CLASS 6 SCI CHP 7 THINGS AROUND US PART 1
**Characteristics Common to Living Things**
The first step in differentiating living things from nonliving things is to identify characteristics that are common to all living organisms. One such characteristic is eating and feeding. All living things require nutrition to survive, and they obtain this energy by consuming food. This process of taking in food and using it for energy is essential for the survival of living beings on Earth.
Plants, which are a type of living thing, can be differentiated into two main categories: animals and plants. Animals depend on other organisms to prepare their food, whereas plants have the ability to photosynthesize, meaning they produce their own food using sunlight, water, and carbon dioxide.
In addition to eating and feeding, another characteristic common to all living things is respiration. Respiration is the process by which energy is released from food, allowing living beings to perform various functions such as breathing, growth, and maintenance of bodily functions. The process of respiration involves the breakdown of food molecules to produce energy, carbon dioxide, water, and other waste products.
**Respiration vs. Breathing**
It is essential to distinguish between respiration and breathing, as they are two distinct processes that serve different purposes. Breathing refers to the process of taking in oxygen and expelling carbon dioxide through the mouth or nose. This process allows living beings to obtain oxygen, which is necessary for cellular respiration, and to release waste products.
Respiration, on the other hand, is a chemical reaction that occurs within cells to produce energy from food molecules. This process involves the breakdown of glucose and other carbohydrates to produce ATP (adenosine triphosphate), which is then used by cells to perform various functions.
**Breathing Mechanisms in Humans and Animals**
The breathing mechanism in humans and animals is similar, with the primary function being to exchange gases. However, some animals have adapted to different environments, leading to variations in their breathing mechanisms. For example, animals living on land have evolved lungs as a means of exchanging gases, while those living in water have developed gills.
In vertebrates, such as humans and many other animals, the breathing mechanism involves the movement of air in and out of the body through the nose or mouth. This process is essential for obtaining oxygen and releasing carbon dioxide.
**Growth in Living Organisms**
Another characteristic common to all living things is growth. Growth refers to the increase in size or development of an organism over time. This can occur in various forms, such as an increase in height, weight, or the development of new tissues.
In human beings, growth occurs from birth to adulthood, with the individual increasing in height and weight as they develop. Similarly, plants grow by increasing in size, producing new leaves, stems, and roots. Other living organisms, such as animals, may undergo metamorphosis, a process of physical transformation that allows them to adapt to their environment.
**Excretion in Living Organisms**
Excretion is the process by which living beings remove waste products from their bodies. This can occur through various methods, including urination, defecation, or sweating.
In human beings, excretion occurs through the kidneys, which filter waste products from the blood and produce urine, a waste product that is then eliminated from the body. Other organs, such as the liver and intestines, also play important roles in removing waste products.
**Movement in Living Organisms**
Another characteristic common to all living things is movement. Movement refers to the ability of an organism to change its position or shape in response to external stimuli. This can occur through voluntary action, such as walking or running, or through involuntary movements, such as the beating of the heart.
In animals, movement is often associated with locomotion, which involves the use of muscles to propel oneself forward. In plants, movement occurs through the growth and bending of stems and branches in response to external stimuli, such as changes in light intensity.
**Response to Stimuli**
Finally, all living organisms are capable of responding to external stimuli, such as changes in temperature, light, or touch. This response can be either voluntary or involuntary, depending on the complexity of the organism's nervous system.
In humans and animals, responses to stimuli can include movement, changes in behavior, or physiological reactions, such as the release of hormones or other chemical signals. In plants, responses to stimuli often involve changes in growth patterns or the production of chemicals that help protect the plant from environmental stressors.