Category: Biology

Introduction

Mammals, fish, amphibians, birds, and reptiles are among the five classes into which animals are divided. Each one of them needs the environment to survive, including air, food, water, and shelter. The only vertebrates that live part of their lives in water and part on land are amphibians. As a result, they differ from other animal species. An amphibian is a tiny vertebrate organism that requires water or a moist environment to exist. As amphibian’s body temperatures are influenced by their surroundings and they can thrive in both terrestrial and aquatic habitats, they are also referred to as cold-blooded vertebrates. Frogs, toads, newts, caecilians, and salamanders are amphibians.

Characteristics of Class Amphibia

Body 

• Amphibian bodies are separated into the head, trunk, and tail. Few amphibians just have a head and a tail (frogs). The neck can be absent or present.
• Some amphibians are limbless, while others have two sets of pentadactyl limbs.
• The skin is smooth, moist, scale-free, and abundant with mucous glands.

Sense organs

• Amphibians have two olfactory lobes that are responsible for their ability to smell.
• Eyes are well developed.
• Although they lack an external ear, the tympanum shields their middle ear.

Digestive system

• Amphibians have digestive systems that include the mouth, oesophagus, stomach, and intestine closing in a division called the cloaca.
• Cloaca participates in the digestive, excretory, and reproductive systems.

Circulatory system

• Amphibians have a closed circulatory system.
• They have three-chambered hearts, that are made up of two auricles and one ventricle.
• There are two circulatory paths; one is for the oxygenation of the blood through the lungs and skin and another route is to carry oxygen to the remaining parts of the body.
• However, there is incomplete double circulation because the oxygenated blood obtained in the left atrium and the deoxygenated blood received in the right atrium mix very slightly.

Diet

• Invertebrates like bloodworms, mealworms, earthworms, snails, slugs, locusts, and other creatures are eaten by amphibians. Larger amphibians can also consume small mammals.
• Young frogs require food most days of the week, whereas adult frogs only require it every two to three days.

Excretory system

• Amphibians have mesonephric kidneys during the adult stage and have pronephric kidneys at the larval stage.
• When on land, they expel the majority of their metabolic waste as ammonia (in tail form) and urea (in tailless forms).
• Kidneys are the primary excretory organ of amphibians.

Reproduction

• Amphibians can be fertilized internally (by a salamander) or externally (by most amphibians).
• They attract their mates by making various sounds; for instance, the loud croaking of frogs may be a signal for mates.
• Since the eggs don’t have shells and get dry when kept on land, the eggs must be laid in freshwater.

Classification of Amphibia

Based on their order, amphibians can be divided into three groups they are-

Apoda (Gymnophiona or Caecilia)

• The body is elongated and can be differentiated into the head and trunk. 
• They do not have limbs and hence resemble earthworms.
• They have small dermal scales
• As their eyes are covered by bone or skin, they are known as blind worms.
• They lack tails or may have short tails.
• Internal fertilization takes place.
• Eg-Caecilians

Urodela (Caudata)

• The body is long and differentiated into a head, neck, tail, and four limbs which are of similar length.
• Their skin is smooth and moist.
• Through their skin, they breathe.
• At both the larval and adult stages, they have teeth in their jaws.
• They are incapable of making sounds.
• They undergo fertilization either internally or externally.
• Examples-Newts and Salamanders

Anura (Salientia)

• The body is differentiated into the head and trunk. But both of them are fused.
• They have four limbs that are designed specifically for jumping.
• Their mouth is large.
• At the larval stage, the tail is present and the adult tail is absent.
• Due to the presence of a chemical called magainin, the skin secretions of anurans have a naturally occurring antibiotic effect.
• In anurans, external fertilization takes place.
• Examples: Toads and frogs

Scientific Classification of Amphibia

The scientific classification of amphibians is as follows-

Domain	Eukaryote
Kingdom	Animalia
Phylum	Chordata
Subphylum	Vertebrata
Class	Amphibia
Order	Urodela  Apoda Anura

Summary 

Cold-blooded creatures called amphibians descended from lobe-finned fish. When they are larvae, they can survive in water, but as adults, they must live on land. Frogs, toads, salamanders, newts, and caecilians are some examples of amphibians that are grouped into orders such as  Apoda, Urodela, and Anura. They have different body types. During the younger stage they breathe through the skin(gills) and as they reach adulthood, their lungs develop and they now breathe through both skin and lungs.

Frequently Asked Questions

1. Explain metamorphosis.
Ans: Metamorphosis is the term used to describe the changes an animal undergoes during its life cycle. When a frog egg hatches, a tadpole is released, which first grows rear legs then develops the front legs, and then finally becomes an adult frog.

2. Give the 5 kingdom classification with examples.
Ans: The 5 kingdom of classification was proposed by RH Whittaker in 1969. 

The 5 kingdom classification is-

• Kingdom Monera- it includes the prokaryotes.
• Kingdom Protista- it includes single-celled eukaryotes.
• Kingdom Fungi- it includes various fungi.
• Kingdom Plantae- it includes all types of plants
• Kingdom Animalia- it includes all types of animals.

3. How do amphibians breathe?
Ans: The majority of amphibians can breathe through their skin, which is a thin, permeable organ that is dense with blood vessels. In their larval stage, some aquatic animals, like frogs, have gills that absorb oxygen from the water and expel carbon dioxide as waste.

Introduction

Apiculture is the practice of culturing honey bees on a bigger scale to yield beeswax and honey. It is a scientific approach to rear the bees in man-made hives, raising their numbers and caring for them. Beekeepers or apiarists are those who practice apiculture. Man-made beehives are artificial bee hives. These are made of wooden boxes and contain rows. Bees stay in these hives and fill the rows with wax, honey, etc. The designs of these hives should be such that they will facilitate the healthy growth of bees and honey harvesting.

How honey is collected by honey bees?

Long distances are covered by worker bees as they search for food. Their honey stomachs serve as temporary storage for the nectar they obtain from flowers. When they get to the hive, they regurgitate this nectar and deposit it in honeycombs. The regurgitation is a viscous liquid called honey that has undergone dehydration.

The life cycle of the Honey bee

Honey bees go through four developmental stages. They begin as eggs, grow into larvae, then transition into the pupa stage before reaching adulthood.

• Egg stage- After a drone successfully fertilizes a queen bee,  she lays both fertilized and unfertilized eggs. A queen bee may produce between 2000 and 3000 eggs every day, each of which is contained in a cell. Unfertilized eggs grow into male drones, whereas fertilized eggs become worker bees.
• Larval stage-After three days the eggs hatch into worm-like larvae.  Larvae are without legs, wings, or other appendages. Royal jelly is provided to larvae during the first two to three days, followed by pollen and honey. Only royal jelly is used to feed the queen larva.
• Pupal stage-In this stage the larvae wrap themselves up in a cocoon and enclose themselves in their cells. During the pupal stage, all organs such as the abdomen, head, eyes, thorax, and appendages including wings, legs, and antennae are developed completely.
• Adult stage- Once the larvae develop, they appear like adult bees after they hatch out from the capped cell.

Common varieties of bees

Common honey bee species include-

• Apis dorsata.– As well known as rock bees they are enormous, vicious bees. The raising of rock bees is challenging.
• Apis Florea– Referred to as “little bees” because of their tiny size. They rarely sting, but because they move around a lot, domestication is fairly challenging.
• Apis mellifera– Also known as the western bee or European bee. It is the most domesticated species in the world and stings less frequently.
• Apis indica– Frequently called Asian bees or Indian bees. They originated in Asia and are simple to domesticate to make honey.

Importance of Beekeeping

• The purpose of apiculture is to produce bee products that have a marketable value.
• Honey is the main apicultural product that is obtained. Because of its distinct sweetness, honey is employed extensively in the food sector.
• Additionally, several therapeutic herbs and honey are combined in some traditional medicines.
• The glandular fluid made by honey bees for the construction of the honeycombs in which they store their honey is known as beeswax.
• In the production of soaps, candles, and cosmetics, beeswax is commonly used.
• Another type of glandular fluid produced by worker honey bees, which is used for feeding queen bee larvae is the royal jelly.
• This royal jelly improves collagen synthesis and helps women who are experiencing menopause-related issues.
• Propolis, a resin-like substance made by honey bees, has antiviral and antibacterial properties.
• Bee venom has been shown in several trials to be effective in combating the Human Immunodeficiency Virus (HIV).
• Beekeeping also has environmental benefits as bees are great pollinators and help in fruit formation.

Summary

Apiculture is the scientific process of rearing honey bees in artificial hives to produce bee products such as honey, wax, royal jelly, and propolis for the market. An apiculturist is a person who does apiculture. In addition to providing advantages to business and industry, apiculture supports numerous plant species through pollination.

• The species of bee most frequently raised for the production of honey is Apis mellifera.
• Apiculturists take care of wooden-framed hives where honey bees can breed and grow.

Most apiaries are designed around bee pastures because they make excellent locations for bee foraging. Queen bee, worker bees, and drones are present in every bee colony. Within their colony, they are assigned specific duties. The life cycle of honey bees has four stages. Queen bee lays eggs that completely metamorphose into adult bees. 

Frequently Asked Questions

1. How do bees act as pollinators?
The pollen grains from stamens land on the hairy region of the hind legs of the bees while they are collecting nectar. When the honey bees visit another flower they deposit pollen grains there and hence aid in cross-pollination. Honey bees are therefore referred to be pollinators because of this.

2. What are the various types of bees found in a bee hive?
Ans: There are a lot of bees within the bee hive. They can be divided into three primary groups.

• Queen Bee- The only female in the bee hive with the ability to lay eggs is the queen bee. The queen uses pheromone emissions to regulate the entire hive population.
• Drones or male bees- They are the male population of the hive that fights it to mate with the queen bee. After mating, the drone bee dies.
• Worker bees- These bees are female and unable to lay eggs. They are the bee hive’s active population. Worker bees perform a variety of tasks, such as maintaining and cleaning the hive, and feeding larvae and queen bees. They produce honey and gather the nutrients required for the hive population.

3. Who is known as the father of apiculture?
Ans: The father of modern apiology and apiculture is Johann Dzierzon. Most modern beehives derive from his design.

Introduction

The word ‘amnio’ (Greek in origin) means inner membrane around the foetus and ‘centesis’ means to prick i.e. amniocentesis refers to the procedure of obtaining amniotic fluid by making a tiny puncture in the inner membrane surrounding the foetus. It is a prenatal test which is carried out before or during pregnancy. Amniocentesis is a procedure used to detect particular genetic disorders which may be due to some chromosomal abnormalities or aberrations. Genetic disorders such as colour blindness, haemophilia, Turner’s syndrome, Down syndrome, etc can be detected through this process. It is often carried out after 15 weeks of pregnancy, or after the first trimester (3 months). If an abnormality is found during this process, then depending upon the health of the baby the decision will be taken whether to continue the pregnancy or not.

Procedure of Amniocentesis 

Amniocentesis is performed by a team of professionals. A small amount of amniotic fluid is removed from the abdomen using a needle and is submitted to a lab for analysis. Amniocentesis is an intrusive process that involves inserting a needle into the uterus.

The procedure of amniocentesis is as follows-

• Ultrasound-To determines the position of the placenta, the foetus’ movements, and the features of the amniotic fluid an Ultrasound is conducted. An ultrasound helps to decide which needle to use, the area where the needle will be inserted and the angle at which the needle can be administered.
• Sterilisation-To reduce the danger of infection, the abdomen is first sterilised with an antiseptic, and tools with heparin coatings are used to prevent blood clotting.
• Needle insertion-Depending on the doctor’s preference, either a single-needle or two-needle approach is employed for the needle insertion. To ensure that a good quality sample is extracted the needle is injected in a specific location, and 20 ml of amniotic fluid is extracted.
• This fluid collected is sent to the laboratory for analysis of any genetic disorders.

Reasons  for performing  Amniocentesis 

Some of the common reasons to perform amniocentesis are as follows-

• The main purpose of amniocentesis is to find genetic disorders such as Down syndrome, Turner’s syndrome etc.
• Additionally, neural tube abnormalities, in which the brain and spinal cord are still immature, can also be found through this process.
• It is used to determine whether the lungs of the developing foetus are mature enough for the foetus to take birth.
• When a mother’s blood has an Rh infection i.e. the mother’s blood produces antibodies against foetal blood the baby may develop anaemia. This can be detected by amniocentesis and can be cured.
• Sometimes excessive amniotic fluid gets accumulated in the body, then this process can detect it and excessive amniotic fluid can be removed.
• DNA from the collected amniotic fluid is used in paternity tests to determine blood relations.

Summary

Genetic disorders in the growing foetus are identified using a procedure called amniocentesis. The defects in chromosomes created during cell division are the root cause of genetic diseases. Amniotic fluid, which contains foetal cells, surrounds the foetus. This fluid is sampled in small amounts to perform the examination and look for any abnormalities in the foetus. If there are any abnormalities then depending on the condition of the baby and its health the decision of aborting the child or keeping the child is taken.

Frequently Asked Questions

1. What are the various risks involved in the process of amniocentesis
Ans: There are various risks associated with the process of amniocentesis such as-

• Amniocentesis can cause miscarriages as a small cut is made to extract the amniotic fluid.
• This procedure can cause cramping in the mother as she has to stay still during the entire process.
• There is a high chance that this process can cause injuries to the foetus.
• If the process is not done correctly then it might cause leaking of the amniotic fluid through the point of puncture.
• If by chance this process is done in the second trimester of the pregnancy then there are chances of preterm labour.

2. What precautions should be taken post performing amniocentesis
Ans: Following precautions should be taken post-amniocentesis-

• Normal activities can be resumed after the amniocentesis operation, however rigorous activities should be avoided for up to 24 hours.
• If post operation she suffers vaginal bleeding or a significant loss of amniotic fluid, she must immediately see a doctor.
• If the mother has a fever, severe uterine cramps for more than a few hours, and no abnormal foetal activity and redness or inflammation where the injection was made, then she should immediately see the doctor.

3. What happens if a test for Down syndrome is positive?
Ans:  If the test results are positive you will be offered a diagnostic test, typically a chorionic villus sample (CVS) or maybe an amniocentesis, Whether or not the pregnancy is truly impacted will be depended on the test that is performed. CVS is usually done between 10 and 13 weeks of pregnancy.

Introduction

A metabolic pathway consists of a series of chemical reactions in which a certain molecule is transformed from one product to another. Enzymes catalyze each step in a metabolic pathway. The anabolic pathway involves biosynthesis, or the creation of new molecules, and is a constructive mechanism. On the other hand, the catabolic pathway is a degradative process that causes compounds to break down. An energy input would be necessary for both of these kinds of pathways. An amphibolic pathway is a type of biological process that involves both anabolism and catabolism. In these pathways, the catabolic end products or intermediates are utilized in anabolic pathways as precursors and provide free energy for the production of further molecules.

Glycolysis -an amphibolic pathway

In the metabolism of plants, animals, and numerous microbes, glucose plays a crucial role. It is employed to carry out aerobic or anaerobic respiration, which produces energy in the form of ATP. Through a sequence of processes, glucose is converted to two molecules of pyruvate during glycolysis. Although it is primarily understood as a catabolic process, some of the pathway’s intermediates are also used in the production of a few different biomolecules. Hence glycolysis is an amphibolic pathway. 

The following shows how glycolysis is an amphibolic pathway-

• The pentose phosphate pathway uses glucose 6-phosphate, to produce ribose 5-phosphate, which is then employed in the synthesis of nucleic acids.
• The process that produces glyceraldehyde 3-phosphate also produces glycerol, which is necessary for the synthesis of phospholipids.
• Pyruvate, the final byproduct of the glycolytic process, is further converted to Acetyl-CoA, which is utilized in the production of fatty acids.
• The NADPH generated in the pentose phosphate pathway, which utilizes glycolysis intermediates, is employed as a reducing agent to enable a number of anabolic processes, such as the production of fatty acids, nucleic acids, carotenoids, etc.
  

Krebs cycle -an amphibolic pathway

In aerobic organisms, the Krebs Cycle (also known as the TCA cycle) is amphibolic because it participates in both catabolic and anabolic processes. The Krebs Cycle, which takes place in the mitochondria, results in the production of ATP, NADPH, and FADH2.

The Krebs Cycle’s key component, acetyl-CoA, is produced from-Pyruvate oxidation (from glycolysis), Fatty Acids (Beta-oxidation), and Amino acid degradation.

• Krebs Cycle is catabolic because it completely oxidized acetyl-CoA into carbon dioxide (CO2).
• The Krebs cycle is also referred to as being anabolic since various biomolecules, such as nucleic acids, fatty acids, amino acids, and porphyrins, are synthesized from its intermediates.
• At each cycle turn, the Krebs cycle intermediate oxaloacetate is created again in order to condense with a new molecule of acetyl-CoA which continues the cycle.

Other intermediates of the Krebs Cycle serve the following anabolic functions-

• Porphyrins, which are necessary for the synthesis of myoglobin and hemoglobin, are created using succinyl-CoA.
• Oxaloacetate is the starting material for synthesizing amino acids such as proline, alanine, glutamate, and aspartate. Purines are created by using glutamate and aspartate amino acids.
• In the mitochondria, oxaloacetate is also transformed into phosphoenolpyruvate, which is then transformed into glucose via the gluconeogenesis pathway. Malate is also employed for gluconeogenesis.
• ɑ-Ketoglutarate is a component in succinate synthesis.
• By way of transamination processes,ɑ- ketoglutarate is also utilized in the synthesis of glutamate and pyruvate.
• Acetyl-CoA, the precursor for the production of fatty acids and cholesterol, is formed when citrate and CO2 interact.
• The fatty acids are further metabolized into triacylglycerols and diacylglycerols and ultimately form the phospholipids.
• The cholesterol formed is then used to synthesize steroids and bile acids.

How is the Respiratory Pathway an Amphibolic Pathway?

• Complex molecules are converted into simpler ones during respiration, which gives organisms energy in the form of ATP.
• The four steps of respiration are glycolysis, pyruvate oxidation, the tricarboxylic acid cycle, and oxidative phosphorylation.
• These include the tricarboxylic acid cycle(TCA) and glycolysis, which both generate intermediates used in the creation of numerous other biomolecules.
• The pentose phosphate pathway uses glucose 6-phosphate, the first glycolysis intermediate, to branch off from glycolysis.
• The formation of ribose 5-phosphate, which is produced through the pentose phosphate pathway, is crucial for the biosynthesis of nucleotides.
• Erythrose 4-phosphate, which is necessary for the synthesis of aromatic amino acids like tryptophan, phenylalanine, and tyrosine, is also produced by the pentose phosphate pathway.
• As a result, it may be said that the respiratory system is an amphibolic pathway since it produces a number of precursor metabolites that are used in the biosynthesis of several cellular components. It also involves the oxidation of organic carbon into carbon dioxide and water, which releases energy.

Summary 

• Amphibolic pathways are both catabolic and anabolic.
• Glycolysis intermediates, glucose 6-phosphate, and glyceraldehyde 3-phosphate are used to produce purines and phospholipids, respectively.
• Krebs Cycle is a well-known amphibolic process, and its intermediates are employed in the synthesis of different amino acids, fatty acids, sterols, nucleic acids, etc.
• The respiratory pathway is referred to as amphibolic since it contains a variety of catabolic intermediates that act as anabolic precursors.

Frequently Asked Questions

1. Difference between Krebs cycle and Glycolysis
Ans:

Glycolysis	Krebs Cycle
Occurs in the cytoplasm	Occurs in the mitochondrial matrix
It marks beginning of respiration	It is the 3rd step in respiration.
It is a linear pathway	It is a cyclic pathway
Glucose converted to 2 molecules of pyruvate.	Acetyl-CoA is converted into carbon dioxide.
No release of CO2	CO2 released
Net ATP generated = 8 ATP	Net ATP generated = 24

2. What are two forms of glycolysis?
Ans: The two forms of glycolysis are Aerobic and anaerobic glycolysis-

• Pyruvate enters the citric acid cycle under aerobic conditions and proceeds through oxidative phosphorylation, which results in the net synthesis of 32 ATP molecules.
• Pyruvate is converted to lactate under anaerobic conditions by the process of anaerobic glycolysis.

3. Who gave the term Amphibolic Pathway?
Ans: In 1961, B. Davis gave the term amphibolic Pathway. It is a pathway that involves both anabolism and catabolism.

Introduction 

Human Anatomy is the discipline of science that focuses on the structural composition of humans. It is a Greek word wherein “ana” is (up) and “tome” is (cutting). Anatomy is the study of how the human body is arranged and made up of cells, tissues, organs, and organ systems. Human physiology is a branch of science that deals with the activities and functions of the vital life processes within the human body. There are various types of physiology such as Cell physiology, Special physiology, Systemic physiology, and Pathophysiology. The human body is comprised of multiple organ systems such as the respiratory system, digestive system, nervous system, cardiovascular system, urinary system, and reproductive system.

Learn More about Anatomy and Physiology of Human Body. Check out more videos in Science Class 6 Lesson no 08.

Circulatory system

The human circulatory system is made up of the heart, arteries, veins, and capillaries. This system is used to transport blood and lymph throughout the body. It also provides nutrition and removes nitrogenous waste from the body. It is also called the cardiovascular system. Humans have a closed circulatory system, where blood flows in specific blood vessels. Below given are the components of the circulatory system and their function.

Organ	Structure and Components	Functions
Heart	The human heart contains four chambers: the right and left atrium, and the right and left ventricle. It has specialized cardiac muscle with many valves.	It pumps blood throughout the body.
Arteries(blood vessels)	Thick-walled, valveless.	Transport blood from the heart to other parts of the body (exception- the pulmonary artery).
Veins   (blood vessels)	Thin-walled and have valves.	Transport blood from the other parts of the body to the heart (Exception- for the pulmonary vein).
Capillaries	Thinnest blood vessels.	Connects arteries and veins.
Blood	50–55 % of blood is made up of plasma and 45-50% is made of blood cells like RBC, WBC, and platelets.	Act as the medium of transport of nutrients, gases, and nitrogenous wastes.

Respiratory System

• Respiration is the process of oxidation of food materials to liberate energy. 
• There are two types of respiration internal and external respiration. The inhalation and exhalation of air with the help of the lungs are known as external respiration. Here carbon dioxide is exhaled and oxygen is inhaled.
• Internal respiration is also known as cellular respiration which occurs in the mitochondria and produces energy in the form of ATP. 
• The human respiratory system is made up of the Nostrils, pharynx, Larynx, a pair of lungs, and Diaphragm. 
• The lungs are made up of Trachea, Bronchi, Bronchioles, and Alveoli.

Digestive system

• Digestion is the breakdown of complex food substances into simpler nutrients such as carbohydrates, proteins, etc. which are easily absorbed by the body. 
• The digestive system secretes various enzymes which assist in the digestion of food material. Digestion occurs in 5 steps given as follows-

Steps	Involved organs	Function
Ingestion	teeth, tongue, and palate.	Intake of food materials such asrice, fruits, vegetables, etc.
Digestion	Mouth, salivary glands, liver, stomach, pancreas, small intestine.	Food is digested and broken down into simpler soluble and absorbable forms such as sugars, amino acids, fatty acids, etc.
Absorption	Villi of the small intestine.	The food thus broken into simpler substances is absorbed in the blood and transported to various organs of the body.
Assimilation	Cells, tissues	Absorbed food is utilized by cells and tissues for their cellular activities.
Egestion	Large intestine and anus.	Excretion of unusable or undigested material from a cell.

Reproductive System

• Humans are sexually dimorphic. They perform sexual reproduction and give rise to the next generation. 
• The human reproductive system is different for males and females. 

Female reproductive system–

• The female reproductive system is situated in the pelvic girdle.
• It produces eggs that are haploid and fuse with the sperm to form the zygote and then the fetus.

The female reproductive system is made up of the following-

Sex organs	Functions
Pair of Ovaries	That Contain eggs and perform Oogenesis and ovulation.
Genital Tract (Fallopian Tubes, Uterus, Vagina)	Fertilisation, ovulation, carrying a baby, and giving birth.
External Genitalia	Respond to sexual stimulation.
Mammary Gland	Produces milk for the newborn child.

Male reproductive system –

• The male reproductive system is situated in the pelvic girdle and produces sperm.
• They contain the penis which is an ejaculatory organ that transfers sperm in the female body.

The male reproductive system is made up of the following organs

Sex organs	Functions
Pair of Testis	Secreting testosterone and producing sperm.
Epididymis	Develop the sperm.
Ejaculatory ducts	Transport mature sperm to the urethra.
Urethra	Ejaculating semen.

Nervous system

• The body’s primary controlling, regulating, and communication system is the nervous system.
• The ability to move, breathe, see, think, learn, remember, and more is controlled by this system,
• The nervous system is made up of neurons, nerves, and ganglia which carry messages to the brain and the entire body.
• Neurons are made up of axons, dendrons, and a  cell body.
• The brain and spinal cord make up the central nervous system.
• The Somatic Nervous System and the Autonomic Nervous System make up the Peripheral Nervous System.

Urinary system

• The urinary system of the body is used for expelling waste products from the body. The waste products are in the form of urine. 
• A pair of kidneys perform the function of excretion. Its structural and functional unit is a nephron. 

Following are the parts of the urinary system.

Organ	Function
A pair of Kidney	Performs ultrafiltration of the blood and removes waste products from the body in the form of urine. It also performs the function of osmoregulation.
A pair of Ureter	Carries the urine downward.
Urinary Bladder	Storage organ which stores urine temporarily.
The urethra	Passes the urine outside the body.

Immune system

• The immune system of an organism protects the body from infection.
• The immune system fights the antigen (pathogen) by forming antibodies. These antibodies kill the pathogen and thus the steady state of the body is maintained.
• The organs of the immune system are-spleen, thymus, lymph nodes, blood, etc.
• The cells of the immune system include-Stem cells, T-lymphocytes, B-lymphocytes, Monocytes, Cytotoxic and Helper cells, Neutrophils, etc.

Summary

Anatomy of the human body is the study of the structure and relationship between all organs of the body. However, the physiology of the human body explains how each organ performs. The body’s organ systems collaborate to carry out a certain activity or set of duties. The respiratory system, digestive system, nervous system, cardiovascular system, urinary system, and reproductive system are various organ systems in the body that operate together and support healthy body development, growth and reproduction.

Frequently Asked Questions

1.State the types of anatomy.
Ans: The different types of anatomy are-

• Gross anatomy- Gross anatomy entails the dissection of organs on a larger scale for examination.
• Cellular anatomy- Investigating cells and cellular components under a microscope are called “cellular anatomy.”
• Molecular anatomy- DNA, RNA, proteins, and other biochemical components are studied in molecular anatomy.

2. How is the human body organized?
Ans: Cells are the structural and functional unit of life. The human body is made of cells. These cells combine and form tissues, tissues form organs, organs form organ system and all these systems together build the human body.

3. What are primary and secondary sex organs in humans?
Ans. The primary sex organs are those organs that produce gametes. In females, the primary sex organ is the ovaries which produce egg cells. In males, the primary sex organ is the testes which produce sperm.

Secondary sex organs are those that transport and store the gametes and nourish the growing baby. Male secondary sex organs are Epididymis, vasa deferentia, penis, etc. Female secondary sex organs are- the fallopian tube, vagina, uterus, etc.

Introduction

Animals have sophisticated nervous systems. It is a vital system that controls all of our body’s voluntary and involuntary movements.  The nervous system controls all complicated functions, including reading, remembering, feeling emotions, and logical thought.  The brain, spinal cord, and nerve network are all parts of the nervous system.

Together, these organs carry out the complex functions of the nervous system.

Nervous System Classification

The nervous system is classified into 3 types i.e the Central nervous system(CNS), the Autonomic nervous system(ANS), and the Peripheral Nervous System (PNS).

Central nervous system(CNS)

• The spinal cord and brain together make up the CNS. 
• The brain is covered by a fluid known as a Cerebrospinal fluid(CSF).
• Three membranes—the dura mater, arachnoid, and pia mater—cover the brain.
• Humans are made up of the forebrain, midbrain, and hindbrain.
• The forebrain is made up of the diencephalon and cerebrum and is further divided into the dorsal thalamus and ventral hypothalamus.
• The cerebrum is in charge of our motivation, reasoning, imagination, memory, thinking, and consciousness.
• The midbrain is made up of four circular structures called the cerebral aqueduct and corpora quadrigemina.
• The hindbrain is made up of the cerebellum, medulla oblongata, and pons.
• All voluntary motions and body equilibrium are controlled by the cerebellum, whereas the pons regulates breathing and the sleep cycle.
• The medulla oblongata regulates breathing, circulation, gastric secretions, vomiting, and salivation.
• The spinal cord is a cylindrical structure that resides in the neural canal of the vertebral column.
• The spinal cord is the location where all the nerves join and the information is sent to the brain.

Autonomic nervous system(ANS)

• ANS is known as the Autonomic Nervous system.
• It regulates the body’s internal organs’ involuntary functions.
• The sympathetic and parasympathetic nervous systems are the two types of ANS.

Peripheral Nervous System (PNS)

• The PNS is made up of nerves that emerge from the spinal cord and brain.
• The term “cranial nerves” refers to nerves that are emerging from the brain.
• Spinal nerves are nerves that arise from the spinal cord.

Parts of the nervous system

Neurons are the structural and functional components of the nervous system. Neurons are typically referred to as nerve cells. It is the longest cell in the human body and sends electrical impulses as messages. 

Following are the parts of a neuron.

• Cyton: The cell body is the main component of the neuron. The cyton contains cell organelles, a nucleus, and cytoplasm.
• Dendrites: These cytoplasmic extensions that protrude from the cell body are numerous and highly branched. They carry electric impulses both inside and outside of the cell body.
• Axon: It emerges from the cyton as a solitary, unbranched cylindrical projection. A myelin sheath protects the axon. It transports impulses away from the cyton.

Functions of the nervous system

• The network of neurons is in charge of message reception and transmission, which in turn controls and coordinates the various bodily parts.
• The cerebrum is in charge of our intelligence, thinking, consciousness, memory, imagination, reasoning, and willpower.
• The nervous system also controls voluntary movement and body balance. The cerebellum is in charge of this activity.
• The spinal cord is involved in the reflex action and helps in quick response during dangerous situations.
• The Nervous system of the body is responsible for controlling all automatic reactions to peripheral nerve stimulation such as breathing, stomach secretion, vomiting, etc.

Types of nerves

Classification of nerves is based on function, structure, and myelin sheath.

Classification based on function

• Afferent or  Sensory  Neurons: These nerves perform the function of carrying impulses to the Central Nervous system from the various sense organs such as eyes, nose, skin, etc.

• Efferent or Motor Neurons: These nerves perform the function of carrying impulses from the Central Nervous system to various effector organs such as muscles, organs, etc.
• Interneurons or Association Neurons: This neuron help in transferring impulses between the Sensory and Motor neurons.

Classification based on the structure

• Unipolar Neurons: In these neurons, the cell body gives rise to only a single nerve process that performs the function of both axon and dendron. These are seen in the spinal and cranial nerve ganglia.
• Bipolar Neurons: Here, two nerve processes are formed from the cell body. One of these becomes the axon and the other becomes the dendron. These are found in various sensory organs such as the nose, tongue, eye, etc.
• Multipolar Neurons: Multiple dendrons are generated from a single-cell body. These are the most common types of neurons found in the nervous system.

Classification based on the myelin sheath 

• Myelinated nerve fiber: A myelin sheath protects the axon 
• Non-myelinated nerve fiber: The nerve fiber here is not protected by the myelin sheath.

Summary

The human nervous system is the body’s most complicated network system. It is made up of the autonomic, peripheral, and central nervous systems. It enables us to carry out routine tasks, difficult activities, and bodily functions.  With the aid of a sophisticated network of nerves, the nervous system functions as a communication network that sends and receives signals from the brain and spinal cord to every area of the body. The nervous system is made up of neurons and based on their structures, functions, and whether or not myelin sheaths are present, neurons are further classified.

Frequently asked question

1. What is the Cerebrospinal fluid?
Ans: The brain’s ventricles (hollow spaces) are lined with tissue. This tissue produces cerebrospinal fluid. This fluid circulates around and inside the brain and spinal cord to nourish and protect them.

2. What signs of a weak neurological system?
Ans: Symptoms of disorders of the nervous system are-

• headaches that develop suddenly or persistently.
• tingling feeling or loss of sensation.
• loss of muscle strength or weakness.
• eyesight loss or double vision
• memory deterioration
• reduced mental capacity

3. Which components have a negative impact on the nervous system?
Ans: Following have a negative impact on the nervous system 

• Trauma (injuries), particularly spinal cord and head trauma.
• Issues that exist from birth (congenital).
• Mental health issues such as depression, psychosis, or anxiety disorders.
• Exposure to poisons like lead, arsenic, or carbon monoxide.

Introduction

The smallest structural and functional units in all living things are cells. Together, several cells make up tissues. Plants and animals both have eukaryotic cells and hence all cells contain many membrane cell organelles such as the nucleus, nuclear membrane, endoplasmic reticulum, etc. Organs are made up of tissues that perform the same functions. To carry out specific tasks, tissues are organized in a specific way. Animals and plants are made up of several tissues. Meristematic tissue and permanent tissue are the two types of tissues found in plants. Epithelial, connective, muscle, and nerve tissue are the four different types of tissues found in animals. Animal tissues solely include living cells, but plant tissues contain both living and dead cells.

Plant tissues

Organs are made up of tissues that are united to carry out certain functions. These organs and tissues work together and help in growth, development, and reproduction. Plant organs include leaves, roots, flowers, fruits, and stems, which are made of many types of tissues.

The majority of plant tissues are composed of dead cells, and they give the plants their structural stability and defense against extreme environmental changes. Plant tissues can be divided into two kinds, such as permanent and meristematic tissue.

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Types of plant tissues

• Meristematic tissue: Meristematic tissues support the plant’s primary growth. These tissues’ cells regularly divide, and they can be found at the root and stem tips. Spherical, tightly packed cells with no interstitial space are a common feature of meristematic tissues. These cells contain a thick cytoplasm surrounding the nucleus. Depending on where they are, meristems can be divided into
  • Apical meristems-At the growing tip of the stem and roots apical meristems are present. They help increases the length of the plant.
  • Lateral meristems- Lateral meristems are located at the lateral portion of the root or stem. These cells help in increasing the girth of the plant. They include cork cambium and vascular cambium which assist in secondary growth.
  • Intercalary meristems-These tissues are usually located in the internodes, nodes, or base of the leaves. They help in the growth of the leaves in the direction of light also they help in increasing the height of the plant.

• Permanent tissue: Permanent tissues are those that have fully developed and lost the capacity to reproduce. The permanent tissues are formed by the division and differentiation of the meristematic tissues.
  • Simple permanent tissues- Cells are identical and simple in simple tissues. These tissues are made up of cells that share a common origin, a similar structure, and related functions. Further, these tissues are divided into the parenchyma, collenchyma, and sclerenchyma.
  • 

• Complex permanent tissues: These tissues are made up of various cells which are complex in nature. Phloem and xylem are examples of complex permanent tissues. These tissues aid in the transportation of  food, water, and mineral throughout the plant body.
• 

• Animal tissues are constructed from a collection of the animals’ cells. Animals have a range of tissues that each carry out a specific function for the organism. Organs are created when the tissues come together. Organisms are composed of organs. So, with the aid of tissues, a multicellular creature is created as a whole structure. The animal body contains four main types of tissues: epithelium tissues, muscular tissues, nerve tissues, and connective tissues. These tissues have various origins and functions.

Types of animal tissues

• Epithelial tissues
  • These were the first to arise during evolution and can be single or multilayered.
  • Covers both the body’s interior and exterior organs. They are very tightly packed and lack an intercellular matrix.
  • The cells may regenerate. 
  • Major functions of these tissues are to protect layers of organs, absorb, and secrete various fluids.
  • Based on the structure of the cells, there are four different types of epithelial tissues: squamous, cuboidal, stratified, and columnar epithelium.

Muscle tissues: 

• Muscle tissues are the tissues that surround the muscles.
• They aid in the body movement of the animal by contraction and relaxation.
• Skeletal muscle, smooth muscle, and cardiac muscle are the three different types of muscles found in an animal body.

• Connective tissues:
  • These tissues assist in connecting organs, other tissues, and various other body parts.
  • They also assist in the transportation of various materials throughout the body.
  • There are six different types of connective tissues: cartilage, adipose, lymph, bone, and blood.

• Nervous tissues:
  • The electrochemical impulse transmission between various neurons is carried out by these cells.
  • They help in the control and coordination of the entire body.
  • Nervous tissues are made up of nerve cells like neurons and neuroglia.

Differences between plant and animal tissue

Plant tissues	Animal tissues
They are defined as groups of cells performing the same task in plants.	They are defined as groups of cells performing the same task in animals.
The tissues here are comparatively simple.	The tissues here are comparatively more complex.
They have two types of tissues- Permanent and Meristematic tissues.	They are of 4 types-  Epithelial, Connective, Nervous, and Muscle tissues.
Differentiation is seen in both permanent and meristematic tissues.	No such differentiation is seen in animal cells.
These include living as well as dead tissues.	It mostly includes living tissues.
Maintenance of plant tissue requires less energy.	Maintenance of animal tissue requires more energy.
The cells of these tissues have cell walls.	The cells of these tissues are devoid of cell walls.
They provide mechanical support to the plants.	They help in movement and locomotion.

Summary 

The cells that makeup tissues collaborate to carry out various functions of the body. Meristematic and permanent tissues are the two categories of plant tissues. Epithelial, connective, neuronal, and muscle tissues are the four different types of tissues found in animals. Plant tissues support nutrient delivery and plant growth, whereas animal tissues support body movement or locomotion. This is the major distinction between plant and animal tissues. The healthy development and functioning of both plants and animals depend on both plant and animal tissues respectively.

Frequently Asked Questions

1. What are the similarities between plant and animal tissue?
Ans: Following are the similarity between plant and animal tissues-

• Cells of both tissues are eukaryotic i.e. they contain all cell organelles such as the Nucleus, nucleolus, RNA, DNA, Endoplasmic reticulum, etc.
• These tissues lead to the formation of organs and organ systems.
• Cells of these tissues release ATP which is used as an energy source to carry out all cellular activities.

2. Give the components of the xylem and phloem.
Ans: Phloem tissue aids in transporting materials throughout the plant body and is made up of sieve tubes, companion cells, phloem parenchyma, and phloem fibers. The xylem transports water and nutrients throughout the plant body and is made up of tracheids, vessels, xylem parenchyma, and xylem fiber.

3. Describe sclerenchyma.
Ans: Sclenechyma is simple permanent tissue found in plants. It provides mechanical support to plants and is made up of dead cells. These dead cells are highly lignified. Sclerenchyma is mostly found in the mature parts of the plants such as barks, thick stems, etc. It is made up of long and narrow cells. Cells are usually without protoplasts.

Introduction

Animals come in a variety of shapes and sizes. Members of this kingdom are Multicellular, eukaryotic animals that have a heterotrophic mode of nutrition and their cells are devoid of cell walls. They are typically motile that move from one place to another. Animals come in a variety of shapes and sizes. 

Classification of Animal kingdoms based on their characteristics

Animal classification is based on various characteristics such as

• Arrangement of cells
• Symmetry
• Coelom or body cavity

Arrangement of cells

All animals are multicellular but the arrangement of cells within them is different. This arrangement of cells is known as the levels of the organization. Based on this animals are classified under

• The cellular level of organization- Animals at this level of organization generate loose clusters of cells. Eg. Sponges.
• Tissue level of organization-Animals under this level has cells that combine to form tissues and all tissues perform various bodily activities.
• Organ level of organization-  Animals with an organ-level organization are those in which tissues with the same functions group together to form an organ.
• Organ system level of organization-Organ system degree of organization is displayed when organs work together to produce an organ system that performs many physiological functions.

Symmetry

• The symmetry of an animal’s body can be used to classify it.
• The body exhibits three different types of symmetry.
• Asymmetry is symmetry where the plane is not divided into two equal halves. It was observed in the phylum Porifera (sponges).
• Radial symmetry is a symmetry that divides a plane passing through the central axis into two halves. This is seen in phylum Coelenterates, Ctenophores, and Echinoderms.
• When a  plane separates the body into two identical left and right halves then such symmetry is known as bilateral symmetry.
• Arthropods and annelids are two examples of animals with bilateral symmetry.

Coelom or body cavity

• The coelom is the space that is found between the body wall and the alimentary canal. Based on body activity organisms are classified as-
• Acoelomates- They do not have a body cavity. Eg- members of Phylum Platyhelminthes.
• Pseudocoelomates–They have a false body cavity. Eg. members of Phylum Aschelminthes.
• Coelomate- They have a true body cavity that is filled with coelomic fluid. This is seen in members from Phylum Annelida to Phylum Chordata.

Phylum belonging to Kingdom Animalia

Phylum Porifera

• They are also known as sponges.
• They are multicellular organisms that are organized at the cellular level.
• They have asymmetrical body shapes and are typically found in marine environments.
• They have a water canal system. Water enters the body through the Ostia (pores) that are lined up on the surface of the body. From here it is conveyed into the spongocoel. Water exists in the body through the osculum.
• The movement of water facilitates gas exchange, food capture, and water excretion.
• Porifera members are Hermaphrodites.
• Common examples are Spongilla and Sycon.

Phylum Cnidaria

• They are aquatic, sessile, free-living, and radially symmetric creatures.
• On their body, tentacles, have stinging capsules called cnidoblast. These cnidoblasts
• are defense mechanisms of the organism and it also helps in anchorage.
• They display tissue-level organization and diploblastic structure.
• They have a single opening mouth on the hypostome and both internal and external digesting systems.
• The basic body forms that Cnidarians displays are the polyp and the Medusa.
• Physalia and Adamsia are two examples.

Phylum Platyhelminthes

• They are called flatworms because of their dorsally flattened bodies.
• They live inside animals, including humans, and are endoparasitic.
• Some of them take nourishment straight from their host.
• They are triploblastic, bilaterally symmetric animals that are organized at the organ level.
• They have no true internal body to accommodate well-developed organs for proper functioning. 
• The development happens throughout several larval stages. Fertilization is internal.
• Taenia and Fasciola are two examples.

Phylum Annelida

• They can have a closed circulatory system and can either be terrestrial or aquatic, parasitic or free-living.
• They exhibit bilateral symmetry and organ-level organization.
• Segments and metameres are found on the body surfaces.
• Circular muscles in their bodies aid in mobility.
• The Annelida species perform sexual reproduction.
• Examples-Nereis and Hirudinaria.

Phylum Arthropoda

• In the Kingdom Animalia, it is the largest phylum that includes insects.
• They show bilateral symmetry and organ-level structure.
• They have joint legs and a tough exoskeleton
• Arthropods have a chitinous layer covering their belly, thorax, and other body parts.
• Through Malpighian tubules, they excrete.
• The development may be direct or indirect, and fertilization is typically internal.
• Eg- Cockroaches, Flies, Bees, etc.

Phylum Mollusca

• They are the second-largest phylum of the kingdom Animalia.
• They have an organ level of organization and may be terrestrial or aquatic.
• They have true bodies, triploblastic organization, and show bilateral symmetry.
• Most molluscs have calcareous shells covering their bodies.
• The head, visceral hump, and muscular foot make up the body.
• Internal fertilization occurs and they show indirect development.
• Examples include Pila and Chaetopleura.

Phylum Echinodermata

• Animals have calcareous skin coverings.
• They exist in aquatic settings that are organized at the organ level.
• While adults have radial symmetry, larval-stage animals have bilateral symmetry.
• They have a water vascular system that aids in breathing, locomotion, and food collection.
• There is no excretory system in them.
• Echinoderms show external fertilization and reproduce through sexual reproduction.
• Asteria and Echinus are examples.

Phylum Protochordata

• These creatures are triploblastic and bilaterally symmetric.
• They have a true body and, at some point in their life cycle, a notochord is present.
• They typically inhabit marine areas.
• Examples are Herdmania and Amphioxus.

Phylum Chordata

• This phylum includes creatures like birds and humans.
• The presence of a notochord is a trait shared by all species in this phylum.
• They have a single, hollow central nervous system that is located dorsally.
• A post-anal tail is present, which aids with movement.
• A pharynx is penetrated by gill slits.
• The phylum is further divided into subphyla Urochordata, Cephalaochordata, and Vertebrata.

Summary 

The largest kingdom that includes all animals is called Kingdom Animalia. Several criteria, including the level of organization, symmetry, coelom, segmentation, and notochords, are used to classify these species. Various phyla such as  Porifera, Cnidaria, Ctenophora, Platyhelminthes, Annelida, Arthropoda, Mollusca, Echinodermata, Protochordata, and Chordata make up this Kingdom.

Frequently asked question

1. Describe protozoans.
Ans: Protozoans are-

• Microscopic, unicellular, free-living protozoa are present in practically all ecosystems.
• They are typically parasitic and mobile. 
• Digestion of food by these organisms takes place through the process of Osmotrophy, which is the engulfment of food through cell membranes.

2. How are animals classified based on the circulatory system?
Ans: A network of arteries, veins, capillaries, and the Heart together is known as the circulatory system. There are two types of circulatory systems: open and closed systems.

• In an open system, the blood is pumped into a chamber outside the heart known as the hemocoel rather than being constrained to the blood vessels.
• In a closed system, the blood circulates in one direction from the heart to the surrounding vessels and then returns to the heart. In this system, the blood is contained within the blood capillaries.

3. What do diploblastic organization and triploblastic organization mean?
Ans:

• Diploblastic organization – It is the arrangement of cells in two layers, i.e outer ectoderm and inner endoderm. It is seen in Coelenterates 
• Triploblastic organization -It is a  three-layered arrangement of cells, i.e ectoderm, mesoderm, and endoderm. Common examples are Platyhelminthes, chordates, etc. 

Introduction

The definition of agriculture is frequently misunderstood to mean just the production of crops for food and fiber. Agriculture, however, extends beyond just growing plants, it includes the breeding of livestock for their beneficial products. Since the beginning of time, humans have been raising animals for their own needs. Since humans first domesticated animals some 13,000 years ago, they have developed innovative techniques to increase both the quality and quantity of the things they can produce from animals. 

Types of Animal Husbandry

Dairy Farming

• The practice of raising dairy animals, such as cows, buffalo, goats, and others, for milk production and its subsequent processing to produce products like butter, ghee, cheese, and cream, among other things, is known as dairy farming.
• Native Indian cow and buffalo breeds including the Gir, Sahiwal, Red Sindhi, Siri, Mahiwal, Surti, and Jaffarabadi, as well as exotic breeds like Jersey, Red Dane, and Holstein Friesian, are frequently bred for their desirable traits.
• When raising cows to extract milk, it is essential to maintain the required standards of health and hygiene.
• Good quality and safe-to-consume products are ensured by the good health and excellent living conditions of the animals.

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Poultry Farming

• The practice of domesticating and raising birds, such as hens, cocks, ducks, geese, and turkeys, for their meat, eggs, and other products is known as poultry farming.
• Different techniques are used by poultry farmers to raise chickens.
• The most popular method is intensive poultry farming, in which hundreds of birds are frequently raised in tier-by-tier battery cages.
• Farmers are becoming more conscious of the drawbacks of intensive farming, which has led to a rise in the popularity of free-range farming.
• In this style of poultry farming, the birds are given free access to a large area during specific hours of the day.
• Better health and disease resistance are encouraged by this practice.
• In poultry farming, hens are raised primarily for two products: eggs or meat.
• It is advised to provide a healthy, disease-free environment, along with decent, nourishing meals and spacious places.

Pisciculture

• Fish rearing for food is often known as pisciculture or fish farming.
• Typically, fish tanks or other enclosures such as ponds are used to raise the fish.
• The fish are fed artificially and later harvested.
• In composite fish culture, both domestic and foreign varieties are raised in the same pond or enclosure.
• The fish that are selected to be raised together must be able to co-exist.
• The most popular fish species raised for food include trout, carp, salmon, tuna, tilapia, etc.

Apiculture

• Apiculture is the practice of raising bees in colonies in places called apiaries to produce honey and other items like royal jelly, beeswax, etc.
• In addition, bees are also utilized for their pollination services.
• For the colonies to expand, beekeepers frequently employ wooden hives.
• Bee farming is a low-cost, low-labor method of farming.
• Bees can be easily grown without the requirement for any fertile ground.
• However, it is important to make sure the bee farm is situated close to a flower garden with enough pollen and nectar.
• In addition, it is necessary to prevent the use of insecticides near the apiaries.

Advantages of Animal Husbandry

Following are the advantages of animal husbandry in agriculture and human welfare.

• The dairy industry in animal husbandry makes a significant contribution to the global food sector by offering a wide range of goods, including milk and its derivatives like butter, various types of cheese, ghee, cream, etc.
• Dairy farming makes a vital contribution to a nation’s economy. With 186 million tonnes of milk consumed yearly. India is one of the world’s largest milk producers.
• In addition to being raised for their milk, dairy farm animals are also used for their flesh.
• Because of its high protein content and flavor meat is a very popular food item.
• Livestock and poultry raised on the grounds, generally graze there, this helps in suppress weed development.
• The items that are obtained from all the reared animals help in increasing the nation’s economy as they are exported to various foreign countries.
• All these animal-rearing activities have generated employment options in rural areas. 
• It has increased food security and provided money to rural impoverished people.
• Utilizing animal waste as manure on farmland is one example of how sustainable practices to aid in the efficient management of waste. It encourages effective nutrient cycling.
• Moreover, manure can be used in fish meals.
• Manure and cow dung are valuable sources of fuel.
• Additionally, animal husbandry is managed to produce fibers that are crucial to the textile industry.

Summary

• The process of raising livestock to exploit their products is known as animal husbandry.
• Dairy farming, poultry farming, fish farming, and bee farming are the four main subfields of animal husbandry.
• Animal husbandry procedures must assure a safe, secure, and healthy environment for the animals’ well-being, which will in turn yield high-quality goods.
• Animal husbandry produces a number of significant goods that are essential to our daily life.
• Additionally, animal husbandry creates job opportunities.

Frequently Asked Questions

1. Differentiate between layers and broiler.
Ans: 

Layers	Broilers
These are chickens that are raised for egg production.	These are chickens that are raised for meat production.
They need protein in less quantity in their  diet.	They require a protein-rich diet.
They need proper spacing and lighting.	They do not need much spacing and lighting.

2. Enlist types of Honey bees used in apiculture.
Ans: Honey bees reared for apiculture are-

• Apis dorsata or The Rock Bee
• Apis cerana indica or The Indian hive Bee
• Apis mellifera or The European Bee
• Apis florea or The Little Bee.

3. Which state of India produces the maximum number of fish under pisciculture?
Ans: Andhra Pradesh is the highest fish-producing state in India. It produces around 34.50 lakh tonnes of fish per year.

Introduction

A population is a collection of people belonging to the same species who coexist in one location. These people are susceptible to the same environmental factors and need the same resources to survive and develop. When analyzing the population, we categorize the population based on its size and location.

A population is never constant and always exhibits some fluctuations. Natality, mortality, immigration, and emigration are some terms used to characterize these dynamic oscillations that occur in a population. Mathematical methods, such as the logistic growth models and the exponential growth curve, are used to study population dynamics.

Population Growth

The term “population growth” describes the shift in the total number of people within a population. This growth can be positive if the no.of individuals increases in an area and population growth can be termed negative if the no.of individuals decreases in an area.

Birth, immigration, death, and migration are the four main factors that influence change in the number of individuals in an area. The first two elements increase the population, whilst the latter two cause it to decrease.

Growth models that describe the basic growth trend in a population

There are two growth models which describe the basic growth trend in a population. The two models are-

Exponential Growth Model

• When an ideal environment with unlimited resources is taken into account, this growth model represents the rapid growth rate of a population.
• Under ideal circumstances, a small number of individuals would have the means to develop and propagate. This is because they are not constrained by any external forces.
• Every birth would result in an increase in population and every death will decrease the population.
• This model, is often employed to find out the maximum capacity of growth and the kind of ideal conditions required for such growth to take place.

Mathematically, it can be shown as follows-

\(\frac{{\Delta {\rm{ }}N{\rm{ }}}}{t} = {\rm{ r}} \times {\rm{N }}\; –  –  –  –  – 2\)

\(\frac{{\Delta {\rm{ }}N{\rm{ }}}}{t} = {\rm{ }}B{\rm{ }} – {\rm{ }}D{\rm{ }}\; –  –  –  –  – 1\)

Where \(\frac{{\Delta {\rm{ }}N{\rm{ }}}}{t}\)= change in population size(Δ N) over a time interval (t)

B – D = per capita number of births – per capita number of deaths

B – D can be substituted by the quantity r, hence the equation becomes:

\(\frac{{\Delta {\rm{ }}N{\rm{ }}}}{t} = {\rm{ r}} \times {\rm{N }}\; –  –  –  –  – 2\)

Applying differential calculus to the above equation, we get:

\(\frac{{{\bf{dN}}}}{{{\bf{dt}}}}{\rm{ }} = {\rm{ }}{\bf{rN}}\;\)

where r = per capita change in population size occurring at each instant of time / intrinsic rate of population growth 

From this equation, the following cases arise:

1. If r = 0, there’s no change in population size
2. If r > 0, population size increases exponentially 
3. If r < 0, population size declines exponentially

Logistic Growth Model 

• The Logistical Model is based on the notion that as an individual is “added” to a population, they have access to fewer resources, due division of resources amongst individuals. This is in contrast to the exponential model, which assumes limitless resources.
• Realistically, a certain geographic area can only support a certain number of inhabitants while ensuring that each has equal access to all available resources.
• This maximum limit of population growth that an environment can sustain is known as its carrying capacity, represented as (K).  
• Limiting variables such as water, food, shelter, protection from predators, etc. govern the carrying capacity of an environment.
• The reproductive capacity of individuals is reduced when resources are scarce and the area is congested.
• Similar to this, factors like an increase in disease incidence can cause the per capita death rate to rise.
• Declining per capita population growth rate is the result of higher per capita mortality rates and lower per capita birth rates.
• Therefore, r decreases as N increases. In the logistic growth the model, per capita growth rate tends to 0 as population size approaches K. 
• If (K-N) = no. of excess individuals that the environment can support, then 
• (K-N)/K = the amount of K still available for population growth
  

           \[\;{\rm{\;}}\frac{{{\rm{dN}}}}{{{\rm{dt }}}}{\rm{ =  }}\frac{{{\rm{rN }}\left( {{\rm{K – N}}} \right)}}{{\rm{K}}}\;\]

Where dN/dt = rate of change in population size at time t

            N = population density 

           r= intrinsic rate of growth under ideal conditions

           K = carrying capacity  

Factors that Influence Population Fluctuation:

The population is susceptible to regular dynamic variations brought on by the influx of new inhabitants into a region or the emigration of residents from that region. The following are the factors that influence population change.

• Natality- It is also known as birth rate and is defined as the number of children born in a certain area per unit of time. Natality rises when an organism reaches its maturity and declines as it nears senescence. There are two types of natality-

• • Maximum/ absolute natality– This refers to the maximum number of persons that might theoretically be born under optimal and non-resource-limiting circumstances. It is also called the fecundity rate.
  • Ecological/realized natality- This is the actual population growth brought on by births under given environmental circumstances. It is  also known as the “fertility rate.”

• Mortality-It is also known as the death rate and is defined as the number of individuals that have died in a population per unit of time. There are two types of mortality-
  • Specific or potential mortality- This refers to a theoretical decrease in the no. of indualivials under ideal climatic and resource availability conditions. People pass away through natural reasons, such as old age.
  • Ecological/realized mortality-Ecological/realized mortality is the actual death of members of a population as a result of ongoing environmental issues and resource shortages. With changes in population and environment, this type of mortality keeps on changing.

• Immigration-
  • The term “immigration” describes the flood of new people from other places into a new geographic area.
  • It enhances population growth by increasing the number of individuals who already live in the area.

• Emigration
  • Emigration is the movement of people away from a certain geographic area.
  • It drives people out of the area, which decreases the local population there.

Summary

• Population growth refers to an increase in the number of people living in a particular location.
• Four significant factors—natality, death, immigration, and emigration—affect population growth.
• Models of population growth aid in analyzing and forecasting trends in population growth.
• The exponential model is theoretical since it is based on unlimited resource availability.
• The logistical model is realistic and takes into account the environment’s carrying capacity and limited resources.
• Natality is the number of children born in a region per unit of time.
• The number of individuals who die in a population per unit of time is known as mortality.
• Immigration is the movement of new people into a country or region from other places.
• Emigration is the movement of people out from a specific location.

Frequently Asked Questions

1. What benefits does population growth have?
Ans: Benefits of population growth are-

• Economic growth can be caused by population expansion. 
• more parents are investing in their children as a result of more births.
• The economy is supported by rising spending on food, clothing, textbooks, recreational equipment, and toys.

2. What effects does population expansion have on the environment?
Ans: Population growth has the following impacts on the environment-

• The consumption of resources including land, food, water, air, fossil fuels, and minerals increases to a great extent.
• Lots of waste products are generated due to the consumption of various resources.
• Waste products such as hazardous substances, greenhouse gases, and air and water pollutants are also generated, harming the environment.

3. Mention different types of populations.
Ans: The different types of the population are-

• Finite population
• Infinite population
• Existent population
• Hypothetical population