Diversity In Living Organisms

The regions of the earth which have a rich biodiesel of species are called biodiversity hotspots. More than half of the earth's biodiversity is supposed to be concentrated in these areas. For example Brazil, Columbia, Ecuador, Australia, India, etc. Biodiversity hotspots in India are present in Western Ghats, Eastern Himalayas, Indo- Burma border, etc.

Aristotle classified organisms into two groups- plants and animals. The animals were further classified based on their habitat, i.e. whether they lived on land, in water, or in air. The plants were categorised as small medium and large.

Bacteria is one such organism which carries out all its body functions through a single cell. Belonging to kingdom Monera , the bacteria are single celled organisms which don’t have a well defined nucleus or organelles. But , they have special mechanisms to carry out metabolic functions through single cell only.

In situations where cells are grouped together to form an indivisible organism , the principle of division of labour is followed. All cells in these organisms are not identical and particular group of cells perform particular functions. This functional similarity of cells leads to their organisation in a specific manner which dictates their body design. This makes a basic distinction in the body design of organisms, simplifying the classification process.

Charles Darwin wrote “The Origin of Species” in 1859. It was his most famous work .

Ernst Haeckel, Robert Whittaker and Carl Woese made attempt at classifying all organisms into category or kingdoms.

Robert Whittaker proposed a five kingdom classification, which includes Monera, Protista , Fungi, Plantae and Animalia , and Woese modified it by dividing Monera into archaebacteria and eubacteria.

All organisms have been grouped into five categories called kingdoms , based on cell structure, mode of nutrients, source of nutrition and body organization. Kingdoms include organisms of different species, genus , class , family, order and phylum. Hence, it is the highest category of taxonomic study.

Blue-green algae belong to kingdom Monera, because they lack well defined nucleus, organelles, and don’t have a multicellular body organization. They are autotrophic in nature.

Though both are unicellular, bacteria are prokaryotic whereas amoeba is eukaryotic in body design. This means that the bacteria don’t have a well defined nucleus or organelles, but in amoeba, the nucleus and organelles are well defined. Thus they are grouped separately.

An organism which feeds on dead and decaying matter is called a saprophytic organism. Such organisms belong to kingdom fungi.

Multicellular eukaryotic organisms without cell wall are placed under kingdom Animalia. Organisms of kingdom Plantae have cell wall and the organisms of other kingdoms are unicellular.

Bryophytes are differentiated into stem and leaf like structure. Thallophyta don’t have such structures and Pteridophytes are differentiated into stem and leaf.

Pteridophytes such as Marsilea are vascular cryptogams, because they have specialised structures for transportation of water and nutrients, but their reproductive organs are hidden.

Gymnosperms have naked seeds while the seeds in angiosperms are enclosed in a flower. Hence, they are grouped separately.

Examples: woody shrubs and trees include pines, spruces, firs, and ginkgoes.

Angiosperms are known as flowering plants, because they produce flowers.

Examples: pines, cedars, spruces and firs.

Seed leaves are called cotyledons in scientific terms.

On the basis of presence or absence of coelom, animals are classified into three groups :

1. Acoelomate – which don’t have coelom.

2. Pseudo coelomate - which have a false cavity.

3. Coelomate- which have a true body cavity.

Nematodes are first animals to have complete alimentary canal.

1. They are pseudo coelomate.

2. They are cylindrical in body structure

Annelida is the first phylum to have animals with true body cavity.

Explanation: Annelida is a group commonly referred to as segmented worms, and they are found worldwide from the deepest marine sediments to the soils in our city parks and yards

Nereis of phylum Annelida has parapodia for locomotion.

Phylum arthropoda has the highest number of animals. It’s features are :

1. Open circulatory system.

2. It has blood filled coelomic cavity.

3. They have jointed appendages.

Chiton and Pila belong to Mollusca phylum. It’s features are :

1. Reduced coelomic cavity.

2. Little segmentation.

3. Kidney like organ for excretion

4. Open circulatory system

5. Foot like appendage for movement.

Vertebrates are most advanced group of animals because they have a true vertebral column and internal skeleton.

Sponge is the simplest animal of the given because it has the minimally differentiated body design.

No, feather star is an echinoderm, because it has a slender skinned body, and is exclusively marine. It also has a water driven tube system to help in moving around.

Scientific name provides the genus and species name of an organism, thus indicating the group in which the organism belongs . It also helps in grouping organisms of same category together, thus helping in classification.

Carolus Linnaeus proposed binomial nomenclature.

1. The name of genus should start with a capital letter and that of species with a small letter.

2. When printed, the scientific name should be in italics.

Carolus Linnaeus is considered the father of taxonomy. He wrote a book called Systema naturae.

Solanum melongena – eggplant

Solanum dulcamara – bittersweet.

Diversity in living world is defined as the variety of living organisms present in the world.

The objectives of classification are:

1. Grouping of related organisms based on similar characteristics.

2. Simplifying the identification of organisms.

Cyanobacteria are autotrophic in nature and obtain energy through photosynthesis.

These are a phylum of bacteria that obtain their energy through photosynthesis and are the only photosynthetic prokaryotes able to produce oxygen.

Amoeba belongs to kingdom Protista.

the This kingdom comprises of Eukaryotic organisms that are mostly unicellular with some exceptional multicellular algae

Yes, it is true. The cell wall of different organisms differs in their composition.

Cell walls exist in all kingdoms except for the animals: plants, protists (algae), fungi, bacteria, and archaea. And in all these, the cell wall is made of different materials and composition.

Example:

The difference between monocot and dicot can be made by opening the seed of the weed. Presence of one or two cotyledons respectively would differentiate between them.

Yes, protozoans are early animals. This is because:

1. They have a very basic body design and minimal differentiation.

2. They are unicellular organisms, and only one cell performs all necessary functions.

(i) prawn

A prawn is a small shellfish with a long tail and many legs.

An “arthropod” is an invertebrate animal that has an exoskeleton, a segmented body, and jointed appendages. Examples of arthropods:

1. Insects such as ants and bees

2. Spiders and scorpions

3. Crabs, lobsters, and shrimp

(ii) octopus

Sea cucumber or holothuria belongs to phylum Echinodermata. For locomotion, sea cucumbers use tube feet , which are small sucker like projections present on the three ambulacral canals on the surface close to the substratum. These are numerous and allow the animal to crawl .

Whale is a mammal, belonging to class Mammalia. The electric ray or torpedo is a fish belonging to class Pisces . Whale is warm blooded whereas the electric ray is cold blooded animal.

Jellyfish is an animal belonging to phylum coelentrata of kingdom Animalia. It is not a chordate like true fishes. It is a medusa form of certain species of cnidarians.

Lowest structural organisation is seen in phylum Porifera. Its features are:

1. They are marine nonmotile animals.

2. They have minimal differentiation of body design.

3. The outer skeleton is hard.

4. Canal system is present for the exchange of food and oxygen.

5. They have pores all over the body.

Phylum Annelida has segmented worms. Its characters are:

1. They are bilaterally symmetrical, triploblastic animals with true coelom.

2. They have extensive differentiation in body design.

1. Thallophyta

● Not well differentiated body design

● Primarily aquatic

2.Bryophyta

● Plant body differentiated into stem and leaf like structures.

● No specialised tissue for conducting food and water.

3.Pteridophyta

● Plant body differentiate into root stem and leaf.

● Have specialised tissue for conduction of food and water.

4.Gymnosperms

● They bear naked seeds.

● They are usually woody and perineal.

5.Angiosoerms

● They have enclosed seeds.

● Plant embryo in seed have structures called cotyledons.

Two types of symmetry, i.e. bilateral and radial both is found in phylum Ctenophora. The characters are:

1. Incomplete gut, only mouth present.

2. No organ for excretion, respiration or circulation.

3. Diploblastic.

4. Biradially symmetrical

5. Eight rows of ciliated comb-like structures.

Biological classification bases have to keep on changing depending on our understanding of life forms.

The initial very basic methods of classification gradually have been replaced by more advanced and complex ideas. For example:

1. The two kingdom classification proposed by Aristotle based only on the habitat was replaced by three kingdom classification suggested by Haeckel.

2. Even the most accepted classification suggested by Whittaker which is the five kingdom classification was modified by whose based upon his understanding of bacteria dividing the Monera into archaebacteria and eubacteria.

(i) Anukool must have advised his father to either learn the different languages or to use a translator for better communication.

(ii) speaking the same language over the world would provide room for easier communication and decrease the chances of confusion and misunderstanding. It will also bring about global harmony.

(iii) Anukool is considerate and caring.He has a sense of responsibility and Helping Nature.

Scoliodon is a mammal while the rest three are fishes. Thus it is an odd one.

lion fish is called Pterios volitans. Synchiropus splendidus is scientific name for mandarin fish, Torpedo is the name of electric ray and Caulophryne is the name given to fanfins.

chloroplast in spirogyra are arranged with pyrenoids.

All the other options are true statements.

Figure (a) is of Pinus, a gymnosperm.

Figure (b) is of Funaria, a bryophyte.

Figure (d) is of Cladophora, a thallophyte.

bat is not a bird. It is a mammal. All the other options are correctly matched pairs.

Cray fish belongs to arthropoda. Devil fish is a chordate , jellyfish is a coelentrate , and starfish is an echinoderm .

coelentrata are radially symmetrical, as they have vertical symmetry around a central axis.

whales are mammals, not fishes. All other statements are correct.

Ascaris belongs to nematodes. They are not as well differentiated as Annelida or Arthropoda, but have different sexual forms unlike Platyhelminthes.

Sea cucumber is a coelentrata. It has a very basic structural organisation as compared to Mollusca, echinoderms and protochordate.

family is a taxonomic group between order and genus. The order of taxonomic hierarchy is as follows:

Species, genus , family, order , class , phylum / division , kingdom .

Nematodes are pseudocoelomate. The others are not nematodes and hence are not pseudocoelomate.

ostrich is a mammal, which is warm blooded. The other three are cold blooded organisms.

Both reptiles and mammals have four chambers in the heart. Reptiles are cold-blooded organisms, while mammals are warm-blooded organisms. Three-chambered heart is found in other reptiles, except crocodile.