• Third Preparatory, Science, Term 1 (English edition).
• Two lessons (1) The Fossil Record and (2) Geologic Time.
• In the first lesson you learn what fossils are, how they form, which kinds exist, and what they tell us about the history of life: when organisms appeared, why some died out, and how ancient and modern animals are related.
• In the second lesson you learn how Earth’s very long history is divided into time units (the geologic time scale) and how scientists work out the age of rocks and fossils, both in relative terms (older/younger) and in actual years (using radioactivity).

🌳 Concept tree

Unit 4 — Dating Planet Earth

• ├── Lesson 1 The Fossil Record
• │ ├── 1.1 How do we know that dinosaurs lived millions of years ago?
• │ ├── 1.2 What is a fossil and how does it form?

│ ├── 1.3 Types of fossils

│ ├── 1.4 The fossil record

│ ├── 1.5 The importance of the fossil record

• │ ├── 1.6 Causes of the diversity of life forms through time

│ ├── 1.7 Comparative anatomy

│ └── 1.8 Summary of Lesson 1

1. Geologic Time
2. │ ├── 2.1 How old is Earth?

│ ├── 2.2 The geologic time scale

• │ ├── 2.3 Reading Earth's history from rocks and fossils

│ ├── 2.4 Determining the age of rocks

│ ├── 2.5 Relative age

│ ├── 2.6 Absolute age

│ ├── 2.7 Comparing relative and absolute dating

• │ ├── 2.8 Exploiting resources and extinction (issue)

│ └── 2.9 Summary of Lesson 2

├── How a fossil forms, step by step

├── How to read a rock column (relative dating)

├── Choosing a dating method

├── Half-life calculation recipe

└── Common mistakes