PSEB 8th Class Science Notes Chapter 2 Microorganisms: Friend and Foe

This PSEB 8th Class Science Notes Chapter 2 Microorganisms: Friend and Foe will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 2 Microorganisms: Friend and Foe

→ Micro-organisms are very small organisms that can be seen with the help of a microscope.

→ Micro-organisms can survive in almost all kinds of environments like hot springs, ice-cold water, saline water, desert soil or even in marshy land.

→ Micro-organisms are classified as bacteria, fungi, protozoa, algae, and viruses.

→ Micro-organisms exist in all types of habitats.

PSEB 8th Class Science Notes Chapter 2 Microorganisms: Friend and Foe

→ Generally, they are single-celled (unicellular) sometimes occur in a chain or group of cells.

→ Micro-organisms play an important role in our life.

→ Bacteria are present almost everywhere and are smaller in size.

→ The average size of bacteria is 1.25 times one-thousandth of a millimeter in diameter.

→ Bacteria are divided into three types

  • Bacillus or rod-shaped
  • Coccus or round-shaped
  • Spirillum or spiral

→ Bacteria are autotrophic as well as heterotrophic in nutrition.

→ Bacteria reproduce by cell division or binary fission.

→ There are many similarities between algae and bacteria.

→ They are called cyanobacteria. They are helpful in fixing atmospheric nitrogen and in increasing soil fertility.

→ Diatoms are microscopic algae that occur in springs, estuaries, sediments, and the ocean.

→ Fungi are saprophytic or parasitic in their mode of nutrition.

PSEB 8th Class Science Notes Chapter 2 Microorganisms: Friend and Foe

→ Some fungi damage and spoil food products, leather, paper, and textile whereas others are pathogenic to crops and animals.

→ Yeasts are unicellular and saprophytic fungi used in fermentation to produce beer, wine, and other beverages.

→ Viruses are the smallest parasitic organisms that have the ability to replicate inside the living cells.

→ Protozoans are unicellular organisms that cause serious diseases like dysentery and malaria.

→ Food poisoning is due to the consumption of food spoilt by some microorganisms.

→ Micro-organisms that grow on our food produce toxic substances.

→ The common methods used to preserve our food are chemical methods, salting, sugar, oil, and vinegar, by heat and cold treatments.

→ Protozoa: These are single-celled microorganisms, which may cause some serious diseases like dysentery and malaria.

→ Fungi: Fungi are non-green plants (micro-organisms) that spoil most of the food items.

→ Virus: These are micro-organisms that are present on the borderline between living and non-living. They reproduce only inside the host organism.

→ Bacteria: Bacteria are microorganisms that are present almost everywhere ant) are smaller in size. They are autotrophic as well as heterotrophic in nutrition.

→ Yeast: Yeast is fungi that are unicellular used in fermentation to produce beer, wine, and other beverages.

→ Rhizobium: It is a bacteria that helps in the fixation of nitrogen. It is present in root nodules of leguminous plants.

→ Soil Fertility: It means enriching the soil with nutrients especially nitrogen. It is done by some bacteria and blue-green algae.

PSEB 8th Class Science Notes Chapter 2 Microorganisms: Friend and Foe

→ Micro-organisms: These are very small organisms that cannot be seen with the naked eye. They can only be seen under a microscope. They exist in all types of habitats.

→ Microbes: The other name of micro-organisms is a microbe.

→ Lactobacillus: The bacteria present in curd is called lactobacillus which promotes the formation of curd.

→ Carriers: Carriers are insects and other animals which carry the disease-carrying micro-organisms.

→ Antibodies: When a disease-carrying microbe enters our body, the body produces antibodies to fight the invader.

→ Antibiotics: These are the chemicals that are produced by micro-organisms and are used to kill harmful micro-organisms.

→ Vaccine: It is a dead or weakened microbe which is introduced into a healthy body.

→ Pathogen: The disease-causing micro-organism is called a pathogen.

→ Fermentation: The conversion of sugar into alcohol with the help of micro-organisms is called fermentation.

PSEB 8th Class Science Notes Chapter 2 Microorganisms: Friend and Foe

→ Nitrogen Fixation: The process of conversion of atmospheric nitrogen into nitrites and nitrates with the help of Rhizobium bacteria is called nitrogen fixation.

→ Nitrogen Cycle: When atmospheric nitrogen after going through various phenomenon like nitrogen fixation, nitrification, denitrification again enters the atmosphere, it is called the nitrogen cycle.

PSEB 8th Class Science Notes Chapter 1 Crop Production and Management

This PSEB 8th Class Science Notes Chapter 1 Crop Production and Management will help you in revision during exams.

PSEB 8th Class Science Notes Chapter 1 Crop Production and Management

→ Any plant grown and cared for in a field for some output is known as a crop plant or simple crop.

→ Crops that are raised basically for obtaining cash are known as cash crops.

→ In addition to crop plants, vegetables, fruits, and flowers are also grown on a large scale. These come under horticulture.

→ The necessary conditions for the healthy growth of plants are oxygen, water, sunlight, and nutrients.

PSEB 8th Class Science Notes Chapter 1 Crop Production and Management

→ Agriculture involves the systematic use of some basic practices that fulfill the needs of plants grown in a field.

→ The process of loosening and turning the soil is known as tilling or ploughing.

→ This allows the roots to penetrate freely and deeper into the soil.

→ The supply of water to crops at different intervals is called irrigation.

→ The sources of irrigation are wells/tubewells, ponds/lakes, rivers, dams, and canals.

→ The latest irrigation methods are sprinkler systems, drip systems.

→ Seeds are sown in the field by hand or by using a seed drill. This is called broadcasting.

→ Seedlings are tiny plants. The transference of seedlings from nurseries to the main fields is called transplantation.

→ Humus is a layer of mixed organic matter on the topsoil which is made of partially or fully decomposed plant and animal remains and wastes.

PSEB 8th Class Science Notes Chapter 1 Crop Production and Management

→ Manure is made of waste products of animals and plants.

→ A fertilizer is a mixture of chemicals rich in potassium, nitrogen, and phosphorus.

→ When added to soil, manure and fertilizers replenish the soil with nutrients.

→ Weeds are unwanted plants that grow in the fields along with crops. They are removed by spraying weedicides.

→ Pests destroy our crops which are removed by spraying pesticides or insecticides.

→ There are two groups of crops according to the season

  • Kharif
  • Rabi

→ In harvesting, crops are removed or cut close to the ground.

→ The process of separation of grains from the chaff is known as threshing.

→ Winnowing helps in separating seeds from the chaff.

→ Mixed cropping is the process of growing two or more crops together.

→ Animals such as cows, buffalo, poultry birds, and fish are reared for major food items like meat, eggs, and milk.

→ Domesticated animals need proper feeding, weeding, and protection against diseases and parasites.

→ The animal food output can be increased through proper animal husbandry practices as well as through cross-breeding.

PSEB 8th Class Science Notes Chapter 1 Crop Production and Management

→ Special festivals are associated with the harvest season such as Pongal, Baisakhi, Holi, Diwali, Nabanya, and Bihu.

→ Agricultural Practices: Cultivation of crops involves several activities undertaken by the farmers spread over a time period. These are called agricultural practices.

→ Soil Preparation: Before growing a crop, the soil is first prepared by ploughing, levelling, and adding manure. This is called soil preparation.

→ Sowing: Sowing is the process of putting seeds in the soil.

→ Manure and Fertilisers: The substances which are added to the soil in the form of nutrients for the healthy growth of plants are called manure and fertilizer;

→ Irrigation: Giving water to the fields at different intervals for the growing crops is called irrigation.

→ Weeding: The removal of unwanted plants (weeds) from the field is called weeding.

→ Harvesting: The cutting of crops after maturity is called harvesting.

→ Storage: The storing of grains after harvesting and threshing in large godowns is called storage.

→ Animal Husbandry: The study of all aspects such as food, shelter, health care of domesticated animals is called animal husbandry.

→ Silo: Silos are the storage structures for storing food grains on small scale.

→ Granaries: Granaries are the storage structures for storing food grains on large scale.

PSEB 8th Class Science Notes Chapter 1 Crop Production and Management

→ Threshing: The process of separation of grains from the chaff is known as threshing.

→ Weeds: Unwanted plants which grow along with the crops in the field are called weeds.

→ Weedicides: The chemicals which are used to destroy the weeds are called weedicides.

PSEB 9th Class Agriculture Notes Chapter 11 Important Current Issues in Agriculture

This PSEB 9th Class Agriculture Notes Chapter 11 Important Current Issues in Agriculture will help you in revision during exams.

PSEB 9th Class Agriculture Notes Chapter 11 Important Current Issues in Agriculture

→ Man has been practicing farming since time immemorial.

→ By using specialized genetic engineering technologies crops can be genetically modified by the transfer of genes of other plants or organisms into the crop.

→ Such improved crops are known as G.M. or transgenic crops.

→ Bt is an abbreviation for the soil bacterium Bacillus thuriengiensis.

PSEB 9th Class Agriculture Notes Chapter 11 Important Current Issues in Agriculture

→ A crystalline protein is produced in Bt cotton which is highly toxic for bollworms; insects pests of cotton.

→ Initially Bollguard-I hybrid had only one Bt gene and later on, Bollguard-II had two Bt genes.

→ The yield of Bt cotton is five quintal lint per acre.

→ After the introduction of Bt cotton use of insecticides has reduced a lot.

→ GM crops of Brinjal, soybean, maize, rice, etc. have been developed.

→ Some organisations, social activities consider GM crops have an adverse effect on the environment, human health, biodiversity of plants, and species of cultivated plants.

→ The government of India enacted ‘protection of plant varieties and the Farmers’ Rights Act (PPV & FR act) in 2001.

→ This act provided protection for general crops for six years and the protection period can be extended for 15 years.

→ Trees and vines were protected for 9 years and the period can be extended for 18 years.

→ One can get information about registration from the site www.plantauthority.gov.in.

→ Developed countries are using the new concept of precision farming, for this, they are using sensors, G.P.S., etc.

→ In developed countries nitrogen sensor is used to find out the requirement of nitrogen in different sections of a field.

PSEB 9th Class Agriculture Notes Chapter 11 Important Current Issues in Agriculture

→ We can save water by using a laser land leveler and Tensiometer.

→ In some of the developed countries, G.P.S. is used to accurately measure the fields.

→ According to reports, due to global warming earth has warmed by 0.5°C over the past 100 years.

→ Green House Gases are Carbon dioxide, nitrogen oxide, chlorofluorocarbon (CFC), methane, etc.

PSEB 9th Class Agriculture Notes Chapter 10 Fishery

This PSEB 9th Class Agriculture Notes Chapter 10 Fishery will help you in revision during exams.

PSEB 9th Class Agriculture Notes Chapter 10 Fishery

→ Fish farming or fishery is a subsidiary occupation and is more profitable than agriculture.

→ Indian breeds of fish are Catla, Rohu, Mrigal.

→ Exotic carps – Common carp, silver carp, Grass carp.

→ The fish pond should be made in clayey land.

→ Pond size should be 1-5 acres and it should be 6-7 feet deep.

PSEB 9th Class Agriculture Notes Chapter 10 Fishery

→ Keep water level in pond upto 5-6 feet.

→ The pH of the water should be 7-9. If it is less than 7 use lime water.

→ Put seed fish of 1-2 inch size at the rate of 4000 per acre.

→ Seed fish can be put in the following ratio:

  • Katla 20%, Common carp 20%, Mrigal 10%, Rohu 30%, Silver carp 10%, and Grass carp 10%.
  • Katla 25%, Mrigal 20%, Rohu 35%, Common carp 20%.

→ There should be 25% protein in fish feed.

→ 500-gram fish is ready for marketing.

→ One should get training before starting the occupation of the fishery.

PSEB 9th Class Agriculture Notes Chapter 9 Pig, Sheep, Goat and Rabbit Rearing

This PSEB 9th Class Agriculture Notes Chapter 9 Pig, Sheep, Goat and Rabbit Rearing will help you in revision during exams.

PSEB 9th Class Agriculture Notes Chapter 9 Pig, Sheep, Goat and Rabbit Rearing

→ Reproduction in pigs is very rapid and they also eat less.

→ Exotic breeds of pigs – White Yorkshire, Landrace.

→ A healthy female pig comes in beat at the age of 5-6 months for the first time.

→ A female pig can give birth twice a year and can produce 10-12 piglets per farrowing.

→ In a shed of 160 square feet, 20 young pigs can be reared.

PSEB 9th Class Agriculture Notes Chapter 9 Pig, Sheep, Goat and Rabbit Rearing

→ Goat milk is valuable for patients and old persons.

→ Indigenous breeds of goat are Beetal, Jamnapari.

→ Exotic breeds of Goat are Saanen, Alpine, and Boer.

→ Breeds of sheep are Marino, Corriedale.

→ Selection of good quality goat is done on the basis of 120 days lactation milk production.

→ The gestation period of sheep and goats is the same and is 145-157 days.

→ Sheep or goat requires 10 sq. feet of space whereas young lamb needs only 4 sq. feet of space.

→ Males which are for mutton purposes should be castrated at the age of 2 months.

→ A female rabbit can become pregnant at the age of 6-9 months for the first time.

→ The average age of rabbits is 5 years.

→ Breeds of rabbit for wool – German Angora, British’ Angora, Russian Angora.

PSEB 9th Class Agriculture Notes Chapter 9 Pig, Sheep, Goat and Rabbit Rearing

→ Breeds of rabbit for meat – Grey Giant, Soviet Chinchilla, White Giant, Newzealand White.

→ Annual wool yield from Russian, British and German Angora is respectively 215, 230, 530 grams.

→ Wool can be taken at the age of 4 months from a rabbit.

→ Before starting the rearing of sheep, goats, or rabbits, first, get training for this purpose.

PSEB 9th Class Agriculture Notes Chapter 8 Poultry Farming

This PSEB 9th Class Agriculture Notes Chapter 8 Poultry Farming will help you in revision during exams.

PSEB 9th Class Agriculture Notes Chapter 8 Poultry Farming

→ ‘Poultry’ is a word that includes all types of birds that are reared to fulfill their economical needs.

→ Sutlej Layer is a type of breed of hen that gives about 255-265 eggs annually and the weight of the egg is 55 grams. A hen starts laying eggs at the age of 160 days.

→ IBL – 80 Broiler is a breed of hen which is reared for meat purposes. At the age of 6 weeks, its body weight becomes 1350-1450 grams.

→ White Leghorn is an exotic breed that lays 220-250 eggs annually.

PSEB 9th Class Agriculture Notes Chapter 8 Poultry Farming

→ Rhode Island Red gives about 180 eggs annually, the egg is of brown colors.

→ White Plymouth Rock gives 140 eggs annually and chicks’ weight at the age of two months is 1 kg.

→ Hens require about 40 feed nutrients in their feed.

→ Feed is divided into 6 parts i.e. carbohydrates, proteins, fat, minerals, vitamins, and water.

→ The device which is used to keep chicks warm is called a brooder.

→ A Hen needs 2 question foot space.

→ Birds cannot sweat because they don’t have sweat glands in the skin.

PSEB 9th Class Agriculture Notes Chapter 7 Milk Products and their Marketing

This PSEB 9th Class Agriculture Notes Chapter 7 Milk Products and their Marketing will help you in revision during exams.

PSEB 9th Class Agriculture Notes Chapter 7 Milk Products and their Marketing

→ Milk is a boon to mankind. Milk is ideal and unique food for mankind.

→ Milk has high nutritive value like protein, calcium for bones, and other minerals.

→ Co-operative institutes play important role in the marketing of milk.

→ Cow milk should have at least 4% of fat in it and the value of solid-not-fat (S.N.F.) is 8.5%.

→ Buffalo milk should have 6% of fat and the value of solid not-fat (S.N.F.) should be 9%.

→ Types of milk are-Toned milk, double-toned milk, and standardized milk.

PSEB 9th Class Agriculture Notes Chapter 7 Milk Products and their Marketing

→ Raw milk can spoil easily. Therefore, milk can be processed and preserved for a long time by preparing different milk products.

→ We can earn more profit by preparing different milk products.

→ Milk products are Khoa, Paneer (Cheese), Ghee, Dahi (curd), etc.

→ We can get 200 grams of Khoa and 180 grams of Paneer from one-kilogram cow milk.

→ We can get 250 grams of Khoa and 250 grams of Paneer from one kg buffalo milk.

→ One can get information from Punjab Agricultural University, Ludhiana, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, and National Dairy Research Institute, Karnal (Haryana) on the preparation of milk products by adopting the latest technology.

PSEB 9th Class Agriculture Notes Chapter 6 Dairy Farming

This PSEB 9th Class Agriculture Notes Chapter 6 Dairy Farming will help you in revision during exams.

PSEB 9th Class Agriculture Notes Chapter 6 Dairy Farming

→ Nearly 70% population in Punjab lives in villages.

→ There are 17 lakh cows and 50 lakh buffaloes in Punjab.

→ In Punjab, 937 grams per day per capita milk is produced whereas at the national level it is 291 grams.

→ Holstein-Friesian is the highest milk-giving exotic breed of cow.

→ Indigenous breeds of cows have average lactation milk yield varying from 1000 kg to 1800 kg.

PSEB 9th Class Agriculture Notes Chapter 6 Dairy Farming

→ Indigenous breeds of cows are Hariana, Sahiwal, Red Sindhi, Tharparkar.

→ Dual-purpose breeds are Tharparkar and Hariana.

→ Exotic breeds of cows are Holstein-Friesian, Jersey. Average lactation milk yield is 5500-6500 kg and 3000, 5000 kg respectively.

→ An average cow or buffalo with a bodyweight of 400 kg needs approximately 35 kg green fodder.

→ Feed nutrients for animals can be classified into four categories i.e. energy, protein, minerals, and vitamins.

→ Animals are given concentrate which is prepared by mixing cereals, oilseed cakes, etc.

→ If a milking machine is used*, clean teats by dipping in 50% betadine and 50% glycerin solution.

→ Do not transport the pregnant animal to avoid slipping of animals.

→ The animal should be milked within 2 hours of calving.

→ Dress the navel cord of the newly born calf 2-3 times daily with a tincture of Iodine or Dettol.

→ Feed milk to the calf and avoid sucking.

→ Disbud the buffalo calves at the age of 7-10 days and cow calves at the age of 15-20 days.

→ Heifer, if given proper feed it will become 300 kg in 18months.

→ Milking should be complete in 6-8 minutes with the full hand method.

→ Adult animals need 120-140 square feet of space.

→ Surplus green fodder is dried to get Hay and non-legume fodder is conserved as silage.

PSEB 9th Class Agriculture Notes Chapter 6 Dairy Farming

→ The average lactation milk yield of Indian breeds of buffalo is 500 kg at the National level and in Punjab, it is 1500 kg.

→ In India, there are 15 breeds of buffaloes. In Punjab, there are two breeds-Murrah and Nili Ravi.

→ The best breed of buffalo should have an average lactation milk yield of 2000 kg in the first lactation and in successive lactation. it should be 2500 kg.

→ Preserve the milk at 5°C. It prevents the growth of bacteria.

→ Clean the milk containers properly.

PSEB 9th Class Agriculture Notes Chapter 5 Quality Control of Seeds, Fertilizers and Insecticides

This PSEB 9th Class Agriculture Notes Chapter 5 Quality Control of Seeds, Fertilizers and Insecticides will help you in revision during exams.

PSEB 9th Class Agriculture Notes Chapter 5 Quality Control of Seeds, Fertilizers and Insecticides

→ For profitable farming, the main commodities required are seeds, fertilizers, and insecticides.

→ The government of India has made certain laws under the Essential Commodities Act.

→ These acts are Seed Control Order, Fertilizer Control Order, Insecticides Act.

→ License officers are appointed in Punjab according to Seed Control Order Act. These laws are implemented by the Department of Agriculture, Punjab.

PSEB 9th Class Agriculture Notes Chapter 5 Quality Control of Seeds, Fertilizers and Insecticides

→ If the seed seller sells lower quality seeds to the farmer, the farmer can complain to the Seed Inspector.

→ If a crop fails due to damaged or low-quality seed, Seed Inspector can cancel the sale license of the dealer.

→ Under article 7 of the Seed Act, only notified seeds can be sold.

→ Fertilizer testing laboratories are located at Ludhiana and Faridkot.

→ Fertilizer Control Order was made in 1985, which is used to prevent adulteration, low quality, and non-certified fertilizers, and to ensure quality and correct weight of fertilizers.

→ Insecticides Act was made in 1968.

→ Central Insecticide Board gives advice to the government to implement the laws.

PSEB 9th Class Agriculture Notes Chapter 5 Quality Control of Seeds, Fertilizers and Insecticides

→ Central Registration Committee provides registration for the manufacturing of agrochemicals and also provides permission for their import and export.

→ Insecticides samples are sent to the laboratories located at Ludhiana, Bathinda, Amritsar for testing.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

This PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce? will help you in revision during exams.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ The phenomenon of the formation of new individuals by the existing ones is called reproduction.

→ Reproduction is a means of the perpetuation of the species, and also a method of their multiplication.

→ Reproduction, unlike other life processes, is not essential to maintain the life of an individual organism.

→ Reproduction is the formation of similar organisms with the same body design, due to information of inheritance. (DNA or RNA).

→ Reproduction involves the creation of a DNA copy and additional cellular apparatus by the cell involved in the process.

→ DNA copies formed are not identical and have some variations but if variations are drastic then-new DNA copies cannot work.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ All organisms reproduce. The reproducing organisms create new individuals that look very much like themselves.

→ The chromosomes in the nucleus of a cell contain information for the inheritance of features from parents to the next generation in the form of DNA (Deoxyribose Nucleic Acid) molecules.

→ The DNA in the cell nucleus is the information source for making proteins. Cells use chemical reactions to build copies of their DNA.

→ No biochemical reaction is absolutely reliable. Therefore, the process of copying the DNA will have some variations each time.

→ Some of the variations might be so drastic that the new DNA copy cannot work with the cellular apparatus it inherits. Such a newborn cell will simply die.

→ The inbuilt tendency for variation during reproduction is the basis for evolution.

→ If a population of reproducing organisms were suited to a particular niche and if the niche were drastically altered, the population could be wiped out.

→ If the water temperature increases by global warming, most of the bacteria living in temperate waters would die.

→ In unicellular organisms, cell division or fission leads to the creation of new individuals.

→ Many bacteria and protozoa simply split into two equal halves during cell division.

→ In Leishmania (which causes kala-azar), binary fission occurs in a definite orientation of the body.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ The malarial parasite, Plasmodium, divides into many daughter cells simultaneously by multiple fission.

→ Yeast can produce small buds that separate and grow into new individuals.

→ Multicellular organisms have more complex ways of reproduction.

→ Hydra and Planaria can be cut into any number of pieces and each piece grows into a complete organism. This is known as regeneration. It is carried out by specialized cells.

→ Organisms such as Hydra use regenerative cells for reproduction in the process of budding.

→ There are many plants in which parts like the roots, stems, and leaves develop into new plants under appropriate conditions.

→ The methods such as layering or grafting to grow many plants like sugarcane, roses, or grapes are used for agricultural purposes.

→ Plants raised by vegetative propagation can bear flowers and fruits earlier than those produced from seeds.

→ Such methods also make possible the propagation of plants such as banana, orange, rose and jasmine that has lost the capacity to produce seeds.

→ In tissue culture, new plants are grown by taking tissue or cells from the growing tip of a plant.

→ This technique is commonly used for ornamental plants.

→ The hyphae of Rhizopus grow on the bread. They have sporangia, which contain cells or spores, which can eventually develop into new Rhizopus individuals.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ In sexual reproduction, both sexes, males and females, are needed to produce new generations.

→ Combining variations from two or more individuals would create new combinations of variants.

→ As organisms become more complex, the specialization of tissue increases.

→ The motile germ cell is called the male gamete (pollen) and the germ cell containing the stored food is called the female gamete (ovule).

→ The reproductive parts of angiosperms are located in the flowers.

→ The flower may be unisexual (papaya, watermelon) when it contains either stamens or carpels or bisexual (Hibiscus, mustard) when it contains both stamens and carpels.

→ The ovary contains ovules and each ovule has an egg cell.

→ The fusion of the germ cells or fertilization produces the zygote.

→ The transfer of pollen from one flower to another is achieved by agents like wind, water, or animals.

→ After fertilization, the zygote divides several times to form an embryo within the ovule.

→ The seed contains the future plant or embryo which develops into a seedling under appropriate conditions. This process is known as germination.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ Humans use a sexual mode of reproduction.

→ As adolescence starts, there are some changes taking place that are different among boys and girls. These do not happen all at the same time in one person, nor do they happen at an exact age.

→ The period of adolescence is called puberty.

→ The male reproductive system consists of portions that produce the germ cells and other portions that deliver the germ cells to the site of fertilization.

→ The formation of germ cells or sperms takes place in the testes.

→ In addition to regulating the formation of sperms, testosterone brings about changes in appearance seen in boys at the time of puberty.

→ The female germ cells or eggs are made in the ovaries.

→ The fertilized egg, the zygote, gets implanted in the lining of the uterus and starts dividing.

→ The embryo gets nutrition from the mother’s blood with the help of a special tissue called the placenta.

→ Since the ovary releases one egg every month, the uterus also prepares itself every month to receive a fertilized egg.

→ If the egg is not fertilized, the uterus lining slowly breaks and comes out through the vagina as blood and mucus. This cycle takes place roughly every month and is known as menstruation. It usually lasts for about two to eight days.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ The process of sexual maturation is gradual.

→ Gonorrhea and syphilis and viral infections such as warts and HIV-AIDS are sexually transmitted diseases.

→ The sexual act always has the potential to lead to pregnancy.

→ Many mechanical, hormonal, and surgical methods are used to avoid pregnancy.

→ Pre-natal sex determination has been prohibited by law.

→ Because of reckless female foeticides, the child sex ratio is declining at an alarming rate.

→ Population explosion is raising problem in our country.

→ Birth control is an attempt to control the number of births in a family so that a couple may not have more children than required.

→ Physical barriers include the use of condoms, diaphragm, and cervical caps.

→ Chemical methods include the use of specific drugs by females i.e. oral pill and vaginal pill.

→ The use of IUCD (Copper-T) is very effective.

→ Surgical methods include vasectomy and tubectomy.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ The communicable diseases occurring due to sexual contact are called sexually transmitted diseases such as gonorrhea, syphilis, and AIDS.

→ Reproduction: It is the process of producing new organisms by existing organisms of a species.

→ Sexual reproduction: The production of offspring by the fusion of male and female gametes is called sexual reproduction. It is biparental.

→ Asexual reproduction: The production of progeny without the fusion of male and female gametes is called asexual reproduction. It is uniparental.

→ Fission: The division of an organism into two or more individuals is called fission.

→ Budding: The process of development of an outgrowth due to repeated cell division at one specific site which grows into a tiny individual is called budding.

→ Vegetative propagation: The process of development of the new individual from any part of the body is called vegetative propagation.

→ Grafting: The technique of joining the different parts of two different plants to grow into one plant.

→ Unisexual: When the male and female are separate individuals, they are called unisexual.

→ Bisexual/Hermaphrodite: The organisms having male and female in a single individual are called bisexual/hermaphrodite.

→ Scion: A stem piece of good quality plant is grafted to grow into a new plant is called the scion.

→ Layering: The production of a new plant by covering the leaned branches of a plant under the soil.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ Pollination: The transfer of pollen from another to stigma.

→ Fertilization: The fusion of male and female gametes is called fertilization.

→ Syngamy: The fusion of male gamete with female gamete is called syngamy.

→ Double fertilization: When the fertilization occurs two times (with ovum and polar cell) in angiosperms the process is called double fertilization.

→ DNA Replication: Duplication of DNA molecule by copying from a molecular template of DNA.

→ Regeneration: The formation of the lost part is called regeneration.

→ Gamete: Haploid sex cell is called gamete.

→ Zygote: Diploid fertilized egg is called a zygote. If undergoes cleavage (non-motile division) to form a complete organism.

→ Sperm: Haploid male gamete is called sperm.

→ Ovum: Haploid female gamete is ailed ovum.

→ Ovule: A structure in the ovary of a seed plant that develops into a seed after fertilization.

→ Puberty: The process of becoming sexually mature.

PSEB 10th Class Science Notes Chapter 8 How do Organisms Reproduce?

→ Ovulation: The release of the ovum from the ovary.

→ Implantation: The fixation of the embryo in the uterus is called implantation.

→ Placenta: It is the connection between mother and embryo.

→ Parturition: The process of giving birth to foetus is called parturition.