Chapter 1: The Living World

Ans: A living organism is a self-replicating, evolving, and self-regulating interacting system that can respond to cues from the environment. Living beings have diverse properties such as growth, reproduction, feeding, excretion, and so on. However, most of these properties aren't considered defining characteristics of life forms.

The following characteristics define a living form: The term "growth" refers to a rise in mass. Plants continue to grow throughout their lives, but most animals only reach a specific age. However, some non-living entities, such as clouds and snowballs, can also grow in numbers. As a result, growth cannot be considered a defining characteristic of life.

Reproduction is the process by which a live being reproduces its type.

Many species reproduce sexually, whereas others reproduce asexually, using a variety of techniques. Many biological beings, on the other hand, do not reproduce at all, such as the worker bee in a beehive. However, because we regard it to be a living being, reproduction cannot be considered an all-encompassing defining element of life. Because non-living creatures are unable to reproduce, reproduction might be considered a distinguishing property of life (with certain exceptions).

Metabolism involves various biochemical processes during which various molecules are formed, and many others get broken down. Metabolic reactions cannot occur in a cell-free system. While several in-vitro reactions have been tested in laboratories, they are not considered to be true metabolisms. As a result, metabolism is one of life's defining characteristics.

Another characteristic of living beings is a structural organization, which begins with a cellular organization or the highest level of organization. To make a cell organelle, some molecules come together and act in perfect synchrony, and different cell organelles accumulate together to form a cell. Cells eventually create tissue, which then becomes organs, and the system made up of those organs eventually forms the entire organism. It is the finest and most advanced level found in most multicellular organisms. Cells are altogether different from their constituent organelles; in terms of characters and functions. Similarly, a tissue is entirely different from its component cells; in terms of functions. Similar demarcation and hierarchy of organization are not possible in non-living things. Hence, the cellular organization is a defining feature of life.

External stimuli can reach in various forms to a living organism, either externally as external stimuli like temperature, light, etc., or internal stimulus like hormones. And the living being responds to each stimulus in a different way.

This can be termed as consciousness of the environment. Such a consciousness is not possible in non-living things. Hence, response to external stimuli is a defining feature of life.

Ans: The scientist should examine the plant's morphological characteristics. He should start with broad characteristics like root type and venation. If the plant has fibrous roots, it is most likely monocotyledonous. The plant may be dicotyledonous in the case of the taproot. The existence of parallel or reticulate venation, as well as the number of cotyledons in the seeds, might further support this.

The scientist should then examine the type of phyllotaxy, inflorescence, and other characteristics that will aid in classifying the plant into order and family. If it's a flowering plant, a close examination of the various floral parts might reveal a lot about the family or order. The arrangement of seeds inside the fruits can be used to determine the kind of placentation. 

Finally, the arrangement of antheridium and gynoecium can aid scientists in confirming the new species’ family. Scientists' study on the basis of these characteristics should be confirmed before concluding that a new species has been discovered. Before coming up with a unique name for the new species discovered, the scientist must rule out any exact parallels with any other existing species.

Ans: The common name of Brassica campestris linn is mustard.

Ans: The first part denotes the genus of the plant, while the second part denotes the species.

Ans: To emphasize their Latin origins, these names are written in italics. Furthermore, it is a mandatory rule that scientific names be written in italics.

Ans: Linnaeus was the first to identify and study this species, as the epithet 'linn' implies.

Ans: Taxonomic aids are tools that aid scientists in the study of plants and animals. Live plants and animals, as well as preserved remains, are used as taxonomic aids. When it comes to animals, museum specimens are carefully preserved. Herbariums are used to store preserved specimens in the case of plants.

Herbarium's Importance: Herbarium serves as a storage facility for specimens that will be used in the future. This also provides information regarding a specimen's classification in great detail. In many circumstances, the herbarium is used as a rapid reference system while researching a specific species or a higher taxonomic level. The herbarium is simple to construct and keep up with. A herbarium is also simple to travel.

Museums are important because they have a considerably larger collection of plant and animal specimens. Many extinct creatures' skeletons may be found in museums. As a result, a museum offers additional opportunities to learn about a particular plant or animal. Museums are usually run by educational institutions and serve as a valuable research resource for both students and scientists.

Botanical and Zoological Parks Play an Important Role in Biodiversity Conservation: Botanical and Zoological Parks play an important role in biodiversity conservation. The safest environment for plants and animals to live in their natural habitat is a botanical or zoological park. Plants and animals are cared for by specially trained workers. They also practise selective breeding of diverse plants and animals in order to ensure the survival of a species. Furthermore, if the plants and animals in such parks have a disease, effective treatment is provided. As a result, botanical and zoological parks can be regarded to serve an essential role in biodiversity conservation.

Ans: A taxon is a level of biological taxonomy, such as phylum, order, family, and so on.

Taxonomic Hierarchy: Distinct taxa have different levels in taxonomy. This means that a specific taxon will only appear after another specific taxon. Species, for example, always come after the genus and never the other way around.

Plant Categories Flow Chart

Kingdom→Division→Class→Order→Family→Genus→Species

Flow Chart of Animal Categories

Kingdom→Phylum→Class→Order→Family→Genus→Species 

The common characteristics decrease as we progress up the taxonomic ladder. All members of a species, for example, will have the greatest amount of common traits. All members of a genus, on the other hand, will have a smaller number of common characters. The number of individuals increases as we go up the taxonomic hierarchy.

Ans: A key is a useful tool for researching a taxonomic category. A key is made up of two distinct characters. These characters are usually found in pairs, which is known as a couplet. Either of the opposing characters is rejected or accepted while examining a key.

As a result, a decision must be made between the two opposing characters in a key. A lead is a name given to each assertion in the key. It's worth noting that most keys are analytical in character.

Furthermore, distinct keys for different taxonomic categories must be employed. Keys aid in the identification of a certain organism in a step-by-step manner. The presence or lack of a notochord, for example, can indicate whether an organism belongs to the Vertebrate or invertebrate subphylum. Similarly, whether an organism has lungs or not determines whether it belongs to the Tetrapoda or Pisces groups.

Ans: “The total of all chemical reactions occurring in a live cell or organism" is how metabolism is defined. It involves the production of various compounds, as well as the breakdown of many molecules. Protozoans, algae, fungi, bacteria, and other creatures all have metabolism.

In a cell-free system, metabolic responses are impossible. Because they are carried in a controlled environment and are mimicked, isolated in-vitro reactions carried out in laboratories cannot be called metabolism. However, because such reactions occur within a living system, they are referred to as living reactions.

Ans: When it comes to humans, defining their living state is quite challenging. A person could be in a coma for a long time. The person is alive by technical definition because he is not brain-dead. Most of their essential organs, however, have stopped working. The life support system keeps such a person alive. The oxygenation and circulation functions of a heart and lung machine are performed continuously. To fulfill the function of the kidneys, a dialysis unit may be used. Intravenous fluids provide nutrients to the patient.

Because the person is in a coma, he is completely unaware of his surroundings. To put it another way, he is unable to respond to stimuli, which is one of life's defining characteristics. Metabolic activities are ongoing since the person is kept alive by the life support system.  As a result, the individual can be considered deceased.

However, we must remember that once he is taken off the life support system, he will become brain-dead and, by technical definition, dead. So, determining whether a person in a coma is alive or dead is a challenging task.

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Ans: Some of the qualities of tissues are not the constituents of their cells, which is true. This statement is supported by the following three examples: 

1. Although muscle tissue can contract, not all of its constituent cells may be able to do so.

2. Bones and cartilage make the skeletal system. A bone is hard and lightweight, while cartilage is soft. But they possess different constituents.

3. Blood is capable of carrying oxygen, but WBCs are not capable of doing so in spite of being the constituents of blood.