Characteristics of Living Things

 CHARACTERISTICS OF LIVING THINGS — CLEAN & FORMATTED NOTES

Living organisms possess certain features that qualify them as living things. These characteristics set them apart from non-living things. In addition to the common secondary-school acronym MR NIGER D / MR NADCEL, there are more advanced characteristics that you learn at higher levels of biology.

1. Reproduction

Reproduction is the ability of living organisms to produce offspring of their own kind.
It ensures the continuity of life. Without reproduction, species would go extinct.

2. Adaptation

Adaptation means being able to survive in one’s environment.

• The environment influences survival.
• Organisms must adjust to changes in temperature, food availability, predators, etc.
• If an organism cannot adapt, it may die off or become extinct.

Example:
If you leave Nigeria and travel to Canada, you must adapt to the cold environment to survive.

Adaptation occurs in plants, animals, microorganisms, and even humans.

3. Growth and Development

Growth means increase in size and mass.
Development refers to the changes and transformations an organism undergoes during its life cycle.

Example:
A baby giraffe developing into an adult giraffe.

4. Regulation

Regulation refers to the coordination and control of internal body functions.
It ensures the body maintains stable conditions despite external changes.

Examples of regulatory processes:

• Thermoregulation – maintaining body temperature
• Osmoregulation – maintaining salt and water balance
• Glucose regulation – keeping blood sugar levels stable

If glucose is too high, the body must reduce it. If it is too low, the body must raise it.
This constant adjustment is regulation.

5. Homeostasis

This means maintaining a constant internal environment.

The body keeps conditions like:

• Temperature
• pH
• Water level
• Salt concentration

within stable ranges, even when the environment changes.

Homeostasis = stable internal balance.

6. Energy Utilization (Metabolism)

All living organisms must use energy to survive.
Energy is obtained from food (in animals) or photosynthesis (in plants).

Metabolism

Metabolism is the sum total of all chemical reactions occurring in the body.

Metabolism has two major divisions:

A. Anabolism (Building up)

• Reactions that build complex molecules
• Require energy
  Examples:
• Protein synthesis
• Photosynthesis
• Cell growth
• Reproduction processes

B. Catabolism (Breaking down)

• Reactions that break down molecules to release energy
  Examples:
• Respiration
• Digestion
• Breakdown of glucose

All these reactions together = metabolism.

7. Orderliness / Organization

Living organisms are highly ordered and structured.

Biological organization hierarchy:
Cell → Tissue → Organ → Organ System → Organism

This orderliness ensures proper functioning.

8. Response to Stimuli

Living things respond to changes in their environment (stimuli).
These responses help them protect themselves, find food, and survive.

Examples:

• Plants closing when touched
• People withdrawing from a hot object
• Animals running from predators
• Plants bending towards light

Non-living objects like books, chairs, and pencils do not respond.

9. Evolutionary Adaptation

Organisms change over time to suit their environment better.
These changes occur over generations and help species survive.

Examples:

• Animals developing thicker fur in cold regions
• Plants developing deep roots in dry areas
• Birds developing beaks suited for their food

10. Competition

This is also a characteristic of life.

Organisms compete for:

• Space
• Food
• Mates
• Light
• Minerals

Types:

• Intraspecific – among the same species
• Interspecific – among different species

Those that fail to compete may:

• Be overpowered
• Die
• Or go extinct

11. Somatic Cells and Gametic Cells (Clarification)

Somatic Cells

• These are body cells.
• They do not take part in reproduction.
• The word soma means body.

Examples:

• Skin cells
• Blood cells (RBCs and WBCs)
• Liver cells
• Nerve cells
• Bone cells

Gametic Cells (Sex Cells)

• These are reproductive cells
• They participate in reproduction
  Examples:
• Sperm cell (male)
• Egg/Ovum (female)

All other cells aside from sperm and egg = somatic cells.

IS MR NIGER D A LIE?

No.
MR NIGER D (or MR NADCEL) is correct.
However, it only covers the basic secondary-school characteristics.

At the university level, we add:

• Regulation
• Homeostasis
• Adaptation
• Competition
• Orderliness
• Evolutionary adaptation
• Energy processing

So MR NIGER D is not wrong; it is just not complete at a higher level.