IGCSE Biology 0610 - 1.3 Features of Organisms

Objective: State the main features used to place animals and plants into the appropriate kingdoms.

Introduction

Organisms are classified into different groups called kingdoms based on shared characteristics. Understanding these features is crucial for placing organisms correctly within the biological classification system.

Animal Kingdom Features

Animals belong to the Kingdom Animalia. Key features used for classification include:

• Multicellular: Animals are made up of many cells.
• Heterotrophic: Animals cannot make their own food and must obtain nutrients by consuming other organisms.
• Lack Cell Walls: Animal cells do not have rigid cell walls.
• Motile: Most animals are capable of movement at some point in their life cycle.
• Complex Organisation: Animal bodies are typically organised into tissues, organs, and organ systems.
• Reproduction: Animals typically reproduce sexually.

Plant Kingdom Features

Plants belong to the Kingdom Plantae. Key features used for classification include:

• Multicellular: Plants are also made up of many cells.
• Autotrophic: Plants can make their own food through photosynthesis using sunlight, carbon dioxide, and water.
• Possess Cell Walls: Plant cells have rigid cell walls made of cellulose.
• Immobile: Plants are generally fixed in one place.
• Complex Organisation: Plant bodies are organised into tissues and organs (e.g., roots, stems, leaves).
• Reproduction: Plants can reproduce both sexually and asexually.

Table Summarising Key Differences

Feature	Animals	Plants
Cell Type	Animal cells	Plant cells
Cell Wall	Absent	Present (cellulose)
Nutrition	Heterotrophic	Autotrophic
Mobility	Generally Motile	Generally Immobile
Organisation	Complex (tissues, organs, systems)	Complex (tissues, organs)
Reproduction	Typically Sexual	Sexual and Asexual

Conclusion

By observing and comparing these key features, biologists can accurately classify organisms into their respective kingdoms. These features reflect the evolutionary history and adaptations of different groups of life.