Reproduction, Variation and Heredity

Reproduction Introduction

• Reproduction is a process where an organism produces a new, similar individual.
• The new individual should belong to the same species as the parent organism
• Reproduction isn't essential for an individual's survival, but it's crucial for the species' continuation.
• Teachers should openly educate about sex and reproduction to address societal misconceptions.
• Reproduction ensures the continuation of a species and population stability.
• Lack of reproduction leads to population decline and potential extinction of a species.
• The term "reproduce" means to produce again, highlighting the cyclical nature of creating offspring.

Variation

• Variation refers to the differences among individuals within the same species.
• Despite sharing similarities, individuals of the same species aren't 100% identical.

Genetics

• Variations arise from changes in the genetic material (DNA) within cells
• DNA carries the genetic code that determines individual characteristics.
• The characteristics are not ONLY dependent on genetic factors, but environment and culture as well.
• DNA resides in the nucleus, inside chromosomes.
• Chromosomes consist of compacted DNA
• Chromosome are responsible for every attribute in the human body
• Cells create copies of their DNA before dividing
• During DNA copying, errors can occur, leading to variations, even when it was not intended
• DNA errors can alter protein formation, resulting in different traits and physical characteristics.

Importance of Variation

• Variation is essential for species survival and adaptability to changing environments.
• Variations enable some individuals to survive environmental changes, ensuring species stability.
• Global warming example: bacteria copies with different temperature resilience can adapt
• Variation is also a key factor in evolution over long periods
• A singular example: humans evolving from apes
• Variations in genes allow for the diversity of forms in a species.
• It can also result in the formation of new species alongside existing ones

Asexual vs. Sexual Reproduction:

• Asexual Reproduction:
  • Involves a single parent.
  • No gamete formation (no reproductive cells).
  • No fertilization.
  • Offspring are genetically similar.
  • Can be beneficial for uniformity
• Sexual Reproduction:
  • Involves two parents (male and female).
  • Gamete formation occurs (reproductive cells).
  • Fertilization is necessary.
  • Offspring are genetically dissimilar, with variation.
  • Can be better for an evolving enviornment.

Asexual Reproduction Methods:

• Fission, fragmentation, regeneration, budding, spore formation, and vegetative propagation

Fission:

• Involves the division of a cell into two or more new cells.
• Occurs in unicellular organisms like bacteria and protozoa.
• Binary Fission in Amoeba:
  • Amoeba, a unicellular organism, divides into two cells
  • Splitting of cells can occur in any plane.
• Binary Fission in Leishmania:
  • Leishmania, a protozoan, also divides into two cells
  • Division occurs in a fixed longitudinal plane due to its whip-like structure.
• Multiple Fission in Plasmodium:
  • Plasmodium, a protozoan, divides into many cells simultaneously.
  • This process creates a ball-like structure that bursts to release numerous cells
  • This is a method of creating as many duplicates as possible

Fragmentation:

• An organism breaks into smaller pieces, each growing into a new individual upon maturity.
• Example: Spirogyra, a multicellular organism
• Spirogyra breaks itself into multiple fragments, each one becoming it's own organism

Regeneration:

• Some organisms can regenerate lost body parts or create new individuals from fragments.
• Example: Planaria, a flatworm, can regenerate into new individuals when cut into pieces.
• Planaria does not reproduce by its own will, rather forced. Allthough it serves as a method of achieving a similar concept.

Budding:

• An outgrowth (bud) forms on an organism, eventually detaching and growing into a new individual.
• Example: Hydra, an aquatic animal, forms buds on its body from specialized cells
• Bud expands with cells into a new indepedent indvidual

Spore Formation:

• Some organisms reproduce by forming spores, protected by thick walls, that develop into new individuals under favorable conditions.
• Example: Rhizopus, a bread mold fungus, forms spores in a sporangium
• These spore are self-contained and able to transfer elsewhere by air
• These spores are covered by walls that protect them from bad weather
• As condition clear and improve, the walls disintegrate and seed the spores

Vegetative Propagation:

• New plants grow from roots, stems, or leaves.
• No traditional reproduction methods are necessary.

Types of Vegetative Propagation:

• Layering: Bending and burying a plant stem to encourage root formation.
• Grafting: Joining parts of two plants to combine desired traits.

Examples of Vegetative Propagation

• Potato, featuring small buds along the stem of the plant
• Bryophyllum, features a leaf that is able to create plantlets, then grow into individuals.
• Sugarcane, Roses and Grapes feature grafting and layering.

Advantages of Vegetative Propagation:

• Plants like banana don't have or cannot rely on seeds
• Faster growth compared to seed propagation
• Preservation of desired traits
• Genetically similar ofspring

Sexual Reproduction Introduction

• Sexual reproduction involves the fusion of male and female gametes during fertilization
• This process results in offspring with genetic variation, promoting diversity.
• The process involves the production of gametes (sex cells), fertilization, and growth of the zygote.
• Flowchart: Male gametes with an female gametes creates fertilization, creating zygote. It goes through cell divison to create embryo, then matures into fitus, and finally, baby.

Gametes

• Gametes must have half the complete pair from each parent
• Humans have 23 pairs of chromosomes of 46
• The sex cell must have a division to separate the complete chromosomes into half to ensure a correct and complete fetus when fused
• Meiosis is the process of creation of sex cells, that split completely chromosomes.

Sexual Reproduction in Flowering Plants (Angiosperms):

Flower Anatomy:

• Sepals: Form the protective outer layer of a flower bud.
• Petals: Attract pollinators with their color and fragrance.
• Stamen (male part):
  • Anther produces pollen grains containing male gametes.
  • Filament supports the anther.
• Pistil (female part):
  • Stigma receives pollen grains.
  • Style connects the stigma to the ovary.
  • Ovary contains ovules, which house the female gametes.

Process of Fertilization

• Pollen from the ather are transferred by wind, water or animal into sigma
• A tube called the pollen tube stretches into the ovule with the style wall
• As the ovule expands ,the eggs from both sides are inserted, creating an embrion or food.

Changes After Fertilization:

• Zygote develops into an embryo within the ovule.
• Ovule develops a tough coat and gradually turns into a s seed.
• Ovary matures into a fruit

Flower Types

• Unisexual Flowers: Contain either stamens or pistils, not both
• Example: papaya, watermelon.
• Bisexual Flowers: Contain both stamens and pistils.
• Example: hibiscus, mustard.

The three aspects to remember

• Zygote =>Embryo
• Ovule=>Seed,
• The outer layer Ovary=>Fruit

Pollen

• Transfer of pollen from anther to stigma.
• Types:
• Self-Pollination: - Pollen transfer within the same flower or between flowers on the same plant.
• Cross-Pollination: - Pollen transfer from a different flower to another of a different plant.

Germination

• Seed develops to seedlings when ready
• Embryo to form to things:
• plumpule: for fire root
• redicle: for future shoot
• cotyledon: that stores food and stores it with the other contents

Sexual Reproduction in Human Beings:

Introduction

• Involves unique reproductive systems

Sexual Maturation in Body

The phases

• Adolescence: growth into adulthood.
• Puberty:
• This is the decrease of general growth rate to a normal size.
• It involves the development of secondary sexual characteristics.

Typical age ranges

• 10-14 in men
• 12-16 in women

Signs

• Hair at genitals
• Darkening of skin
• thin hair on parts

Signs in Males

• voice deepens
• Penis enlarges
• Body becomes larger in mass
• Facial hair growth

Signs in Females

• start of menstruation
• breast development
• skin darkens

Quick Facts

• All the phases do not occurs at the same time
• It is only seen on others when it is completed
• Males gametes: sperms, females: Eggs
• Sperms developed from testes, eggs in ovaries

Male Reproductive System

• Four parts that matter: scrotum, testes, vans deferens, urethra.

Scrotum

• Supports testes *Maintains low temp. for production -This is necessary, else sperms may die due to lack of

Testes

• Two major purposes: makes sperms, & produce testosterone
• Testotersterone: causes 2ndary traits *Testosterone is needed to make sperms too.

Van Defernes

• carries sperm made by testis to urethra, it hooks to sides from the bladder

Urethra

• common channel for sperm+urine

Semantic Vesicles

• The sperm needs to get transported so this adds fluid for easy shipment -Prostate gland helps out as well

Penis,

• Used for shipment of fluids for impregnation

Sperm

• made with genetic information and a swimmy tail

Female Repro System

• Ovaries, oviducts, uterus, cervix, and vagina

Ovaries

• eggs are created here
• They develop throughout the month

Oviducts/fallopian tubes

• These are what catch the eggs, but where fertilization occurs
• Then sent to the uterus, a fertilized egg just stays in tube.

Uterus

• a holding place for pregnancy

Cervic

• The walls that are there during pregnancy
• Birth pushes it and dialates

Vagin

• The outer channel used for giving birth
• where intercourse begins

Sexual Intro-Course Introduction

A simple process is outlined

The Steps

• Enters from Vag
• Travels and Meets the egg.
• the joined cell gets implanted

The Three areas from the outer circle to the inner

• The outer is zygote becoming embryo
• The middle comes full and becomes good
• the inner is a single seed
• This structure provides new traits to the plant

Placenta

The embryo gets nutrients from an embded tissue on the uterine wall

• This provides a larger space for the embryo
• Villi to also increase contact, which provides access to : nutrient, and helps take the waste.

Other Important Facts

• Releases 1 egg each time.
• The uterine wall prepares itself for a fertilizer to occur

Menstruation Cycle

• The uterus prepares like a house
• This lining gets wasted because of how long its going to last or was there
• And thus menstrual bleeding happens from shedding wall
• Menarche: is in this case called woman who have been menstruating for the first amount of time due to these walls.
• Menopause is when women lose control of these things at an old age losing the ability to give birth.

Reproductive -Health

Introduction

• people engage in s3x just for pleasure and that's ok
• there were those who could engage, some may not engage, and some may not even decide too.

Method 1 physical barriers.

• Physical Barriers
• condoms are the greatest way as they : protect, can be found for free on internet.
• These do have cons as it could leak
• A benefit to avoid s*x if a friend pressure

Method 2 Hormonal

• hormone are to avoid ovulation
• There are pills but not for everyday regular use
• This occurs before or after ovulation.

Method 3-IUD

Intrauterine

• IUDS: this keeps it from fertilizing it.
• Like the Copper-T it keeps sperms from reaching uterus.
• Loop + C can make it so it stays in the uterus forever, however it has problems with long time

Method 4: surgical

• This is a method to control the amount of pregnancy by cutting off the sources, known as sterilization
• Vasectomy cut the vas deferens, so sperms cannot get to the delivery.
• Tubectomy this is a method of not going into the uterus by cutting the fallopian tubes leading to the fallopian tubes not being able to reach