Biology-III

Fertilization:

The fusion of male and female gametes is called fertilization.

Types Of Fertilization:
Following are the major types of fertilization:
i) External Fertilization
ii) Internal Fertilization
iii) Self-Fertilization
iv) Cross-Fertilization

External Fertilization:
• This type of fertilization is generally observed I simple aquatic animals.
• In such animals both ova and sperms are released into the water where fertilization occurs.
• In terms of evolution external fertilization is of primitive type and is not better biologically as compared to internal fertilization.

Internal Fertilization:
• In the internal fertilization the females keep ova inside their bodies and males deposit sperms within the tube of reproductive tacts of females.
• For all land animals internal fertilization is almost must because sperms are quickly killed by dehydration.
• In terms of evolution internal fertilization is highly evolved and much better biologically as compared to external fertilization.

Self-Fertilization:
• Self-fertilization occurs within the same animal.
• It is that fertilization in which sperms are used by the ovaries of same animal e.g. Tapeworm

Cross-fertilization:
• Cross-fertilization is the process in which sperms of one animal are transferred into the body of another animal e.g. Earthworm.

Animals:

Types Of Animals:
i) Invertebrates: Animals having no backbone or vertebral column.
ii) Vertebrates: Animals with backbone or vertebral column.

Classification Of Invertebrates:
The invertebrates are classified into following categories:
i) Phylum Protozoa
ii) Phylum Porifera
iii) Phylum Coelentrata
iv) Phylum Platyhelminthes
v) Phylum Nematode
vi) Phylum Annelida
vii) Phylum Mollusca
viii) Phylum Arthropoda
ix) Phylum Echinodermata

Following are the most common examples of invertebrate animals with their relative phyla:
– Euglena: Phylum Protozoa
– Paramecium: Phylum Protozoa
– Amoeba: Phylum Protozoa
– Sponges: Phylum Porifera
– Hydra: Phylum Coelentrata
– Jelly fish: Phylum Coelentrata
– Tapeworm: Phylum Platyhelminthes
– Ascaris: Phylum Nematode
– Hookworm: Phylum Nematode
– Filaria: Phylum Nematode
– Snails: Phylum Mollusca
– Squids: Phylum Mollusca
– Cockroach: Phylum Arthropoda
– Honey bee: Phylum Arthropoda
– Mosquito: Phylum Arthropoda
– Butter fly: Phylum Arthropoda

Classification Of Vertebrates:
Vertebrates have been divided into following five major classes:
i) Fishes
ii) Amphibians
iii) Reptilian
iv) Birds
v) Mammals

Some Animals & Their Location
i) Blue whale: Found in all oceans
ii) Panda: China
iii) Dolphin: In seas
iv) Porpoises:
v) Kangaroo: Australia
vi) Snow Leopard: Central Asia
vii) Yak: Central Asia
viii) Llama: South America
ix) Ibex: Wild mountain goat
x) Cobra: South Asia
xi) Alligator: N.America
xii) Tortoise: Water
xiii) Rattle Snake: America
xiv) Lizards:
xv) Crocodiles:
xvi) Ostrich: Deserts Of Africa
xvii) Penguin: Antarctic Region
xviii) Kiwi: New Zealand
xix) Rhea: South America
xx) Emu: Australia
xxi) Shark: Found in all oceans
xxii) Trout: Fresh water fish
xxiii) Cod:

Scavenger:
Scavengers are the animals that ‘Clean up’ after the other animals by consuming their leavings and sometimes prey on sick or dying animals or consume dead bodies. Scavengers are also called detritus feeders. Vultures, coyotes, jackals, hyenas and wild dogs are scavengers which eat the left over prey or dead bodies of hunted animals.

Quote: Originally Posted by Roshan wadhwani Scavengers are the animals that ‘Clean up’ after the other animals by consuming their leavings and sometimes prey on sick or dying animals or consume dead bodies. Scavengers are also called detritus feeders. Vultures, coyotes, jackals, hyenas and wild dogs are scavengers which eat the left over prey or dead bodies of hunted animals. Brother Roshan Wadhwani, let me make an addition (not a correction) to “Scavangers” here. Environment is made of two components: living components and non-living components: Living components include Producers, Consumers and Decomposers. Scavengers and micro-organisms fall into the category of decomposers which feed on dead plants and animals and break them down into smaller parts. Your effort, anyway, is worthwhile. Keep it up! __________________ Real richness is that you are so expensive that no one can buy your character.

The Baikonur Cosmodrome The Baikonur Cosmodrome , also called Tyuratam[1], is the world’s first and largest operational space launch facility. It is located in the desert steppe of Kazakhstan ,

Ecosystem:

Definition:
A natural of habitat or system where living organisms and physical components of their environment interact with one another and exchange materials so as to achieve a functional stability is called an ecosystem.

Characteristics Of Ecosystem:
An ecosystem is a basic unit of ecology of living organisms.
An ecosystem may be natural like a pond, lake, stream, river, ocean or a forest.
It may also be artificial like an Aquarian, an artificial pond or an agricultural field.
A pond is an excellent example of a small ecosystem to demonstrate interrelationship between abiotic and biotic component of the ecosystem.

Components Of Ecosystem:

i) Abiotic Components Of Ecosystem.
Following are the abiotic components of ecosystem.
a. Light
b. Temperature
c. Water
d. Atmosphere and wind
e. Fire
f. Soil
g. Topography
h. Gravity
i. Inorganic nutrients

ii) Biotic Factors.
Following are the biotic components of ecosystem.
a. Producers: Green Plants
b. Consumers: Animals and Man
c. Decomposers and reducers: Bacteria, fungi

Types Of Ecosystem:
There are two main types of ecosystem:
i) Terrestrial Ecosystem: it includes Forest and Desert Ecosystem
ii) Aquatic Ecosystem: it includes small pool, a pond, stream, river, lake and an oceanic ecosystem

Heredity:

Terminology Of Genetics:

Gene:
The basic unit of hereditary material which is responsible for development of a trait.

Alleles:
Alternatives forms of genes are called alleles, e.g. tall versus dwarf.

Dominant:
The dominant alleles are those traits which show complete expression even in heterozygous state. Dominant alleles dominate the recessive alleles in heterozygous state.

Recessive:
Recessive alleles or traits are those which fail to express themselves in heterozygous state. For example r and y are recessive alleles for wrinkle and green seeds.

Homozygous:
Homozygous is a condition in which an individual possess similar alleles for a particular trait. For example TT for tallness and tt for dwarfness.

Heterozygous:
Heterozygous is a condition in which an individual possess dissimilar alleles for a particular trait. For example Tt for tallness.

Genotype:
Genetic make of an organism is called genotype.

Phenotype:
External appearance or expression of genotype is called phenotype. For example, roundness, wrinkleness of seeds and tall or dwarf plants represent different phenotype.

Gene:

Definition:
The fundamental unit of heredity, formed as a sequence of bases in DNA.

Characteristics Of Genes:
Each gene has a definite position at the chromosome and may occur as alleles.
The name gene was introduced by Johannsen in 1909 and the structure of DNA was elaborated by Watson and Crick in 1953.
Genes determine all the structural and functional characters of an individual, like eye colour, skin colour, height, weight, blood group, hair, intelligence, temperament and all others.
The characters from one generation to other are taken by genes.
They sometimes change through the process of mutation. This gives variety in characters.
The accurate structure of the proteins and enzymes in the body is determined by genes.

Chromosomes:

A chromosome is a rod-like portion of the chromatin of a cell nucleus, performing an important part in meiotic cell division, and in the transmission of heredity characteristics. Normally they are constant in number for any species; there are 22 pairs of chromosomes and two sex chromosomes in the human.

Types Of Chromosomes: in higher animals and plants, there are two fundamental types of chromosomes, which are classified on the basis of sex determination these are:
i) Autosomes
ii) Sex Chromosomes:

Autosomes:
These are paired somatic chromosomes that play no part in sex determination of organisms. These chromosomes are similar in males and females.

Sex Chromosomes:
The chromosomes that determine sex in organisms are called sex chromosomes. There are two types of sex chromosomes.
a) X- chromosome
b) Y- Chromosome

Genetic Engineering:

The deliberate modification of the characteristics of an organism by manipulating its genetic material.

OR

Scientific alteration of the structure of genetic material in a living organism. It involves the production and use of recombinant DNA and has been employed to create bacteria that synthesize insulin and other human proteins.

Significance Of Genetic Engineering:

i) To Cure the genetic disorders
Heredity diseases can possibly be treated by this technique by transplanting normal genes in the place of abnormal or diseased genes.

ii) To Prepare Better Crops
Crops with desired characteristics could possibly be produced by introducing desired genes.

iii) To Get Better Breeds Of Animals
Like plants better breeds of animals can also be produced by the introduction of recombinant DNA.

iv) Interferon
Interferons are effectively used in the treatment of Hepatitis of A & B.

v) Insulin
Human insulin is being produced by genetic engineering to treat diabetes

vi) Vaccines
Genetic engineering has also helped in the production of vaccines which are used for controlling and treating viral diseases.

Biotechnology:

The exploitation of biological processes for industrial and other purposes, esp. the genetic manipulation of microorganisms for the production of antibiotics, hormones, etc.

OR

Biotechnology is the use of living organisms (especially microorganisms) in industrial, agricultural, medical and other technological applications.

Importance Of Biotechnology:
i) To increases production
ii) To introduce improved quality of seeds and plants
iii) To introduce plants resistant to disease and insect pests
iv) To introduce verities suited to particular climates and soils.
v) To introduce verities resistant to lodging
vi) To improve nutritional value of crops
vii) To save rare varieties of plants by rapid clonal propagation for breeders to use in future.

Teeth:

The humans have two sets of teeth one replaced by the second. The primary set or milk or deciduous teeth are 20 in number while there are 32 permanent teeth in adults.

1. In children there are 20 deciduous or milk teeth. These are
Incisor: 2 pair × 2= 8
Canine: 1 pair × 2= 4
Premolars: 2 pair× 2=8

2. In adults there are 32 permanent teeth. In each jaw on each side there are:
Incisors: 2 pair × 2=8
Canines: 1 pair × 2=4
Premolars: 2 pair × 2=8
Molars: 3 pair × 2= 12

Incisors:
The central front teeth are called incisors. There are four in upper jaw and four in lower jaw.

Canines:
The pointed, dark colored teeth on either side of the incisors are canines. 2 in upper jaw and 2 in lower jaw.

Premolars:
These are bi-cusped teeth after the canines. There are 8 premolars. 4 in the upper jaw and 4 in the lower.

Molars:
There are 12 molars, 6 in the upper jaw and 6 in the lower jaw.

Structure Of Teeth:
Each tooth consists of a crown which is the visible part and the root, which anchors it in sockets in the jaw. A tooth consists mainly of dentine. The crown is coated with even harder enamel, while the root is covered with cementurn to help another it in the jaw. Inside each tooth, there is a cavity full of pulp, carrying nerves and the tooth’s blood and eats through the dentine to the pulp when the decay reaches the pulp, pain and inflammation follows and tooth may die.

A nerve, an artery, a vein and lymph duct enters the pulp cavity through the root canal. The nerves give sensation of hot and cold.

Antibody:

Antibody is a protein produced by white blood cells that help to destroy bacteria. Antibodies react with the antigens and inactivate or destroy them. A large number of antibodies are produced in blood which are targeted against various types of antigens. Antigens are foreign molecules, cells, bacteria, viruses or fungi which enter the body usually a disease causing microorganisms. Antibodies are the integral part of the defence mechanism of human body. They are also involved in immunity against disease.

Hemophilia:

It is a disease in which the peron have prolonged blood clotting time resulting in excessive bleeding fron injury.
It is due to the deficiency of vitamin K.
It is a semilethal disease controlled by recessive gene.
It is less common in women than in men.

Important Facts About Human Physiology:

The largest gland of the body: Liver

The largest organ of the body: Skin

The longest bone of the body: Femur

The total number of bones in the body: 206

The hardest bone of the body: Tooth

The smallest bone of the body: Stapes

Total number of muscles in the body: 600

The filter of the body: Kidney

The pump of the Body: Heart

Total number of bones in vertebral column: 33

The normal body temperature: 98.4 F (37 C)

The normal respiratory rate of the Body: 16-18 per min

The total volume of blood in body: 4-5 litres

Total number of bones in face: 14

Vascular connection between foetus and uterus: Placenta

Brain:

Human brain is contained in skull. It has three major parts.
i) The Cereberum ot bigger brain
ii) The Cerebellum or Smaller brain
iii) Medulla Oblongata or hind brain

The cereberum constitutes the major volume of brain. It consists of two large masses of nervous material known as cereberal hemispheres. Human consciousness, thought, emotions, sight, will, hearing, sensation of pain, memory and speech are centere in the creberum. Some parts of it also control motor nerves, operating the arms and legs.

The cerebellum or the smaller brain is related with the coordination of action of nerves and muscles. In this way movements of body are manged. Medulla or hind brain contains the centres for reflex actions in addition to automatic movements such as breathing and walking.

Reflex Action:

– Reflex actions are the responsed to environmental changes both internal and external and are immediate or automatic and are without intervention of will.
– These reflexes amy be simple or conditioned e.g. watering of mouth on seeing or smelling of food.
– Simple reflexes are inborn, inherited or unlearnt responses to stimuli.
– The structural and functional basis of simple reflex is called reflex arc.
– Impulses are carried from receprtors to sensory neurons to CNS from where they are passed on via motor neurons to the effectors for necessary response.

Thermoplastics:

Substances (esp. synthetic resins) that become plastic on heating and harden on cooling and are able to repeat these processes

OR

A type of plastic that can be softened by heat, hardened by cooling, and then softened by heat over and over again.

Properties of Thermoplastics:
Thermoplastics have wide ranging properties.
– They can be very much like rubber, or as strong as aluminium.
– are light in weight,
– Can withstand temperature extremes of up to 600 F, while others retain their properties at -100 F. Some
– Thermoplastic materials have no known solvents at room temperature.
– Most thermoplastic materials are excellent insulators, both electrical and thermal.
– Are recyclable materials that are used frequently today to create objects such as foam cups, polyethylene squeeze bottles, acrylic lenses and safety helmets.
– In general the combination of light weight, high strength, and low processing costs make thermoplastics well suited to many applications.

Uses:
– They are useful for a variety of applications, including consumer goods, machine parts, medical equipment and packaging and storage materials.

Examples:
• PVC/Vinyl
• Polystyrene
• Polyethylene
• Cellulose Acetate
• PTFE/Teflon
• Nylon/Polyamide
• Polyester

Synthetic Polymers:

Polymers are composed of very large molecules (macromolecules) formed by linking together many smaller, more simple units called monomers. There can be as few as five or as many as several thousand monomers units in a polymer. There are a large number of synthetic polymers prepared and in use. Some of these are polyamides(nylon), polyethylene, propylene, polyvinylchloride, synthetic rubber, cellulose acetate, cellulose nitrate and silicones.

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