AP State Board Notes

Students can go through AP State Board 9th Class Biology Notes Chapter 5 Diversity in Living Organism to understand and remember the concept easily.

AP State Board Syllabus 9th Class Biology Notes Chapter 5 Diversity in Living Organism

→ Diversity is the symbol of nature.

→ Diverse organisms are grouped based on the similarities and differences found among them.

→ The presence of differences between organisms of the same species is called variation.

→ Plants those having two seed leaves are dicotyledons while those having single seed leaves are monocotyledons.

→ Variation between different species is always greater than the variation within a species.

→ Variations form a basis for the selection of characters to group organisms.

→ No two organisms are identical in nature.

→ The way in which the organisms may have evolved is classification.

→ Classification is the systematic study of organisms present in nature with respect to their evolution.

→ Classification helps us in exploring the diversity of life forms.

→ Classification helps to study the organisms in a proper and systematic manner.

→ Classification helps in understanding the relationship among the organisms and their interdependence.

→ Classification gives us an idea of evolution.

→ Classification helps to make comparisons in an easier way.

→ Charles Darwin proposed a theory known as Natural selection in 1859 and wrote a book on evolution known as ‘Origin of Species.’

→ In the first and second centuries AD, Charaka and Sushruthad classified plants on the basis of their medical importance.

→ Parasar in his book ‘Vrikshayurveda’ classified several land plants on the basis of the structure of flowers.

→ In 1758, Carl Von Linnaeus classified living organisms into Animalia and Plantae.

→ The major characteristics considered for the classifying all organisms into five major kingdoms by Whittaker are

1. Whether they are made of prokaryotic or eukaryotic cells.
2. Whether the ceils are living singly and organized into multicellular and thus complex organisms.
3. Whether the ceils have a cell wall and whether they prepare their own food

→ According to Whittaker, all living organisms are classified into five kingdoms namely

1. Monera
2. Porifera
3. Fungi
4. Plantae
5. Animalia.

→ All cells are similar and are originated from a single ancestor ceil called Last Universal Common Ancestor (LUCA).

→ Recently Cavalier-Smith (1998) classified the organisms into six kingdoms namely Bacteria, Protozoa, Chromista, Plantae, Fungi, and Animalia.

→ Plants are divided into five groups: Thailophytes, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.

→ Animals are divided into ten groups: Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, Protochordata, and Vertebrate.

→ Monera kingdom includes unicellular prokaryotes. Eg: Bacteria, Anabaena.

→ Protista includes unicellular or multicellular eukaryotes. They are autotrophic or heterotrophic organisms. Eg: Paramoecium, Algae, Diatoms.

→ Fungi include uni or multicellular organisms which reproduce by spores.
Eg: Yeast, Mushroom, Lichens, etc.

→ The Porifera group animals have pores or holes in the body. They form a canal system in the body. Eg: Sycon, Spongilla.

→ The coelenterate animals are diploblastic and have a body cavity or coelom. Eg: Hydra, Jellyfish.

→ In Platyhelminthes animals, the body is flat, bilaterally symmetrical, and are triploblastic. Eg: Tapeworms, Liver flukes.

→ In nematodes, the body is round bilaterally symmetrical triploblastic and pseudocoelomates Eg: Wucheraria Bancroft, Ascaris.

→ Annelids’ body is bilaterally symmetrical, triploblastic segmented, and has a true body cavity. Eg: Earthworm, Leech, Nereis.

→ Arthropods are bilaterally symmetrical, segmented, and have jointed legs.
Eg: Prawn, Housefly, Cockroach.

→ In Molluscs, the body is bilaterally symmetrical, Coelomic cavity is reduced and little segmented Body differentiation starts. Eg: Octopus, Pila, Unio, etc.

→ Echinoderm animals are triploblastic, Coelomate, and Spiny skinned animals.
Eg: Echinos (Sea urchin), Antedon, Asterias (Starfish).

→ Protochordate is bilaterally symmetrical, triploblastic coelomate animals. Notochord may not present at all stages in their life. Eg: Balanoglossus, Amphioxus.

→ Vertebrates have a true vertebral column and internal skeleton.

→ The naming of organisms with distinctive scientific names is called nomenclature.

→ The binomial nomenclature is made up of two words a generic name and a specific name and was introduced by Carl Linneaus.

→ Diversity: Variety of people or things that are very different from each other.

→ Biodiversity: Variety of life forms found in a particular region.

→ Variation: Difference in structure or function, which is shown in individuals of the same species.

→ Cotyledon: The first leaf that is grown from seed.

→ Monocotyledons: Plants having single cotyledons.

→ Dicotyledons: Plants having two cotyledons.

→ Lineage: People of the family who lived in the past; the way ¡n which members of a family are descended from other members.

→ Classification: It ¡s the systematic study of organisms present in nature with respect to their evolution.

→ Designation: Formally choose for a particular purpose.

→ Thermophiles: Prokaryotes that live in hot springs and other places where the temperatures were near or even above the boiling points of water.

→ Halophiles: Prokaryotes that live in places of very high salt concentration.

→ Ancestor cell: A cell that lived ¡n the past from which a modern cell has developed.

→ Interbreed: To produce young ones from parents of different breeds or groups.

→ Solitary: Only one.

→ Cryptogams: Non-flowering and non-seed bearing plants.

→ Phanerogams: Flowering and seed-bearing plants.

→ Porifera: Organisms with holes.

→ Bilaterally symmetrical: The left and right halves of the body have the same design.

→ Triploblastic: Different tissues are formed from three layers of cells.

→ Coelom: Space present inside the body.

→ Pseudocolor: False cavity present inside the body of an organism.

→ Arthropod: Jointed legs.

→ Protochordate: Chordates are developed from these animals. They are marine animals.

→ Notochord: A cylindrical chord/string-like structure which ¡s along mid-dorsal line ¡n all chordates.

→ Cold-blooded animals: These animals can change their body temperature according to their surroundings.

→ Hippocampus: Known as a sea horse. Fish are like animals in which males carry babies as our mothers.

→ Endangered: A type of animal or plant that may soon no longer exist. e.g.: Whale.

→ Nomenclature: Naming of organisms with a distinctive scientific name.

→ Flora: AIl plant life ¡n a region.

→ Fauna: All animal life in a region.

→ Binomial nomenclature: The binomial nomenclature is made up of two words a generic name and a specific name.

→ Evolution: Change gradually.
The scientific idea that plants and animals developed gradually from a simple to more complicated forms.

→ Animal kingdom: One of the five major groups into which all living things are organized by Whittaker. The biggest stage in classification.

→ Domain: An area of activity, interest, or knowledge. The organization of organisms starts here formed by the union of one or two parts.

→ Phylum: One of the major groups into which the animal kingdom is divided.

→ Class: A term used for describing a collection of similar orders.

→ Order: A collection of similar families.

→ Family: Principal sub-division of an order of animals/plants.

→ Genus: Collection of similar species.

→ Species: A group of plants or animals having common characteristics that are similar enough to interbreed and perpetuate.

→ There are various hypotheses as to the origin of prokaryotic and eukaryotic cells. Because all cells are similar in nature, it is generally thought that all cells came from a common ancestor cell termed the Last Universal Common Ancestor (LUCA). These LUCA eventually evolved into three different cell types, each representing a domain. The three domains are the Archaea, the Bacteria, and the Eukarya (a classification as suggested by Woese).

→ Archaea and bacteria are prokaryotic cells that are they do not have a membrane-bound nucleus, the nuclear material is presently dispersed in the cytoplasm.

→ The cell walls of bacteria unlike the archaea contain fat-like chemical peptidoglycan.

→ Eukarya have eukaryotic cells or cells having a membrane-bound nucleus.

→ Fishes are cold-blooded animals. They can change their body temperature according to their surroundings. Most of the fishes are oviparous but some like sharks give birth to young ones.

→ Father of Taxonomy: Carl Von Linnaeus

• Carl Von Linnaeus was born in Sweden and was a doctor by profession.
• While serving as a personal Physician of a wealthy gov¬ernment official Linnaeus studied the diversity of plants in his employers garden.
• Linnaeus published a book ‘Systema Naturae’ from which all fundamental taxonomical researches have taken off.
• In 1758 Carl Von Linnaeus proposed a system that was dominated classification for centuries.
• Linnaeus gave each organism two names denoting genus and species.

Students can go through AP State Board 9th Class Biology Notes Chapter 4 Movement of Materials Across the Cell Membrane to understand and remember the concept easily.

AP State Board Syllabus 9th Class Biology Notes Chapter 4 Movement of Materials Across the Cell Membrane

→ Cell performs different functions.

→ Different types of substances like glucose, water, and oxygen are required by the cell to perform functions.

→ Saturated solutions do not dissolve substances further.

→ The cells in the outer layer of Kishmish permit water to pass through.

→ In Greek ‘Osmos’ means pushing.

→ The movement of solvent molecules through a semipermeable membrane in a solution from a low high concentration till the concentration on both sides becomes equal is called ‘Osmosis’.

→ Permeability means allowing substances into the cell through a semipermeable membrane.

→ The plasma membrane is selectively permeable allows entry of certain substances to pass through it

→ The plasma membrane is semipermeable to solvent but prevents the passage of solutes.

→ The process in which water molecules leave the cell is called ‘Exosmosis’.

→ The process in which water molecules enter the cell is called ‘Endosmosis’.

→ Freddie Mercury and David Bowie removed salt from seawater by using a semipermeable membrane by a process called desalination.

→ Reverse osmosis helps in removing salt from seawater.

→ The process by which some materials when kept in a medium like air and water spread equally throughout, is called diffusion.

→ Air freshness, Agarbathi, mosquito repellants work on the principle of diffusion.

→ Thomas Graham measured the rate of diffusion of gases and also studied the diffusion of substances in solutions.

→ Osmosis does not take place in dead cells.

→ Solute: Dissolved substance in a solution.

→ Solvent: A fluid substance that dissolves solid substances.

→ Selectively permeable: Allows entry of certain substances only.

→ Endocytosis: Flexibility of the cell membrane to engulf food and other substances from the external environment. E.g.: Amoeba.

→ Osmosis: The movement of water molecules towards concentrated solutions.

→ Plasmodesmata: The strands of cytoplasm passing through cell walls and connecting the protoplasts of adjacent cells.

→ Permeability: The extent to which molecules of a given kind can pass through a membrane.

→ Semipermeable: Only certain materials are allowed to enter the cell.

→ Circumference: A line that goes around a circle or any other curved shape, the length of this line.

→ Exosmosis: The process in which water molecules leave the cell.

→ Endosmosis: The process in which water molecules enter the cell.

→ Reverse Osmosis: A process used to remove salts from the water.

→ Diffusion: Some materials when kept ¡n a medium like air and water spread equally ¡n that medium.

→ Saturated solution: It is a solution in which solute further can not dissolve.

→ Three fourth of the earth is covered with oceans. Though plenty of water is there, we cannot use it, since it is salty. If we can remove salts from it we can use it. Freddie Mercury and David Bowie removed salt from seawater by using a semi-permeable membrane by a process called desalination. When heavy pressure is applied to a salt solution, which is separated from freshwater with a semi-permeable membrane, the water moves from the salt solution into freshwater leaving the salt behind. This process is known as reverse osmosis. Nowadays domestically used reverse osmosis machines are available in the market, which filters saltwater through three membranes.

→ Thomas Graham, the Scottish physical chemist, worked on the diffusion of gases. Graham measured the rate of diffusion of gases and also studied the diffusion of substances in solutions. He had inferred that a more soluble substance in a medium diffuse faster than a less soluble substance. This is popularly known as ‘Graham’s law’.

→ Thomas Graham:

• Thomas Graham a Scottish physical chemist, worked on the diffusion of gases.
• He also studied the diffusion of substances in solutions.
• Thomas Graham inferred that a more soluble substance in a medium diffuse faster than a less soluble substance.
• This is popularly known as Graham‘s law.

Students can go through AP State Board 9th Class Biology Notes Chapter 3 Animal Tissues to understand and remember the concept easily.

AP State Board Syllabus 9th Class Biology Notes Chapter 3 Animal Tissues

→ Tissue is a group of cells similar in structure and functions.

→ In animals, 4 types of tissues are there.
They are:

1. Epithelial,
2. Connective,
3. Muscular,
4. Nerve.

→Depending on shape and function, epithelial tissue is classified as squamous, cuboidal, columnar, ciliated, and glandular.

→ Epithelial tissues are present in the skin, lining of the mouth, lining of blood vessels, lung alveoli, and kidney tubules.

→ Squamous epithelium found, where transportation of substances selectively occurs through a permeable membrane.

→ Nails, hair, scales of fishes and reptiles, feathers of birds are modified epithelial cells.

→ Connective tissue connects organs and muscles.

→ The different types of connective tissues in our body include areolar tissue, adipose tissue, bone, tendon, ligament, cartilage, and blood

→ The blood consists of plasma, RBC, WBC, and platelets.

→ Osteocytes secrete salts present in the bone marrow.

→ Cartilage is found in the joints of bones, the tip of ribs, the tip of the nose, external ears, and the trachea.

→ Embryos of several vertebrates have only cartilage.

→ Ligaments and tendons are made of collagen.

→ Hemoglobin gives the red color to the blood, present in RBC.

→ The cockroach has white blood and the snail has blue colored blood

→ Heparin helps to prevent blood clotting in blood vessels.

→ RBC is also called erythrocytes.

→ WBC is also called leucocytes.

→ Dead WBC comes out of the wound as pus.

→ Four types of blood groups are found in human beings by Carl Land Steiner.

→ The different types of connective tissues in our body include areolar tissue, adipose tissue, bone, tendon, ligament, cartilage, and blood.

→ Striated, unstriated, and cardiac are three types of muscle tissues.

→ Nervous tissue is made of neurons that receive and conduct impulses.

→ Tissue: A group of cells similar in structure and function.

→ Epithelial tissue: Tissue present inside or outside of the animal body.

→ Connective tissue: Connects organs and muscles.

→ Insulator: Detachment from other objects, separatec1 isolated

→ Bone marrow: central hollow portion of the bone.

→ Bone: A hard one, made of calcium phosphate and calcium carbonate.

→ Cartilage: One type of bone, but not hard

→ Muscle tissue: Responsible for movements in the body.

→ Nerve tissue: A specialized tissue that responds to internal and external stimuli.

→ Ranvier nodes: Gas or nodes present at regular intervals on myelin sheath are known as Ranvier nodes.

→ Sometimes a portion of epithelial tissue folds Inward and formed a multi-cellular gland. Hence It Is called the granular epithelium.

→ Bone is made of calcium phosphate and calcium carbonate. These salts are secreted by cells called osteocytes. These cells are present in the central hollow portion of the hone called bone marrow.

→ Marcello Malpighi (1628 – 1694):

• Marcello Malpighi was born at Crevalcuore near Bologno, Italy in 1628. In 1649 he began his professional studies at the University of Bologna and in 1653 graduated in Philosophy and Medicine.
• He is regarded with justification as the founding father of animal histology and a number of histological structures still bear his name: Malpighian capsules in the kidney, the malpighian layer in the skin, malpighian tubules in the excretory system of insects, man, etc

Students can go through AP State Board 9th Class Biology Notes Chapter 2 Plant Tissues to understand and remember the concept easily.

AP State Board Syllabus 9th Class Biology Notes Chapter 2 Plant Tissues

→ Tissue is a group of cells similar in structure and performing similar functions.

→ Tissues that bring about overall growth and repair are called Meristematic Tissues.

→ Tissues that form outer coverings are called Dermal tissues.

→ Tissues that form the bulk of the plant body, helping in packing other tissues are called Ground tissues.

→ Tissues that help in the transport of materials are called Vascular tissues.

→ Meristematic tissue is of three types.

1. Apical Meristem
2. Lateral Meristem
3. Intercalary Meristem.

→ The epidermis, Mesodermis, and Endodermis are formed from dermal tissues.

→ The dermal layer protects the plant from loss of water, mechanical damage, and diseases

→ Gum is secreted from the dermal layer.

→ Ground tissue is divided into three types.

1. Parenchyma
2. Collenchyma
3. Sclerenchyma.

→ Parenchyma containing chloroplasts is chlorenchyma, with air cavities is Aerenchyma and that stores food is storage tissue.

→ The cells of the parenchyma are soft, thin-walled, and loosely packed

→ Collenchyma tissues have thicker walled large cells compared to the parenchyma.

→ In sclerenchyma, the cells are thick-walled and compactly arranged with nearly no intercellular spaces between them.

→ Nehemiah Grew give the term parenchyma for the pithy part

→ Vascular tissues are involved in transportation.

→ Vascular tissues are the xylem and phloem.

→ Xylem conducts water and mineral salts from the root, while phloem transports food I materials from leaves to the growing region.

→ Xylem consists of tracheids, vessels, fibers, and xylem parenchyma.

→ Phloem consists of sieve cells and sieve tubes, companion cells, phloem fibers, and phloem parenchyma.

→ Xylem carries water up to 200ft in Eucalyptus and up to 330ft in Redwood trees.

→ Tissue: A group of cells similar in structure and performing similar functions.

→ Meristematic tissue: Dividing tissue present in growing regions of plants.

→ Apical Meristem: Present at the growing tip that brings about growth in length.

→ Lateral Meristem: Present around the edges in a lateral manner and rise the growth in diameter of the stem and root.

→ Intercalary Meristem: Meristem present at the branches, leaf, or flower stalk grows.

→ Dermal tissue: A single layer of tissues showing variations in the types of cells gives protection to the plant.

→ Epidermis: Outermost layer ¡n stem, root, and leaf

→ Bark: The layers formed above the epidermis in big trees.

→ Ground tissue: Forms the Bulk of the plant body.
e.g.: parenchyma, collenchyma, and sclerenchyma.

→ Parenchyma: Cells of this tissue are soft thin-walled and loosely packed.

→ Collenchyma: It has thicker walled, longer cells compared to the parenchyma.

→ Sclerenchyma: Cells are thick-walled, compactly arranged without intercellular spaces.

→ Vascular tissue: Helps in the transport of materials in plants.

→ Xylem: Helps in the transport of water and minerals.

→ Phloem: Helps in the transport of food material from leaves to other growing regions in plants.

→ Vascular bundles: Stands for one of a number of strands of primary vascular tissue having both xylem and phloem.

→ Trachieds : It is a xylem element. It conducts water and gives mechanical strength. A long narrow pipe-like, non-living cell with narrow students and thick walls.

→ Vessels: Non-living element of the xylem conducts water and gives mechanical support to the plant.

→ Arrangement Of The Cells in Tips:


→ Plants have the ability to store certain substances that are either their excretory products of accumulated food or some secret substances in different ways. Gum is secreted from the dermal layer of a gum tree.

→ Nehemiah Grew (1641-1712) was a practicing physician and worked as the secretary of the Royal Society, London. He began his work on the study of the internal structure of the plants in the year 1664.

→ Grew’s fundamental inference was “Every plant organ consists of two types of organic parts. One is pithy and other is ligneous part”. Grew gave the term “parenchyma” for the pithy part. Grew initiated the study of tissues (Histology in plant bodies and published his work in the book ‘Anatomy of PLants’ in the year 1682.

→ Marie Francous Xavier Bichat (1771 – 1802):

• Marie Francois Xavier Bichat (1771-1802) was the first person to look beyond the recognizable organ system and suggest that each part of the body was composed of various kinds of tissues.
• In addition, he suggested that disease acted upon these tissues in ways that could be seen and studied
• For these insights, Bichat is considered the father of Histology.

Students can go through AP State Board 9th Class Biology Notes Chapter 1 Cell its Structure and Functions to understand and remember the concept easily.

AP State Board Syllabus 9th Class Biology Notes Chapter 1 Cell its Structure and Functions

→ We can see the cell wall cytoplasm, nucleus, chloroplast and mitochondria with \ a compound microscope.

→ Under the electron microscope, a few other structures became visible.

→ Chloroplasts occur only in the ceils of green plant parts like the leaf and tender I stem.

→ The fundamental organizational unit of life is the cell.

→ Cells are enclosed by a plasma membrane composed of lipids and proteins.

→ A plasma membrane is a selectively permeable membrane.

→ The plasma membrane defines the shape and size of the cell and protects from the exter¬nal environment

→ The cell wall is a tough, flexible porous layer.

→ During growth and development, the cell wall continuously exchanges information with other cells.

→ The plant cells can withstand much greater changes in surroundings medium than animal cells.

→ In-plant cells, a cell wall composed of cellulose is located outside the cell membrane. % Nucleus was named by Robert Brown in 1831.

→ The nucleus is the most important organelle of the cell

→ Schleiden called it the cytoblast

→ The nucleus regulates and controls all the functions and determines the characteris¬tics of the organism.

→ It is the bearer of genetic information and is closely involved in cell division.

→ Eucaryotic cells have a nucleus except for Red blood cells, phloem sieve tubes in plants.

→ The nuclear membrane separates the nucleus from the cytoplasm.

→ On the basis of the presence of nuclear membrane, cells are categorized into two types, i.e., Prokaryotic and Eucaryotic cells.

→ Prokaryotic cells nuclear membrane is absent e.g.: Bacteria, Cyanobacteria.

→ The cytoplasm is the fluid content, contains cell organelles.

→ In prokaryotes, membrane-bound cell organelles are also absent

→ Endoplasmic Reticulum transports the substances.

→ Two types:

1. Rough Endoplasmic Reticulum (RER)
2. Smooth Endoplasmic Reticulum (SER)

→ RER is the site of protein manufacture.

→ SER helps in the manufacture of fat molecules and lipids.

→ Invertebrate liver cells, SER plays a crucial role in detoxifying many poisons and drugs.

→ Camillo Golgi had observed Golgi body or Golgi apparatus in 1898.

→ It is made up of several membranes.

→ Its function is to package various substances.

→ The number of Golgi bodies is large in those cells that secrete hormones and enzymes.

→ Lysosomes contained destructive enzymes.

→ Lysosomes are also known as the suicidal bags of the cell « Mitochondria are also known as the powerhouse of the cell

→ They are small, spherical or cylindrical in shape and 150 times smaller than the nucleus.

→ It is made of a double-membrane wall

→ The inner wall protrudes and forms structures called cristae.

→ Plastids are of two types:

1. Chromoplasts (coloured)
2. Leucoplasts (colourless)

→ In Algae plastids are found as ladders, stars, spirals or reticulate.

→ Chloroplasts trap the energy of sunlight and transform it into chemical energy in photosynthesis.

→ The large empty spaces visible in the cells are vacuoles.

→ They are fluid-filled sacs i.e., storage sacs.

→ In mature plant cells, they might occupy almost the entire cell space.

→ All living beings are made of cells.

→ Matthias, Jakob Schleiden and Theodar Schwann together form cell theory.

→ Rudolf Carl Virchow (1855) first explained that new cells can be formed from the preexisting cells.

→ All living organisms are composed of cells and products of cell

→ All cells arise from pre-existing cells.

→ Plasma membrane: The outermost layer of the cell that separates cytoplasm from the external environment.

→ Selectively permeable: Plasma membrane allows certain substances to pass membrane through it hence membrane is called a selectively permeable membrane.

→ Cell wall: It is an extra layer outside the cell membrane in plant cells.

→ Prokaryotic cell: Cell that does not have a nuclear membrane-bound nuclear material or cell without a distinct nucleus.

→ Eukaryotic cell: Cell contains a membrane-bound nuclear material or cell with a distinct nucleus.

→ Chromo plants: These are the coloured plastids present ¡n only in plant cells.

→ Chlora plants: Chloroplasts are a type of plastids in green colour. They are of different shapes disc, oval, etc.

→ Leucoplasts: These are colourless plastids present only ¡n plant cells.

→ Cisternae: Enclosed spaces ¡n the cytoplasm of a cell, which gets separated from the ground substance by the cytoplasmic membrane.

→ Vesicles: Used for a cavity within the cytoplasm which is surrounded by a membrane.

→ Cristae: These are the folds of the inner membrane of mitochondria

→ Matrix: It is the space between cristae.

→ Unicellular: Organism made of a single cell.

→ Multicellular organism: Organism made up of many cells.

→ Cytoplasm: Used for the part of protoplasm excluding the nucleus.

→ Nucleus: It ¡s the control room of a cell having genetic information.

→ Mitochondria: Cell powerhouse and is a seat for cellular respiration.

→ Proteins: They are synthesized from amino acids and form one of the main constituents of protoplasm.

→ Cytoplasm: Schlelden called the nucleus a cytoplasm he thought that new cells were created from the nucleus.

→ Suicide bags: Lysosomes cause the destruction of cells hence they are called suicide bags.

→ Cellular respiration: Respiration taking place within the cell.

→ Succulent plants: A xerophyte that stores water in the tissue giving it a fleshy appearance.

→ Unique: Being the only one of its kind.

→ Specific: Detailed or exact.

→ Flexible: Able to change to new conditions or situations.

→ Hormone: An organic substance produced in small amounts at one site ¡n an organism and transported to another site where it acts.

→ Enzyme: An organic catalyst that catalyses a reaction within a cell.

→ Certain organelles are present in large numbers in the cell for example cells involved in photosynthesis may contain around 50 to 200 chloroplasts.

→ The Father of Cell Biology:

• Albert Claude is considered to be the father of cell biology.
• He was awarded the Nobel Prize for physiology medicine in 1974.
• Born in Belgium, he moved to the United States and worked at the Rockefeller Institute to develop cell fractionation and ultracentrifugation.

Students can go through AP State Board 8th Class Biology Notes Chapter 1 What is Science? to understand and remember the concept easily.

AP State Board Syllabus 8th Class Biology Notes Chapter 1 What is Science?

→ The word Science comes from the Latin word “Scientia”. It means knowledge.

→ Science is an organized study of knowledge that is based on experimentation.

→ Science is a tool for searching truths of nature.

→ Science is the way of exploring the world.

→ Questioning is the primary or fundamental step in scientific thinking.

→ Many scientists find their greatest joy in a previously unknown fact that explains something problem, previously not explained, or that overturns some previously accepted idea.

→ Scientists observe nature and its laws. Scientists follow a specific way for their innovations. The way they follow is called Scientific Method.

→ In the words of Karl Popper,” Science is a history of corrected mistakes”.

→ Primitive: Of early times, of long ago, original, first of kind.

→ Concerted: Planned or carried out by two or more people working together or with the same aim.

→ Phenomena: Facts, (or) circumstances that can be observed

→ Exploring: Searching (or) investigating, to make a careful investigation (or) study of something.

→ Territorial: To land and water owned or claimed by an entity especially a government.

→ Discrete: Completely separate and unconnected

→ Perspective: The art of picturing objects on a flat surface so as to give the appearance of distance or depth.

→ Investigation: Into something especially a detailed one that is undertaken officially (or) an examination (or) inquiry.

→ Hypothesis: A tentative explanation for a phenomenon used as a basis for further investigation.

→ Predict: To announce or tell before head, forecast, prophesy, foretell.

→ Variables: Apt to change, changeable, uncertain, that can be varied.

→ Vocabulary: A list of words usually in alphabetical order with their meaning (or) grammar, glossary (or) dictionary.

→ Narrative: A story or an account of a sequence of events in the order in which they happened, narration, account.

→ Expressive: Conveying something, significant.

→ Persuasive: Able to persuade; fitted to persuade, convincing

→ Informative: To communicate information or knowledge to somebody.

→ Interpreting: To establish or explain the meaning or significance of something.

→ Analysis: A detailed examination of the elements or structure of something.

→ There are over 1000 organisms living on our skin. In the chapter on microorganisms, you have already seen the pictures of some of them. The biotic community consists of bacteria, fungi, and small arthropods, etc. The abiotic factors are dead skin cells, water, salts, and oil of our sweat, air, etc.

→ Albert Einstein:
Albert Einstein was born in 1879 in Germany. He was famous for his Theory of Relativity. He proved that light travels in, the form of particles called “Photons”. In 1921 he was awarded Nobel Prize in Physics E = MC² is his famous equation. He died in 1955.

→ Isaac Newton:
Sir Isaac Newton was born on 25 – 12 – 1642 in Lincolnshire. He was the discoverer of Laws of Gravitation. He worked as a professor of Mathematics at the age of 27 in Trinity College. He invented many things which are helpful to mankind. He died on 20 -3 -1727 in London.

Students can go through AP State Board 9th Class Physical Science Notes Chapter 12 Units and Graphs to understand and remember the concept easily.

AP State Board Syllabus 9th Class Physical Science Notes Chapter 12 Units and Graphs

→ A unit is a standard measure used for comparing measurements.

→ Units should be placed right side of the magnitude of every physical quantity.
For Example 2 kilograms, 100 grams.

→ The main fundamental quantities are mass (m), length (l), time (t).

→ Fundamental quantities are those physical quantities that cannot be expressed in terms of other quantities.

→ Fundamental quantities are also called base quantities.

→ Scientists evolved different types of measuring systems such as FPS, CGS, MKS, etc.

• FPS System: Foot – Pound – Second.
• CGS System: Centimeter – Gram – Second.
• MKS System: Meter – Kilogram – Second.

→ SI System is an International System of units.

→ In addition to mass, length, and time some other fundamental quantities were added to the SI system.

→ Units in SI System:

• Length – Meter (m)
• Mass – Kilogram (kg)
• Time – Second (s)
• Electricity – Ampere (A)
• Light intensity – Candela (Cd)
• Quantity of substance – Mole (Mol)
• Temperature – Kelvin (K)
• Plane angle – Radian (rad)

→ The quantities that are obtained by combining fundamental quantities either by multiplication or division or both operations are called derived quantities.

→ Some derived quantities are speed, velocity, area, volume, density, acceleration, force, pressure, etc.
→ Derived units are units of measurements derived from the fundamental units.

→ Some examples of derived units are

• Area – m²
• Volume – m³
• Speed – m/s
• Velocity – m/s
• Acceleration – m/s
• Force – \(\frac{\mathrm{kg}}{\mathrm{m} / \mathrm{s}^{2}}=\frac{\mathrm{kg} \cdot \mathrm{s}^{2}}{\mathrm{~m}}\) , etc.

→ We need to convert units of a physical quantity into a single system to compare both values.
For example: To compare 1500 m and 1.5 km Convert km into meters.
Then 1500 m = 1500 m, 1.5 km = 1500 m
Hence both values are equal.

→ 1000 m = 1 km
1000 is prefixed to meter called as ‘Kilo’

→ 1 km/hr = \(\frac{5}{18}\)m/s

→ Meter is the distance travelled by light in a vacuum in \(\frac{1}{299792458}\) seconds

→ There are some rules to follow while writing units.

→ A pictorial form of representation that shows the relation between two quantities can be called a graph.

→ The expressed quantity depends on the independent and dependent variables taken for plotting the graph.

→ Generally, independent variables are controlled or decided by us, but dependent variables are changed due to the change independent variable.

→ The thick horizontal line on the graph paper is called X-axis.

→ The thick vertical line on the graph paper is called Y-axis.

→ The Independent variable should be taken on the x-axis, whereas the dependent variable is on the y – axis.

→ The range is the difference between the highest value and lowest value of the data.
Range = highest value – lowest value.

→ Scale on X-axis = \(\frac{\text { Range }}{\text { The number of grids on } \mathrm{X} \text { -axis }}\)
Scale on y-axis = \(\frac{\text { Range }}{\text { The number of grids on } \mathrm{Y} \text { -axis }}\)

→ Axes should be named with the quantity taken on it along with their units.

→ The values taken as pairs such as (x₁, y₁), (x₂, y₂), are called data points.

→ If a graph is curved in shape, it is called a curved graph.

→ If a graph is a straight line, it is called a straight line graph.

→ Both curved, straight-line graphs are called line graphs.

→ Hooke’s Law: Elongation of the spring is proportional to mass.
The graph of extension and mass is a straight-line graph and it indicates the relationship of direct proportional between extension and mass.

→ Direct proportion:

• The initial values should be counted as “0”.
• The ratio of any pair has to be constant.
• If the value of one quantity increases, the value of the second quantity also increases.

→ Inverse proportional:

• The value of one quantity should be “0”, the value of the second quantity cannot be defined, it can be infinite.
• The product of any two pairs should be constant.
• The value of one quantity increases, the value of the second quantity should be decreased.

→ Pressure ∝ \(\frac{1}{\text { Volume }}\) [inversely proportionally]
The graph of pressure and volume is parabolic in shape.

→ Slope of the straight line = \(\frac{\text { Change in } y \text { -coordinates }}{\text { Change in } x \text { -coordinates }}=\frac{\text { rise }}{\text { run }}\) (or) tan θ = \(\frac{\Delta y}{\Delta x}\)

→ The slope of the graph is denoted by “m”.

→ The slope of the straight line increases along with the increase of angle.

→ The slope of the X-axis is zero.

→ Slope can be determined by coordinates of x, y, or by the angle of a straight line with the X-axis.

→ A curved line graph has an infinite number of slopes.

→ We can calculate the slope at any point on the curve by drawing a tangent to it.

→ The ratio of the Y and X-axis represents slope.

→ The product of quantities on the Y and X-axis is said to be an area of the graph.

→ Unit: A unit is a standard measure used for comparing measurements.

→ Fundamental: Fundamental quantities are those physical quantities that quantities cannot be expressed in terms of other quantities.

→ Basic quantities: Fundamental quantities are also called basic quantities.

→ FPS: Foot, Pound, Second.

→ CGS: Centimeter, Gram, Second.

→ MKS: Meter, Kilogram, Second.

→ SI System: International System of units.

→ Derived quantities: The quantities that are obtained by combining fundamental quantities either by multiplication or division or both operations are called derived quantities.

→ Some fundamental: Length, Mass, Time, Electricity, Light intensity, Quantity of quantities substance, Temperature, Plane angle.

→ Some derived quantities: Area, Volume, Density, Velocity, Acceleration, Force, Pressure.

→ Fundamental Units: Meter, Kilogram, Second, Ampere, Candela, Mole, Kelvin, Radian.

→ Derived Units: Derived units are units of measurement derived from the fundamental units. m², m³, kg/m³, m/s, m/s².

→ Meter: Meter is the distance travelled by light in a vacuum in \(\frac{1}{299792458}\) seconds

→ Graph: A pictorial form of representation that shows the relation between two quantities can be called a graph.

→ Independent: The variable which is controlled or decided by us to plot a graph variable is called the independent variable.

→ Dependent variable: The variable which is changed due to the change in the independent variable is called the dependent variable.

→ Grids: Grids of one square centimeter form by the intersection of thick lines and one square millimeter grid form with the intersection of thin lines in graph paper.

→ X-axis: The thick horizontal line on the graph paper is called X-axis.

→ Y-axis: The vertical thick line is called Y-axis.

→ Range: The highest value – the lowest value.

→ Scale: The interval taken to point the values on the axes is called scale.
Scale = \(\frac{\text { Range }}{\text { The number of grids on the axis }}\)

→ Data points: The values are to be taken as pairs in order to mark them as points on the graph such as (x, y) is called data points.

→ Curved line graph: If the line in a graph is in a curved shape, then the graph is called a curved line graph.

→ Straight-line graph: If the line in a graph is a straight line, then the graph is called a straight-line graph.

→ The slope of a straight: The ratio between the change in y-coordinates and the line graph x – coordinates gives the slope of the straight-line graph.

→ Slope = \(\frac{\text { Change in } y \text { -coordinates }}{\text { Change in } x \text { -coordinates }}=\frac{\text { rise }}{\text { run }}\) (or) tan θ = \(\frac{\Delta y}{\Delta x}\)
The slope is denoted with ‘m’.

→ Area of graph: The product of the physical quantity of the Y-axis and X-axis is said to be an area of the graph.


→ Robert Hooke:

• Born: 28th July (O.S. 18 July) 1635
• Died: 3rd March 1703 (aged 67)
• Nationality: English
• Alma mater: Wadham College, Oxford
• Known for: Hooke’s law, Microscopy,
• Coining the word ‘cell’
• Fields: Physics and Chemistry
• Institutions: Oxford University Academic
• Advisors: Robert Boyle
• Influences: Richard Busby

Students can go through AP State Board 10th Class Biology Notes Chapter 10 Natural Resources to understand and remember the concept easily.

AP State Board Syllabus 10th Class Biology Notes Chapter 10 Natural Resources

→ The earth’s natural resources are water, soil, minerals, fuels, plants, and animals.

→ Resources that can be replaced after they are used are called renewable resources.

→ Resources that cannot be replaced at all after they are used are called non-renewable resources.

→ Percolation tanks are normally earthen dams with masonry structures where water may overflow.

→ Conservation is the practice of caring for the resources so all living things can benefit from them now and in the future.

→ Management of resources is essential for their conservation and restoration.

→ Resources are usually local specific and local people need to have control over them.

→ People need to be motivated to reduce pressure on the environment by reducing the utilization of resources and reusing some of them.

→ Less than 0.01% of the water on the earth is surface water, but if used judiciously, shall last for a long time.

→ Drip irrigation can reduce water consumption by 70%.

→ Sustainable forestry practices are critical for ensuring resources well into the future.

→ Contour strip cropping helps in reducing soil erosion.

→ Biodiversity is the variety of living things that populate the earth.

→ We need to protect biodiversity to ensure we have plentiful and varied food sources, medicines, etc.

→ Fossil fuels were produced from the remains of ancient plants and animals.

→ We must use our resources judiciously especially fossil fuels, coal, and petroleum as they will be ultimately exhausted.

→ Scientists are trying to produce renewable biofuels to power cars and trucks.

→ Seeds from the Jatropha curcas plants are used for the production of biofuel.

→ Earth’s supply of raw mineral resources is in danger.

→ Four R’s help to save the environment. They are Reduce, Reuse, Recycle and Recover.

→ Interstate and intercountry disputes should not hamper the availability of a resource.

→ International Union for the Conservation of Nature (IUCN) works to protect wildlife and habitats.

→ Percolation tank: These are the structures for recharging groundwater, normally earthen dams.

→ Micro-irrigation: Irrigating crop fields with less amount of water by drip irrigation and sprinkler irrigation. Water conservation method.

→ Borewells: A well constructed by boring a vertical hole.

→ Sustainable development: When we use the environment in ways that ensure we have resources for the future it is called sustainable development.

→ Biofuels: A fuel derived from living matter (biological raw materials).

→ Contour strip farming: Forming by planting several crops, such as corn, wheat, and clover, in alternating strips across a slope or across the path of the prevailing wind.

→ Dyke Management: Dykes or barriers, nearly 30 cm thick of brick – cement or stone cement barriers, extending down to the compact bedrock with mud or clay fillings were built in underground streams to tap groundwater optimally.

→ Open dug well: A well made by excavating with hand tools or power machinery Instead of by drilling or driving.

→ Natural resources: Anything In the environment which can be used is called a natural resource.

→ Conservation: The protection of natural things such as animals, plants, forests, etc., to prevent them from being spoiled or destroyed.

→ Renewable resources: Any natural resource that can be replenished or replaced naturally after they are used is called renewable resources.
e.g.: Soil, water, plants, etc.

→ Non-renewable resources: Any natural resource that cannot be replaced at all or takes a long time for their formation are called non-renewable resources. e.g.: Coal, petroleum, natural gas, etc.

→ Selective harvesting: The practice of removing Individual plants or small groups of plants leaving other plants standing to anchor the soil is called selective harvesting.

→ Biodiversity: The variety of living things that populate the earth.

→ Jean-Baptist Joseph Fourier (1768 – 1830):

• Jean-Baptist Joseph Fourier was a French mathematician and physicist born in Auxerre and best known for initiating the investigation of the Fourier series and their applications to problems of heat transfer and vibrations.
• He was the First one to spoke about the Green House Effect in 1827.
• Gases like Carbon dioxide, Nitrogen oxides, Chlorofluorocarbons, Methane, etc. are called greenhouse gases.
• They warm up the earth and when fossil fuel is burnt Carbon dioxide is released.

Students can go through AP State Board 9th Class Physical Science Notes Chapter 11 Sound to understand and remember the concept easily.

AP State Board Syllabus 9th Class Physical Science Notes Chapter 11 Sound

→ Sound is produced by a vibrating body.

→ Sound is transmitted through a medium and received by our ears.

→ A sound is a form of energy.

→ Sound travels through disturbances in the form of waves.

→ The matter or the substance through which sound is transmitted is called the medium. If the particles of the medium vibrate along the direction of the wave, then the wave is called a longitudinal wave. Sound waves are longitudinal.

→ Longitudinal waves consist of compressions and rarefactions.

→ The region of the high density of particles in the medium during propagation of sound is called compression and low-density regions are called rarefaction.

→ The distance between two consecutive compressions or two successive rarefactions is called the wavelength of a sound wave.

→ If the particles of the medium vibrate perpendicular to the direction of the wave, then the wave is called a transverse wave.

→ The maximum variation in density or pressure from the mean value is called amplitude. The number of oscillations of the density of the medium at a place per unit time is called the frequency of the sound wave.

→ The time taken to complete one oscillation of the density of the medium is called the time period of the sound wave.

→ Frequency and time period are related as T = 1/u or o = 1/T

→ The distance by which a point on the wave, such as a compression or rarefaction travel in unit time is called the speed of the sound wave.

→ The relation between the speed of a sound wave, wavelength, and frequency is v = uA.

→ The sounds which produce pleasing effects on the ear are called musical sounds, while the sounds which produce unpleasant effects are called noises.

→ The characteristics by which one can distinguish a musical note from another are pitch, loudness, and quality.

→ Pitch is a characteristic of sound which distinguishes between a shrill sound and a deep, low sound.

→ The loudness of sound is defined as the degree of sensation produced in the ear, measured in decibels.

→ The quality of sound is the characteristic that enables us to distinguish between musical notes emitted by different musical instruments.

→ Sound reflects as light reflects.

→ A reflection of sound, arriving at the listener in more than 0.1 s after the direct sound is called an echo.

→ A reflection of sound, arriving at the listener in less than 0.1 s after the direct sound is called reverberation.

→ The human ears are able to hear sound in a frequency range of about 20 Hz to 20 kHz. Sounds of frequency less than 20 Hz are known as infrasonic sounds.

→ Sounds of frequency higher than 20 kHz are known as ultrasonic sounds.

→ Ultrasonic waves are used in drilling holes or making cuts of different shapes, cleaning, detection of defects in metals, in the medical field to imaging of organs, surgeries, etc.

→ SONAR stands for Sonographic Navigation and Ranging.

→ SONAR is equipment or a system for finding objects underwater using sound waves.
→ Mechanical energy: Energy produced by mechanical means like pushing, pulling, beating, vibrating, etc. is known as mechanical energy.

→ Tuning fork: A tuning fork is an acoustic resonator. It is a steel bar, bent in U-shape, with a handle at the bend. It resonates at a specific constant pitch when set into vibration by a string with a rubber hammer.

→ Longitudinal wave: If the particles of the medium vibrate along the direction of the wave, then the wave is called a longitudinal wave.

→ Transverse wave: If the particles of the medium vibrate perpendicular to the direction of the wave, then the wave ¡s called a transverse wave.

→ Compression: Compression is the region where density, as well as the pressure of particles in the medium, is high.

→ Rarefaction: Rarefaction is the region where density, as well as the pressure of particles in the medium, is low.

→ Crest: Crest is a point where the amplitude of a wave is maximum in a transverse wave.

→ Trough: A trough is a point where the amplitude of a wave is minimum in a transverse wave.

→ Pressure: Pressure is force per unit area applied in a direction .perpendicular to the surface of an object. The SI unit of pressure is the newton per square meter, which is called the pascal (Pa) after the seventeenth-century philosopher and scientist Blaise Pascal.

→ Wavelength: The distance between two consecutive compressions or two consecutive rarefactions is called the wavelength of a sound wave.

→ Amplitude: The maximum variation in density or pressure from the mean value is called amplitude.
(or)
The maximum disturbance of the particles of a medium from their mean position is called amplitude.

→ Frequency: The number of oscillations of the density of the medium at a place per unit time is called frequency.

→ Pitch: Pitch is a characteristic of sound which distinguishes between a shrill sound and a deep, low sound.

→ Loudness: Loudness of sound is defined as the degree of sensation produced in the ear.

→ Quality of sound: The quality of sound is the characteristic that enables us to distinguish between musical notes emitted by different musical instruments.

→ Echo: A reflection of sound, arriving at the listener in more than 0.1 s after the direct sound is called an echo.

→ Reverberation: A reflection of sound, arriving at the listener in less than 0.1 s, after the direct sound is called reverberation.

→ Infrasonic: Sound of frequency less than 20Hz is known as infrasonic sound.

→ Sonic: Of or relating to audible sound. e.g: a sonic wave.

→ Ultrasonic: Sound of frequency greater than 20 kHz is known as ultrasonic sound.

→ SONAR: SONAR stands for Sonographic Navigation And Ranging. It is equipment or a system for finding objects underwater using sound waves.

→ Heinrich Rudolf Hertz:
Heinrich Rudolf Hertz was born on 22 February 1857 in Hamburg, Germany, and educated at the University of Berlin. He was the first to conclusively prove the existence of electromagnetic waves. He laid the foundation for the future development of radio, telephone, telegraph, and even television. He also discovered the photoelectric effect which was later explained by Albert Einstein. The SI unit of frequency was named Hertz in his honor.

Students can go through AP State Board 10th Class Biology Notes Chapter 8 Heredity to understand and remember the concept easily.

AP State Board Syllabus 10th Class Biology Notes Chapter 8 Heredity

→ Variations arising during the process of reproduction can be inherited.

→ Variations may lead to increased survival of the individuals.

→ Gregor Johann Mendel known as the father of genetics started working on the problem of how variations were passed from one generation to another.

→ Mendel had chosen 7 pairs of contrasting characters in pea plants for his study: flower colour, flower position, seed colour, seed shape, pod colour, pod shape and stem length.

→ The Pea plant is an annual plant that contains vitamins A, C, E, K and B and minerals like Ca, Fe, Mn. Mg, P, S and Zn.

→ Cross-pollinating a pure breed of yellow and green gave all pea seeds in the F₁ generation were yellow.

→ On self-pollination plants of Ft generation, they gave about 75% yellow seeds and 25% green seeds in the F₂ generation.

→ The phenotype ratio of F₂ plants is 3: 1.

→ In the F₂ generation out of 75%, 25% were pure yellow seeds, 50% were yellow seeds but green was a recessive factor. The remaining 25% were pure green. This is called genotype. The ratio is 1: 2: 1.

→ In the F₃ generation, Mendel self-pollinated F₂ generation pea plants and found that about 25% gave only yellow seed giving pea plants, the rest of the yellow pea plants gave about 75% yellow and about 25% green seed giving pea plants.

→ And the set of green peas gave only green seed giving pea plants.

→ Every pea plant has two factors that are responsible for producing a particular property or trait called “allele”.

→ During sexual reproduction, one factor from each parent is taken to form a new pair in the offspring.

→ Crossing yellow and green seeds produced all yellow seeds because yellow is the dominant factor.

→ In the inheritance of more than one pair of characters, the factors for each pair of characters assort independently of the other pairs. This is known as Law of independent assortment.

→ The factors which are responsible for the character or trait of an organism, are now named genes.

→ Law of dominance states that among a pair of alleles for a character only one expresses itself in the first generation, as one of the alleles is dominant over the other.

→ The Law of segregation states that every individual possesses a pair of alleles for any particular trait and that each parent passes a randomly selected copy (allele) of only one of these to its offspring.

→ Traits that may be passed from one generation to the next are called heritable traits.

→ Sexual reproduction and errors in DNA copying lead to variations in offspring in a population.

→ Change in the frequency of genes in small populations is known as genetic drift.

→ Jean-Baptist Lamarck was the first person to propose the theory of evolution. He proposed the inheritance of acquired characters.

→ Characters that are developed during the lifetime of an organism are called acquired characters.

→ August Weismann proved that bodily changes are not inherited.

→ Charles Darwin proposed the famous theory of evolution called Natural Selection.

→ Transmission or passing of characters or traits from parent to offspring is called Heredity.

→ The process in which traits are passed from one generation to another generation is called Inheritance.

→ Gene is a segment of a nucleic acid called DNA which is present in the nucleus of every cell.

→ The detailed structure of DNA was discovered by Francis Crick and James Waston.

→ Each human cell contains 23 pairs of chromosomes out of which 22 pairs of chromosomes are autosomes.

→ 1 pair of chromosomes are called allosomes or sex chromosomes.

→ Gametes produced by women will be with only ‘X’ chromosomes.

→ Gametes produced by man will be of two types one with X chromosomes and the other with Y chromosomes.

→ If the sperm carries the X chromosome and fertilizes the ovum with the X chromosome, the resultant baby will have XX condition. So the baby will be a girl.

→ If the sperm carries the Y chromosome and fertilizes the ovum with the X chromosome, the resultant baby will have XY condition. So the baby will be a boy.

→ According to the theory of Natural selection, nature only selects or decides which organism should survive or perish in nature.

→ Alfred Russel Wallace concluded that natural selection contributed to the origin of new species.

→ Walter Setton and Thomas Morgan conducted experiments on (fruit fly) Drosophila melanogaster about sex-linked inheritance in them.

→ In the struggle for existence, only the fittest can survive.

→ Darwin published his famous book The origin of species’ in 1859.

→ The small changes within the species are called Micro Evolution.

→ The changes beyond the species are called Macro Evolution.

→ The organs which perform different functions but have similar structures and origins are called homologous organs, eg.: Forelimb of whale, a wing of bat. leg of cheetah, the claw of a mole and the hand of man.

→ The organs which are similar in appearance and function, but have different structures and origins are called analogous organs, eg.: Wings of butterflies, bats and birds.

→ Embryology is the study of the development of an organism from egg to the adult stage.

→ The developmental stages of different animals reveal that they are evolved from common ancestors.

→ Preserved traces of living organisms are called fossils.

→ The study of fossils is called palaeontology.

→ Archeopteryx is recognised as connecting link between Aves and reptiles.

→ Human evolution is the evolutionary process leading up to the appearance of a modern human being.

→ There are nearly 180 vestigial organs are present in human beings.

→ Variations: Differences in characters within closely related groups of organisms are referred to as variations. They result in organisms belonging to a species being different from each other.

→ Offsprings: The organism or organisms resulting from sexual or asexual reproduction. The product of the reproductive processes of an animal or plant.

→ Traits: A distinguishing characteristic or quality, typically one belonging to a person or animal.

→ Phenotype: It is the composite of an organism’s observable characteristics or traits such as its morphology, development, etc.

→ Genotype: It Is the genetic makeup of an individual usually with reference to a specific characteristic tinder consideration.

→ Heterozygous: It refers to have two different alleles for a single trait.

→ Homozygous: Homozygous refers to have two identical alleles for a single trait.

→ Independent assortment: It states that allele pairs separate independently during the formation of gametes.

→ Allele: It is an alternative form of a gene that is located at a specific position on a specific chromosome.

→ Heredity: The process of acquiring characters or traits from parents to offspring.

→ Autosomes: An autosome is any chromosome that is not a sex-determining chromosome. In humans, there are 22 Pairs of autosomes.

→ Allosomes: Sex determining chromosomes that differ from an ordinary autosome in size, form and behaviour human sex chromosomes are a typical pair of sex chromosomes.

→ Natural selection: Darwin’s most famous theory. A process resulting in the survival of those individuals from a population of animals or plants that are best adapted to the prevailing environmental conditions.

→ Analogous organs: Organs that have similar appearance and functions but have different structures and origins. eg.: Wings of butterfly, of a bat and of a bird.

→ Embryological: Evidence available from the embryonic development of evidence organism for organic evolution.

→ Human evolution: It Is the evolutionary process leading to the appearance of anatomically modern humans.

→ F₁ Generation: FIrst filial or progeny of first-generation. The first generation was produced by a cross and consisting of hybrid organisms.

→ F₂ Generation: The generation produced by interbreeding individuals of an F₁ generation.

→ Gene: A gene is the basic physical and functional unit of heredity. Gene is a working subunit of DNA.

→ Dominant gene: Gene that produces the same phenotype in the organism whether or not its allele is identical.

→ Recessive gene: Gene that produces its characteristic phenotype only when its allele is identical.

→ Inheritance: The process in which traits are passed from one generation to another generation.

→ Evolution: Evolution is a change in heritable traits of biological populations over successive generations.

→ Genetic drift: It is the change ¡n the frequency of genes in a small population.

→ Acquired characters: The characters that are developed during the lifetime of an organism are called acquired characters.

→ Microevolution: Evolutionary change within a species or small group of organisms, especially over a short period.

→ Macroevolution: Macroevolution generally refers to evolution above the species level.

→ Homologous organs: The organs which perform different functions but have similar structures and origins. eg.: Wing of the bat, the flipper of a seal, front leg of a horse, an arm of a man, etc.

→ Subtle: So delicate or precise as to be difficult to analyse or describe.

→ Ancestors: Ancestors ¡s any person from whom one is descended.

→ FossIl: These are evidence of ancient life forms which have been preserved by natural processes.

→ Palaeontology: The study of fossils is called Palaeontology.

→ Vestigial organs: The organs which are not useful in animals are called vestigial organs.

→ Heredity:

→ Monohybrid cross:

→ Sex Determination in Human:

→ Mechanism of Heredity:

→ Genetic Drift:

→ Human Evolution:

→ Genetic footprints of Humans hundreds/thousands of years ago Earliest members are in Africa:

→ Gregor Johann Mendel (1822 – 1884):

• Gregor Johann Mendel was considered as ‘Father of Genetics’.
• He was the first person to trace the characteristics of successive generations of a living thing.
• He was an Augustinian monk. So he did all his experiments in the monastery garden.
• Mendel made many careful observations of plants and chose pea plants for his experiments through which he made the law of inheritance.
• His work was so brilliant and unprecedented at the time it appeared, that it took thirty-four years for the rest of the scientific community to catch up to it.

Students can go through AP State Board 9th Class Physical Science Notes Chapter 10 Work and Energy to understand and remember the concept easily.

AP State Board Syllabus 9th Class Physical Science Notes Chapter 10 Work and Energy

→ Two conditions need to be satisfied in order to say that work has taken place. One is a force that should act on the object and another is the object must be displaced or there must be a change in the position of the object.

→ Work W = F × s (This formula for work is used in only translatory motion of the object)

→ Units of work ‘N-m’ (or) ‘Joule’.

→ Work has only magnitude, no direction. So work is a scalar.

→ If a force acting on an object and displacement are in opposite directions, then the work done by the force is taken as negative.

→ If work has a positive value, the body on which the work has been done would gain energy.

→ If work has a negative value, the body on which the work has been done losses energy.

→ The capability of doing work by an object is defined as the energy of the object.

→ The energy of an object depends on the position and state of the object which is doing work.

→ Whenever work has been done on an object, its energy either increases or decreases,
i. e., energy transfer takes place from one object to another object.

→ The sun is the biggest natural and primary source of energy.

→ Energy can exist in several forms like mechanical energy, light energy, thermal energy, sound energy, electrical energy, magnetic energy, etc.

→ The main source of energy for the human body is food.

→ The energy possessed by an object due to its motion is called kinetic energy.
K.E = \(\frac{1}{2}\)mv²

→ The K.E. of an object increases with its speed.

→ The energy possessed by an object because of its position or shape is called its potential energy.
P.E. = mgh

→ The sum of the kinetic energy and the potential energy of an object is called it’s mechanical energy.

→ Energy will be converted from one form to other forms in nature.

→ The law of conservation of energy states that the energy neither is created nor destroyed. It can only be changed from one form to another.

→ Power is defined as the rate of doing work or the rate of transfer of energy.
Power (P) = \(\frac{\text { Work }(W)}{\text { Time }(t)}\)

→ The unit of power is ‘watt’.

→ Work: A work is said to be done when the following conditions are satisfied.

• A force should act on the object
• The object must be displaced or there must be a change in the position of the object

(or)
Work is equal to the product of the force applied and displacement. W = F × s

→ Energy: The capability of doing work by an object is known as the energy of the object.

→ Transfer of energy: Energy transfer will take place from one object to another object when work has been done by the object.

→ Sources of energy: Sun is the main natural source of energy. There are so many derived sources of energy due to the sun. Some artificial sources of energy are thermal energy, electrical energy, etc.

→ Conservation of energy: Energy can neither be created nor destroyed. It can only be changed from one form to another. This is called the law of conservation of energy.

→ Kinetic energy: The energy possessed by an object due to its motion is called kinetic energy.
K.E. = \(\frac{1}{2}\)mv²

→ Potential energy: The energy possessed by an object because of its position or shape is called its potential energy.
P.E. = mgh

→ Mechanical energy: The sum of kinetic energy and the potential energy of an object is called it’s mechanical energy.

→ Gravitational potential: An object increases its energy when it is raised through a height, because of the work done on the object against gravity acting on it. The energy of such an object is known as gravitational potential energy.

→ Power: Power is defined as the rate of doing work or the rate of transfer of energy.


→ Gaspard-Gustave Coriolis:

• Coriolis was born in Paris on 21 May, 1792.
• He was a French mathematician and physicist.
• He worked to extend the notion of kinetic energy and work to rotating systems.

Students can go through AP State Board 9th Class Physical Science Notes Chapter 9 Floating Bodies to understand and remember the concept easily.

AP State Board Syllabus 9th Class Physical Science Notes Chapter 9 Floating Bodies

→ Density is defined as mass per unit volume. Mass
Density = \(\frac{\text { Mass }}{\text { Volume }}\)
Unit of density = gm/cm3 or kg/m3

→ The relative density of an object is the ratio of the density of the object to the density of the water.
Relative density of an object = \(\frac{\text { Density of the object }}{\text { Density of water }}\)

→ Experimentally relative density of a solid object = \(\frac{\text { Weight of the object }}{\text { weight of water equal to the volume of the object }}\)

→ Relative density of liquid = \(\frac{\text { Weight of liquid }}{\text { Weight of the same volume of water }}\)

→ Lactometer is used to measure the purity of milk.

→ A hydrometer is used to measure the relative density of liquids.

→ Objects having a density less than the liquid in which they are immersed float on the surface of the liquid.

→ Every fluid exerts upward pressure on the objects immersed in them. If the upward pressure is less than the gravitational force on the object, the object sinks otherwise it floats on the liquid.

→ The pressure exerted by the air in our surroundings is known as atmospheric pressure. Atmospheric pressure P₀ = ρhg.

→ The barometer is used to measure the atmospheric pressure at a place.

→ Pressure at a depth ‘h’ in a liquid P = P₀ + ρhg
P₀ = Atmospheric pressure ; ρ = density of the liquid h = depth ; g = acceleration due to gravity

→ Buoyancy is the upward force exerted by the liquid on any object less dense than itself.

→ When an object is immersed in a fluid, it appears to lose weight (because of buoyancy).

→ The apparent loss of weight of an object, which is immersed in a liquid, is equal to the weight of the liquid displaced by the object. (Archimedes principle)

→ When an object floats on the surface of a liquid, it displaces a weight of liquid equal to its own weight.

→ The pressure exerted by a liquid increases with depth below the surface of the liquid.

→ Pascal’s principle states that external pressure applied to an enclosed body of fluid is transmitted equally in all directions throughout the fluid volume and the walls of the containing vessel.

→ Density: When two objects of equal volume are considered the object
with higher mass is said to be a dense object. Density is defined as mass per unit volume.
∴ Density = \(\frac{\text { Mass }}{\text { Volume }}\)
Unit of density gm/cm (or) kg/rn3.

→ Relative density: Relative density is the ratio of the density of an object to the density of water.
Relative density of an object = \(\frac{\text { Density of the object }}{\text { Density of water }}\)
(or)
Relative density of an object = \(\frac{\text { Weight of the object }}{\text { weight of water equal to the volume of the object }}\)

→ Lactometer: Lactometer is a device used to measure the purity of milk. It works on the principle of relative density.

→ Hydrometer/ Densitometer: Hydrometer/Densitometer ¡s an instrument used to measure the relative density of any liquid.

→ Atmospheric pressure: Air in our surroundings exerts pressure on the surface of the earth called atmospheric pressure.
Atmospheric pressure P₀ = ρhg
ρ = average density of air
h = height of the atmosphere
g acceleration due to gravity

→ Barometer: Atmospheric pressure can be measured using a barometer. The first barometer was invented by ‘Torricelli’, using mercury. The height of the mercury column at normal atmospheric pressure is 76 cm.
The increase or decrease in the height of the mercury column indicates sudden changes in the atmosphere.

→ Buoyancy: The upward force that a fluid exerts on an object less dense than itself.
(or)
Buoyancy is the ability of an object to float in a liquid.

→ Archimedes principle of buoyancy: An object in a fluid is buoyant up by a force equal to the weight of the fluid the object displaces.

→ Archimedes:

• Archimedes was born in 287 BC and died in 212 BC.
• He was a Greek mathematician, physicist, engineer, inventor, and astronomer.
• He is well known for his Archimedes principle.
• Among his advances in physics are the foundations of hydrostatics.