Cell-Organelles-Structures-Lesson-Presentation-in-Blue-and-Pink-Hand-Drawn-Style.pptx

Presentation

1. ALL LIVING THINGS REPRODUCE

2. DO YOU REMEMBER THE DEFINITION OF REPRODUCTION?

3. DEFINITION OF REPRODUCTION Reproduction is a biological process by which an organism reproduces an offspring that is biologically similar to the organism. Reproduction enables and ensures the continuity of species, generation after generation. It is the main feature of life on earth. Let us have a detailed overview of reproduction, its types and the modes of reproduction in plants and animals.

4. WHAT IS REPRODUCE ? All living things must reproduce. Reproduction involves the transfer of genetic material from parent to offspring. There are 2 types of reproduction. Asexual and Sexual reproduction.

5. Reproduction is fundamental for the continuation of life because it ensures the survival of species over time. Without reproduction, individuals within a species would eventually age and die, leading to the extinction of that species. Reproduction allows organisms to pass on their genetic material to the next generation, maintaining the biological traits and adaptations that have allowed the species to thrive in its environment. IMPOPRTANCE

6. ASEXUAL REPRODUCTION Asexual reproduction refers to the type of reproduction in which only a single organism gives rise to a new individual. Example: hydra, starfish, strawberry plants and onion

7. Hydra Starfish Strawberry Onion

8. Types of Asexual Reproduction

9. Types of Asexual Reproduction 1. Binary fission. This method, in which a cell simply copies its DNA and then splits in two, giving a copy of its DNA to each “daughter cell,” is used by bacteria and archaebacteria. 2. Budding. Some organisms split off a small part of themselves to grow into a new organism. This is practiced by many plants and sea creatures, and some single-celled eukaryotes such as yeast.

10. 3. Vegetative propagation. Much like budding, this process involves a plant growing a new shoot which is capable of becoming a whole new organism. Strawberries are an example of plants that reproduce using “runners,” which grow outward from a parent plant and later become separate, independent plants. 4. Sporogenesis. Sporogenesis is the production of reproductive cells, called spores, which can grow into a new organism. Spores often use similar strategies to those of seeds. But unlike seeds, spores can be created without fertilization by a sexual partner. Spores are also more likely to spread autonomously, such as via wind, than to rely on other organisms such as animal carriers to spread.

11. Advantages of asexual reproduction

12. 1. Rapid population growth . This is especially useful for species whose survival strategy is to reproduce very fast. Many species of bacteria, for example, can completely rebuild a population from just a single mutant individual in a matter of days if most members are wiped out by a virus. 2. No mate is needed to found a new population. This is useful for species whose members may find themselves isolated, such as fungi that grow from wind-blown spores, plants that rely on pollinators for sexual reproduction, and animals inhabiting environments with low population density. 3. Lower resource investment. Asexual reproduction, which can often be accomplished just by having part of the parent organism split off and take on a life of its own, takes fewer resources than nurturing a new baby organism. Many plants and sea creatures, for example, can simply cut a part of themselves off from the parent organism and have that part survive on its own.

13. Disadvantage of asexual reproduction

14. 1. Negative mutations linger longer in asexual organisms. Because the offspring of an asexual organism is essentially a clone of the parent, any negative mutations that are within the genetics of the organism will be passed down to the offspring. This increases the risks of an asexual species to eventually become extinct as most mutations tend to be more negative than positive, especially with the limited evolution that is available to such a species. 2. Diversity is limited. Because only one parent is involved in reproduction with an asexual organism, the diversity within the species is extremely limited. This makes a species more susceptible to various diseases or infections because there is a lack of an ability to adapt or fight off such a problem. Without outside intervention, many asexual organisms would either need to adapt over time to increase genetic diversity or their population numbers would be extremely limited. 4. There can be an inability to adapt. Asexual organisms are not always able to adapt to a changing environment or habitat. This is especially true if there is some sort of predator or disease which can develop the ability to seek and destroy the asexual organism. With its limited evolutionary access, any evolution that targets the organism could destroy the entire species in a short amount of time.

15. SEXUAL REPRODUCTION Sexual reproduction is a biological process in which offspring are produced by the fusion of gametes from two parent organisms, typically a male and a female. This intricate mechanism ensures genetic diversity within a species. Specialized cells, gametes (sperm and egg), unite during fertilization, forming a zygote with a unique genetic combination. This process introdtuces variation and adaptation, enhancing the species' resilience to environmental changes. Sexual reproduction is prevalent among multicellular organisms and is fundamental for the perpetuation of diverse life forms, contributing to the evolution and survival of species over generations.

16. Example: Human and Animal: Sperm and egg combine during fertilization to create offspring. Plants: Many plants reproduce sexually by producing seeds through the fertilization of pollen and eggs in flowers.

17. SEXUAL REPRODUCTION IN ANIMAL Fertilization The semen contains millions of sperm. A single sperm fuses with the ova during fertilization. The nuclei of the egg and the sperm fuse together to form a single nucleus. Thus, a zygote is formed.

18. The fertilization that takes place inside the body of the female is known as internal fertilization. For eg., humans, cows, dogs, etc. This method is more prevalent in terrestrial animals. However, some aquatic animals also adopt this method. This may take place by direct introduction of sperms by the male in the female reproductive tract, or the male deposits the sperms in the environment which is picked up by the female in her reproductive tract. Internal Fertilization

19. There are three ways by which offspring are produced by internal fertilization: Oviparity – The fertilized eggs are laid outside, where they receive nourishment from the yolk. Ovoviviparity – The fertilized eggs are retained in the female’s body where they receive nourishment from the yolk. The eggs are laid right before they are hatched. Viviparity – The offspring are born directly instead of hatching from the eggs. They receive nutrition from the mother. This can be seen in mammals.

20. The fertilization that takes place outside the female is called external fertilization. For eg., frogs, and fish. Most fertilization takes place during the process of spawning. Environmental signals such as water temperature trigger spawning. EXTERNAL FERTILIZATION

21. A life cycle is the stages animals go through from birth to death. The word cycle means circle, and it is called a life cycle because it repeats over and over. Life Cycle Life Cycle of Turtle The number of stages and the length of the life cycle depends on the species or type of animal, and every animal in the same species goes through the same stages. For example, a monarch butterfly has four stages in its life cycle and only lives for a few weeks. But an elephant’s life cycle has three stages and lasts up to 70 years.

22. Advantages of Sexual Reproduction

23. 1. It creates genetic diversity within a species. In asexual reproduction, a direct copy, a clone, is produced. This allows for reproduction to occur without a mate, but it also increases the chances of a mutation developing within the species. Should the wrong mutation occur, the entire species could eventually be wiped out. 2. There is a natural level of disease resistance throughout the species. A greater level of genetic diversity allows for higher levels of natural disease resistance within a species. That is because the bacteria, parasites, and viruses which may affect the health of a species are unable to adapt to one specific genetic profile. There will always be disease, but genome diversity allows for the immune systems of people, plants, and animals to fight off the intrusions so a healthy life can be maintained. 3. It improves health. In humans, practicing sexual reproduction is directly linked to better health. Men who have sex 1-2 times per week, for example, have a lower risk of developing heart disease compared to men who have sex 1-2 times per month or less. At the same time, sexual activity can lower blood pressure and reduce the influence of cortisol, a stress hormone, on the body.

24. Disadvantages of Sexual Reproduction

25. 1. It takes time and energy to find a mate and reproduce. In sexual reproduction, the two genders must find each other to be able to reproduce. It takes time and energy to locate a suitable mate with the preferred traits that are desired so that the offspring produced by the union can thrive. For some species, the process of mating is an all-encompassing task that requires a sole focus on the reproductive cycle until it is completed. 2. Reproduction through sexual means is uncertain. Sexual reproduction is not a 100% successful method of creating offspring. Some chosen mates may be infertile. Others may not have the gametes come together, despite numerous attempts at creating offspring. Although there are diversity advantages that come through this method of reproduction, it is an uncertain method. If population numbers are low for a species, it is possible for it to become extinct despite efforts at sexual reproduction because a zygote is unable to form. 3. Fewer offspring are typically produced. Sexual reproduction can produce numerous offspring at one time. Humans may typically have one child through reproduction, but twins, triplets, and larger multiples are possible. Horses may typically have one foal, but cats and dogs may have more than a dozen in a litter. Compared to asexual reproduction, however, there are usually fewer offspring produced over time. With asexual reproduction, whenever an offspring is required, it can be produced. The same is not always true by using sexual reproduction.

26. Interactive Activity: Use a T-chart or Venn diagram to compare the advantages and disadvantages of both types of reproduction.

27. RESPETOOO RESPETOOO RESPETOOO

28. Identify the following characteristics if it is Sexual or Asexual Reproduction Asexual 1. Binary fission 2. It takes longer time to reproduce. 3. Fertilization is needed to form new organism. 4. It does not involve gametes. 5. has a rapid reproduction. 6. The offspring are identical to the parent. 7. It has 2 parents. 8. It has slow reproduction 9. The offspring show genetic variation. 10. Natural Vegetative Propagation

29. ANY QUESTION?