1.1 Characteristics and classification of living organisms

Describe the characteristics of living organisms by describing: #

Movement as an action by an organism or part of an organism causing a change of position or place. #

• Movement refers to the action by an organism or part of an organism causing a change of position or place.
• It allows organisms to interact with their environment, find resources, avoid danger, and perform essential activities.
• Movement can occur at different levels, from whole organism locomotion to internal cellular movements.
• Examples of movement include walking, flying, swimming, muscle contractions, cytoplasmic streaming, and growth movements.

Respiration as the chemical reactions in cells that break down nutrient molecules and release energy for metabolism. #

• Respiration refers to the chemical reactions that occur in cells to break down nutrient molecules and release energy for metabolism.
• It is a process that involves the oxidation of glucose or other organic compounds to produce ATP (adenosine triphosphate), the energy currency of cells.
• Respiration can be aerobic (requiring oxygen) or anaerobic (without oxygen), depending on the organism and the availability of oxygen.
• It takes place in specialized organelles called mitochondria, where the breakdown of nutrients occurs through a series of enzymatic reactions.

Sensitivity as the ability to detect and respond to changes in the internal or external environment. #

• Sensitivity is the ability of living organisms to detect and respond to changes in the internal or external environment.
• It allows organisms to perceive stimuli, process information, and initiate appropriate responses for survival and adaptation.
• Sensitivity involves the presence of specialized structures called sensory receptors that detect specific types of stimuli, such as light, sound, touch, chemicals, temperature, and internal changes.
• Organisms exhibit both external sensitivity (responding to stimuli from the environment) and internal sensitivity (responding to internal physiological changes).

Growth as a permanent increase in size and dry mass. #

• Growth is a characteristic of living organisms that refers to a permanent increase in size and dry mass.
• It involves the accumulation and organization of new materials, such as proteins, nucleic acids, and other organic compounds, leading to the enlargement of cells, tissues, and ultimately the whole organism.
• Growth is a result of cell division, cell enlargement, and the synthesis of new cellular components.
• It is regulated by complex interactions between genetic factors and environmental conditions.
• Growth is a result of cell division, cell enlargement, and the synthesis of new cellular components.
• It is regulated by complex interactions between genetic factors and environmental conditions.

Reproduction as the processes that make more of the same kind of organism. #

• Reproduction is the characteristic of living organisms that involves the processes by which they produce offspring or make more of the same kind of organism.
• It ensures the continuation of a species and the passing on of genetic information to subsequent generations.
• Reproduction can occur through sexual reproduction, involving the fusion of gametes (sperm and egg), or asexual reproduction, where offspring are produced from a single parent without the involvement of gametes.
• Different organisms exhibit various reproductive strategies, including fertilization, mating, pollination, budding, spore formation, and fragmentation.

Excretion as the removal of the waste products of metabolism and substances in excess of requirements. #

• Excretion is the characteristic of living organisms that involves the removal of waste products of metabolism and substances in excess of requirements.
• During metabolic processes, organisms produce waste products, such as carbon dioxide, urea, and excess salts.
• Excretion ensures the elimination of these waste products, preventing their accumulation and potential harm to the organism.
• Excretory organs, such as kidneys, lungs, and skin, play a crucial role in removing waste materials from the body.

Nutrition as the taking in of materials for energy, growth and development #

• Nutrition is the characteristic of living organisms that involves the taking in of materials for energy, growth, and development.
• Organisms require nutrients, including carbohydrates, proteins, lipids, vitamins, minerals, and water, to sustain their metabolic activities.
• Autotrophs, such as plants, can produce their own nutrients through photosynthesis, while heterotrophs, including animals and some bacteria, obtain nutrients by consuming other organisms or organic matter.
• Nutrition encompasses processes such as ingestion, digestion, absorption, and assimilation, which allow organisms to obtain and utilize essential nutrients.