Reproduction Class 10th One-Shot PDF

Class 10th One -Shot series HOW DO ORGANISMS REPRODUCE? BIOLOGY  Topics to be covered Reproduction Asexual reproduction Fission, Budding, Regeneration and Fragmentation, Spore Formation, Vegetative Propagation, Tissue Culture Sexual Reproduction in Flowering...

Class 10th One -Shot series HOW DO ORGANISMS REPRODUCE? BIOLOGY  Topics to be covered Reproduction Asexual reproduction Fission, Budding, Regeneration and Fragmentation, Spore Formation, Vegetative Propagation, Tissue Culture Sexual Reproduction in Flowering Plants Human Reproduction Puberty Reproductive Health Sexually Transmitted Diseases  REPRODUCTION.Reproduction is the biological process by which an organism reproduces a new individuals of the same kind.  Advantages of Reproduction Reproduction ensures continuity of a particular species on earth. It creates genetic variation which leads to stability of a species. It helps in evolution of a species.  Topic : Key Terms DNA - a group of molecules that is responsible for carrying and transmitting the hereditary materials or the genetic instructions from parents to offsprings. Chromatin - a genetic material or a macromolecule comprising DNA, RNA, and associated proteins, which constitute chromosomes in the nucleus of a eukaryotic cell. Chromosomes - a DNA molecule that consists of a part or all of the genetic material of an organism Genes - the fundamental unit of heredity.  A basic event in reproduction is the creation of a DNA copy. DNA copying is accompanied by the creation of an additional cellular apparatus.  Variations Variations are the differences present between the individuals of the same species or different species. All sexually reproducing organisms show variations.  Variations Some variations are Non - useful.  Variations Some variations are Useful.  Importance of Variation Variation help organisms to adapt in the changing environment. Variation provides stability to a species and thereby helps in evolution.  Fission Unicellular organisms such as protozoans (Amoeba, Paramecium, Euglena, Plasmodium) reproduce by this mode of asexual reproduction. In fission, parent body divides into two or more daughter cells and each one then grows into an adult organism.  Types of Fission Binary FIssion: Binary fission involves the division of parent into two small, nearly equal sized daughter individuals. During binary fission nuclear division takes place first, followed by the division of cytoplasm into two parts producing two daughter organisms. Binary fission occurs in unicellular protozoans like Amoeba, Paramecium, Euglena, etc Amoeba Paramecium Euglena Types of Binary Fission:  Types of Fission Multiple Fission: Multiple fission involves the division of parent into many small daughter individuals. Nucleus divides several times many daughter nuclei, without the division of cytoplasm. Example: Plasmodium. When the conditions become unfavourable, a tough coat called cyst is formed around the cell. On return of favourable conditions, the cyst wall is broken and many daughter cells are released.  Difference Between Binary and Multiple Fission Binary Fission Multiple fission 1. One nucleus divides into two 1. A single nucleus directly divides into nuclei. multiple parts. 2. It occurs under normal conditions. 2. It takes place only in unfavorable conditions like the formation of internal cysts. 3. The division of cytoplasm forms two 3. The division of cytoplasm directly forms individuals. multiple individuals. 4. Cytoplasm divides only after one 4. Cytoplasm can divide only after multiple karyokinesis or nuclear divisions. karyokinesis or nuclear divisions. 5. Example: Amoeba. 5. Example: Plasmodium.  Budding Formation of a daughter individual from a small projection, the bud, arising on the parent body is called budding. For Example: Unicellular (Yeast, Bacteria) multicellular (Flatworms, Jellyfish, Sea anemone, Hydra)  Fragmentation Some organisms like Spirogyra upon maturation break into smaller pieces. These pieces or fragments grow into new individuals. For Example: Hydra, Spirogyra Spirogyra breaks into many pieces and each piece grows into a complete filament. This process is known as fragmentation.  Regeneration A number of animals have power to grow the lost organs of their body. This ability of organisms to replace their lost parts by growth is known as regeneration, e.g., in starfish, spiders, etc. Small fragments or pieces of their bodies can grow into complete individuals. For example, in Hydra and Planaria. Regeneration in Planaria  Spore Formation (Rhizopus) Different types of asexual spores are produced in these organisms. In many fungi, at the time of spore formation, a swollen structure known as sporangium develops at the top of fungal hypha. These spores are very small, light and variously coloured in different fungi. The spores germinate to give rise to new fungus after falling on a suitable substratum.  Vegetative Propagation New Organisms can grow with the help of propagules (leaves, roots & stem) but not with seeds. Two Types: Natural Vegetative Propagation Artificial Vegetative Propagation  Natural Vegetative Propagation Grown without any human help. New plants grow from leaves, roots & stem of the parent plant. By Underground stem Tubers: Swollen and fleshy Example - Potato Buds (eyes) are present on potato, which grows into new plant.  By Root By Root Plants like sweet potato (Tuberous roots), Dahlia, Tulip have fleshy roots. Roots have buds which detach & give rise to new plants. By Leaves Leaves like Bryophyllum & Kalanchoe produce adventitious buds on the margin of their leaves. The buds fall and develop into plantlets.  Artificial Vegetative Propagation Adopted by human beings. It is a Faster Method. It is used in gardens and nurseries.  Cutting Vegetative Propagation A propagule is cut from the parent plant & put into the soil, which will form new plant. Stem Cutting: Example: Rose, Bougainvillea, Chrysanthemum, Grapes, Sugarcane, Banana, Cactus etc. Root Cutting: Example: Raspberry, Blackberry, Dahlia, Fig, Lilac  Layering Mound Layering Branch with leaves is bent to ground & a part of stem is buried in the soil. A cut is made in parent plant, which grows into new plant.  Grafting Stem of one plant (scion) is cut and attached to the root of another plant(Stock). After some time, the attached stem and root combine to form single plant. Cambium of both scion and stock should be in contact.  Advantages of Vegetative Propagation Quick and cheap method to produce large number of plants. Disease free plants can be produced. Desired characteristics of plants can be introduced. Genetically identical plants can be produced. Survival rate of new plants is almost 100%.  Tissue Culture This tissue is Grown in a suitable nutrient medium. They divide rapidly to form a small group of cells or cell us. The cell us is transferred to another medium containing hormones for growth and differentiation. The plantlets are then placed in the soil so that they can grow into mature plant. This technique is commonly used for ornamental plants. Eg. Banana, egg plant, rose etc.  Sexual Reproduction Involves two different sexes, Male & Female. Each parent produces special sex cells or germ cells (gametes) Fusion of male and female gametes forms Zygote. Zygote then divides repeatedly to form multicellular organisms (by cell differentiation). Significance: Promotes diversity of characteristics. Creates a new combination of variations, which is necessary for evolution. Parts of a Flower Parts of Flower:  Types of Flowers Bisexual Flower Unisexual Flower Both stamen and Either stamen or pistil are present in a pistil is present. same flower  Events in Sexual Reproduction Pre-Fertilization Involves formation of male & female gametes. Pollination Double Fertilization  Pollination Transfer of pollen grains from the anther of the stamen to the stigma of the carpel is called Pollination. Some agents of pollination are Wind, Water, Animals, Insects, etc.  Ex. Peanuts, Wheat, Rice, Apricots, Ex. Maize, Corn, Squash, Broccoli etc Tomatoes etc.  Agents of Pollination Abiotic Biotic Wind and Water. Birds, Insects, Reptiles and Mammals.  Fertilization One pollen tube grows into the stigma and passes through style and then to ovary. Two non-motile male gametes are formed. The tip of pollen tube ruptures releasing two male gametes into the embryo sac. The embryo sac consists of an egg apparatus (one haploid egg cell and two synergids), two polar nuclei & three antipodal cells.  Post Fertilization Development of Endosperm and Embryo. Maturation of ovules into seeds and ovary into fruits  Seed Germination Seed is the final product of Sexual Reproduction. Seed develops into embryo and embryo develops into seedling under favourable conditions. A seed consists of SEED COAT, COTYLEDON & an EMBRYO AXIS.  Human Reproduction Gametes Fertilization The Zygote  Human Reproduction Germ Cells These are special cells which are involved in Reproduction. Produces gametes - Male cell / sperm produces male gamete - female cell / egg produces female gamete  Human Reproduction PUBERTY Puberty is the time period or stage of human develop during which an individual show growth and becomes mature.  Human Reproduction Male Reproductive System ❖ Testes Testes are primary male reproductive organs. They lie in small sac like muscular structure outside the abdominal cavity called scrotum. Testes form sperms throughout the reproductive life. ❖ Scrotum contains the testicles  Human Reproduction ❖ Epididymis It receives sperms from testes and store them temporarily till ejaculation. ❖ Seminal Vesicle, Prostate Gland Secretions of these glands protect sperms from acidity of male urethra and female reproductive tracts. Secretions also increase sperm motility. Secretions of these various glands and sperms collectively form semen.  Human Reproduction ❖ Vas Deferens (sperm duct) Works in transporting sperm to the urethra ❖ Bladder Stores urine ❖ Urethra Conveys sperm and urine to the penis where they are discharged. ❖ Penis Deposits sperm inside the vagina; furthermore disposes of urine  Human Reproduction Female Reproductive System ❖ Ovary Ovaries are the primary sex organs of a female. Each ovary performs a dual function of 1) Production of female gamete (ovum or egg) 2) Secretion of female sex hormones (estrogen and progesterone). ❖ Ovulation Release of ovum from ovary.  Human Reproduction ❖ Fallopian Tubes (oviducts) Channels the egg down to the uterus. Fertilization happens here. It also provides site for fusion of ovum and sperm. They receive eggs, released from the ovary. ❖ Uterus Ensures and supports the creating child. The uterus is lined by endometrium.  Human Reproduction ❖ Cervix Ring of muscles that is nearby the lower end of the uterus. ❖ Vagina Gathers sperm deposited by the penis, act as birth channel for a child  Fertilization After copulation, millions of sperms are released during ejaculation. Sperms swim to towards female egg, with the help of tail. Only sperm will fertilize the egg. The fertilized egg will move towards the uterus. Zygote forms foetus and Foetus changes to embryo. Implantation Attachment of growing embryo to endometrium of uterus Formation of Foetus from Zygote  How does growing embryo/foetus get nutrition? The embryo grows inside the mother's womb and gets nourishment from mother's blood through the tissue called placenta. Villi on placenta (embryo side) provides a large surface area for : glucose and oxygen to pass from the mother to the developing embryo wastes to pass from the embryo tr mother through the placenta. What happens if Fertilisation doesn’t occur? Q. What happens when the egg is not fertilised? Menstruation occurs. MENSTRUATION: Since the ovary releases one egg every month , the uterus also prepares itself every month to receive a fertilised egg. Thus, its lining becomes thick and spongy. If egg is not fertilised , it lives for about one day. Now however, this lining is not needed any longer. So, the lining slowly breaks and comes out through the vagina as blood and mucous. This cycle takes place roughly every month and is known as menstruation. It usually lasts for about two to eight days. What happens when Egg is not fertilised? Female Ovary Produces egg (ovum) once a month Uterus wall becomes thick Fertilised by Sperm Not Fertilised by sperm Egg+ uterus wall + blood vessels shed Pregnancy Cause bleeding in females called menstruation 50+ years 12-50 years Menopause Menstruation 11-12 years Menarche Menstrual Hormones  Difference between Zygote and Foetus Zygote Foetus It is fertilized egg formed after It is a state of the embryo that the fusion of the sperm with shows all the main the egg. recognizable body parts of a mature organism. The zygote divides several times to form an embryo. An embryo gradually develops into a foetus.  Reproductive Health Reproductive health is a condition of overall physical, mental and social prosperity, and not just the nonattendance of reproductive disease or ailment. It covers two probable aspects as follows: Population Explosion and Birth control measures. Sexually Transmitted Diseases and Treating Infertility.  CONTRACEPTION Methods or techniques adopted to prevent pregnancy as a consequence of sexual intercourse. Types of Contraceptive Methods : 1. Mechanical/ Barrier Methods 2. Chemical Methods 3. IUCD 4. Surgical Methods  MECHANICAL /BARRIER METHOD 1. Physical devices like condoms (for males & females) and diaphragms (for females) are examples of this method. 2. These work by preventing the meeting of sperm and ovum. 3. Barrier methods prevent the transmission of Sexually Transmitted Diseases by preventing the intermixing of body fluids.  CHEMICAL METHOD 1. These include oral pills and vaginal pills 2. These pills contain certain hormones which works in the following ways: prevent the production of ovum kill sperm cells prevent implantation 3. These methods have certain side-effects 4. It cannot prevent transmission of STDs  SURGICAL METHOD VASECTOMY: In vasectomy, vas deferens is cut and the ends joined TUBECTOMY: In tubectomy, the fallopian tube is cut and the two ends are sealed INTRAUTERINE CONTRACEPTIVE DEVICES (IUCDs)  Sexually Transmitted Diseases and Treating Infertility or Reproductive Tract Infections (RTI) or Venereal Diseases (VD) Sexually transmitted diseases are infections or diseases transmitted to healthy females or males because of sex with contaminated people. Most basic STDs are Gonorrhoea, Syphilis, Genital herpes, Chlamydiosis, Genital warts, Trichomoniasis, Hepatitis-B and AIDs. Sexually Transmitted Diseases Bacterial infections Viral infections Gonorrhoea: AIDS (Acquired Immunodeficiency Inflammation of the mucous Syndrome): membrane of urogenital tract, AIDS is caused by HIV virus. It is rectum, victim feels burning fast spreading incurable disease, sensation and pain during which weakens the body’s immune urination. system. Syphilis : Warts : Is caused by bacterium, which A small bump on the genitals affects the mucous membrane of caused by a common sexually genital, rectal area. transmitted infection. THANK YOU.