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IB Diploma · Biology · Chapter 6
Ch 6 A3.1 Diversity of organisms: complete notes
Neat, exam-ready notebook-style notes for Ch 6 A3.1 Diversity of organisms, following the IB Diploma syllabus, SL and HL. This chapter is part of the complete Biology Notes for IB Diploma Students (SL and HL): All 40 Topics.
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Free preview: Ch 6 A3.1 Diversity of organisms notes
A quick look at the chapter from our IB Diploma Biology notes. The full chapter notes have the detailed explanations, diagrams and practice questions with answers.
Topics in this chapter
- What you must be able to do
- Variation, species and naming
- Species, naming and the biological species concept
- Populations versus species; chromosomes
- Evidence for the fusion that formed human chromosome 2
- Genomes: unity and diversity
- Genome sizes and sequencing
- A3.1.10 Comparing genome sizes
- A3.1.11 Whole genome sequencing (WGS)
- Limits of the species concept, keys and barcodes
“I can” checklist: what you must be able to do
- I can explain variation and name organisms using the binomial system.
- I can state the biological species concept and its challenges.
- I can interpret karyograms and evaluate evidence for the fusion that formed human chromosome 2.
- I can describe genome diversity within and between species and the uses of whole genome sequencing.
- HL: I can explain limits of the species concept, make a dichotomous key and describe eDNA barcoding.
What is inside the full chapter notes
- Concept notes with 8 worked examples
- Karyogram, fusion, genome-size and key diagrams
- Common mistakes; investigation (IA) ideas
- 15 Paper 1A-style MCQs, explained (11 SL, 4 HL)
- 3 Paper 2-style structured questions with mark schemes (one data-based)
- Quick-reference sheet and "I can" checklist
What you get in the pack
- All 40 topics of IB Diploma Biology for students taking Standard Level or Higher Level (first assessment 2025): water, nucleic acids, the origin of cells, cell structure, viruses, diversity and classification, evolution and speciation, conservation, carbohydrates, lipids and proteins, membranes, organelles, cell specialization, gas exchange, transport, muscle and motility, adaptation and niches, enzymes and metabolism, cell respiration, photosynthesis, chemical and neural signalling, integration of body systems, defence against disease, populations and communities, transfers of energy and matter, DNA replication, protein synthesis, mutation and gene editing, cell division, gene expression, water potential, reproduction, inheritance, homeostasis, natural selection, stability and change, climate change
- Every syllabus statement covered in order, each marked SL or HL, with clear notes, tables and diagrams drawn for these notes
- Worked examples in every topic: calculations and model answers that show how to earn the marks
- Original Paper 1A-style multiple-choice questions with explained answers, plus Paper 2-style structured and data-based questions with full mark schemes (no past-paper reprints)
- Common mistakes and investigation (internal assessment) ideas for every topic
- Quick-reference sheet and an "I can" checklist at the end of every topic
- Colour PDF and a black and white copy of every chapter for printing
- Independent notes for IB Diploma students; not endorsed by or affiliated with the International Baccalaureate Organization (IBO)
All chapters in this pack
- Ch 1 A1.1 Water
- Ch 2 A1.2 Nucleic acids
- Ch 3 A2.1 Origins of cells
- Ch 4 A2.2 Cell structure
- Ch 5 A2.3 Viruses
- Ch 6 A3.1 Diversity of organisms
- Ch 7 A3.2 Classification and cladistics
- Ch 8 A4.1 Evolution and speciation
- Ch 9 A4.2 Conservation of biodiversity
- Ch 10 B1.1 Carbohydrates and lipids
- Ch 11 B1.2 Proteins
- Ch 12 B2.1 Membranes and membrane transport
- Ch 13 B2.2 Organelles and compartmentalization
- Ch 14 B2.3 Cell specialization
- Ch 15 B3.1 Gas exchange
- Ch 16 B3.2 Transport
- Ch 17 B3.3 Muscle and motility
- Ch 18 B4.1 Adaptation to environment
- Ch 19 B4.2 Ecological niches
- Ch 20 C1.1 Enzymes and metabolism
- Ch 21 C1.2 Cell respiration
- Ch 22 C1.3 Photosynthesis
- Ch 23 C2.1 Chemical signalling
- Ch 24 C2.2 Neural signalling
- Ch 25 C3.1 Integration of body systems
- Ch 26 C3.2 Defence against disease
- Ch 27 C4.1 Populations and communities
- Ch 28 C4.2 Transfers of energy and matter
- Ch 29 D1.1 DNA replication
- Ch 30 D1.2 Protein synthesis
- Ch 31 D1.3 Mutation and gene editing
- Ch 32 D2.1 Cell and nuclear division
- Ch 33 D2.2 Gene expression
- Ch 34 D2.3 Water potential
- Ch 35 D3.1 Reproduction
- Ch 36 D3.2 Inheritance
- Ch 37 D3.3 Homeostasis
- Ch 38 D4.1 Natural selection
- Ch 39 D4.2 Stability and change
- Ch 40 D4.3 Climate change