AP Biology Introduction

BIG IDEAS OF AP BIOLOGY

AP Biology is built on four central themes, called Big Ideas:

Big Idea 1 — Evolution

  • Evolution explains diversity and unity among species.

  • It is the driving process behind all adaptations and changes in populations over time.

Big Idea 2 — Energetics

  • Biological systems use energy and molecules to grow, reproduce, and maintain homeostasis.

  • Includes metabolism, photosynthesis, respiration, and transport.

Big Idea 3 — Information Storage & Transmission

  • How living systems store, retrieve, transmit, and respond to internal and external information.

  • Appears in genetics, DNA structure, gene expression, and cell communication.

Big Idea 4 — Systems Interactions

  • Organisms and ecosystems consist of interacting components that create complex behaviors.

  • Includes feedback loops, interactions within cells, organisms, populations, and ecosystems.

EIGHT AP BIOLOGY UNITS & WEIGHTING

(Important for knowing what is most tested)

Unit

Topic

% of Exam

1

Chemistry of Life

8–11%

2

Cell Structure & Function

10–13%

3

Cellular Energetics

12–16%

4

Cell Communication & Cell Cycle

10–15%

5

Heredity

8–11%

6

Gene Expression & Regulation

12–16%

7

Natural Selection

13–20%

8

Ecology

10–15%

AP EXAM FORMAT

SECTION I — Multiple Choice (MCQ)

  • 60 questions

  • 90 minutes

  • 50% of exam score

  • Many questions use graphs, data tables, diagrams

  • 4 answer choices each

  • You must interpret data and apply concepts

Skills needed:

  • Reading graphs

  • Identifying trends

  • Evaluating experimental data

  • Using the formula sheet (chi-square, water potential, rate formulas)

SECTION II — Free Response (FRQ)

6 total questions

  • 2 Long FRQs (9 points each)

  • 4 Short FRQs (4 points each)

  • 90 minutes total

  • 50% of exam score

Long FRQs

  • Often involve experiments

  • Require graphs, data interpretation, and explanation

  • Question 1 usually includes a graph/table

  • Question 2 usually requires constructing a graph WITH error bars (95% CI)

Short FRQs

Each includes multiple parts:

  • Experimental design

  • Conceptual analysis

  • Model/diagram analysis

  • Data analysis

IMPORTANT ACTION VERBS FOR FRQs

You MUST follow these exactly or you lose points:

  • Identify → name something

  • Describe → give characteristics, details

  • Explain → give cause-and-effect (“because… therefore…”)

  • Predict → state what will happen

  • Justify → provide evidence

  • Make a claim → a statement that will be backed by data

  • Support a claim → use data/evidence

  • Calculate → show work + units!

  • Construct → draw a graph or diagram

  • Evaluate → check accuracy or validity

HOW THE AP BIOLOGY EXAM IS SCORED

Score

Meaning

5

Extremely well qualified

4

Well qualified

3

Qualified

2

Possibly qualified

1

No recommendation

Both sections (MCQ & FRQ) are worth 50% each → you must practice FRQs heavily.

KEY TAKEAWAYS FROM THE INTRODUCTION

  1. AP Biology is about application, not memorization.

  2. You must know how to read graphs, design experiments, and analyze data.

  3. Every major concept connects to one of the 4 Big Ideas.

  4. Statistics (especially chi-square and 95% CI) are essential.

  5. FRQs must be written in complete sentences, be clear, and avoid contradictory statements.