1. Prologue
  2. Reproduction: Two Types
    1. Asexual reproduction: Subtypes
    2. Sexual reproduction in plants
      1. Pollinating Agents: Two Types
      2. Pollination: Two types
      3. Fruits: Types of
    3. Sexual reproduction in Animals
  3. Family planning Methods Classification
    1. Current Affairs: Injectable contraceptives
    2. Current Affairs: Three Parent Baby
    3. Twin Babies- Theory
    4. Cloning- Theory
    5. Surrogacy: theory

Prologue

  •  “Reproduction” related Current affairs topics in news 1) injectable contraceptive 2) three parent baby.
  • And since UPSC combined the preliminary exam of both civil services and forest services- agriculture / plant reproduction related things also need to be prepared.
  • इसलिए भगवान का नञऎ लेके let’s take a look at both theory and current of “reproduction”.

Reproduction: Two Types

Asexual Sexual
Faster Slower, because gestation period involved
  • Only one sex involved
  • Baby identical to single parent. They’re “clones” of parent.
  • Two sexes (male-female)
  • Baby’s genetic material contains of both parents’ DNA.
Plants and lower organisms can do it. Plants and higher organisms do it.

Asexual reproduction: Subtypes

Fission
  1. Binary fission:  One parent divides into two babies e.g. Amoeba, Leishmania (Kala Azar).
  2. multiple fission: parent makes a cyst cover, divides internally into multiple daughters, then cyst breaks and daughters liberated. e.g. Plasmodium and other protozoans.
Budding bulb-like projection or outgrowth arises from the parent body and makes new baby. Eg. Hydra, yeast, bryophyllum.
Regeneration or Fragmentation an individual breaks up into two or more parts and each part develops into a complete individual. Examples: Spirogyra, Planaria.
Spore formation Protoplast of the cell divides to form 4–8 spores/ zoospores. E.g. Fungi, Chlamydomonas, Moss, fern, rhizopus.
Vegetative propagation
or reproduction		 any vegetative part of the plant body like leaf, stem or root develops into a complete new plant.  This can happen either naturally or artificially:

  1. Naturally: bulbs of onion and tulip, rhizomes of ginger, corms of gladiolus and Colocasia, and tubers of potato, leaves of bryophyllum, bigonia; runners of grass, suckers of mint and Chrysanthemum.
  2. Artificially: by grafting, layering, cutting and tissue culture.
    1. Grafting: root (stock) of one plant combined with shoot (scion) of another plant to product superior variety e.g. mango, apples, roses, rubber and citrus
    2. Layering: roots develop on a stem while it is still attached to the parent plant e.g. black raspberries, jasmine, Magnolia,etc
    3. Cutting: stem cuttings planted in soil e.g.  rose, sugarcane.
    4. Tissue culture: a small piece of tissue is cut from a plant and is transferred to a container with nutrient medium. Then callus->plantlets->put them into soil. e.g. Orchids, Chrysanthemum, Asparagus

Q. What are the characteristics of vegetative propagation?

  1. All plants produced are genetically similar to the parent plant to have all its characteristics
  2. It’s possible to replicate plants that have lost capacity to product seeds e.g. banana, orange, rose and jasmine.
  3. Such reproduced plants bear fruits and flowers faster than the ‘naturally’ cross-pollinated plants.
  4. All of above.

Sexual reproduction in plants

Pollen

  • Spherical. Produced in male part of flower, and sent to female part.
  • Considered to increase performance of athletes and race horses. Hence pollent tablets used as “food supplements” in first world.
  • Can cause allergy. e.g. carrot grass (Parthenium) in imported wheat. [given in class-12 NCERT, hence needs to be remembered]

Pollinating Agents: Two Types

Abiotic
  • Water. For lower plants such as Algae, bryophyts and pteridophytes.
  • Wind e.g. corn cobs, water-lily whose flower comes out of water.
  • Wind and water pollinated flowers are not very colorful and don’t have sweet fragrance.
Biotic
  • Animals e.g. bees, butterfly, wasp, moth, birds, bats, beetles, Lizards (reptiles), lemur (primate), rodents.
  • These flowers usually have bright colors, nutritious nectar and sweet/bitter fragrance to attract insects.

Pollination: Two types

Self-pollination /
autogamy
  • In bisexual flowers, same flower has both male and female organs. e.g. pea, mustard, pistil, rose, petunia, hibiscus.
  • Hence reproduction happens within same plant.
Cross pollination /
allogamy
  • In unisexual flowers: corn, papaya, cucumber, watermelon.
  • Here pollen lands on flower of another flower in same plant or different plant.

In either method: male + female fusion -> fertilization -> Zygote -> endosperm->embryo-> mature ovary-> fruit -> seed.

Fruits: Types of

False fruit They are born from parts other than ovaries. E.g. Apple, strawberry, cashew, jackfruit, pineapple.
True fruit They are born only from ovaries. Mango, Maize, Grape
Parthenocarpic fruit Fruits develop without fertilization e.g. Banana, seedless grape-orange-watermelons. This is done via growth hormones and the resultant fruit is seedless.

Seed dispersing agents

Seed is the final product of sexual reproduction in angiosperms.

Wind Drumstick, maple, aak (Madar), sunflower. Their seeds get blown by wind to faraway places
Water Coconuts because they’ve floating ability.
Animals Xanthium and Urena: they’ve hooks that attach to fur of sheep / goat.

Q. Seed dispersal helps the plants to

  1. prevent overcrowding
  2. avoid competition for sunlight, water and minerals
  3. invade new habitats.
  4. All of above

Sexual reproduction in Animals

just a quick revision from NCERTs
In vitro fertilization
  • Fertilization happens outside female body. e.g. test-tube babies.
Internal fertilization  / in-vivo
  • Takes place inside female body e.g. human, dogs.
  • Surrogacy: fertilization of Amir, Kiran’s baby happens inside third female.
  • Artificial insemination.
External fertilization
  • Fertilization happens outside female body e.g. jelly of eggs in water -> male lays sperms. e.g. frog, fish, starfish.
Viviparous
  • They give birth to live baby e.g. mammals.
  • Changes in height, voice, reproductive organs is called “puberty“
Oviparous
  • They lay eggs. e.g. hen
  • egg-> larva-> adult frog / moth: this  process is called “metamorphosis“

Family planning Methods Classification

just a quick revision from NIOS
Preventive
methods
  • methods prevent the fusion of the egg and the sperm.
  • Vasectomy in males
  • Tubectomy in females. This is the most prevalent preventive method in India, as rural husbands force their wives to undergo it.
Contraception
methods		 Methods prevent of fertilization and conception. Three types

  • Natural : rhythm method (avoiding copulation when ovum available) ; coitus interruption
  • Mechanical: condom for males; diaphragm and Intra uterine device (IUD), cervical caps, vaults for females. In IUD- copper is used to stop mobility of sperms inside female.
  • Chemical: Spermicide jellies, Oral contraceptive pill (contain progesterone, estrogen or both), emergency contraceptive pill / morning after pill, and injectable contraceptives (contain progesterone).
Corrective
methods		 If preventive or contraceptive method not used or fails, then fetus destroyed using these methods. Also known as Medical Termination of Pregnancy (MTP)

  • Abortion:  using hormone pills.
  • Aspiration: using vacuum pump / surgery.

Current Affairs: Injectable contraceptives

  • Injection of Deoxymedroxy progesterone acetate (DMPA).
  • Given to the arm or buttock muscle every 3 months.
  • It blocks Luteinizing Hormone (LH) –> hence Ovulation doesn’t take place -> egg doesn’t goto ovary -> sperm and egg can’t meet.
  • Why in News? Health ministry told parliament that it’ll be given free to Government hospitals and primary health centres (PHC)

Q. Injectable contraceptive contains ___ hormone?

  1. Luteinizing hormone
  2. Estrogen
  3. Progesterone
  4. None of the above

Current Affairs: Three Parent Baby

Old topic from 2013-14. But again in NEWs because one such baby born in Q3-2016.
Background: Mitochondria

  • Mitochondria crucial to the energy supply of cells.
  • Defective Mitochondria will disrupt energy supply to muscles, heart, liver and brain.
  • In Britain alone, around one in 6,500 children is born annually with a severe mitochondrial disease like muscular dystrophy.
  • Mitochondrial diseases are incurable.
  • Current methods can only reduce but not eliminate the risk; no treatment is available either.

Solution: mitochondrial transfer/ 3-Parent IVF
3 Parent Baby

Mom gives egg but her DNA material has defective genes for Mitochondria. So that part related to Mitochondria is removed.
Dad Sperm
donor (female) gives DNA that has right ‘codes’ for healthy Mitochondria.
  • Thus, with help of genetic material from ^three people, an IVF baby is created. Embryo transferd to mother and baby is born without any disease related to mitochondria.
  • UK government allowed doctor to use this method.

Arguments in favour and against 3-Parent Baby

Favour Against 3-parent baby
  • Mitochondria from a healthy woman donor doesn’t affect the appearance of the baby. It merely prevents baby from getting defective mitochondria related diseases.
  • Thus the donor-lady is not ‘third’ parent.
  • Nature and God designed us to have ‘two-parents’ only.
  • You are ‘playing God’ by making three-parents, and interfering with his creation and hence against the (Christianity) religion.
  • Mitochondria are the power producers of a cell and do not in any way contribute to the traits that make us humans.
  • Hence, any fear that the latest development is a slippery slope that would lead to producing ‘designer babies’ is unfounded.
  • This research will lead to “Designer babies” for example, pick DNA of Sachin for Stamina, DNA of Bacchan for Height, Hrithik Roshan for white skin and thus assemble an embryo like assembling a mobile phone or computer.
  • Then poor people have no chance of becoming athletes or film-heros.
  • The inheritance of donated mitochondria, will stop with the succeeding generation if the baby is male.
  • Designer babies are bad because then society will be divided into two parts: those with superior looks-body thanks to genetically engineering vs. those normally born.
  • Hitler tried to  murder all the Jews, handicapped and gypsies and create the strong Aryan race with pure genes.

Twin Babies- Theory

Happens when either:

  1. One than 1 egg fertilized by more than 1 sperm. OR
  2. After fertilization, ovum divides into two or more cells.
Identical twins When a fertilized egg divides into two independent sets of cells-> two identical embryos products from same egg.
Non-identical or fraternal twins When two eggs are produced at the same time and a different sperm fertilizes each egg, non-identical or fraternal twins are produced.

Cloning- Theory

  • A clone is a cell or an organism that is produced asexually from an ancestor. (=without sperm meeting egg)
  • A Clone cell genetically identical to its ancestor.
  • Thus the clone of Lennon, produced today, will be genetically the same John Lennon of the 70s.

Dolly Sheep Cloning (Scotland, 1996)

Cloning Dolly Sheep

Polly (Black face) they removed genetic material from her egg-cell. Thus her egg remained only an empty reaction vessel.
Molly (White face) they took cells from her udder, extracted genetic material out of it, and planted in Dolly’s empty egg cell. Thus an embrayo created.
Holly they planted above embryo in Holly’s womb. Thus holly served as a surrogate mother.

Result: Dolly sheep was born. White faced, inherited the genes from Molly only. The only male DNA of Dolly came from Molly’s father’s DNA contained in her somatic cells.

  • A Man does not live by body alone. What goes into the brain is interaction with the external world. Culture is not coded in our DNA. Experience, education, environment — all these matter.
  • If Cloned Mohandas Gandhi isn’t thrown out of a train going to Pretoria (or face similar racial discrimination), he may not become “Mahatma”.
  • Cloned John Lennon will not be an equally good singer-musician like original John Lennon, Cloned Adolph Hitler will not be a mass-murderer, IF they don’t live through similar circumstances like their “fathers”.

Surrogacy: theory

  • Husband has healthy sperms and Wife has healthy eggs
  • but Wife cannot carry a baby to its full term. For example, Aamir Khan’s wife Kiran Rao suffered a miscarriage earlier and had uterine medical problems so the couple opted for surrogacy.
  • In surrogacy: Wife’s egg is fertilized with husband’s sperm through in-vitro fertilization (IVF) and an embryo is created. (In Vitro=outside body. In-vivo=inside body.)
  • This embryo is implanted in the womb of a “surrogate mother”, she will carry It for nine months and deliver the baby.
  • Baby thus produced, will have genetic make-up of the husband and wife (and not that of surrogate mother.)
  • Ethical Merits and demerits are given here