Organisms

Organisms are living things that have the characteristics of life, including the ability to grow, reproduce, respond to their environment, and maintain homeostasis. They can be single-celled, like bacteria, or multicellular, like plants and animals. Organisms are classified into different kingdoms based on their characteristics and evolutionary relationships.

Characteristics of Organisms

• Growth: Organisms increase in size through cell division and the synthesis of new materials.
• Reproduction: Organisms produce offspring either sexually or asexually, ensuring the continuation of their species.
• Response to Environment: Organisms can detect and respond to changes in their environment to maintain their internal conditions.
• Homeostasis: Organisms have mechanisms to regulate their internal environment and maintain a stable internal balance.

Classification of Organisms

Organisms are classified into different kingdoms based on their characteristics:

• Animalia: Multicellular organisms that are heterotrophic (obtain food by consuming other organisms) and have the ability to move.
• Plantae: Multicellular organisms that are autotrophic (produce their own food through photosynthesis) and have cell walls.
• Fungi: Multicellular or unicellular organisms that are heterotrophic and have cell walls made of chitin.
• Protista: Mostly unicellular organisms that do not fit into the other kingdoms and have diverse characteristics.
• Monera: Single-celled organisms, including bacteria, that lack a distinct nucleus and other membrane-bound organelles.

Study Guide

1. What are the characteristics of organisms?
2. Give an example of a multicellular organism from each kingdom.
3. How do organisms maintain homeostasis?
4. Explain the difference between sexual and asexual reproduction in organisms.
5. How are organisms classified into different kingdoms?