Test: Organism & Its Environment - 1 (Only in NEET, Not in NCERT) - NEET MCQ

Hibernation is an adaptation which has evolved in certain group of animals to conserve energy by slowing down metabolism and keeping their body temperature low in winters.

• Bats and bears are well known for hibernating. Some of the hibernating animals includes fish, frogs and turtles, snakes, bees, hedgehogs which have no way to keep warm during winter.
• Hibernation helps animal to survive when there is inadequate food supply. Before entering into hibernating state an animal stores enough fat to consume it during hibernation.

So, the correct option is 'Hibernation'.

A natural association of interdependent populations of different species inhabiting a common environment of habitat as a viable, self-contained unit is called a biotic community of biocoenosis.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

An organism (or an individual is a living unit of nature and is the most basic unit of ecological hierarchy.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

Ecology is the study of inter-relationship between organisms and their natural environment, both living and non-living. The study of ecological interactions provides important information about the nature and mechanisms of evolutionary change.

Topic in NCERT: Organisms and populations

Line in NCERT: "you have already learnt in previous classes that ecology is a subject which studies the interactions among organisms and between the organism and its physical (abiotic) environment."

The interaction among organisms is necessary for survival within their environment. Survival is the state of being alive. Organisms are inter-depending on one another of their well-being.

Topic in NCERT: Population interactions

Line in NCERT: "it is obvious that in nature, animals, plants and microbes do not and cannot live in isolation but interact in various ways to form a biological community."

The revolution of our planet around the sun and the tilt of its axis cause annual variations in the intensity and duration of temperature, resulting in distinct seasons. These variations together with annual variation in precipitation account for the formation of major biomes such as deserts, rain forest and tundra.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

A biome is a large regional unit caracterized by a major vegetation type and associated fauna found in a specific climatic zone. Some examples of terrestrial biomes are desert, temperate deciduous forest, tropical rain forest, etc.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

Environment is the sum of all biotic (living) and abiotic (non-living)  factors that surround and practically influence the organism. All components are inter-linked and inter-dependent. Biotic factors include organisms. Abiotic factors are non-living factors, substances and conditions of the environment which infuence survival, form, function, behaviour and reproduction of organism. There are manu abiotic factors. The four major abiotic factors are temperature, water light and soil.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is the study of the relationships of living organisms with the abiotic (physico-chemical factors) and biotic components (other species) of their environment."

Temperature is the most relevant environmental factor. The everage temperature varies seasonally. The physiological functions and the geographical distribution of many plants and animals is governed by temperature.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is the study of the relationships of living organisms with the abiotic (physico-chemical factors) and biotic components (other species) of their environment."

An ecosystem involves interaction among communities and their physical environment. It is the functional unit of nature. It involves biotic and abiotic components. This ecosystem may be natural or artificial (man-made).

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is the study of the relationships of living organisms with the abiotic (physico-chemical factors) and biotic components (other species) of their environment."

Temperature has a direct effect on working of enzymes. Through enzymes, it influences basal metabolism, activity and other physiological functions of the organisms. Hence, mango trees cannot grow in temperate countries like Canada and Germany.

Water makes the major part of an organism's life next to temperature. It is an important factor which influences the life of organisms. The productivity and distribution of land plant are dependent upon availability of water. Water is required for growth and development of plants.

Protoplasm is the material comprising the living contents of a cell. It consists of 90% water alongwith the minerals, sugars, amino acids, proteins, enzymes, etc. The translocation of nutrients inside the body occurs via blood which also, majorly consists of water. In an environment with excesive heat, water loss in the form of sweating and transpiration keeps the body cool. Thus, water maintains body temperature.

The plants which grow in dry or xeric conditions or where availability of water is negligible, are known as xerophytes. Opuntia and Asparagus are succulents which store water in their stem and root respectively.

For aquatic organisms the quality (chemical composition pH) of water is very important. The salt concentration (measured as salinity in parts per thousand), is less than 5 per thousand parts in inland waters, 30-35 per thousand parts in the sea and more than 100 per thousand parts in some hypersaline lagoons. Many fresh water animals cannot live for long in sea water and vice versa because of the osmotic problems they would face.

An organism's physical environment includes temperature, light, humidity, etc. whereas its biological environment includes other organisms and its relationship with them.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is the study of the relationships of living organisms with the abiotic (physico-chemical factors) and biotic components (other species) of their environment."

• Ecology is the study of interaction between living organism and their environment. The basic unit of study in ecology is organism.
• An organism is a single living entity that can carry out all the functions of life, such as obtaining energy and nutrients, responding to the environment, and reproducing.

Topic in NCERT: Ecology

Line in NCERT: "ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

• A xerophyte is a species of plant that has adaptations to survive in an environment with little liquid water, such as a desert or an ice- or snow-covered region in the Alps or the Arctic.
• Succulent (a xerophyte) plants store water in their stems or leaves.

Topic in NCERT: Defences against herbivores

Line in NCERT: "plants therefore have evolved an astonishing variety of morphological and chemical defences against herbivores. thorns (acacia, cactus) are the most common morphological means of defence."

• This is a large regional unit characterised by a major vegetation type and associated fauna found in a specific climate zone.
• The biome includes all associated developing and modified communities occurring within the same climatic region, e.g., forest biomes, grassland and savanna biomes, desert biome, etc.
• On a global scale, all the earth’s terrestrial biomes and aquatic systems constitute the biosphere.

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

The Father of Ecology in India is Ramdeo Misra.

• Raja Ram Mohan Roy was a freedom fighter.
• Verghese Kurien is the Father of the White Revolution of India while MS Swaminathan is the Father of Green Revolution of India.

Topic in NCERT: Ramdeo misra

Line in NCERT: "ramdeo misra is revered as the father of ecology in india."

The place where a particular organism lives called a habitat.

• It is a place where an organism can find shelter, food, mates for reproduction and, protection from predators.
• It depends on both biological and physical factors present within it.

Topic in NCERT: Organisms and populations

Line in NCERT: "you have already learnt in previous classes that ecology is a subject which studies the interactions among organisms and between the organism and its physical (abiotic) environment."

Homeotherms: Animals who maintain a constant internal body temperature across a wide range of environmental conditions. Most mammals and birds are homeotherms.

• Ectotherms are so-called cold-blooded animal that is any animal whose regulation of body temperature depends on external sources, such as sunlight or a heated rock surface.
• The ectotherms include the fishes, amphibians, reptiles, and invertebrates.
• The body temperatures of aquatic ectotherms are usually very close to those of the water.
• Ectotherms do not require as much food as warm-blooded animals (endotherms) of the same size, but most cannot deal as well with cold surroundings.

• Biological organisms starts with sub-microscopic molecular level like viruses, bacteria etc.
• These organisms are unable to be seen by naked eyes without the help of microscope or even electron microscope. 

Topic in NCERT: Organisms and populations

Line in NCERT: "ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

The correct answer is Option B. Temperature is the most ecologically relevant environmental factor, as it influences the kinetics of enzymes and impacts the basal metabolism, activity, and other physiological functions of organisms.

Topic in NCERT: Ecology

Line in NCERT: "ecology is a subject which studies the interactions among organisms and between the organism and its physical (abiotic) environment."