Living Things & Non-Living Things

Living things are entities that possess the fundamental characteristics of life, which include growth, reproduction, metabolism, responsiveness to stimuli, adaptation, and the ability to undergo homeostasis. These objects exhibit a level of organization and complexity that allows them to function, interact with their environment, and maintain their internal processes. Plants and animals are prime examples of living things, as they possess cells, biological structures, and physiological mechanisms that enable them to carry out vital life processes.

Table of Contents

Plants, as living organisms, are capable of photosynthesis, using sunlight to convert carbon dioxide and water into glucose and oxygen. They grow, develop, and reproduce through processes such as germination, flowering, and seed dispersal. They also respond to stimuli, such as light and gravity, by orienting their growth and movement accordingly. Furthermore, plants exhibit adaptations to their environments, such as the ability to withstand extreme temperatures or thrive in arid conditions.

Similarly, animals are characterized by their ability to move, obtain energy from food through digestion and metabolism, and exhibit various forms of locomotion. They possess complex organ systems that support their survival, reproduction, and interaction with their surroundings. Animals display a wide range of behaviors and adaptations, from hunting and foraging to migration and social interactions. They also have the ability to learn and exhibit cognitive functions, making them capable of problem-solving and complex decision-making.

In contrast, non-living things lack the essential qualities of life. They do not possess cells, and they do not grow, reproduce, or exhibit metabolism. Non-living objects are inert and do not have the capacity to respond to stimuli or adapt to changing conditions. Examples of non-living things include rocks, minerals, water, air, and human-made objects like buildings, vehicles, and tools. These entities are subject to physical laws and processes, but they do not display the characteristics that define living organisms.

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It’s important to note that while the distinction between living and non-living things is generally clear-cut, there are some entities that blur the boundaries. Viruses, for instance, are considered to be on the borderline of life as they exhibit some characteristics of living things, such as reproduction, but they lack the ability to carry out metabolic processes independently. Similarly, certain scientific debates may arise regarding the classification of complex systems like artificial intelligence or self-replicating machines, as they possess some characteristics of life but are not based on organic matter.

Overall, the classification of living and non-living things helps us understand the diversity of the natural world and provides a basis for studying the unique properties and behaviors exhibited by living organisms.

CHARACTERISTICS OF LIVING THINGS

Living things possess several characteristics that distinguish them from non-living things. These characteristics enable them to carry out vital life processes and maintain their existence within their respective environments. Let’s explore each characteristic in more detail:

1. Movement: Living organisms have the ability to move either their entire bodies or specific parts of their bodies. This characteristic serves various purposes, including finding food, escaping from predators or unfavorable conditions, seeking a mate for reproduction, and responding to external stimuli. Movement allows organisms to explore their surroundings, find resources, and adapt to changing environments.

2. Nutrition: Living organisms require a source of energy and nutrients to sustain their life processes, such as growth, respiration, and reproduction. There are two primary methods of nutrition:

a. Autotrophic/Photosynthetic Nutrition: This method is employed by green plants and some bacteria. Through the process of photosynthesis, they can manufacture their own food using simple inorganic compounds, such as carbon dioxide and water, in the presence of sunlight. This allows them to convert light energy into chemical energy stored in glucose and other organic molecules.

b. Heterotrophic/Nutritional: This method is specific to animals. They depend on other organisms for their nutrition, either directly or indirectly. Herbivores consume plants, carnivores eat other animals, and omnivores have a mixed diet. Heterotrophic nutrition involves the ingestion, digestion, and absorption of organic materials to obtain energy and essential nutrients.

3. Respiration: Respiration is the process by which living organisms extract energy from organic molecules obtained through nutrition. It involves the oxidation of food substances within the cells, usually in the presence of oxygen, to release energy in the form of adenosine triphosphate (ATP). Respiration allows organisms to carry out their metabolic activities, including growth, movement, reproduction, and maintenance of internal homeostasis.

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4. Excretion: Excretion is the removal of metabolic waste products from the body or cells of living organisms. As part of their metabolic processes, living organisms produce waste substances that can be toxic if they accumulate. Excretion ensures the elimination of these waste products, maintaining the proper functioning and health of the organism. Examples of excretory processes include the elimination of carbon dioxide through respiration and the excretion of nitrogenous waste products like urea or ammonia.

5. Growth: Growth refers to a permanent increase in the size or complexity of an organism. Living organisms undergo growth through cell division and cell differentiation. Cell division allows for the multiplication of cells, while cell differentiation leads to the development of specialized tissues and organs. Growth is influenced by genetic factors, nutrition, and environmental conditions. Adequate nutrition is essential for organisms to grow and increase their body mass.

6. Irritability/Sensitivity: Living organisms possess the ability to respond to changes in their internal and external environments. This characteristic allows them to detect and react to various stimuli such as heat, light, pain, water, sound, and chemical substances. Organisms exhibit different forms of sensitivity, ranging from simple reflex actions to complex behaviors and cognitive processes. Sensory receptors in their bodies enable them to perceive and interpret these stimuli, facilitating appropriate responses for survival and adaptation.

7. Reproduction: Reproduction is the ability of living organisms to produce offspring. It ensures the continuity of a species over generations. Reproduction can occur through two primary methods:

a. Asexual Reproduction: This involves the production of offspring without the involvement of gametes (sex cells). A single-parent organism generates genetically identical or similar offspring through processes such as binary fission, budding, fragmentation, or vegetative propagation.

b. Sexual Reproduction: This involves the fusion of gametes from two parent organisms to produce genetically diverse offspring. Sexual reproduction introduces genetic variation through processes such as meiosis, fertilization, and genetic recombination. Offspring inherit traits from both parents, leading to diversity within the population.

These characteristics collectively define what it means to be a living organism, enabling them to adapt, survive, and propagate within their respective environments. Each characteristic contributes to the complexity and diversity of life on Earth.

Types

1. Sexual Reproduction: Sexual reproduction involves the fusion of gametes from two organisms of the same species to produce offspring. It requires the involvement of specialized reproductive cells, such as sperm and eggs. These gametes are formed through a process called meiosis, which ensures genetic diversity in the offspring. During sexual reproduction, the genetic material from both parents combines, resulting in offspring that inherit a unique combination of traits. This genetic variation contributes to the adaptability and evolution of species over time.

2. Asexual Reproduction: Asexual reproduction is a method of reproduction that involves a single organism giving rise to offspring without the involvement of gametes or the fusion of genetic material from two parents. Asexual reproduction methods include binary fission, where the parent organism splits into two identical offspring, budding, where a smaller version of the parent grows out and separates, and fragmentation, where a piece of the parent organism breaks off and develops into a new individual. Asexual reproduction results in offspring that are genetically identical or similar to the parent, as there is no genetic recombination.

3. Adaptation: Adaptation refers to the process by which living organisms adjust to their environment in order to survive and reproduce successfully. Through adaptation, organisms acquire traits and behaviors that enhance their chances of survival in specific environmental conditions. Adaptations can be structural, physiological, or behavioral. Structural adaptations include features like specialized body parts, camouflage, or protective coverings. Physiological adaptations involve changes in internal processes to cope with environmental challenges, such as hibernation or the ability to tolerate extreme temperatures. Behavioral adaptations are actions or strategies that organisms adopt to increase their chances of survival, such as migration or the formation of social groups. Adaptations allow organisms to exploit available resources, avoid predators, and respond to environmental changes.

4. Competition: Competition is a fundamental aspect of living organisms’ interaction within their environment. It occurs when organisms of the same or different species compete for limited resources necessary for their survival and reproduction. These resources can include food, water, light, space, mates, and more. Competition drives the evolution of species, as organisms with traits that provide a competitive advantage are more likely to survive and reproduce, passing on those advantageous traits to future generations. Interspecific competition occurs between different species, while intraspecific competition occurs among individuals of the same species.

Death: Death is an inevitable part of the life cycle of all living organisms. It refers to the cessation of vital life processes and the irreversible loss of function of an organism. All living things have a finite lifespan, and death occurs due to various factors such as aging, disease, predation, or environmental conditions. While death is often associated with the end of an individual’s life, it also plays a crucial role in the balance of ecosystems. Dead organisms provide nutrients and energy for other organisms through processes like decomposition and serve as part of the nutrient cycle. The cycle of life and death ensures the renewal of resources and the continuation of the natural world.

Differences Between Plants and Animals:

1. Growth: Plants exhibit indefinite and apical growth, meaning they continue to grow throughout their lifespan and growth occurs uniformly in their body. On the other hand, animal growth is definite and interactive, meaning they have a fixed number of body parts, and growth typically stops once they reach maturity.

2. Response to External Stimuli: Plants generally have a slower response to external stimuli. Their responses to stimuli like light, gravity, or touch occur at a slower pace compared to animals, which often show faster and more immediate responses.

3. Food Storage: Plants store food in the form of starch, except for fungi which store glycogen. Animals, on the other hand, store food as glycogen, which is stored in liver and muscle cells.

4. Sense Organs: Plants lack specialized sense organs. They do not possess organs like eyes, ears, or noses to detect environmental stimuli. In contrast, animals have well-developed and specialized sense organs that enable them to perceive and respond to various stimuli in their environment.

5. Fixed Number of Parts: Plants do not have a fixed number of body parts and can continue to grow new structures throughout their life. In animals, the number of body parts is usually fixed and relatively constant.

6. Gaseous Exchange: Plants carry out gaseous exchange through the entire surface of their bodies, including leaves, stems, and roots. Animals, however, have specialized respiratory organs like lungs, gills, or tracheae for efficient gas exchange.

7. Cell Structure: Plant cells have a rigid cell wall composed of cellulose, which provides structural support and protection. Animal cells, on the other hand, have a flexible and living cell membrane that surrounds the cell.

8. Vacuoles: Plant cells typically have a large central vacuole that contains cell sap and helps maintain turgidity. Animal cells, in contrast, have smaller or no vacuoles.

9. Mode of Nutrition: Plants are autotrophic and produce their own food through photosynthesis, using sunlight, water, and carbon dioxide. They convert these raw materials into glucose and other organic molecules. Animals are heterotrophic and obtain their food by consuming other organisms or their byproducts since they are unable to synthesize their own food.

10. Excretory System: Plants do not possess a specialized excretory system. They eliminate waste products mainly through diffusion and excretion at the cellular level. Animals, on the other hand, have well-developed excretory systems that help eliminate metabolic waste products efficiently. Examples of animal excretory systems include kidneys in vertebrates or Malpighian tubules in insects.

These differences highlight the distinct characteristics and adaptations of plants and animals, reflecting their diverse evolutionary pathways and strategies for survival in different ecological niches.

Microscope (Parts and function)

A Microscope is an instrument used to view or magnify organisms smaller than 0.001mm which cannot be seen by human naked eyes. A microscope is made of the following parts.

(i) Eyepiece lens or ocular (x10) is used for viewing a magnified object.

(ii) Body tube: It provides attachment to the eyepiece and revolving nose piece

(iii) Revolving nose piece is used for selecting objective lenses to be used and to be in line with the eyepiece

(a). Low power objective lens(x4) is used for the lowest magnification of an object

(b) Medium power objective lens (x10) magnifies objects more than low power objective lens

(iv) Coarse focus knob: it is used for focusing an object at low power

(v) Fine adjustment knob: it is used for focusing objects at medium and high power magnification so that object is sharper in focus

(vi) Arm is used for lifting or carrying the microscope

(vii) Stage: is for displaying slides and specimens under focus

(a) Clips: are the stage for holding glass slides on the stage

(b) Hole: is present on the stage for the light source to the viewing object

(viii) Condenser: it is used to regulate the number of light rays entering the microscope and object