Diversity In Living Organisms

organs

Single

Locomotary

Spicules, sponging

Scales

Exoskeleton

Decomposers

Echinodermata

Wings

Bilateral

Gymnosperms

Pteridophytes

Each category, referred to as a unit of classification, in fact, represents a rank and is commonly termed as taxon (pl.: taxa).

Plants that do not have well-differentiated body design fall in the Thallophyta group. The plants in this group are commonly called algae.

Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic (both fresh water and marine) organisms. They have unicellular and non-jacketed sex organs. Most of the members have one or more storage bodies called pyrenoids located in the chloroplasts.

This group includes many kinds of unicellular eukaryotic organisms. Some of these organisms use appendages, such as hair-like cilia or whip-like flagella for moving around.

These are heterotrophic eukaryotic organisms. They use decaying organic material as food and are therefore called saprophytes.

Fungi are filamentous. Their bodies consist of long, slender thread-like structures called hyphae. The network of hyphae is known as mycelium.

Lichens are symbiotic associations i.e. mutually useful associations, between algae and fungi. The algal component is known as phycobiont and fungal component as mycobiont.

Comb jellies belong to Ctenophora.

Among the given options, Lizard is cold-blodded animal. Cold blooded animals maintain their body temperature by seeking environments that match the temperature they require

The gymnosperms (gymnos: naked, sperma: seeds) are plants in which the ovules are not enclosed by any ovary wall and remain exposed. The seeds that develop after fertilisation are not covered, i.e., are naked. E.g., Pinus.

Plants with seeds having a single cotyledon are called monocotyledonous or monocots. Wheat is a example of monocot plant.

Entamoeba is a microscopic endoparasite of man.

These are non-motile animals attached to some solid support. These animals have a water transport or canal system that helps in circulating water throughout the body to bring in food and oxygen.

It is marine animal with streamlined body and have cartilaginous endoskeleton. The skin is tough, containing minute placoid scales.

Metamerism is a characteristic feature of Annelida.

The excretory organs of Annelida are nephridia which help in osmoregulation and excretion.

Respiration in arthropods occurs through gills, book gills, book lungs or tracheal system.

Arthropoda is the largest phylum of Animalia which has insects.

Spiders and scorpions are arachnids.

Amphioxus belongs to Cephalochordata. In cephalochordate, notochord extends from head to tail region and is persistent throughout the life.

Sea squirts (Herdmania) is a urochordate.

Ostrich, penguin and kiwi all are flightless birds.

Labeo is a member of pisces which have two chambered heart.

It includes both marine and fresh water fishes with bony endoskeleton. They have swim bladder which regulates buoyancy.

The organisms which do not possess well defined nucleus and membrane bound cell organelles are grouped under the kingdom Monera. Carl Woese divided the Monera kingdom into Archaea and Eubacteria (cyano bacteria).

Carl von Linnaeus is known as Father of Taxonomy.

The book Systema Naturae was written by Carolus Linnaeus in 1735. He described his binomial system of classification in this book.

Charles Darwin (1859) has described the idea of evolution in book “The origin of species”.

R.H. Whittaker proposed five kingdom classification system. The five kingdoms are Monera, Protista, Fungi, Plantae and Animalia.

: In taxonomic hierarchy family comes between order and genus. Family has a group of related genera with still less number of similarities as compared to genus and species.

The organisms which do not possess well defined nucleus and membrane bound cell organelles are grouped under the kingdom Monera. Eg., blue green algae.

Binomial nomenclature was proposed by Carl Linnaeus (1707-1778). It is a simplified system of naming organisms. Under Binomial system of nomenclature, each organism has scientific name consisting of two parts. First part is genus and second part is the species. For example, the scientific name of mango is Mangifera indica.

Monerans do not possess well defined nucleus and membrane bound cell organelles like mitochondria, lysosomes, etc.

The plants of this group bear naked seeds and are usually perennial, evergreen and woody.

Pteridophyta and gymnosperms have specialised tissue for the conduction of water and other substances from one part of the plant body to another.

The plant body of pteridophytes is differentiated into roots, stem and leaves but they do not have flowers.

Dogfish is a true fish as it has all the characters which a fish has like streamlined body, cartilaginous endoskeleton, gill slits, fins, etc.

These are exclusively free-living marine animals. They are triploblastic and have a coelomic cavity.

Elephantiasis disease of human beings is caused by a filarial worm, Wuchereria.

In arthropods, open circulatory system is present and so the coelomic cavity is filled with blood.

Arthropods and Molluscs have open circulatory system.

The criteria which are used for classification of organisms are presence or absence well defined nucleus and membrane-bound cell organelles (cell structure), Body design of the organism and the ability to produce one’s own food.

Filaria (Wuchereria) belongs to Phylum Nematoda. It causes an Elephantiasis disease in human beings.

The characteristic features of vertebrate is presence of notochord.Notochord is a mesodermally derived rod-like structure that runs along back of the animal separating the nervous tissue from gut.

The skin of Pisces and Reptiles is covered with scales. Amphibians skin is moist without scales. The skin of mammals is covered with hair.

Fishes, amphibians and reptiles are not oviparous. They lay eggs.

Members of the phylum Porifera are commonly known as sponges. They are generally marine and mostly asymmetrical animals. Example- Spongilla

Nereis, earthworm and leech are annelids while Urchins is not an annelid. Sea urchin belongs to Phylum Echinodermata.

Coelentrates are multicellular, diploblastic and acoelomate animals having tissue level of organization i.e., they lack true organs, mollusca, Arthropoda and Echinodermata have organ level of organization.

Some of the cnidarians that ive in colonies (corals) while others have a solitary like–span (Hydra).

Echinoderms have tube feet that helps in respiration and locomotion.

Leech belongs to Phylum Annelida. They have metameric segmentation i.e., their body is divided into segments which are identical to each other and bear set of organs in each segment.

Echinodermata animals have hard calcium carbonate structures that they use as a skeleton.

Fishes have two chambered heart-one auricle and one ventricle.

Cartilaginous fishes have endoskeleton made up of cartilage, e.g., Scoliodon (dog fish) shark Torpedo, sting ray etc.

The amphibian skin is moist (without scales). They have mucus glands in their skin. Heart is three chambered and respiration through either gills or lungs.

Protochordates are bilaterally symmetrical, triploblastic and coelomate. They have a closed circulatory system. Example- Amphioxus

(i) Asymmetry-Amoeba,

Radial symmetry- Hydra

Bilateral symmetry - Nereis.

(ii) Acoelomate - Platyhelminths (flatworms),

Pseudocoelmate - Nematodes (round worms)

Haemocoelomate - Arthropods (crab).

Euglena is called plant-animal because it possess characteristics of both plants and animals. Like plants, Euglena has chloroplast by which it can synthesise its own food by the process of photosynthesis. Like animals, Euglena does not have cell wall and acts as a heterotroph in dark.

Protozoa are regarded as early or primitive animals because they are microscopic with primitive mode of reproduction and they exhibit a cellular level of organisation.

(i) Nereis, (ii) Starfish.

The blood-filled cavity consisting of spaces in between organs is known as haemocoel. Mollusca and Arthropoda have haemocoel.

In gymnosperms, seeds are naked or exposed whereas in angiosperms, they are covered by fruit wall or pericarp.

Phylogeny is study of evolutionary relationship among different groups of organisms.

(a) Mollusca; (b) Echinoderrnata; (c) Aves; (d) Arachnida; (e) Mammalia.

(i) Hemichordata - Balanoglossus

(ii) Urochordata - Herdmania

(iii) Cephalochordata - Amphioxus (Branchiostoma)

Notochord is a mesodermally derived rod-like structure formed on the dorsal side during embryonic development in some animals. Animals with notochord are called chordates and those animals which do not form this structure are called non-chordates,

Nerve cord is a collection of nerve fibres that runs throughout the length of an animal. It is hollow and dorsal in chordates where it gets modified into central nervous system of brain and spinal cord. Nerve cord is solid and ventral in nonchordates.

Amphibians are advanced than the fishes because

(i) Amphibians have three-chambered heart while fishes have two chambered hearts.

(ii) Amphibians have lungs for respiration while fishes have gills for respiration.

The nafure of skin in four classes of tetrapoda are:

(i) Class Amphibia –moist skin without scales.

(ii) Class Reptilia – Dry and cornified skin having epidermal scales or scutes.

(iii) Class Aves – Dry skin without glands.

(iv) Class Mammalia - Glandular skin with hairs.

Fight adaptations of the birds are the following:

(1) Forelimbs are modified into wings for flying.

(2) Body is light as they have hollow (pneumatic) bones.

(3) Body is streamlined to reduce air resistance during flight.

(4) Flights muscles are well developed.

(5) Body is covered with exoskeleton of water-proof and light-weight feathers.

(6) They have actue vision.

Although whales can swim in water like fishes, but they are not grouped in it because they have characteristic like mammals such as they have four chambered heart, lungs for respiration, diaphragm and mammary glands. They are viviparous like other mammals so they are grouped in the mammals not in the fishes.

(a) The figure illustrates Amphioxus (Branchiostoma).

(b) 1. Nerve Cord; 2. Notochord; 3. Atriopore; 4. Oral hood

(c) Notochord is present in phylum Chordata.

(d) In cephalochordate, notochord extends from head to tail and is persistent throughout the life.

(a) The figure illustrates liver fluke (Fasciola hepatica).

(b) 1. Oral sucker;

2. Ventral sucker (acetabulum)

(c) Liver fluke is a endoparasite which lives in bile duct of sheep.

(a) It is a bony fish which belongs to class Pisces.

(b) 1. Operculum; 2. Dorsal fin; 3. Pectoral fin; 4. Pelvic fin; 5. Anal fin; 6. Caudal fin; 7. Lateral line.

(c) The lateral line is a sensory system in fish that allows them to identify position of objects and movement in the surrounding water.

Wings are absent in bed bug (Cimex) even then it is considered an insect because it possesses following basic characteristics of class Insecta;

(i) Its body is divisible into head, thorax and abdomen.

(ii) Its exoskeleton is made up of chitin.

(iii) It has three pairs of jointed thoracic legs.

Protozoa are regarded as early or primitive animals because they are microscopic with primitive mode of reproduction and they exhibit a cellular level of organisation.

Although both whales and fishes are aquatic, both belong to different classes. Whales belong to class Mammalia while fishes belong to class Pisces. Both differ in several basic characters, such as:

(i) Whales are warm-blooded animals while fishes are cold-blooded animals.

(ii) Whales have lungs for respiration while fishes have gills for respiration.

(iii) Whales have four-chambered heart while fishes have two-chambered heart.

(iv) Whales have mammary glands which are absent in fishes.

(a) Identification. A- Male shield fern (Dryopteris); B- Moss (Funaria), C- Pinus; D-Spirogyra; E-Euglena, F- Bread Mould (Rhizopus).

(b) Phylum- D- Thallophyta; E-Protozoa; F-Fungi

(c) Division - A-Pteridophyta; B- Bryophyta; C-Gymnospermae.

(d) Unicelluar and eukaryotic Organism –Euglena

(e) (i) Heterotrophic nutrition - Rhizopus ; (ii) Mixotrophic nutrition – Euglena.

(f) Multicellular decomposer - Rhizopus.

(g) Amphibian of plant kingdom – Funaria

(h) Pinus lacks xylem vessels and phloem is without companion cells.

(i) (i) Dryopteris; (b) Rhizopus

(j) Pinus has haploid endosperm.

(a) A- Scolopendra (Centipede), (B)- Hydra; C-Fasciola hepatica (liverfluke), D-Pheretima posthuma (earthworm).

(b) (i) Diploblastic –Hydra. (ii) Coelomate- Fasciola, Pheretima, Scolopendra

(c) (i) Triploblastic acoelmate – Fasciola

(ii) Triploblastic coelomate – Pheretima, Scolopendra.

(d) (i) Cnidaria. Hydra; (ii) Platyhelminthes. Fasciola; (iii) Annelida. Pheretima; (iv) Athropoda- Scolopendra

(e) (i) Organ level organisation Fasciola; (ii) Organ system level of organization. Pheretima, Scolopendra.

(f) (i) Flame cells - Fasciola; (ii) Nephridia- Pheretima.

(g) Tracheae – Scolopendra.

(a) Bony fish; Class- Osteichthyes (Phylum Chordata).

(b) A-mouth; B-Dorsal fin; C-Pelvic fin; D-Caudal fin; E-Scales.

(c) Gills

(d) It has adaptation to live in water and to swim (i.e. stream-lined body, fins and tail for swimming, slimy and scale covered body, gills for aquatic breathing).

(e) Bony endoskeleton.

The scientific name of cow is Bos taurus.

To improve local breeds of cow, exotic breeds of cattle to be brought to india.

Exotic breed of cow = Jersey

A dicot plants have tap root system, reticulate leaf venation, and pentamerous or tetramerous flowers. The dicots have two cotyledons in their seeds.

A monocot plants have fibrous root system, parallel leaf venation, and trimerous flowers. The monocot seeds contain only one cotyledon.

It is difficult to remember names of a species in five languags. Hence, to overcome this problem, system of nomenclature was devised:

Diaphragm is a muscular partition in mammals which seapartes the thoracic cavity from the abdominal cavity. It increases the efficiency of brething.

Bryophyta

False, Hemidactylus is a wall lizard and reptile.

1. (f); 2 (a); 3(e); 4 (b); 5 (g); 6(c); 7 (h); 8 (d)

A-Fern; B-Cycas; C-Earthworm; D-Ostrich.

aquatic adaptation in fishes are:

(i) Stream-lined body.

(ii) Presence of fins and tail for swimming

(iii) Slimy and scale covered body,

(iv) Gills for breathing in the water.

Binomial nomenclature was proposed by Carl Linnaeus (1707-1778). It is a simplified system of naming organisms. Under Binomial system of nomenclature, each organism has scientific name consisting of two parts. First part is genus and second part is the species. For example, the scientific name of mango is Mangifera indica.

Advantages:

● Scientific names are standardised and accepted universally.

● Scientific names are not changed according to country or language.

Classification of Kingdom Plantae: Plant kingdom includes eukaryotic organisms usually with embryonic stage. The major plant groups are-

● Thallophyta- Plants that do not have well-differentiated body design fall in this group. The plants in this group are commonly called algae. Example- Spirogyra, Ulothrix.

● Bryophyta- These are called the amphibians of the plant kingdom. The plant body is commonly differentiated to form stem and leaf-like structures. Example- Funaria.

● Pteridophyta- The plant body is differentiated into roots, stem and leaves and has specialised tissue for the conduction of water and other substances from one part of the plant body to another. Example- Marsilea

● Gymnosperms- The plants of this group bear naked seeds and are usually perennial, evergreen and woody. Example- Pinus.

● Angiosperms- In the angiosperms or flowering plants, the pollen grains and ovules are developed in specialised structures called flowers. Example- Maize

The vast variety and differences that are found in living organisms of different ecosystems whether terrestrial, aquatic or marine collectively known as biodiversity.

The number of species that are known and described range between 1.7-1.8 million. This refers to

Biodiversity or the number and types of organisms present on earth.

The size of blue whale is 30 meters in length (largest animal).

One of the gymnosperms, the giant redwood tree Sequoia (100 meters) is one of the tallest tree species.

Monkey is close to us.

Megadiversity is the high degree of richness of different types of forms found in an area.

The warm and humid tropical regions of the earth, between the tropic of Cancer and the tropic of Capricorn, are rich in diversity of plant and animal life. This is called the region of megadiversity

India and Brazil.

The science of naming the organism is termed as nomenclature.

Example of ctenophore- Pleurobrachia.

It is a simplified system of naming organisms. Under Binomial system of nomenclature, each organism has scientific name consisting of two parts. First part is genus and second part is the species

Binomial nomenclature was proposed by Carl Linnaeus (1707-1778)..

Common names are names known at some particular place .so it cannot be known at every place.

1. Entamoeba histolytica 2. Alcea rosea

3. Brassica campestris 4. Brassica oleracea.

The scientific name of humans is Homo sapiens.

(a) Azadirachta indica – Margossa, Neem;

(b) Panthera tigris- Tiger, Bagh.

The scientific name for an organism is unique and can be used to identify it anywhere in the world.

Classification is the process by which anything is grouped into convenient categories based on some easily observable characters.

A branch of biology which deals with the identification, nomenclature and classification of organisrns is called taxonomy.

The father of taxonomy is Carolus Linnaeus (Karl von Linne, 1707 – 1778).

The artificial classification was introduced by Pliny the elder. It is based on one or a few superficial resemblances rather than on natural or evolutionary relationship. It, therefore, gives only a little information about the groups.

A natural system of classification is the one which uses several characteristics from various aspects of organisms to bring out natural relationships amongst them.

Artifical systems of classification is used in quick identification of organisms.

Releated organisms are planced into different groups while unrelated organisms put together.

The characteristics that came into existence earlier are likely to be more basic than characteristics that have come into existence later.

Charles Darwin (1859) has described the idea of evolution in book “The origin of species” .

Primitive organisms are those which have primitive or ancient body design.

Advanced organisms are those which possess more complex and elaborate structure and have evolved recently.

The various grouping level or rank in classification are known as category.

The meaning of hierarchy of categories is the arrangement of the categories in an increasing order from species to kingdom or in a decreasing order from kingdom to species on the basis of their relatives dimensions.

Hierarchy Categories were introduced by Linnaeus. They are also known as Linnaean hierarchy.

The basic unit of classification is species.

Kingdom is the highest taxonomic category.

There are seven categories in hierarchy classification.

Species is the basic and lowest taxonomic category. All members of a species are capable of interbreeding.

Robert H. Whittater (1959) proposed the five kingdom classification.

Carl Woese (1977) divided Monera into two groups-Archaebacteria and Eubacteria.

Monera is the kingdom of prokaryotic organisms like bacteria and blue green algae.

Prokaryotes orgnisms are those which do not have membrane bound organelles and have primitive type of nucleus called nucleoid.

It has unique polymer of amino sugars and amino acids called peptidoglycan.

Anabaena (cyanobacteria) and mycoplasma.

Protista is a kingdom of many unicellular eukaryotes.

Eukaryotes orgnisms are those which have membrane bound organelles and have true nucleus i.e., nucleus is bound membrane.

Mixotrophic nutrition is a mixed type of nutrition in which the organisms switches from autotropic nutrition to saprophytic nutrition when there is no light.

Eulgena and Paramecium.

Chlamydamonas is an example of algal protista.

Euglena is called plant-animal.

These are heterotrophic eukaryotic organisms. They use decaying organic material as food and are therefore called saprophytes.

Fungi are filamentous. Their bodies consist of long, slender thread-like structures called hyphae. The network of hyphae is known as mycelium.

The cell walls of fungi are composed of chitin.

Example-Agaricus, Penicillium.

Lichens are symbiotic associations i.e. mutually useful associations, between algae and fungi.

Lichens are very good pollution indicators-they do not grow in polluted areas.

The plant body is not differentiated into roots, stem and leaves and is called thallus.

(i) Green algae usually have rigid cell wall made up of cellulose.

(ii) Brown algal cells have a cellulosic cell wall usually covered on the outside by a gelatinous coating of algin.

Algae cell wall is made up of cellulose.

The plants in the thallophyta group are commonly called algae.

Bryophyta is known as "amphibians of plant kingdom" .

Bryophytes is fixed to the soil through multicellular and branched rhizoids.

The sex organs in bryophytes are multicellular and jacketed.

Examples- Riccia and Funria (Moss).

Examples - Selaginella and Dryopteris.

Pteridophyta is a group of vascular cryptogams as in this group, plant body has well-differentiated vascular tissues.

Bryophtes and pteridophytes require water for fertilization, hence they grow in moist and and shady places.

Spermatophyta includes all those plants which produce seeds.

(i) Gymnosperms bear naked seeds; (ii) Angiosperms are also called flowering plants.

Dicot seeds. bean, gram.

Monocot seeds. Wheat, maize.

(a) Dicots have reticulate venation in their leaves; (b) Monocots have parallel venation in their leaves.

Gymnosperms- Cone as reproductive organs;

Angiosperms- flowers as sex organs

Angiosperms have highly developed vascular tissue system with vessels in the xylem and companion cells in the phloem.

Plants with well-differentiated reproductive tissues that ultimately make seeds are called phanerogams.

Animals in which notochord is absent are called nonchordates.

It is a type of body organization of animals which is based on cells that are not organized into tissues.

A subkingdom of multicellular organisms having less-specialized cells than in the Metazoa; comprises the single phylum Porifera.

Sponges possess special cells called choanocytes or collar cells or flagellated cells which form the inner lining of spongocoel. This cell creates current and ingest food particles from water.

Coelenterates or cnidarians have specialized stinging cells, cnidoblasts or nematoblasts present on the tentacles and the body. Cnidoblasts are used for anchorage, defense and for the capture of prey

Animals in which the cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm, are called diploblastic animals, e.g., coelenterates.

In some animals, the body cavity is not lined by mesoderm, instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called pseudocoelom and the animals possessing them are called pseudocoelomates, e.g., aschelminthes

Enterocoelom is a type of true coelom which is present in Echinodermata. It arises as from the enteron. The animals having enterocoel are called enterocoela.

When the body is divided into identical left and right halves in only one plane, it is called bilateral symmetry. E.g., Annelida

Fresh water sponge - Spongilla.

(a) Central cavity present in the body of sponges is called spongocoel; (b) The cavity present in the body of cnidarians is called coelenteron.

The body of sponges is supported by a skeleton made up of spicules or spongin fibres.

Spicules are formed of calcium carbonate and silica.

(a) Leucosolenia (Simplest sponge); (b) Euspongia (bath sponge)

(i) Sponges have a water transport or canal system.

(ii) The body is supported by a skeleton made up of spicules or spongin fibres.

Mesogloea is a gelatinous layer existing between two germ layer of cnidaria.

Cnidarians have radial symmetry.

Both intercellular and intracellular digestion takes place in cnidaria

In the phylum Cnidarians, nervous sytem develops for the first time.

Hydra and other cnidari

Sponges belong to phylum Porifera.

Alternation of generation is the phenomenon in which asexual generation (polypoid generation) and sexual generation (medusoid generation) alternate each other in the life cycle.

(i) The common name of Pleurobrachia is comb jelly; (b) The common name of Cestum is Venus’s girdle.

Colloblasts are adhesive cells found on the tentacles of Ctenophora.

Bilateral symmetry is present in Platyhelminthes.

The excretory organs in platyhelminthes are flame cells.

(a) Planarians are free living platyhelminthes; (b) The scientific name of pork tape worm is Taenia solium .

Platyhelminthes have organ system level of organisation.

(a) Example of Platyhelminthes- Fasciola hepatica (Liver fluke);

(b) Example of Nematoda - Ascarislumbricoides (Roundworm).

The body of the aschelminthes (Nematoda) is circular in cross-section, hence, the name roundworms.

(a) The scientific name of roungworm is Ascaris lumbricoides.

(b) The scientific name of filarial worm is Wuchereria bancrofti.

Wuchereria bencrofti is the causal organisms of elephantitis.

The common name of annelids is segmented worms.

A closed circulatory system is present in annelids.

The excretory organ of annelid is nephridia which help in osmoregulation and excretion.

(a) The scientific name of earthworm is Pheretima Posthuma.

(b) The scientific name of leech is Hirudinaria.

Hirudinaria (Blood sucking leech) is the parasitic annelid.

Locomotory organs of annelids are parapodia and setae.

Arthropoda is the largest phylum of Animalia which includes insects.

Mollusca is the second largest animal phylum.

(a) The literal meaning of Arthropoda is animals with jointed legs.

(b) The literal meaning of Mollusca is soft bodied or shelled animals.

Phylum Arthropoda and phylum Mollusca have open circulatory system.

(a) The excretory organ of crab is green gland.

(b) The excretory organ of insect is malpighian tubules.

Compound eye is present in insects.

Mantle usually secretes an external limy shell.

Mollusca have muscular foot for moving around.

Examples- Unio and Octopus.

In insects, locomotion takes place through three pairs of legs (jointed) and two pairs of wings.

These are exclusively free-living marine animals.

It is a particular form or function found in all members of one or more organisms.

These are exclusively free-living marine animals. They are triploblastic and have a coelomic cavity. The symmetry is radial in the adults and bilateral in the larvae.

Echinoderms have tube feet that helps in respiration and locomotion.

The literal meaning of echinoderms is spiny skinned animals.

Example -Peripatus.

In phylum Hemichordata, pharyngeal gill slits are present but notochors is absent.

Example of phylum hemichordate is Balanoglossus.

The common name of Balanoglossus is Acorn worm or Tongue worm.

Dorsal nerve tube, notochord and pharyngeal gill clefts are present in the phylum Chordata.

(a) Salpa; (b) Branchiostoma (Amphioxus).

Animals which have cranium (brain box) around the brain are termed as Craniata.

(a) In Urochordata, notochord is present only in larval tail.

(b) In Cephalochordata, notochord extends from head to tail region and is persistent throughout their life.

Examples-Petromyzon (Lamprey) and Myxine (Hagfish).

The term chondrichthyes means cartliaginous fishes.

The class osteichthyes includes bony fishes.

(a) Fishes have two-chambered heart. (b) Frogs have three-chambered heart.

Chordata classes having cold-blooded animals are: Chondrichthyes, Osteichthyes, Amphibia and Reptilia.

Pisces is the superclass of Chordata in which lateral line sense organs are found.

(a) Cartilaginous fish has 5 to 7 pairs of gills for respiration; (b) Air bladder is present in bony fish which regulates buoyancy.

(a) Trygon (Sting ray);

(b) Clarias (Magur)

(a) Gambusia (Mosquito fish); (b) Exocoetus (Flying fish).

Amphibians require water for fertilization and also for keeping body surface moist, hence they are present close to the water bodies.

Animals having for limbs are called tetrapods. Tetrapoda includes classes such as aves and mammals.

(a) External ear (pinna) is present in human beings.; (b) Nictitating membrane is present in frog.

Reptilia and Aves are two classes of chordates in which clawed digits are present.

Reptilia is the class of terrestrial chordates.

Crocodile has four-chambered heart.

The meaning of repiles is creeping animals.

(a) Syrinx is present in aves; (b) Aves have pneumatic bones;

National bird - Peacock

National animal- Tigar.

Aves are warm-blood flying animals in which teeth are absent.

(a) In mammals, digits end up in nail and claws.; (b) In mammals, hair are present as exoskeleton.

Seven cervical vertebrae are found in mammals.

Presence of mammary glands for the production of milk to nourish their young.

Various types of species diversity as follows:

(a) Point diversity: Present on the smallest scale.

(b) Alpha diversity: Includes variety of organisms local to a particular habitat.

(c) Gamma diversity: Represents the diversity of larger unit.

(d) Epsilon diversity: Includes total diversity of a group of gamma diversity areas.

A single plant may be considered as a unit of alpha diversity, a leaf as an area of point diversity, a group of plants occurring together as an area of gamma diversity and forest within which the plants are located may be considered as an area of epsilon diversity.

Classification is necessary because it makes the study of wide variey of organisms easier and systematic. Withoupt proper classification, it would be impossible to study millions of organisms which exist on this earth.

The basis of classification are:

● Type of cell (Eukaryotic or prokaryotic)

● Number of cells present (unicellular or multicellular)

● Mode of nutrition (Autotrophic or heterotrophic)

On the basis of complexity of cell structure, organisms are classified into eukaryotic and prokaryotic organisms. Further eukaryotic organisms are divided into unicellular (Body made up of single cell) and multicellular (body made up of multi cells) based on number of cells present in the organisms.

Seven categories of hierarchial classification are:’

(i) Kingdom

(ii) Phylum (for animals) / Division (for plants)

(iii) Class

(iv) Order

(v) Family

(vi) Genus

(vii) Species

Distinguishing features of plants and animals are:

● Movement: Plants cannot move while animals can move.

● Nutrition: Plants can synthesise their own food by the process of photosynthesis (autotrophic) while animals can not synthesise their own food. They are directly or indirectly depend on plants (heterotropic).

● Cell Wall: Plants have cell wall while animals do not have cell wall.

Disadvantages of two kingdom classification are:

(i) This system did not distinguish between the eukaryotes and prokaryotes, unicellular and multicellular organisms and photosynthetic (green algae) and non-photosynthetic (fungi) organisms.

(ii) There are some organism which neither fall into plant nor animal kingdom like Lichens.

Characteristics of kingdom Protista:

(i) Organisms are unicellular and eukaryotic.

(ii) Organisms use appendages such as hair-like cilia or whip-like flagella for moving around.

Lichens are symbiotic associations i.e. mutually useful associations, between algae and fungi. The algal component is known as phycobiont and fungal component as mycobiont. In this relationship, fungi get food from algae and in returen blue green algae get shelter.

Characters of Thallophyta:

(i) The plant body is not differentiated into roots, stem and leaves and is called thallus.

(ii) Vascular tissues are absent.

(iii) Plants are autotrophic and perform photosynthesis.

(iv) The algae reproduce by vegetative, asexual and sexual methods.

Differences between algae and fungi:’

Characteristics of algae:

(i) The plant body is not differentiated into roots, stem and leaves and is called thallus.

(ii) Vascular tissues are absent.

(iii) Algae grow well in light.

(iv) They possess chlorophyll.

Differences between dicots and monocots:

Differences between bryophytes and pteridophytes:

Characters of Bryophyta:

(I) These are found on both land and water, therefore they are known as amphibhians of the plant kingdom.

(II) The plant body is commonly differentiated to form stem and leaf-like structures.

(III) These plants do not have specialised tissue for the conduction of water and other substances from one part of the plant body to another.

(IV) The main plant body of the bryophyte is haploid. It produces gametes, hence is called a gametophyte.

Examples: Moss (Funaria) and Marchantia.

Characters of Pteriodophyta:

(I) The plant body is differentiated into roots, stem and leaves.

(II) These plants have specialised tissue for the conduction of water and other substances from one part of the plant body to another.

(III) In pteridophyte, the main plant body is sporophyte.

(IV) Reproduce through spores.

Some examples are Marsilea, ferns and horse-tails.

Characters of Gymnosperms:

(I) Plants have well differentiated plant body.

(II) Vessels are absent in xylem and companion cells are absent in phloem.

(III) They are usually perennial, evergreen and woody.

(IV) They bear naked seeds.

Characters of Angiosperms:

(I) Plant body is well differentiated into stem, roots and leaves.

(II) They have highly developed vascular tissue system with vessels in the xylem and companion cells in the phloem.

(III) The seeds develop inside an organ which is modified to become a fruit.

(IV) Plant embryos in seeds have structures called cotyledons.

Difference between Notochordata and Chordata:

Differences between Porifera and Cnidaria:

Characters of Porifera:

(i) These are primitive multicellular animals and have cellular level of organisation.

(ii) These are non-motile animals attached to some solid support.

(iii) They have a canal system that helps in circulating water throughout the body to bring in food and oxygen.

(iv) They are commonly called sponges, and are mainly found in marine habitats.

Examples- Sycon and Spongilla.

Characters of Cnidarians:

(i) They are aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals.

(ii) Cnidarians exhibit tissue level of organisation and are diploblastic.

(iii) Cnidarians exhibit two basic body forms called polyp and medusa.

(iv) Tentacles are found around the mouth.

Examples- Hydra and Aurelia.

difference between bilateral symmetry and radial symmetry:

Characters of Ctenophora:

(i) Ctenophores are commonly known as sea walnuts or comb jellies.

(ii) They are exclusively marine, radially symmetrical and diploblastic organisms.

(iii) They have tissue level of organisation.

(iv) Digestion is both extracellular and intracellular.

Examples: Pleurobrachia and Ctenoplana.

Characters of Platyhelminthes:

(i) They have dorso-ventrally flattened body, hence are called flatworms.

(ii) Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals.

(iii) They are either freeliving or parasitic.

(iv) Hooks and suckers are present in the parasitic forms.

Examples- Taenia (Tapeworm), Fasciola (Liver fluke).

Characters of Nematoda:

(i) The nematode body is also bilaterally symmetrical and triploblastic.

(ii) They are pseudocoelomate animals.

(iii) Sexes are separate (dioecious), i.e., males and females are distinct.

(iv) Roundworms have organ-system level of body organization.

Examples- Ascaris (Round Worm), Wuchereria (Filaria worm

Characters of Annelida:

(i) They are triploblastic, metamerically segmented and coelomate animals.

(ii) These animals are found in a variety of habitats– fresh water, marine water as well as land.

(iii) They exhibit organ-system level of body organisation and bilateral symmetry.

(iv) A closed circulatory system is present.

Examples- Nereis, Pheretima (Earthworm) and Hirudinaria (Blood sucking leech).

When an organism has both the sexes i.e., it can produce both sperms and eggs are called hermaphrodite. Examples- Sponges, earthworms.

Animals having three germinal layers (ectoderm, mesoderm and endoderm) are called triploblastic.

Examples- Nematoda and Annelida.

The body cavity, which is lined by mesoderm is called coelom. Animals possessing coelom are called coelomates. Examples- Annelids and Arthropods.

Characters of Phylum Arthropoda:

(i) These animals are bilaterally symmetrical and segmented.

(ii) They are triploblastic and and coelomate animals.

(iii) The body consists of head, thorax and abdomen.

(iv) They have jointed legs (the word ‘arthropod’ means ‘jointed legs’).

Examples- spiders, scorpions and crabs

Characters of Phylum Mollusca:

(i) Molluscs are terrestrial or aquatic (marine or fresh water) having an organ-system level of organisation.

(ii) They are bilaterally symmetrical, triploblastic and coelomate animals

(iii) They have an open circulatory system and kidney-like organs for excretion.

(iv) Body is covered by a calcareous shell.

Example- Pila and Unio.

Characters of Phylum Echinodermata:

(i) These are exclusively free-living marine animals.

(ii) They are triploblastic and coelomate animals.

(iii) They also have a peculiar water-driven tube system that they use for moving around.

(iv) They have hard calcium carbonate structures that they use as a skeleton.

Examples- starfish and sea urchins

scientific names:

(a) Palaemon (b) Musca (c) Asterias (d) Loligo (e) Pila (f) Unio

Ambulacral system is present in the phylum Echinodermata. This system allows echinoderms to move and to attach to substrates.

There are following adaptations in fishes:

● They have streamlined body which help them to move easily under water .

● They have fins and muscular tail which help them in swimming and change their direction.

● They have paired gills which help breathe oxygen dissolved in water.

Characters of Chondrichthyes:

(i) They are marine animals.

(ii) They have cartilaginous endoskeleton.

(iii) The skin is tough, containing minute placoid scales.

(iv) No air bladder is present.

Examples- Scoliodon (Dog fish) and Trygon (Sting ray).

Characters of Osteichthyes:

(i) It includes both marine and fresh water fishes.

(ii) They have bony endoskeleton.

(iii) Skin is covered with cycloid/ctenoid scales.

(iv) Air bladder is present which regulates buoyancy.

Examples- Hippocampus (Sea horse) and Labeo (Rohu).

(a) differences between Cartilaginous fishes and bony fishes:

(b) differences between Amphibia and Reptila:

(c) differences between Aves and mammals:

Characters of mammals:

(i) Mammals are warm-blooded animals.

(ii) They have four-chambered heart.

(iii) They have mammary glands for the production of milk to nourish their young.

(iv) Their skin has hairs as well as sweat and oil glands.

Examples- Whale and human beings.

Fight adaptations of the birds are the following:

(1) Forelimbs are modified into wings for flying.

(2) Body is light as they have hollow (pneumatic) bones.

(3) Body is streamlined to reduce air resistance during flight.

(4) Flights muscles are well developed.

(5) Body is covered with exoskeleton of water-proof and light-weight feathers.

(6) They have actue vision.

All chordates possess the following features:

(i) have a notochord

(ii) have a dorsal nerve cord

(iii) are triploblastic

(iv) have paired gill pouches

(v) are coelomate.

Protochordates:

(i) Notochord persists throughout the life, no vertebral column.

(ii) These animals are bilaterally symmetrical, triploblastic and have a coelom.

(iii) Protochordates are marine animals.

(iv) Examples are Balanoglossus, Herdemania and Amphioxus.

Urochordata- Herdemania

Cephalochordata - Amphioxus

difference between notochord and nerve cord are:

1-(f); 2- (g); 3- (h); 4- (b); 5- (c); 6- (d); 7 – (a); 8 – (i); 9. (e);

1. a. (iii); 2. (b) (iv); 3. (e) (v); 4. (d) (vi); 5. (c) (ii); 6. (b) (i); 7. (i) (ix); 8. (h) (vii); 9. (g) (viii).

1. Dt; 2. D; 3. H; 4. A; 5. H.

1. P; 2. A; 3. C; 4. C; 5. A; 6. A.

Some characteristics used for the hierarchial classification are:

● Type of cell (Eukaryotic or prokaryotic)- Eukaryotic cell has membrane bound cell organelles and a well defined nucleus which allow cellular processes to be carried out efficiently. While prokaryotic cell lakes membrane-bound cell organelles and have primitive type of nucleus called nucleoid.

● Number of cells present (unicellular or multicellular)- In unicellular organism, single cell performs all vital activities of the organism while in multicellular organism, different cells perform different functions and show division of labour.

● Mode of nutrition (Autotrophic or heterotrophic)- Plants make their own food while animals depend on plants or other animals for their food. For this they will definitely have different body design.

Importance of classification:

● Classification makes the study of wide variety of organisms easier and systematic.

● It reveals relationship among the various groups of organisms.

● Classification gives information about the organisms which do not occur in one's locality.

● It helps to establish a hierarchy of groups of organisms.

● It provides a base for the study of other branches of biology.

● Classification reveals evolution trends by showing gradually increasing complexity of structure in various groups of organisms.

Hierarchy Categories were introduced by Linnaeus. They are also known as Linnaean hierarchy. The meaning of hierarchy is the arrangement of the categories in an increasing order from species to kingdom or in a decreasing order from kingdom to species.

Nearer the categories in hierarchy, the greater is the similarity between their organisms.

Hierarchy can be classified in two ways:

● Obligate hierarchy- Where order is followed strictly from kingdom to species.

● Intermediate hierarchy- It does not follow the order and can be added to the categories in the obligate list like subdivision, subspecies, superfamily, suborder and super class.

Kingdom is the highest rank while species is the lowest rank in the Hierarchy. The hierarchy of major categories is given below:

Kingdom-All animals belonging to various phyla are assigned to the highest category called Kingdom.

Phylum (for animals) / Division (for plants)- Different classes having few common characteristics are placed in a single phylum.

Class- It includes organisms of releated order.

Order-Order is an assemblage of familes resembling one another in a few characters.

Family – Group of related genera are included in a family. More similar genus groups are placed together in a single family.

Genus - Genus comprises a group of related species which has more characters in common in comparison to species of other genera.

Species. It is lowest taxonomic category. Species is a group of fundamentally similar and potentially interbreeding populations that are reproductively isolated from other groups due to morphological features.

Kingdom Monera is the first of the five kingdoms of biological classification. The kingdom Monera includes all prokaryotes such as mycoplasma, bacteria and blue green algae. They are the most primitive organisms. They also live in extreme habitats such as hot springs, deserts, snow and deep oceans where very few other life forms can survive. They are unicellular and do not have a defined nucleus. They have circular DNA, not enclosed by a nuclear membrane and not organized into well-defined chromosomes. It lies as a coiled mass, called nucleoid. Some of them have cell walls while some do not. The mode of nutrition of organisms in this group can be either autotrophic or heterotrophic. Reproduction by asexual method. True mitotic cell division absent.

Carl Woese (1977) divided Monera into two groups-Archaebacteria and Eubacteria.

The kingdom fungi includes yeast, mushrooms, moulds, rusts, etc. These are eukaryotic and non-vascular organisms. They occupy dark and damp habitats and grow in any direction. Fungi are filamentous. Their bodies consist of long, slender thread-like structures called hyphae. The network of hyphae is known as mycelium. Fungi can reproduce vegetatively, asexually and sexually. Most fungi are heterotrophic and absorb soluble organic matter from dead substrates and hence are called saprophytes.

Some fungal species live in permanent mutually dependent relationships with bluegreen algae (or cyanobacteria). Such relationships are called symbiotic. These symbiobic life forms are called lichens.

Spermatophyta includes all those plants which bear seeds. These are of two types-

● Gymnosperms- Plants that bear naked seeds.

● Angiosperms- Plants that contain seeds inside the fruit.

(I) Gymnosperms- (Gk; gymno=naked, sperma=seed)

(i) Gymnosperms includes the cornifer plants like pinus.

(ii) They produce naked seeds which are not enclosed in the fruit.

(iii) They are usually perennial, evergreen and woody.

(iv) The roots are generally tap roots.

(v) In conifers, the needle-like leaves reduce the surface area.

Example- Cycas, Pinus, deodar.

(II) Angiosperms- (Gk. angio = covered, sperma= seed)

(i) These are flowering plants in which seeds are always contained inside the fruit.

(ii) The pollen grains and ovules are developed in a specialised structures called flowers.

(iii) Plant embryos in seeds have structures called cotyledons.

(iv) Plants with seeds having a single cotyledon are called monocotyledonous or monocots. Example-rice and maize.

(v) Plants with seeds having two cotyledons are called dicots. Example- Mango and rose.

Pteridophyta: It is the division of the plant kingdom comprising the vascular cryptogams. The plant body of pteridophytes is differentiated into roots, stem and leaves.

Differences between bryophytes and pteridophytes:

Characteristics of phylum Platyhelminthes:

(1) They have dorso-ventrally flattened body, hence are called flatworms.

(2) Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals.

(3) They have organ level of body organization.

(4) They are either freeliving or parasitic.

(5) Hooks and suckers are present in the parasitic forms.

(6) Flame cells are found for osmoregulation and excretion.

Examples- Taenia (Tapeworm), Fasciola (Liver fluke).

Characteristics of phylum Nematoda:

(i) They are known as roundworms.

(ii) They may be freeliving, aquatic and terrestrial or parasitic in plants and animals.

(iii) The nematode body is also bilaterally symmetrical and triploblastic.

(iv) They have organ-systme level of body organization.

(v) They are pseudocoelomate animals.

(vi) Sexes are separate (dioecious), i.e., males and females are distinct.

(vii) Roundworms have organ-system level of body organization.

Examples- Ascaris (Round Worm), Wuchereria (Filaria worm

Characteristics of phylum Annelida:

(i) They are triploblastic, metamerically segmented and coelomate animals.

(ii) These animals are found in a variety of habitats– fresh water, marine water as well as land.

(iii) They exhibit organ-system level of body organisation and bilateral symmetry.

(iv) A closed circulatory system is present.

(v) Respiration through moist skin.

(vi) Nephridia help in excretion.

(vii) Locomotion takes place through setae and parapodia.

Classes of Annelida:

(I) Polychaeta- Nereis (Sand worm)

(II) Oligochaeta- Pheretima (Earthworm)

(III) Hirudinea – Hirudinaria (Blood sucking leech).

Characters of phylum Mollusca: This is the second largest animal phylum

● Molluscs are terrestrial or aquatic (marine or fresh water) having an organ-system level of organisation.

● They are bilaterally symmetrical, triploblastic and coelomate animals

● They have an open circulatory system and kidney-like organs for excretion.

● Body is covered by a calcareous shell.

● Body divisible into head, muscular foot and visceral hump.

● The mouth contains a file-like rasping organ for feeding, called radula.

● Respiration by gills.

● They are usually dioecious and oviparous with indirect development.

(i) Gastropoda - Pila (Apple snail);

(ii) Pelecpoda- Unio (Mussel);

(iii) Cephalopoda – Sepia (Cuttle fish).

Characters of Phylum Arthropoda: This is the largest animal phylum.

(i) These animals are bilaterally symmetrical and segmented.

(ii) They are triploblastic and and coelomate animals.

(iii) They have organ-system level of organisation.

(iv) The body of arthropods is covered by chitinous exoskeleton.

(v) The body consists of head, thorax and abdomen.

(vi) They have jointed legs.

(vii) Respiratory organs are gills, book gills, book lungs or tracheal system.

(viii) Excretion takes place through malpighian tubules.

(i) Crustacea – Prawn (Palaemon);

(ii) Myriapoda- Scolopendra (Centipede)

(iii) Insecta- Musca (House fly)

(iv) Arachnida- Buthus (Scorpion)

There are ten major phyla of Animal kingdom. These are-

(1) Porifera- Members of this phylum are commonly known as sponges. They are generally marine and mostly asymmetrical animals.

Example- Spongilla (Fresh water sponge)

(2) Coelenterata- They are aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals.

Example- Hydra

(3) Platyhelminthes-They are bilaterally symmetrical, triploblastic and acoelomate animals with organ level of organisation.

Example- Taenia (Tapeworm)

(4) Nematoda- They are bilaterally symmetrical, triploblastic and pseudocoelomate animals.

Example- Ascaris (Round Worm)

(5) Annelida- They are triploblastic, metamerically segmented and coelomate animals.

Example- Hirudinaria (Blood sucking leech).

(6) Arthropoda- They are bilaterally symmetrical, triploblastic, segmented and coelomate animals.

Example- Limulus (King crab)

(7) Mollusca- Molluscs are terrestrial or aquatic having an organ-system level of organisation.

Example- Pila (Apple snail)

(8) Echinodermata- They are spiny skinned free-living marine animals.

Example- Asterias (star fish)

(9) Protochordata- These animals are bilaterally symmetrical, triploblastic and have a coelom.

Example- Amphioxus

(10) Chordata- Animals have notochord.

Example- Scoliodon (Dog fish)

Characters of Mammals:

(i) Mammals are warm-blooded animals.

(ii) They have four-chambered heart.

(iii) They have mammary glands for the production of milk to nourish their young.

(iv) Their skin has hairs as well as sweat and oil glands.

(iv) They have two pairs of limbs, adapted for walking, running, climbing, burrowing, swimming or flying.

(v) Respiration is by lungs.

(vi) Sexes are separate and fertilisation is internal.

Examples- Whale and human beings.

Characters of birds:

1. These are warm-blooded animals and most of them can fly except flightless birds.

2. Forelimbs are modified into wings for flying.

3. The hind limbs generally have scales and are modified for walking, swimming or clasping the tree branches.

4. Body is light as they have hollow (pneumatic) bones.

5. Body is streamlined to reduce air resistance during flight.

6. Flights muscles are well developed.

7. Body is covered with exoskeleton of water-proof and light-weight feathers.

8. Heart is four-chambered.

9. Respiration is by lungs.

10. They have actue vision.

11. Sexes are separate. Fertilisation is internal.

12. They are oviparous.

Example- Pavo (Peacock), Columba (Pigeon), Corvus (Crow).

Pisces: These are fish. They are exclusively waterliving animals. Their skin is covered with scales. Pisces are cold-blooded animals and have two-chamered heart. They obtain oxygen dissolved in water by using gills. The body is streamlined, and a muscular tail is used for movement.

Superclass Pisces is classified into two classes:

(i) Chondrichthyes – The cartilaginous fishes

(ii) Osteichthyes – The bony fishes

(i) Chondrichthyes – The cartilaginous fishes

(Gr; chondros = cartilage + ichthys = fish)

● They are marine animals with streamlined body and have cartilaginous endoskeleton.

● The skin is covered with minute placoid scales.

● Mouth is located ventrally.

● Notochord is persistent throughout life.

● Gill slits are separate and without operculum (gill cover).

● Air bladder is absent.

● Sexes are separate.

● Examples- Scoliodon (Dog fish), Pristis (Saw fish), Torpedo (electric ray), Trygon (Sting ray).

(ii) Osteichthyes – The bony fishes

(Gr; osteon=bone + ichthyes=fish)

● It includes both marine and fresh water fishes with bony endoskeleton.

● Skin is covered with cycloid/ctenoid scales.

● Mouth is located mostly terminal.

● They have four pairs of gills which are covered by an operculum on each side

● Air bladder is present which regulates buoyancy.

● Sexes are separate.

● Examples-Exocoetus (Flying fish), Hippocampus (Sea horse); Labeo (Rohu), Catla (Katla), Clarias (Magur).

The term “Biodiversity” was coined by “Walter G Rosen” in 1986.

As India is rich in diversity of plant and animal life, so it is called as megadiversity centre.

The task of studying the diversity of living organisms can be made easier and more effective if the various organisms are arranged in an orderly manner.

Common names are names known at some particular place .so it cannot be known at every place.

Binomial nomenclature was proposed by Carl Linnaeus (1707-1778). It is a simplified system of naming organisms. Under Binomial system of nomenclature, each organism has scientific name consisting of two parts. First part is genus and second part is the species. For example, the scientific name of mango is Mangifera indica.

Advantages:

● Scientific names are standardised and accepted universally.

● Scientific names are not changed according to country or language.

Certain conventions are followed while writing the scientific names:

1. The name of the genus begins with a capital letter.

2. The name of the species begins with a small letter.

3. When printed, the scientific name is given in italics.

4. When written by hand, the genus name and the species name have to be underlined separately.

In order to facilitate the study, number of scientists have established procedures to assign a distinct and proper name to each known organism. Biologists follow universally accepted principles to provide scientific names to known organisms. This system is called Binomial nomenclature. Under Binomial system of nomenclature, each organism has scientific name consisting of two parts. First part is genus and second part is the species.

Local names used for recognising objects are called common names.

Sometimes common name is misleading since some name may be used for different organisms in different parts of the country. Therefore, it could be difficult to exchange scientific information.

Scientific names are written in Latin since Latin is not longer spoken in many parts of world. Therefore, it does not change.

Linnaeus proposed two-kingdom of classification of organisms.

Natural system of classification indicates phylogenetic relationship and the origin of different taxa. Darwin explained the origin of species through natural selection, hence he is linked with natural system of classification.

Two-kingdom classification was proposed by Carolus Linnaeus in 1758.

Unicellular eukaryotic organisms are included in kingdom Protista. E.g., Amoeba, Euglena, Slime moulds, etc.

Viruses are very simple non-cellular structure and cannot exist independently of other organisms. Thus, they do not fit neatly into any scheme of classification.

R.H. Whittaker classified organisms into five kingdoms.

Flagella, cilia and pseudopodia are used in locomotion in protozoa.

Amoeba moves by pseudopodia.

Mule is not considered as species because it is formed from hybridization between two similar species-a female horse and male ass.

Plants and animals are so different because

(i) Plants are static, i.e., they cannot move while animals can move.

(ii) Plants can synthesise their own food, i.e., they are autotrophic while animals are heterotrophic.

Bryophyta are called the amphibians of the plant kingdom.

An embryonic stage is absent in algae (thallophyte).

A gametophyte is the stage in the life cycle of plants that undergo alternation of generation. It is haploid and produces gametes.

A sporophyte is the diploid spore producing plant.

Gametophytic plant body of bryophytes is fixed to the soil through multicellular and branched rhizoids.

The sex organs in bryophyta are multicellular and jacketed.

Phanerogams (gymnosperms and angiosperms) are called seeded plants.

Vascular bundle are open and arranged in a ring in dicot stem.

Vascular bundles are scattered and closed in monocot plants.

Comb jellies belong to phylum Ctenophora.

Heterotrophic type of nutrition is found in animals.

Members of this group is commonly known as sponges. They are multicellular and mainly found in marine habitat.

Coelenterate exhibits tissue level of organisation.

Round worm belongs to the phylum Nematoda.

Platyhelminthes are triploblastic animals which lacks a coelom.

Canal system is characteristic of phylum porifera.

Hydra is an example of a freshwater cnidaria.

Flame cells is the excretory structure of flatworms.

Leech sucks blood from cattle and human beings.

Arthropoda is the largest phylum of Animalia.

Pearls produced by the Pearl oyster.

Locomotion occurs by tube feet in Echinoderms.

Three pairs of Joined legs

Balanoglossus is a member of Hemichordata.

sea horse (Hippocampus) belongs to Pisces.

Snake does not possess limbs.

Teeth are absent in the beak of a bird.

Diaphragm is a muscular partition in mammals which separates the thoracic cavity from the abdominal cavity. It increases the efficiency of berthing.

One of the gymnosperms, the giant redwood tree, Sequoia is one of the tallest tree species. It reaches a height of 100 m.

A biodiversity hotspot is a region of the Earth that contain high level of endemic species that has experienced great habitat loss.

The number of species that are known and described range between 1.7-1.8 million. This refers to

Biodiversity or the number and types of organisms present on earth.

The science of naming the organism is termed as nomenclature.

Binomial system of nomenclature of organisms evolved by Carolus Linnaeus in 1758.

Binomial nomenclature consists of two parts. First part is genus and second part is the species. For example, the scientific name of mango is Mangifera indica.

Binomial nomenclature consists of two parts. First part is genus and second part is the species. For example, the scientific name of mango is Mangifera indica.

Under Binomial system of nomenclature, each organism has scientific name consisting of two parts. First part is genus and second part is the species. Therefore, in the given example, Homo represents the genus and Sapines represents the species name.

Carl Woese divided the Monera kingdom into Archaea and Eubacteria.

R.H. Whittaker proposed five kingdom classification system. The five kingdoms are Monera, Protista, Fungi, Plantae and Animalia.

Charles Darwin first described this idea of evolution in 1859 in his book, The Origin of Species.

Phylogeny is study of evolutionary relationship among different groups of organisms.

The science of classification is called taxonomy.

Class is a category between phylum and order.

Each category, referred to as a unit of classification, in fact, represents a rank and is commonly termed as taxon (pl.: taxa).

All organisms, including those in the plant and animal kingdoms have species as the lowest category. The basic unit of classification is species.

A species includes all organisms that are similar enough to breed and perpetuate.

Family has a group of related genera with still less number of similarities as compared to genus and species.

Prokaryotes have primitive type of genetic material called nucleoid.

The ability of nitrogen fixation is found only in monerans.

All single-celled eukaryotes are placed under Protista. Example-Amoeba.

The cell walls of fungi are composed of chitin and polysaccharides.

The plant body of bryophytes is more differentiated than that of algae. It is thallus-like and attached to the substratum by unicellular or multicellular rhizoids. They lack true roots, stem or leaves.

Chlorophyll containing, autotrophic thallophytes are called algae.

Lichens are symbiotic associations i.e. mutually useful associations, between algae and fungi.

Pteridophytes have well-differentiated vascular tissues for the conduction of water and other substances from one part of the plant body to another. They are called vascular cryptograms.

The gymnosperms (gymnos: naked, sperma: seeds) are plants in which the ovules are not enclosed by any ovary wall and remain exposed. The seeds that develop after fertilisation are not covered, i.e., are naked.

Angiosperms are also called flowering plants. In the angiosperms or flowering plants, the pollen grains and ovules are developed in specialised structures called flowers.

Mollusca is the second largest animal phylum. The body of molluscs are covered by a calcareous shell and is unsegmented with a distinct head, mantle, muscular foot and visceral hump.

The mollusc composes the large phylum Mollusca of invertebrate animals. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms.

Choanocytes are unique to phylum Porifera.

Cnidarians exhibit tissue level of organization. They have stinging cells or nematoblasts for offence and defense. The body of cnidaria encloses a single cavity, the coelenteron. It provides the phylum is alternative name.

Tapeworm is a member of phylum Platyhelminthes.

Elephantiasis disease of human beings is caused by a filarial worm, Wuchereria.

Annelid animals are also bilaterally symmetrical and triploblastic, but in addition they have a true body cavity. This allows true organs to be packaged in the body structure.

This is the largest phylum of Animalia which includes insects. They have organ-system level of organisation. They are bilaterally symmetrical, triploblastic, segmented and coelomate animals. The body of arthropods is covered by chitinous exoskeleton. They have jointed appendages (arthros-joint, poda-appendages).

In the Pila, a Mollusca, the organ of the locomotion is muscular foot.

Starfish belongs to phylum Echinodermata

The most distinctive feature of echinoderms is the presence of water vascular system which helps in locomotion, capture and transport of food and respiration.

Phylum Chordata is named after the occurrence of notochord.

The members of Vertebrata possess notochord during the embryonic stage. The notochord is replaced by a cartilaginous or bony vertebral column in the adult. Thus, all vertebrates are chordates but all chordates are not vertebrates.

Balanoglossus belongs to Hemichordata which forms a connecting link between nonchordates and chordates.

Lateral line sense organs occur in fishes and amphibian larvae. In fishes, lateral line sense organs note waves and current in water.

Two chambered heart is found in fishes.

The amphibian skin is moist (without scales).

A very long sticky tongue and ability to change colour occurs in chamaelon (Tree lizard).

Duck-billed platypus and echidna are egg-laying mammals.

True, Genus comprises a group of related species which has more characters in common in comparison to species of other genera.

False, In binomial nomenclature, the name of an organism consists of two words in Latin; the first word denotes generic name and the second name denotes species name.

True, Each category, referred to as a unit of classification, in fact, represents a rank and is commonly termed as taxon (pl.: taxa).

False, Order being a higher category, is the assemblage of families which exhibit a few similar characters.

True, Plasmodium is a malarial parasite which causes malaria in human beings.

True, monocots have parallel venation in their leaves while dicots have netted venation.

False, both red and brown algae have chlorophyll alongwith other pigments.

True, bryophytes are known as amphibians of plant kingdom.

True, echinoderms are marine animals.

False, Cartilaginous fishes do not have gill covers (operculum).

False, Blue whale is not a fish. It is a mammal that live underwater.

False, prokaryotes lack true nucleus as well as membrane-bound organelles like mitochondria.

True, Paramecium has hair-like cilia for moving around.

True, Lichen is a symbiotic association between an alga and a fungus.

False, Platypus and Echidna are mammals that lay eggs.

True, Struthio (Ostrich) is a largest bird.

False, chameleon is a reptilia.

False, skin of mammals is covered with hair. The body of reptiles is covered with dry and cornified skin. Reptiles do not have feathers.

Monera

R.H. Whittaker

Carolus Linnaeus

Pseudopodia

Lichens belongs to kingdom fungi.

Pteridophyta

Autotrophic mode of nutrition is found in algae.

Triticum aestivum

Bryophyta

Pteridophyta

Parallel leaf venation

True, During the course of the evolution several species vanished from the surface of the Earth and became extinct.

True, The diversity we see today is the result of 3.5 billion years of organic evolution.

True, Every organism whether plant, animal or microorganism is unique in itself.

Generic name is written first.

Carolus Linnaeus

True, no two organisms can have the same the same combination of genus and species.

1969

Carl Woese (1977) divided Monera into two groups-Archaebacteria and Eubacteria.

In 1982, Margulis and Schwartz modified Whittaker’s five kingdom classification. Their classification included one prokariyotic kingdom- the Prokaryotae and four eukaryotic kingdom - the Protocista, the Fungi, the Plantae and the Animalia.This type of classfication was widely accepted by people and it was regarded that eukaryotes belonged to a super kingdom -the EUKARYOTAE. The diagram below shows the classification

In 1735, he published his book “Systema Naturae”.

Species Plantarum in 1753

The method of arranging organisms into groups on the basis of similarities and differences is called classification.

The theory of natural selection proposed by Charles Darwin.

Genus comprises a group of related species which has more characters in common in comparison to species of other genera.

The reserve food material of algae is starch.

Gymnosperm

Parallel venation is found in monocot leaves.

The common name of Funaria is moss.

Pteridophytes do not produce seeds while phanerogams produce seeds.

In bryophyte, a short-lived sporophyte occurs as a parasite on the gametophyte.

In angiosperms, the seeds are enclosed by fruits.

Algae have photosynthetic pigment, chlorophyll with the help of which it performs photosynthesis and make own food. Therefore, they need sunlight. Hence, algae live in well lighted areas.

Yeast is unicellular fungi.

The botanical name of mushroom is Agaricus.

Acetobacter

Protista

The other name of cyanobacteria is blue green algae.

Rhizobium forms a symbiotic association with roots of leguminous plants.

Some of cyanobacteria can fix atmospheric nitrogen in specialised cells called heterocysts, e.g., Nostoc and Anabaena.

Though they are photosynthetic in the presence of sunlight, when deprived of sunlight they behave like heterotrophs by predating on other smaller organisms.