BIOLOGY 5 Marks Questions

He correct hierarchical arrangement of taxonomic categories in ascending order is Species → Genus → Family → Order → Class → Phylum → Kingdom Therefore, both (a) and (c) represent correct sequences of taxonomic categories. In sequence (b), species should be followed by genus. Therefore, it does not represent the correct sequence.

Species occupies a key position in classification. It is the lowest taxonomic category. It is a natural population of individuals or group of populations which resemble one another in all essential morphological and reproductive characters so that they are able to interbreed freely and produce fertile offsprings. Each species is also called genetically distinct and reproductively isolated natural population. May (1964) has defined species as “a group of actually or potentially interbreeding populations that are reproductively isolated from other such groups”. In higher plants and animals the term ‘species’ refers to a group of individuals that are able to interbreed freely and produce fertile offsprings. But, in case of bacteria interbreeding cannot serve as the best criteria for delimiting species because bacteria usually reproduce asexually. Conjugation, transformation and transduction, which are termed as sexual reproduction methods in bacteria, also do not correspond to true interbreeding. Thus, for bacteria many other characters such as molecular homology, biochemical, physiological, ecological and morphological characters are taken into consideration while classifying them.

The arrangement of various taxa in a hierarchical order is called taxonomic hierarchy. The hierarchy indicates the various levels of kinship. The number of similar characters of categories decreases from lowest rank to highest rank. The hierarchical system of classification was introduced by Linnaeus. The hierarchy of major categories is: Species → Genus → Family → Order → Class Kingdom - 4 — Phylum or Division Increasing specificity → Decreasing specificity Classification of a plant (Wheat): Classification of an animal (Housefly):

Key is another taxonomical aid that helps in identification of plant and animal species. These keys are based on similarities and dissimilarities in characters, generally in a pair called couplet. Each statement in a taxonomic key is referred to as a lead. For categorizing each taxonomic rank, such as family, genus, species, etc., different keys are used. It is also useful in identification of unknown organisms. Keys are of two types- indented and bracketed keys. Indented key provides a sequence of choices between two or more statements while in bracketed key, a pair of contrasting characters are used.

1. Indented key to identify different species of Rhododendron.

Leaves evergreen
leaves densely hairy below, orange or white hair; flower appears to have separate petals
………………………. Rhododendron groenlandicum
2. hair absent on leaves, flower has five petals fused in a shallow tube
………………………. Rhododendron maximus
1. Leaves deciduous
3. pink flowers with two free petals and three fused petals
………………………. Rhododendron canadense
3. white to pink flowers with all petals fused together

2. Bracketed key to identify different species of Rhododendron.

1. Leaves evergree ————– 2
1. Leaves deciduous ———– 3
2. Leaves densely hairy below, orange or white hair; flower appears to have separate petals
……….………………………. Rhododendron groenlandicum
2. Hair absent on leaves, flower has five petals fused in shallow tube
………………………………..Rhododendron maximus
3. Pink flowers with two free petals and three fused petals
……………………………… Rhododendron canadense
3. White to pink flowers with all petals fused together–4.

Similarities between monkeys and man:

• Forelimbs are used for many purposes other than walking.
• Stereoscopic vision is well developed.
• Larger brain size compared to other mammals.
• Complex social life, involving interdependency among members.
• Physical traits of male and female are remarkably different.
• The society can be patriarchal or matriarchal.
• Neonate takes longer time to develop leading to a longer lifespan.
• Presence of menstrual cycle in primates.

Differences between monkeys and man:

• Complete upright walking on hind limbs, which frees fore limbs for other usage.
• Ability to communicate using language.
• Thumbs can be brought opposite to other digits, enabling man to handle tools.
• More developed brain.

Based on similarities it is evident that monkeys and human are closely related. On the other hand certain advanced properties of human indicate towards a more evolved species. It is clear that monkeys are primitive compared to humans but they are closely related. So it is often said that monkeys are the forefathers of human.

We can prepare our own herbarium sheets by following steps.

1. First, for herbaceous species the entire plant with intact parts is collected and for others, shoots having flowers, leaves and fruits are selected and cut with the help of pruning knife.
2. The collected material is placed in polythene bags or vasculum.
3. The collected specimens are spread over magazine or newspaper sheets. Care is taken to spread the leaves properly and to separate the petals so as to expose the essential organs. If the specimen is longer than the sheet, the same can be gently bent in n or w form.
4. Magazine and newspaper sheets are now put inside the press.
5. Details of collection should be jotted down in the field notebook. For this every collected material is given a number. The details include plant size, branching, root system and specialised underground organ, flower colour, topography and date of collection.

Tools for collecting plants for the preparation of a herbarium are as follows:
Digger and pruning knife, sickle with long handle, vasculum, polythene bags, magazines or newspapers, blotting papers, plant press, field notebook, herbarium sheets, glue, labels, small transparent polythene bags.
Preserved plant material on the herbarium sheet provide following information for taxonomical studies:

1. Provides information about the local flora as well as flora of distant areas.
2. It provides information about the ecology of different places.
3. It depicts the morphological variations fohnd in species.

The objects exhibiting growth, development, responsiveness and other characteristics of life are called as living. Four defining feature of life forms are as follows:

1. Consciousness: It is awareness of the surroundings and response to external stimuli. The external stimuli can be physical, chemical or biological. The stimuli are perceived by sense organs in higher animals, e.g., eyes, ears, nose. All organisms, from primitive prokaryotes to most advanced and complex eukaryotes, are able to sense and respond to environmental factors. Organisms also handle chemicals entering their bodies.
2. Metabolism: All organisms operate a network of thousands of chemical reactions. The sum total of all chemical reactions occurring in an organism due to specific interactions amongst different types of molecules within the interior of cells is called metabolism (Gk. metabole- change).
3. Homeostasis: A favourable internal environment suitable for the functioning of body organs is present in every living being. It is quite different from the external environment. Changes in external environment do not have much impact on the internal environment as the living beings have a self regulated system to adjust and maintain the internal environment. The phenomenon is called homeostasis (Gk. homois- alike, stasis- standing.
4. Cellular organisation: Each living being is a complex entity which is formed of one or more cells. Cells work together to form tissues, tissues form organs, organs form organ systems and various organ system form the complete organism. So, cell is the basic unit of every living organism

Taxon: A level of biological classification is called a taxon, e.g. phylum, order, family, etc. Taxonomic Hierarchy: In taxonomy, different taxa have their own different levels. This means that a particular taxon will come only after another particular taxon. For example; species always comes after the genus and it can never be the other way around.Flow Chart of Plant Categories:
Kingdom → Division → Class → Order → Family → Genus → Species
Flow Chart of Animal Categories:
Kingdom → Phylum → Class → Order → Family → Genus → Species
When we go up the taxonomic hierarchy; the number of common characters becomes lesser and lesser. For example; all members of a species will have the maximum number of common characters. On the other hand, all members of a genus will have a lesser number of common characters. The number of individuals increases as we go up the taxonomical hierarchy.

The scientist should look at various morphological features of the plant. He should begin with broad features, such as type of roots and venation. If fibrous roots are present then the plant may belong to monocotyledonous. In case of tap root, the plant may belong to dicotyledonous. This can be further confirmed with the presence of parallel or reticulate venation and number of cotyledons in the seeds. After that, the scientist should look at the type of phyllotaxy, inflorescence, etc. Which will help in classifying the plant in order and family. If it is a flowering plant, then a detailed study of various floral parts can give various clues about a particular family or order. Type of placentation can be studied by looking at the arrangement of seeds inside the fruits. Finally, arrangement of antheridium and gynoecium can help the scientist to confirm a particular family for the new species. The research work of scientists on the basis of these features should be verified to conclude it as a new specie discovered.The scientist also needs to rule out exact similarity with any other existing species before arriving at a unique name for the new species found.

s. No	Characters	Living	Non-living
1.	Metabolism	Living beings show metabolic activities, which are like biochemical processes.	There is no metabolism.
2.	Reproduction	Living beings produce their future generations.	Non-living being do not reproduce.
3.	Growth	Growth in living being is a result of internal processes.	Most of the non-living do not grow. Growth in some, like clouds is a result of accumulation of external substances.
4.	Movement	Living beings show movement.	Non-living are static and if they move then it is a result of some external force.
5.	Nutrition	Living beings take food to carry various life processes.	There is no nutrition in non-living.

BINOMIAL NOMENCLATURE: Binomial nomenclature was first developed by Carolus Linnaeus in 1751 (Philosphica Botanica). All scientific names for animals under binomial nomenclature were given by Linnaeus in the tenth edition of his book Systema Naturae (1758). Linnaeus named plants according to binomial nomenclature in his book Species Plantarum (1753). Binomial nomenclature is the system of providing distinct and appropriate names to organisms, each consisting of two words, first generic name (i.e., name of genus) and second specific epithet i.e., name of species). e.g., scientific name of mango is written as Mangifera indica. In this name, Mangifera represents the genus and indica is a particular species or specific epithet. Rules of Binomial Nomenclature Rules of binomial nomenclature were initially framed by Linnaeus in his books, Species Plantarum and Systema Naturae.The rules were revised again by the following nomenclature codes:

1. International Code for Botanical Nomenclature.
2. International Code of Zoological Nomenclature.
3. International Code of Bacteriological Nomenclature.
4. International Code of Viral Nomenclature.
5. International Code of Nomenclature for Cultivated Plants.

The rules framed by Linnaeus and by these codes are as follows:

1. The names are generally in Latin and written in italics. They are Latinised or derived from Latin irrespective of their origin.
2. The first word in a biological name represents the genus while, the second component denotes the specific epithet.
3. Both the words in a biological name, when handwritten, are separately underlined or printed in italics to indicate their Latin origin.
4. The first word denoting the genus starts with a capital letter while, the specific epithet starts with a small letter, e.g., Mangifera indica.
5. Name of the author appears after the specific epithet, i.e., at the end of the biological name and is written in an abbreviated form, e.g., Mangifera indica is for Linnaeus.
6. When a species is transferred or revised, then the name of the original worker is retained, but in parenthesis, e.g., Syzygium cummini (L.) skeels.
7. No names are recognised prior to those used by Linnaeus in 1753 for plants in Species Plantarum and in 1758 for animals in the 10th edition of Systema Naturde.
8. Generic and common names may be same, e.g., Gorilla.
9. The name of categories higher than the rank of genus are not printed in italics. Bold letters can, however be used.
10. The scientific names are usually derived from Latin or Greek languages, therefore, there is no possibility of any change in meaning of their words.

Taxonomical Aids help scientists keep a record and study common and uncommon characteristics of animals and plants. This study helps them to decide about the correct place of a species in the given taxonomical category. Herbarium: Collected plant species are dried for preservation. The place where they are kept as collection is known as herbarium. Botanical Gardens: Here live plants are reared for ready reference. Through live plants botanists can study certain features, like mode of reproduction, pattern of pollination, etc. Museums: Dead animal specimens are preserved in museums. Extinct species, like Dodo are kept in certain museum and act as good reference source. Zoological Park: They are helpful in studying live specimens of animal species. Certain ferocious animals are easier to study in zoological parks. Keys: Keys are pairs of contrasting characters, out of which either of the characters is carried forward across generations and another is discarded to gain better adaptability. These keys are good tool to understand how complex organisms evolved from simpler organisms. Manuals and Records: Manuals and records show historical data about flora and fauna of a particular geographical location.

Common Name	Scientific Name	Species	Genus	Family	Order	Class	Phylum (Division)	Kingdom
Housefly	Musca domestica	Domestica	Musca	Muscidae	Insecta	Arthropoda	Arthropoda	Animalia
Mango	Mangifera indica	Indica	Mangifera	Anacardiac eae	Sapindales	Dicotyledonae	Angiospermae	Plantea
Man	Homo sapiens	Sapiens	Homo	Hominidae	Primata	Mammalia	Chordata	Animaia

General Rules for Nomenclature:

1. Biological names are generally in Latin and written in italics. They are Latinised or derived from Latin irrespective of their origin.
2. The first word in a biological name represents the genus.
3. The second component denotes the species.
4. Both the words in a biological name, when handwritten, are separately underlined, or printed in italics to indicate their Latin origin.
5. The first word denoting the genus starts with a capital letter while the second word denoting species starts with a small letter.

Living beings has multiple level of organisation. Each level of organisation has its own properties, which are not found in its constituents. Examples of three tissues supporting the statement are as follows:

1. Cardiac muscle tissue: It is a contractile tissue present only in heart. Cell junctions fuse the plasma membrane of cardiac muscle cells and make them stick together. When one cell receives a signal to contract its neighbours also starts to contract. It means a single cell cannot contract, while there are some fusion points, which allow the cells to contract as a unit.
2. Blood: It is a fluid connective tissue. The individual components of blood i.e., RBCs, WBCs and platelets have different properties but as a unit they make the blood, a tissue serving many functions.
3. Bone: It is a hard connective tissue that forms the framework of the body. The individual cells inside the bone do not have this property.
4. Nervous system: Many neurons make nervous system, but individual nerve cell ‘cannot perform the function of control and coordination.

Techniques, procedures and stored information that are useful in identification and classification of organisms are called taxonomic aids.

1. It provides information about the local flora as well as flora of distant areas.
2. Herbaria are used for correct and authentic identification of unknown plants.
3. It provides information about the ecology of different places.
4. The information is useful in locating wild varieties and relatives of economically Important plants. The same is helpful in breeding programmers for evolving newer and better varieties.
5. It depicts the morphological variations found in species.
6. Information is obtained as to the season of flowering of various plants.
7. It serves as a quick referal system for taxonomic studies.

1. Standard museums have collections of plants and animals of various areas.
2. Museums provide information not only about the local fauna and flora but also of other areas.
3. They are used to deposit type specimens whenever new taxa are described.
4. They are important centres for taxonomic studies like important members of various taxa, their important characteristics, study and identification of various organisms. Botanical gardens and Zoological parks are ex situ mode of biodiversity conservation. They have seed banks, tissue culture facilities and other ex-situ technologies to conserve biodiversity. They have well managed captive breeding programmes. As a result many animals which have become extinct in the wild continue to be maintained in zoological parks. Captive breeding is also resorted to in those cases where the number of surviving individuals is so small that there is no realistic chance of in situ survival. As the number increases in captive breeding, the individuals are selectively released in the wild. By this method Californian Candor (Gymnogyps californicus) and Black- Footed Ferret (Mustela nigripes) have been saved from extinction. Ginkgo tree (Ginkgo biloba) has been saved by selective breeding followed by channelling into trade of nature lovers. Therefore, botanical gardens and zoological parks can be used to restock depleted populations, reintroduce species in the wild and restore degraded habitats.