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Inheritance and Reproduction

INHERITANCE

  • Inheritance is the transmission of genetic information from one generation to the next.

  • It leads to the continuity of the species and variation within it.

KEY DEFINITIONS

  • Chromosome: A thread of DNA, made up of genes.

  • Gene: A section of DNA, which codes for the formation of a protein controlling a specific characteristic of the organism.

  • Haploid Nucleus: A nucleus containing a single set of unpaired chromosomes (e.g., in sperm and ova/eggs). In humans, the haploid number is 23.

  • Diploid Nucleus: A nucleus containing pairs of chromosomes (e.g., in somatic/body cells). In humans, the diploid number is 46.

CHROMOSOMES

  • Found in the nucleus of every cell as long threads.

  • Chromosomes are a packaged form of DNA.

  • Usually too thin to be seen except with an electron microscope.

  • During cell division, they get shorter and fatter, becoming visible with a light microscope.

Karyotyping

  • Karyotyping is the process of taking photographs of chromosomes to study their number and identify any abnormalities.

CHROMOSOME PAIRS

  • Chromosomes exist in the nucleus of body cells as identical pairs.

  • The sex chromosomes may be non-identical in males (XY).

  • In females, the sex chromosomes pair is identical (XX).

  • Human cells contain 46 chromosomes, which are in pairs.

  • Sex cells (sperm and ova) contain only 23 chromosomes.

  • During fertilization, a sperm cell unites with an ovum to form a zygote.

  • The zygote has a nucleus with 46 chromosomes.

  • The chromosome number is specific to each species.

GENES

  • Each chromosome contains a large number of genes.

  • Genes code for the formation of different proteins that give us our characteristics.

GENES AND DNA

  • A gene is a certain length of DNA on the chromosomes.

  • Each gene codes for a specific characteristic.

  • Genes for the same character are present on every pair of identical chromosomes.

  • One gene is passed from the mother, and the other from the father.

  • Any one of the genes or a combination of both may be presented in the offspring.

  • Genes bring about variation.

CHROMOSOMES, DNA AND GENES

  • The nucleus of every cell contains threads called chromosomes.

  • Chromosomes were discovered in the nineteenth century when sufficiently powerful microscopes were available.

  • DNA is highly coiled to form chromatin fibers and is stored inside the chromosome.

CHROMOSOMES - SIGNIFICANCE

  • Humans have 23 pairs of chromosomes.

  • The 23rd pair (sex chromosomes) determines male (XY) or female (XX).

DIPLOID & HAPLOID

  • Diploid cells (2n) have 46 chromosomes (e.g., skin cells, brain cells, liver cells).

  • Haploid cells (n) have 23 chromosomes (e.g., sperm, ovum).

CHROMOSOME NUMBER

  • Different species have different numbers of chromosomes in their cell nuclei.

  • Human cells have 46 chromosomes.

  • Fruit fly cells have eight chromosomes.

  • Mango trees have 40 chromosomes.

Karyotyping - Chromosome Analysis

  • Pairing and arrangement of all the chromosomes according to their size.

  • Each chromosome looks like a cross shape; just before cell division, each chromosome makes a copy of itself.

GENES - FUNCTION

  • Each chromosome is made up of hundreds of different genes.

  • Genes are arranged in a particular sequence along the chromosome.

  • Each gene controls a particular characteristic in the organism.

  • Scientists are continually learning more about what each gene does.

  • For example, two genes on chromosome 15 help determine eye color.

  • Everyone has genes for eye color in the same place on their chromosome 15s.

Human Genome Project (HGP)

  • Recent strides in genetics have been made through the Human Genome Project.

DNA

  • Chromosomes are made of a chemical substance called DNA.

  • Each chromosome is one enormously long molecule of DNA.

  • Genes are also made of DNA deoxyribonucleic acid.

DNA Structure

  • A DNA molecule has a shape like a twisted ladder, called a double helix.

  • One gene could be a length of DNA with about 2500 of these twists.

  • DNA carries and transmits hereditary materials or genetic instructions from parents to offspring.

DNA - Functions

  • DNA is responsible for the inheritance of genetic information in all living beings.

  • DNA also plays a crucial role in the production of proteins.

  • Nuclear DNA is contained within the nucleus of every cell in a eukaryotic organism.

  • DNA is also found in chloroplasts and mitochondria.

VARIATION

  • Organisms that belong to different species usually look very different from one another (e.g., horses vs. donkeys, lions vs. tigers).

  • Individual organisms that belong to the same species also have differences between them.

  • "Variation" refers to differences in characteristics of individuals within a species.

FACTORS THAT INFLUENCE VARIATION

  • Genetics

  • Environment

  • Random mixing of genes

  • Errors in DNA copying

Ways to Measure Variation

  • Study a species of plant with different flower colors.

  • Count the number of plants with each flower color in a small area.

  • Represent the information pictorially using a bar chart.

DNA and Variation

  • Different sperm cells and egg cells contain different versions of genes.

  • They will also contain different versions of other genes – for example, for height, or coat color, or tail shape based on the organism.

  • Each gene is different because its DNA is different.

  • Differences in the DNA of organisms within a species are called genetic differences.

  • ‘Genetic’ means ‘to do with genes’.

  • Alleles: One of two or more possible forms of a gene that are found at the same place on a chromosome.

Types of Variations

  • Germinal variation: Inheritable variations as they occur in the germ cells/gametic cells.

  • Continuous variation: A variation in characteristic that changes gradually among the individuals of a population.

  • Discontinuous variation: Sudden changes in the characteristics due to an error in DNA copying (mutation) in the individuals of a population.

Continuous Variation

  • Differences in height, weight, or milk yield of cows are examples of continuous variation.

Discontinuous Variation

  • Lobeless or lobed ears and the presence of an extra finger are examples of discontinuous variation.

Environment and Variation

  • DNA is not the only cause of variation between individuals; an organism’s environment also affects it.

  • Coat color may be genetic.

  • The size of the goat could also be affected by its DNA, but its environment will also affect size.

Somatic Variation

  • Loss of weight

  • Losing or gaining weight doesn't make changes in germ cells/gametes.

Embryo to Baby

  • After fertilization, the zygote moves slowly down the oviduct.

  • As it moves towards the uterus, it divides many times.

  • It takes several hours for the embryo to reach the uterus, and by the time it reaches the uterus it is a ball of 16 or 32 cells

  • The uterus has a thin, spongy lining, and the embryo sinks into it (implantation).

Placenta and the Umbilical Cord

  • Some cells of an embryo form an organ called the placenta.

  • The embryo is linked to the placenta by the umbilical cord.

  • The growth of the fetus requires a good supply of nutrients (glucose, proteins, fats, vitamins, minerals) and O_2 achieved through the link between the placenta and the mother’s blood supply in the uterus lining.

  • The placenta prevents the mixing of maternal and fetal blood to avoid blood clotting.

Umbilical Cord

  • The umbilical cord connects the placenta to the fetus, transporting nutrients (glucose, proteins, fats, vitamins, minerals ) and oxygen towards the fetus from the placenta.

  • It also transports waste products and carbon dioxide from the fetus to the placenta.

Amniotic Sac and Amniotic Fluid

  • The fetus is surrounded by a strong membrane called the amnion.

  • The amnion protects the fetus.

  • Inside the amnion is a liquid called amniotic fluid.

  • Amniotic fluid protects the fetus from mechanical damage and acts like a shock absorber and maintains a constant temperature around the fetus.

Gestation Period

  • Gestation period (pregnancy) is the time period between fertilization and birth.

  • The total gestation period in humans is 40 weeks (9 months, 9 days).

  • The growth and development of the fetus occur in the uterus of the mother.

  • The gestation period is divided into 3 trimesters (each trimester of 3 months).

  • The study of growth of an embryo is called embryology.

  • Doctors who specialize in looking after maternal health and conducting deliveries are called obstetricians.

Foetal Development

  • 6 weeks: Embryo is about 4 mm long (poppy sized).

  • 8 weeks: Embryo is about 13 mm long (pea sized).

  • 11 weeks: The body organs have developed (about 5 cm size).

  • 12 – 36 weeks: Fetus grows steadily, and organs develop during this period.

  • 36 – 40 weeks: The baby is fully developed and ready to be born.

Process of Birth Stage 1

  • Labour is triggered by the hormone oxytocin.

  • The muscular walls of the uterus start to contract.

  • The pressure causes the amniotic sac to break.

  • Contractions become more frequent, pushing the baby down towards the cervix.

  • The cervix becomes dilated to allow the baby to pass.

  • The vagina stretches for the passage of the baby.

Process of Birth Stage 2

  • The baby is still attached to the placenta by the umbilical cord.

  • The placenta breaks away from the uterine wall and passes out.

  • The umbilical cord is cut and tied.

Reproduction in Humans - Gametes

  • Sexual reproduction in humans occurs by the fusion of specialized reproductive cells from the male and female; these are called sex cells or gametes.

Variation

  • The differences in characteristics within a species.

  • Variation in Sexual Reproduction is promoted by the random mixing of alleles.

Sexual Reproduction

  • “Sexual reproduction in humans occurs by fusion of specialised reproductive cells from male and female, these are called sex cells or gametes.”

  • Egg (Female gamete).

  • Sperm (Male gamete).

Main Parts Female Reproductive System

  • A pair of ovaries.

  • A pair of fallopian tubes/oviducts.

  • Accessory organs such as the uterus.

  • The main reproductive organ in a female is a pair of ovaries that produce eggs or ova, and female sex hormones called estrogen and progesterone.

FEMALE REPRODUCTIVE SYSTEM - PARTS Detailed

  • Fallopian tube: Tiny tubes connecting the ovaries to the uterus that transport eggs for possible fertilization.

  • Ovary: Small organs producing eggs and hormones. Eggs may combine with sperm for conception.

  • Uterus: Muscular organ nurturing a developing baby during pregnancy. If no pregnancy occurs, its lining is shed in the menstrual cycle.

GAMETES SIZES

  • Egg Cell: Very small and invisible to the naked eyes. Largest human cell, About 0.05mm in size.

  • Sperm: 30 times smaller than egg. Millions are released at a time.

  • Sperm is motile compared to static egg.

Fallopian Tube

  • Transports the egg from the ovary for fusion.

  • Transports the fused egg to the uterus.

Human Reproduction

  • Humans reproduce sexually.

  • The male produces sperm, and the female produces eggs.

  • When the sperm fuses with the egg, it forms a zygote that gives rise to a new progeny.

Fertilisation

  • Development of Offspring is detailed below:

  • Zygote 1 –3 Weeks

  • Embryo 4 –8 Weeks

  • Foetus 9 –38 Weeks

Human Reproduction Processes

  • Ovulation: The release of the ovum/egg from the ovary

  • Fertilisation: The fusion of the male and female gamete to form the zygote

  • Implantation: The attachment of the embryo to the uterus lining to derive nutrition

Sex Determination

  • Father (XY)

  • Mother (XX)

  • Sperm (X or Y)

  • Ovum (X)

  • Girl (XX)

  • Boy (XY)

Keeping a Fetus Healthy Requires

  • Highly nutritive balanced diet to support growth and development.

Diet During Pregnancy

  • Protein is needed to help the fetus to produce new cells and grow

  • Carbohydrate supplies energy where glucose is combined with oxygen, in respiration to fuel those cells created by the protein

  • Vitamins and minerals are very important. Iron is needed to make hemoglobin

  • Smoking cigarettes is linked to reducing development of feotus Carbon monoxide in the blood reduces the amount of oxygen that hemoglobin can transport.

  • This means that the fetus’s cells get less oxygen, so they cannot respire as much and they cannot release as much energy as they normally would and babies born to mothers who smoked during pregnancy tend to be smaller than babies born to non-smoking mothers.

  • DRUGS ARE HARMFUL FOR HEALTH!

Defining Drugs & Drug Abuse

  • A drug is something that is taken into the body, and that affects the way the body works.

  • Some drugs are good for health where Antibiotics are drugs that kill bacteria in the body.

  • They are used to cure the infections caused by bacteria.

  • Antibiotics are an example of a medicinal drug.

Dangers of Drugs

  • Drugs are addictive in nature and are very difficult to give up if addiction develops

  • Drug abuse leads to depression!

Reproduction in Plants

  • Reproduction is the process in which organisms produce young ones of their own kind

Characteristics of Living Organisms

  • Reproduction, Response to stimuli, Nutrition, Excretion, Growth, Respiration

Reproduction Types

  • Asexual Reproduction: Budding, Fragmentation, Spore formation, Vegetative propagation

  • Sexual Reproduction: Fertilisation between Male and Female gamete

Asexual reproduction

  • Asexual reproduction is the process used to produce genetically identical offspring from one parent.

Process Examples Asexual

  • Budding: Hydra initiates bud, maturate, develop tentacle until detaching

  • Binary Fission: Amoeba prepares for division, separate nucleus, separate cytoplam as daughter cells take form

  • Spore Formation: Rhizopus forms sores, release spores, that grow in young mold after release.

  • Fragmentation: Spirogyra breaks into Fragments each become an individual

  • Regeneration: Planaria regenerates lost removed parts to be made into a new organism

Sexual Reproduction

  • Sexual Reproduction is the process used to produce genetically different organisms offspring from two parent. It involves cells called gametes.

Reproduction in A Wild Population

  • Asexual: Lots of offspring can be produced very quickly, less energy needed. However theres no genetic variation making adaptation hard which causes overpopulation.

  • Sexual: High genetic variation makes survival more likely, diversity leads organisms to become better adapted. However it takes more time and energy requiring two parents may be needed which can be hard if mates are rare

Reproduction in Crop Production:

  • Asexual: Offspring are genetically identical so you can make a consistent product with the same features and Youcan produce plants using cuttings which is faster and more susceptible to crop diseases

  • Sexual: Humans use selective breeding to improve crop production and quality but it longer

Parts of plants

  • Leaf, Stem, Roots, Fruit , Flower

Vegative Parts of a Plant

  • Vegetative, Fruit,Leaft,Stem,Root,Sexual. Parts,Flower

Parts of Flower

  • Stigma,Stamen,Anther,Filament,Pistil,Style,Petals,Ovary, Sepals,Ovules,Thalamus,Pedicel

Whorls of Flower

  • Sepal (calyx is a set),Petals (corolla set) ,Anther Filament (Stamen sets which is androecium) Stigma Style Ovary Ovule (Pistol Set which is Gynoecium)

Types of flowers

  • Bisexual Flower: Both androecium and gynoecium are present in the same flower.

  • Unisexual Flower: Androecium and gynoecium are present in separate flowers; Staminate flower contains pollen and pistillate does not

Types of Reproduction

  • Sexual Reproduction

  • Asexual Reproduction:

  • Biotic and Abiotic

  • Pollination: transfers pollen grains from anther to stigma of flower Self-Pollination Cross-Pollination

Types of Pollination

  • self Pollination Transfer of pollen grains from anther to stigma of the same flower

  • Cross Pollination Transfer of pollen grains between two different flowers present on Different Flowers on Same Plant or 4 Different plants of Species

Asexual Reproduction Types

  • Insects,Birds or Artificial (Biotic Agents) or Wind and Water (Abiotic Agents)

Biotic Agents: Pollination

  • Insects :Sticky Stigma

  • Spiky Pollen

  • Nectar Scent Bright colors Large flowers

  • Birds : Odorless flowers Brightly colored flowers Tubular flowers

  • Humans implement Artificial pollination methods

Methods by Weather

  • Water Methods is where Gravity impacts pollen and has a high specific

  • Wind: large exposure and surface area to blow the pollen , dry smooth and light.

Sexual reproduction events

  • Pollination: pollen spread to stigma

  • Fertilisation: Formed seed and fruit begin production

  • seed formed from ovule in a dry /fleshy pod that fall, petals and sepals wither off.

Seed Dispersal

  • Transfer of Pollen from Anther to Stigma on 2 of Same species:

Section view of single plant showng a single carpel.

  • Section show, pollen grains land on a fertilized stigma that had insects Wind Pollination.

  • Pollengrain develops a pollen tube though style which reaches The male Cell (Haploid Gamete passes Through to Ovule for fertilization.

  • Pollengrain develops a pollen tube though style which reaches The male Cell (Haploid Gamete passes Through to Ovule for fertilization.

  • The walls form a seed coat while embryo forms a fertilized Ovary. Petals widdle along with the dry ripe pod

Methods of Seed Dispersal

  • Animals

  • Wind

  • Water

  • Explosions

Dispersal By Animals

  • Animals: Cherry,Hawthorn, Elderberry, Apple and Blackberry Birds aid seed dispersal Burdock Hazelnuts Mistletoe (sticky fruits are eaten by birds Squirrels bury nuts Goose Grass

Dispersal By Animals, Wind

  • (wind Plants dandelion and foxgloves fruits Sycamore and ash fruits Wings

  • Water : Pond Iris (floating), Coconut (across seas and oceans)

Explosions!

  • Laburnum Broom (split when thrown

Adaptations

  • Allows a living thing to survive in a particular environment.

Blackberry

  • Edible fruit helps animal disperse seed by eating it

Burdock

  • Hooks stick to animal fur to allow seeds to be dispersed

Dandelion

  • Easily fly in wind

Pollination Emphasis Self / Cross-pollination feature Reason Wind insect Pollinated Flowers

Water Methods is where Gravity Impacts Pollen with High Specificity with the goal to:

  • Avoid Using chemical sprays in the your home miniature “Nature Preserve”

Parts of Flower 1

  • the stamen (male part - collectively termed the androecium) and Carpel (often the carpel is referred to as the pistil, the female parts collectively termed the gynoecium).

  • Functions of Parts of a Flower Petal (large and colored), Sepal (protects the bud), Petiole (Supports to to face the wind), Nectray(creates scents for stamen Filament Support stigma Style Ovary

  • Petals (corolla), Sepals (calyx), Stamens (outer ring), and a pistil (center).

  • The familiar calla lily is not a single flower. It is actually an inflorescence of tiny flowers pressed together on a central stalk that is surrounded by a large petal-like bract.

References from Website, IGSE.weebly, Edible Flowers

  • Reproduction is production from one of its kind. There Is Sexual A and Sexual

  • Asexual Reproduction is where there a form from One Organism. No Gametes required but sexual requires it.

  • Fungi requires them as group cells with protective covering

  • Budding, in which the yeast requires the small Part on it

  • humans, where the sexual reproduction requires fustions of female and male, which equals variation

System & Body Parts

  • MALE:Testes ( gland for sperms )Scrotum: alkaline glands Sperm duct Urethral Penis

  • Female Ovaries: egg and system tubes cervical, Uterus - fetus

  • Gametetes sperms and eggs as haoloid nucleus w chromosome, from body as somatic

  • Ovulation: egg is released

After Sexual Intercourse: Oviduts - Eggs and Enzyme forms Zygote w nucleus to form an Embro - implanted wall to gain Vessel.

After Egg is Fertilized w Questions regarding parts

If the egg Carries though, no membrane with menstruation occurs