🌱

Characteristics of Living Things

Aug 26, 2025

Overview

This lecture covers the six main characteristics that define living things: organization, growth and development, reproduction, response to stimuli, maintaining internal conditions, and use of energy.

The Six Characteristics of Life

  • Living things share six traits: organization, growth and development, reproduction, response to stimuli, homeostasis, and use of energy.
  • These characteristics help organisms survive, adapt, and reproduce in their environments.

Organization in Living Things

  • Organization refers to how parts of an organism work together to keep it alive.
  • Unicellular organisms perform all life functions within one cell.
  • Multicellular organisms have specialized cells with specific functions, increasing complexity.

Growth and Development

  • Growth is increasing in size and mass by adding new cells or materials.
  • Development involves changes in structure and function, such as a caterpillar becoming a butterfly.

Reproduction

  • Reproduction creates new life and ensures continuation of species.
  • Sexual reproduction involves two parents and creates genetically diverse offspring.
  • Asexual reproduction involves one parent and produces genetically identical offspring.

Response to Stimuli

  • Organisms respond to internal stimuli (like hunger or thirst) and external stimuli (like light or temperature).
  • These responses help maintain health and adapt to the environment.

Maintaining Internal Conditions (Homeostasis)

  • Homeostasis is maintaining a stable internal environment despite external changes.
  • Examples include regulating body temperature, fluid balance, and blood sugar levels.

Use of Energy

  • Living things need energy for growth, movement, and all life processes.
  • Plants use sunlight through photosynthesis, while animals get energy by eating plants or other animals.
  • Energy flows through food chains, supporting life and ecosystem function.

Key Terms & Definitions

  • Organization — Arrangement of parts within an organism for carrying out life processes.
  • Unicellular — Organism made of one cell.
  • Multicellular — Organism made of many specialized cells.
  • Growth — Increase in size and mass.
  • Development — Structural and functional changes as an organism matures.
  • Reproduction — Process of creating new organisms.
  • Sexual Reproduction — Offspring produced from two parents, increasing genetic diversity.
  • Asexual Reproduction — Offspring produced from one parent, genetically identical to parent.
  • Stimulus — Change in environment causing a response.
  • Homeostasis — Maintaining stable internal conditions.
  • Photosynthesis — Process plants use to make food from sunlight.

Action Items / Next Steps

  • Review the six characteristics of living things and be able to give examples of each.
  • Complete any assigned reading on the characteristics of life for further understanding.