Living and Nonliving
Living and Nonliving – Deep Concept Guide
Living and Nonliving things
Key idea: All objects around us are either living or nonliving. This basic division is used in all biology questions.
| Feature | Living things | Nonliving things |
|---|---|---|
| Cellular nature | Made of cells (unicellular or multicellular) | No cells, only materials like stone, metal, plastic |
| Growth | Internal growth due to cell division | External growth only by adding material from outside |
| Metabolism | Have metabolism – all chemical reactions in the body | No metabolism, no chemical reactions of life |
| Response to stimuli | Respond to light, sound, touch, temperature and chemicals | No true response, only mechanical or programmed changes |
| Movement | Show internal or external movement | Do not move on their own |
| Reproduction | Produce new individuals of their own kind | Do not reproduce |
| Life span | Have definite life span from birth to natural death | No fixed life span |
| Examples | Neem tree, crow, human being, bacteria | Rock, river water, school building, bus, pen |
| Cause | Process | Impact / Consequence |
|---|---|---|
| Presence of cells and metabolism | Continuous life processes run inside the body | Organism can grow, reproduce and respond |
| Only physical forces acting on object | No metabolism, no life processes | Object remains nonliving, even if it moves or grows in size by addition |
Memory Line: Living things always show Cells, Metabolism, Response, Reproduction, Growth → think as CMRRG.
Exam Tip: A stone rolling down, or a car moving on the road, are still nonliving because there is no cell-based movement. Movement alone is not a test for life.
Exam Trap: Seeds, dry spores and some microbes may look inactive but are living because they can grow and reproduce under suitable conditions.
Basics of Life
Key idea: Life is expressed through certain basic units, levels and processes which are common to plants, animals and human beings.
| Concept | Meaning | Simple example |
|---|---|---|
| Organism | Any individual living being | One child, one mango tree, one sparrow |
| Species | Group of similar organisms that can reproduce among themselves | All humans form one species, all banyan trees one species |
| Population | Group of organisms of same species in an area | All pigeons in a park, all coconut trees in a village |
| Community | Different populations living together in one place | Trees, grasses, insects, birds and animals in a forest patch |
| Ecosystem | Living organisms plus their physical environment acting together | Pond, river bank, crop field, garden |
| Biosphere | All ecosystems of Earth where life exists | Entire life-supporting part of Earth |
| Basic life process | What happens | Impact / Importance |
|---|---|---|
| Nutrition | Taking in and using food | Provides energy and materials for growth and repair |
| Respiration | Breaking down food to release energy | Energy is supplied to all other processes |
| Transport | Movement of materials inside body | Delivers oxygen, food and removes wastes |
| Excretion | Removal of metabolic wastes | Keeps internal environment clean and stable |
| Reproduction | Formation of new organisms of same kind | Maintains continuation of species |
| Growth | Increase in size and mass | Shows that new cells and tissues are formed |
| Response and control | Detecting and reacting to changes | Helps organism survive in changing surroundings |
| Cause | Process | Impact / Consequence |
|---|---|---|
| Surroundings keep changing | Organism uses sense organs, hormones and nerves | Can adjust and survive in different situations |
| Energy need in all cells | Respiration continuously releases energy from food | Heart beats, muscles work and brain functions without stopping |
Memory Line: All living beings must “N R T E R G” → Nutrition, Respiration, Transport, Excretion, Reproduction, Growth.
Exam Tip: When a question asks “Which one is not a basic life process?”, look for options like playing, studying or sleeping. These are activities, not basic life processes.
Characteristics of living organisms
Key idea: Certain characteristics are seen in all living organisms. These are used to identify whether something is living or nonliving.
| Characteristic | Short explanation | Typical example |
|---|---|---|
| Cellular organisation | Body made of one or many cells | Amoeba has one cell, a child has many cells |
| Metabolism | All chemical reactions running inside body | Digestion of food, energy release in mitochondria |
| Growth | Irreversible increase in size due to cell division | Height increase of a child, thickening of tree trunk |
| Reproduction | Ability to produce new individuals | Bacteria dividing into two, plants producing seeds |
| Movement | External or internal movement | Running of dog, bending of sunflower towards light |
| Response to stimuli | Reacting to changes in environment | Touch-me-not plant closing leaves, pupil of eye shrinking in bright light |
| Respiration | Using oxygen to break down food and release energy | Breathing and cellular respiration in all living cells |
| Excretion | Removal of waste products of metabolism | Urine formation in kidneys, removal of carbon dioxide from lungs |
| Homeostasis | Keeping internal conditions nearly constant | Body temperature control, water balance |
| Definite life span | Birth, growth, maturity, old age and death | Different for mosquito, dog, human and banyan tree |
| Cause | Process | Impact / Consequence |
|---|---|---|
| Organism has active metabolism | Life processes run continuously | Shows characteristics like growth and response |
| Living body becomes inactive or dies | Metabolism stops completely | Characteristics of life also stop permanently |
Memory Line: Main characteristics of life can be remembered as “G R R M E C H” → Growth, Reproduction, Response, Movement, Excretion, Cellular organisation, Homeostasis.
Exam Tip: Visible movement is not the only sign of life. Seeds, spores and some resting animals may not move but are still living because other life processes continue at a slow rate.
Exam Trap: Fire grows and spreads, but it is not living because it has no cells, no reproduction of its own type and no controlled metabolism.
Different types of habitat and adaptation
Habitat: Place where an organism lives and gets food, water, shelter and space. Adaptation: Special features that help an organism to live successfully in its habitat.
| Main habitat type | Examples | Typical adaptations |
|---|---|---|
| Desert (hot and dry) | Camel, cactus, desert rat | Water storage, thick skin, reduced leaves, deep roots, nocturnal habit |
| Mountains (cold and windy) | Yak, mountain goat, pine tree | Thick fur, layer of fat, small needle-like leaves, strong roots |
| Grasslands | Deer, lion, grass species | Fast running legs, eyes position for prey or predator, camouflaging body colour |
| Forests | Monkey, tiger, climber plants | Gripping hands and tail, stripes for camouflage, climbing stems |
| Freshwater | Fish, lotus, water hyacinth | Gills, fins, streamlined body, air spaces in leaves, flexible stems |
| Marine | Shark, seaweeds, dolphins | Salt tolerance, fins and flippers, thick blubber layer |
| Amphibious | Frog, toad | Moist skin for cutaneous respiration, webbed feet, eyes and nostrils on top of head |
| Aerial | Eagle, pigeon, bat | Light body, hollow bones, wings and strong flight muscles |
| Cause | Process | Impact / Consequence |
|---|---|---|
| Climate and resources differ from place to place | Organisms with useful features survive better and leave more offspring | Population becomes well adapted to that habitat over many generations |
| Scarcity of water in deserts | Plants develop thick cuticle, sunken stomata and reduced leaves | Water loss is reduced, plant survives long dry periods |
| High speed winds in open grasslands | Plants remain short with strong roots, animals become fast runners | Less damage to plants, animals can escape predators or catch prey |
Memory Line: Simple way to remember – “Right body in right place” is adaptation.
Exam Tip: When a question gives features like hump, long legs and thick lips, connect them to desert animals. When it mentions air spaces in leaves and waxy surface, think of aquatic plants.
Exam Trap: Habitat is the place where an organism lives, but niche is its role or job in that place. Many questions try to confuse these two words.