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Biology Student Questions | RevisionDojo

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Biology

A4.1 Evolution and speciation

How Is Darwinian Evolution Different from Lamarckism?

Learn how Darwinian evolution differs from Lamarckism through heritable variation, natural selection and population-level change in IB Biology.

A4.1 Evolution and speciation

What Evidence Supports Evolution?

Learn how molecular sequences, selective breeding, homologous structures and analogous structures provide evidence for evolution in IB Biology.

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A4.1 Evolution and speciation

What Are Homologous Structures? (Pentadactyl Limb)

Learn how homologous structures, especially the pentadactyl limb, provide evidence of common ancestry and evolution in IB Biology at SL and HL.

A4.1 Evolution and speciation

What's the Difference Between Homologous and Analogous Structures?

Learn how homologous and analogous structures differ in ancestry, function and evolution, with IB Biology examples and practical exam guidance.

A4.1 Evolution and speciation

What Causes Convergent Evolution?

Learn how similar selection pressures cause convergent evolution and analogous structures in unrelated lineages, with IB Biology exam guidance for SL and HL.

A4.1 Evolution and speciation

What Is the Difference Between Allopatric and Sympatric Speciation? (AHL)

Learn how geographical separation distinguishes allopatric from sympatric speciation, including reproductive isolation and IB exam technique.

A4.1 Evolution and speciation

How Does Speciation Happen?

Learn how reproductive isolation, genetic variation and differential selection cause speciation, with precise IB Biology terminology and exam advice.

A4.1 Evolution and speciation

What Is Reproductive Isolation?

Learn how reproductive isolation prevents gene flow, allows populations to diverge, and leads to speciation, with key IB Biology exam examples.

A4.1 Evolution and speciation

What Is Adaptive Radiation? (AHL)

Learn how adaptive radiation produces closely related species in vacant ecological niches through natural selection, isolation, and speciation in IB Biology.

A4.1 Evolution and speciation

Why Are Mules Sterile?

Learn why mules are usually sterile, how mismatched horse and donkey chromosomes disrupt meiosis, and how hybrid sterility maintains species barriers.

A4.1 Evolution and speciation

How Can New Plant Species Form Instantly Through Polyploidy? (AHL)

Explain how chromosome doubling causes immediate reproductive isolation and restores hybrid fertility, forming new plant species in IB Biology AHL exams.

A4.2 Conservation of biodiversity

Are There More Species Alive Today Than in the Past?

Learn why fossil evidence suggests more species are alive today than ever before, despite the current biodiversity crisis and accelerating extinction rates.

A4.1 Evolution and speciation

What Is the Definition of Evolution in Biology?

Learn the IB Biology definition of evolution, why populations-not individuals-evolve, and how heritable variation causes change over generations.

A4.1 Evolution and speciation

Why Did Bonobos and Chimpanzees Become Separate Species? (Congo River)

Learn how the Congo River caused geographic and reproductive isolation, allowing differential selection to separate bonobos and chimpanzees in IB Biology.

A4.2 Conservation of biodiversity

What Is Biodiversity?

Learn the IB Biology definition of biodiversity, its genetic, species and ecosystem levels, why each matters, and how to answer exam questions precisely.

A4.2 Conservation of biodiversity

What Caused North Island Giant Moa Extinction?

Learn how human hunting, egg collection and habitat destruction caused North Island giant moa extinction, with evidence and IB Biology exam guidance.

A4.2 Conservation of biodiversity

Why Did the Caribbean Monk Seal Go Extinct?

Learn how hunting, overfishing and slow reproduction caused Caribbean monk seal extinction, with precise IB Biology terminology and exam guidance.

A4.2 Conservation of biodiversity

What Is a Seed Bank?

Learn how seed banks conserve plant genetic diversity through ex situ conservation, why stored seeds matter, and their limitations in IB Biology exams.

A4.2 Conservation of biodiversity

Why Is Deforestation Destroying Mixed Dipterocarp Forests in Southeast Asia?

Learn how logging, agricultural conversion, roads and fragmentation drive ecosystem loss in Southeast Asia’s mixed dipterocarp forests.

A4.2 Conservation of biodiversity

What Is the Difference Between In Situ and Ex Situ Conservation?

Learn how in situ conservation protects species in natural habitats, while ex situ conservation protects them elsewhere, with IB Biology examples.

B1.1 Carbohydrates and lipids

Why Can Carbon Form So Many Different Compounds?

Learn how carbon’s four covalent bonds, catenation, and bonding with other elements create diverse compounds for IB Biology exams at SL and HL.

A4.2 Conservation of biodiversity

What Is the EDGE of Existence Program?

Learn how the EDGE of Existence program prioritizes evolutionarily distinct, globally endangered species and how to explain it clearly in IB Biology.

B1.1 Carbohydrates and lipids

What's the Difference Between Monosaccharides, Disaccharides, and Polysaccharides?

Learn how monosaccharides, disaccharides, and polysaccharides differ in structure, bonding, formation, digestion, and function in IB Biology.

B1.1 Carbohydrates and lipids

What Is a Condensation Reaction?

Learn how condensation reactions join biological molecules, form covalent bonds, and release water in carbohydrates and lipids for IB Biology exams.

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