they also called as splitting Sponges, corals, echinoderms

24. Vegetative Propagation : Asexual Vegetative Propagation : uniform offspring grow from a part of a parent plant Parent plants sends out runners Where the runner touches the ground, roots can grow A new plant is produced even if the runner is broken apart Each new plant is uniform and identical to the parent. Examples : strawberries, potatoes, ivy, crabgrass

25. CUTTINGS One of the easiest way of plant propagation Stem cutting refers to the process of cutting off a portion of a plant’s stem, which is then used to  propagate  a new plant. A  mature , independent plant identical to its parent. cuttings

26. LAYERING Plant propagations in which a portion of aerial stem grows root while still attached to the parent plant and then detaches as an independent plants can be accomplished by bending a low growing, flexible stem to the ground. Cover part of it with soil, leaving the remaining 6 to 12 inches above the soil. Bend the tip into a vertical position and stake in place

27. GRAFTING Cutting from some other plant is attached to the stem of a plant rooted in the ground. The tissues of the graft become integrated with the tissues of the rooted plant and develop as a single plant over time. Joining of the cut stem of two different plants Ex: cucumber, watermelon, eggplant

28. Advantages : Asexual Reproduction Enables organisms to reproduce without a mate No wasted time and energy Enables some organisms to rapidly reproduce a large number of uniform offspring

29. Disadvantages : Asexual Reproduction Because their offspring are identical, there is no genetic variation that can give an organism a better chance for survival Example : If a weed killer can kill the parent, it will also kill the offspring A whole species can be wiped out from a disease Dangerous mutations in DNA – if the parent has the mutation in their DNA, the offspring will have it too.

30. Examples : Asexual Reproduction

31. Activity: Create a creature that reproduces asexually. Draw the creature Describe how the creature reproduces asexually Describe 1 advantage of reproducing this way Describe 1 disadvantage of reproducing this way Name your creature