📖 Lesson 1: Characteristics & Classification of Living and Non-living Things

👩🏽‍🏫 Introduction

Hello, curious scientist! 👋🏽

Look around you. You’ll notice things like plants, pets, books, and maybe even a computer or phone you’re reading this lesson on. Did you ever stop to wonder: what makes something alive or not alive? Understanding these differences helps us make sense of the diverse world around us. In this lesson, we will explore the distinct characteristics that define living and non-living things, and learn how scientists categorize them to better understand nature.

📘 Core Concepts

🔹 What are Living Things?

Living things, also called organisms, have certain common features known as life processes:

• Movement: Changing position or location.

• Nutrition: Taking in and using food.

• Growth: Increasing in size and complexity.

• Respiration: Releasing energy from food.

• Excretion: Getting rid of waste materials.

• Reproduction: Creating new life.

• Irritability (Sensitivity): Responding to environmental changes.

These processes help us differentiate living organisms from non-living objects.

🔹 Non-Living Things

Non-living things do not carry out life processes. Examples include rocks, air, water, and man-made objects like plastic chairs or cars.

👩🏽‍🔬 Real-Life Examples

🍀 Living vs. Non-Living:

A fish swims and grows (living), but a phone doesn’t move by itself or grow (non-living).

🔬 Classification of Living Things

Scientists classify living things to study and understand them better. Classification helps us organize millions of species on Earth. The main levels (from broadest to most specific) are:

• Kingdom → Phylum → Class → Order → Family → Genus → Species

Example of Human Classification:

(Scientific name = Homo sapiens)

🔹 Contribution to Classification

• Aristotle: Grouped animals based on habitat and physical traits.

• Linnaeus: Developed the binomial naming system (genus and species).

• Mendeleev: Classified elements based on atomic weight and properties (for non-living chemical classification).

🧩 Sample Problem Walkthrough

🧠 Problem:

You find an unknown organism. It grows, responds to sunlight, and produces seeds. How can you tell if it’s living, and classify it broadly?

✅ Step-by-Step Solution:

1. Check life processes:

   • Growth ✔️

   • Response (irritability) to sunlight ✔️

   • Produces seeds (reproduction) ✔️

2. Conclusion: It fulfills key characteristics of living organisms.

3. Broad classification:

   • Kingdom: Plant Kingdom (Plantae), because it produces seeds and responds to sunlight.

✍🏽 Practice Exercises

Exercise 1: Fill-in-the-Blanks

Complete the sentences:

1. Living organisms must be able to carry out ____________ like movement, reproduction, and growth.

2. Non-living things cannot perform life __________.

Answers:

1. life processes

2. processes

Exercise 2: True or False?

1. A tree is non-living because it does not move.

2. Water is classified as living because it is essential to life.

3. Aristotle was one of the first scientists to classify organisms.

Answers:

1. False (trees grow, respire, and reproduce)

2. False (water does not carry out life processes)

3. True (Aristotle classified organisms by habitat and appearance)

Exercise 3: Short Answer

Explain why a car is classified as non-living, despite it being able to move.

Sample Answer: A car is non-living because although it moves, it does not independently carry out other life processes such as growth, reproduction, nutrition, respiration, or sensitivity to environmental changes.

🌀 Recap

Today, we’ve learned that:

• Living things perform life processes: movement, nutrition, growth, respiration, excretion, reproduction, and irritability.

• Non-living things lack these life processes.

• Classification helps scientists group living things systematically, making them easier to study and understand.

💭 Reflection Prompt

Take a moment to look around your room or your environment right now. Write down five things you see. Identify clearly if they are living or non-living, and give at least one reason for each of your choices.

Reflect in your science journal, or discuss your findings with a friend or family member!