Biology – 1.1 Characteristics of living organisms | e-Consult

All living organisms exhibit a set of key characteristics that distinguish them from non-living matter. These characteristics are crucial for survival and adaptation. Here's a description of how each characteristic is essential, with examples:

Movement

Movement allows organisms to find food, escape danger, and locate suitable habitats. It can be internal (e.g., movement of blood, cilia in the digestive tract) or external (e.g., walking, flying, swimming). For example, a cheetah's movement is essential for hunting prey. Movement also aids in the transport of substances within the organism.

Respiration

Respiration is the process by which organisms release energy from food. It involves the breakdown of glucose using oxygen (aerobic respiration) or without oxygen (anaerobic respiration). This energy is used for all life processes. For example, humans respire to provide energy for muscle contraction and brain function. Plants also respire, releasing carbon dioxide.

Sensitivity

Sensitivity allows organisms to detect and respond to changes in their environment. This can be through light, sound, temperature, or chemicals. Sensory receptors detect these changes and transmit signals to the nervous system, enabling a rapid response. For example, a plant turning towards sunlight demonstrates sensitivity to light. A bacterium moving towards a chemical signal (like nutrients) shows sensitivity to chemicals.

Growth

Growth is an increase in size and/or complexity. It involves cell division and differentiation. Growth is essential for an organism to develop from a young stage to a mature stage. For example, a plant grows taller and develops more leaves. Animals grow in size and develop specialized tissues.

Reproduction

Reproduction is the process by which organisms create new organisms. It ensures the continuation of the species. Reproduction can be sexual (involving two parents and genetic variation) or asexual (involving one parent and identical offspring). For example, a flower reproduces sexually through pollination, leading to seed formation. Bacteria reproduce asexually through binary fission.

Excretion

Excretion is the removal of waste products from the body. These waste products are produced as a result of metabolic processes. Excretion maintains a stable internal environment (homeostasis). For example, kidneys in humans remove urea from the blood. Plants excrete excess water through transpiration.

Nutrition

Nutrition is the process of obtaining food. Organisms obtain food either by making their own (autotrophs, like plants) or by consuming other organisms (heterotrophs, like animals). Nutrition provides the energy and materials needed for growth, repair, and life processes. For example, a plant makes its own food through photosynthesis. A lion eats a zebra for energy and nutrients.