The Living World: Characteristics and Defining Features of Life

Vocabulary practice flashcards covering the characteristics, properties, and defining criteria of living organisms based on NEET Module-1 Botany notes.

Living organisms

Self-replicating, evolving, and self-regulating interactive systems capable of responding to external stimuli.

Twin characteristics of growth

An increase in mass and an increase in the number of individuals.

Plant growth

Growth by cell division that occurs continuously throughout their life span.

Animal growth

Growth seen only up to a certain age, though cell division continues in certain tissues throughout life to replace lost cells.

Internal growth vs. External growth

Growth occurring from within the body in living organisms, contrasted with growth by accumulation of material on the surface (external) in non-living objects such as mountains, boulders, and sand mounds.

True regeneration

The process observed in Planaria (flat worms) wherein a fragmented organism regenerates the lost part of its body and becomes a new organism.

Budding

A form of asexual reproduction observed in lower organisms like yeast and hydra.

Fragmentation

A form of asexual multiplication observed in fungi, filamentous algae, and the protonema of mosses.

Growth and reproduction in unicellular organisms

Mutually inclusive processes where reproduction is synonymous with growth, referring simply to an increase in the number of cells.

Non-reproducing living organisms

Living organisms such as mules, sterile worker bees, and infertile human couples that do not reproduce, demonstrating that reproduction is not an all-inclusive defining characteristic.

Metabolism

The sum total of all the chemical reactions occurring in our body, representing a defining feature of all living organisms without exception.

Isolated metabolic reactions

Metabolic reactions performed in vitro outside the body of an organism (such as in a test tube) that are not living things, but are surely living reactions, and are considered neither living nor non-living.

Cellular organisation

The structural basis of living forms that serves as a defining feature of life forms.

Consciousness

The most obvious and technically complicated feature of all living organisms, defined as the ability to sense surroundings or the environment and respond to physical, chemical, or biological stimuli.

Self-consciousness

The awareness of oneself, a property found only in human beings among all living organisms.

Photoperiod

An external factor that affects reproduction in seasonal breeders, including both plants and animals.

Brain-dead patients

Comatose hospital patients whose heart and lungs are replaced by machines, who lack self-consciousness and are considered neither living nor non-living.

Emergent properties

Properties not present in the molecular constituents of an organelle or unit, but which arise at higher levels of organisation due to interactions among those molecular components.

Common genetic material

The shared genetic material that links all living organisms—past, present, and future—to one another, though to varying degrees.