Please Explain System of Units (Class 11 – Physics).
The living world is a complex network of interconnected organisms that engage in metabolism, reproduction, and response to environmental cues. We are aware of how intricately connected everything in the living world is. The diversity of living forms on earth gives it a wonderful environment to liveRead more
The living world is a complex network of interconnected organisms that engage in metabolism, reproduction, and response to environmental cues. We are aware of how intricately connected everything in the living world is. The diversity of living forms on earth gives it a wonderful environment to live and thrive. The abundance of diversity suggests the presence of numerous species with unique characteristics. The fact that an organism is either a living thing or a non-living entity is its most striking characteristic. As a result, in order to distinguish between a living item and a non-living one, we first need to define what a “living being” actually is.
What is ‘Living’?
Any organism that breathes and moves is considered ‘Living’. Any life form that exhibits or possesses the qualities of life or being alive is referred to as a living thing. The basic traits include having an organized structure, requiring energy, reacting to stimuli and changing their surroundings, and having the ability to reproduce, grow, move, metabolize, and die. The three Domains that make up the current classification of living things are Bacteria, Archaea, and Eucarya.
Characteristics of Living World
All living organisms grow and increase in mass and number of individuals. Growth, reproduction, ability to sense the environment and mount a suitable response is unique features of living organisms. Given below are some characteristic features of the Living world:
Respiration
- Aerobic respiration: Aerobic respiration is a chemical process in which oxygen is used to make energy from sugars. Aerobic respiration is also known as aerobic metabolism and cell respiration.
- Anaerobic respiration: Anaerobic respiration takes place in the absence of oxygen. examples include alcohol fermentation and lactic acid fermentation.
Nutrition
- Autotrophic Nutrition: It is a type of nutrition in which plants make their own food .they are interdependent on themselves. example- plants. Autotrophic nutrition is of two types: phototrophic, and chemotrophic.
- Heterotrophic Nutrition: It is a type of nutrition in which an organism is dependent on another organism for food. example -humans. Heterotrophic nutrition is of three types: herbivorous, carnivorous, and omnivorous.
Excretion
The process of moving out waste material from the body is known as excretion.
Locomotion/Movement
Locomotion is a term used to describe a movement of an organism from one place to another.
Reproduction
- Asexual Reproduction: A process where a single gamete is responsible for reproduction to take place i.e., new offspring is produced from a single parent. Examples: hydra and paramecium.
- Sexual Reproduction: Process where both the gametes take part in reproduction. Examples: fishes, and mammals.
Structural Organisation
- Unicellular: It is also known as a single-celled organism and only single cells perform all the functions needed for an organism to live. example- protozoa and Protista.
- Multicellular: Multicellular organisms consist of many cells to perform different functions. example-Dogs, cows.
Diversity
A large variety of anything is known as diversity. Diversity is a vast term to include different species, genes, and ecosystem levels. Thomas Lovejoy introduced the term biological diversity in 1980.
Biodiversity
A large variety of organisms or terms used to refer to the number of varieties of plants and animals on earth is termed biodiversity. there are three types of biodiversity: genetic, species, and ecological diversity. There are over 15 Lakh species in the world of which 10 Lakh are animals(8 Lakh of insects and 2 Lakh of others) and 5 Lakh of plants.
Nomenclature
The scientific naming of organisms is known as nomenclature. Nomenclature is defined as the language of sculpture. The scientific name of mango is written as Mangifera indica.
Rules of Nomenclature
- Latinised names are used.
- The first word represents the genus and the second word is the species name.
- Printed in italics, if handwritten then underline separately.
- The first word starts with a capital letter while the species name is written in small letters.
ICBN International Code of Botanical Nomenclature (This is for giving scientific names to plants).
ICZN International Code of Zoological Nomenclature(This is for giving scientific names to animals).
Classification
Grouping organisms into categories on the basis of similarities and differences is known as classification. classification is the process by which anything is grouped into systematic categories based on some easily observable characteristics. For example, we easily recognize groups such as plants or animals, dogs or cats, insects, or reptiles.
Need of Classification
Classification is done to organize the vast number of plants and animals into categories that could be named, remembered, studied, and understood. classification avoids confusion among the different varieties of organisms. Moreover, it makes the study of organisms easier.
Given below are some scientist’s contributions to biology
- Carolus Linnaeus (Father of Taxonomy): He gives the 2 kingdoms system.
- Hackel: He gave the 3 kingdom systems.
- Copeland: He gave the 4 kingdom systems.
- R.H Whittaker: He gave the 5 kingdom system which is the popular one.
- Carl Woese: He gave the 6 kingdom system and is the latest.
Taxonomy
The study of principles and procedures of classification is termed taxonomy. Based on characteristics, all living organisms can be classified into different taxa. This process of classification is taxonomy.
Taxonomic Categories
A. P. Candolle is credited with coining the term “taxonomy,” which refers to the seven main taxonomic categories. It is the listing of categories from the top-most kingdom to the bottom-most species, either in ascending or declining orders. There are two kinds in the hierarchy: intermediate and mandatory. From kingdoms to species, Obligate is rigidly adhered to, yet Intermediate is the exact reverse.
- Species: The smallest and most fundamental distinction in classification is the species. It describes a population that is comparable in terms of form, shape, and reproductive characteristics. Similar reproductive characteristics can lead to the formation of fertile siblings.
- Genus: This is the grouping of a number of closely related species that share linked features and are thought to have shared ancestors. For instance, the genus Panthera is where the leopard and cat belong.
- Family: Families are associations of connected genera. The vegetative and reproductive characteristics are used to categorize the families. The Felidae family includes animals like tigers and lions as examples.
- Order: It is the combination of one or more common families, which is regarded as a higher category. Felidae family members participate in the Carnivora order.
- Class: A class designates a division in a phylum made up of one or more orders. All mammals, including gorillas, monkeys, humans, and gibbons, are included in the Mammalia class.
- Phylum: It contains a group of related classes. Mammalia, along with reptiles, fish, amphibians, and birds, make up the phylum Chordata.
- Kingdom: The highest taxonomic classification known as a kingdom is given to every animal that belongs to various phyla. The kingdom Animalia and Plantae encompasses all living things, including both plants and animals. A taxon is a classification that identifies an organismal group based on external characteristics.
FAQs on Living World
Q1: Define the following terms: Phylum, and Class.
Answer:
- Phylum– Classes comprising animals like fishes, amphibians, reptiles, and birds along with mammals constitute the higher category called phylum. All these, based on the common features like the presence of notochord and dorsal hollow neural system, are included in phylum Chordata.
- Class– This category includes related orders. For example- the order primate comprising monkey, gorilla, and gibbon is placed in class Mammalia along with the order Carnivora which includes animals like tiger, cat, and dog.
Q2: How is a key helpful in the identification and classification of organisms?
Answer:
The key is defined as the taxonomical aid used to identify and classify plants and animals based on their similarities and differences. Keys are generally analytical in nature.
Q3: Define a taxon.
Answer:
Taxon is plural of taxa, it is the taxonomic unit of any rank. ARISTOTLE is known as the father of taxonomy.
Q4: Why are living organisms classified?
Answer:
See lessLiving organism are classified due to the following reasons:
- To make study of organism easy.
- To avoid confusion.
- To learn the interrelationship among the various organisms.
Formula for Gravitational Force,
Strong Nuclear Force
Measurement forms the fundamental principle to various other branches of science, that is, construction and engineering services. Measurement is defined as the action of associating numerical with their possible physical quantities and phenomena. Measurements find a role in everyday activities to aRead more
Measurement forms the fundamental principle to various other branches of science, that is, construction and engineering services. Measurement is defined as the action of associating numerical with their possible physical quantities and phenomena. Measurements find a role in everyday activities to a large extent. Therefore, it is necessary to study and explore the associated elements along with their theoretical foundations, conditions as well as limitations. It defines the units to be chosen for the measurement of various commodities. It also caters to the comparison of plausible units with the ones already existing of a similar kind.
Measurement defined the new standards as well as form transductions for the quantities which do not have any possible access for direct comparison. These physical quantities can be converted into analogous measurement signals.
Measurements may be made by unaided human senses, generally termed as estimates. It can also be estimated by the use of instruments, which may range in complexity from simple rules for measuring lengths to highly complex analogous systems to handle and design the commodities beyond the capabilities of the senses. Thus, the measurements may range from buying some quantity of milk (in L) or to the highly complex mechanisms, such as radio waves from a distant star or the nuclear bomb radiations. Therefore, we can consider that a measurement, always involves a transfer of energy or interaction between the object and the observer or observing instrument.
Measurement of Height of a person
Unit
The unit of a specified physical quantity can be considered as an arbitrarily chosen standard that can be used to estimate the quantities belonging to similar measurements. The units are well accepted and recognized by the people and well within all guidelines.
The chosen standard is recognized as the unit of that corresponding physical quantity. A standard unit, in short, is a definite amount of a physical quantity. These standard units can be quickly reproduced to create a wide variety of units and are internationally accepted and accessible.
The measurement of any physical quantity is based on a formula, nu,
where, n = numerical value of the measure of the quantity,
u = unit of the quantity.
Standard
The actual physical embodiment of the unit of a physical quantity is termed as a standard of that physical quantity. The standard is expressed in terms of the numerical value (n) and the unit (μ).
Measurement of physical quantity = Numerical value × Unit
For example: Length of a rod = 12 m. Here 12 is its numerical segment and m (meter) is the unit.
Fundamental Units
Fundamental units are elementary in nature, that is, they can be expressed independently without any dependence on any other physical quantity. This implies that it is not possible to resolve it further in terms of any other physical quantity. It is also termed as a basic physical quantity. Fundamental quantities have their own values and units.
Supplementary Fundamental Units
There are two other supplementary fundamental units, namely Radian and steradian are two supplementary which measures plane angle and solid angle respectively.
One radian is equivalent to an angle subtended at the center of a circle by an arc of length equal to the radius of the circle. It is the unit represented for the plane angle.
θ = 1 radian
One steradian is equivalent to the solid angle subtended at the center of a sphere by its surface. Its area is equivalent to the square of the radius of the sphere.It is the unit represented for the solid angle. Solid angle in steradian,
Ω = 1 steradian
Properties of Fundamental Units
Any standard unit should have the following two properties:
The standard unit must be invariable. Thus, defining distance between the tip of the middle finger and the elbow as a unit of length is not invariable.
The standard unit should be easily made available for comparing with other quantities.
The seven fundamental units of S.I. have been defined as under.
Defined as 1650763.73 times the wavelength, in vacuum of the orange light emitted in transition from 2p10 to 5d5.
Defined as the mass of a platinum-iridium cylinder kept at Serves.
Time taken by 9192631770 cycles of the radiation from the hyperfine transition in cesium – 133 when unperturbed by external fields.
The constant current which, if maintained in each of two infinitely long, straight, parallel wires of negligible cross-section placed 1 m apart, in vacuum, produces between the wires a force of 2×10-7 newton per meter length of the wires.
Temperature is measured with absolute zero as the zero and the triple point of water as the upper fixed point on the thermodynamic scale. The interval is divided into 273.15 divisions and each division is considered to be unit temperature.
The luminous intensity in the perpendicular direction of a surface of
The mole is the amount of any substance which contains as many elementary entities as there are atoms in 0.012 kg of the carbon isotope
Derived units
The derived units are in usage for the commodities where the units are obtained from a combination of fundamental units. Derived units are sometimes assigned names. For instance, the S.I unit of force is kg ms-2 , termed as Newton (N). The unit of power is kg m2 s-3 , termed as watt (W).
Steps to find Derived Units
Example: Compute the unit of velocity.
Since, we know velocity is a derived quantity, obtained from distance and time(fundamental quantities).
Mathematically ,
velocity = displacement/time
S.I. unit of velocity =
= m/s
Thus S.I. unit of velocity is m/s.
Some Important derived units
Some of the derived units have been given specific names, depending on the increase in their usage , though they are not recognized in S.I units.
Systems of Units
Any system of units contains the entire set of both fundamental as well as derived units, for all kinds of physical quantities. The preferred system of units are the following :
The unit of length is centimeter, the unit of mass is gram and the unit of time is second according to the guidelines of this system.
The unit of length is foot, the unit of mass is pound and the unit of time is second according to the guidelines of this system.
The unit of length is meter, the unit of mass is kilogram and the unit of time is second according to the guidelines of this system.
The System Internationale d’ Units, that is S.I system contains seven fundamental units and two supplementary fundamental units.
Note:
While computation of values for any physical quantity, the units for the involved derived quantities are treated as algebraic quantities till the desired units are obtained.
Advantages of S.I Unit System
The S.I unit of measurement is preferred over other units of measurement, because,
Other Important Units of Length
The distances can be infinitely larger in magnitude, which cannot be depicted in terms of meters or kilometers. For instance, the distances of planets and stars etc. Therefore, it is necessary to use some larger units of length such as ‘astronomical unit’, ‘light year’, parsec’ etc. while making such calculations, some of which are :
1 AU = 1.496 x 1011 m.
1 light year = 9.46 x 1015 m.
1 parsec = 3.08 x 1016 m
1 fermi = If = 10-15 m
1 angstrom = 1A = 10-10 m
Sample Problems
Problem 1. Convert the unit of G, which is gravitational constant, G = 6.67 x 10-11Nm2/kg2 in CGS system.
Solution:
Problem 2. Name the S.I units of the following commodities :
a. Pressure
b. Solid angle
c. Luminous intensity.
Solution:
Problem 3. Derive the S.I unit of latent heat.
Solution:
Problem 4: How are A0 and A.U related?
Solution:
Problem 5: Describe 1 light-year in meters.
Solution:
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