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Biology
Cells, genes, evolution, the human body and the ecosystems that sustain life on Earth.
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Biology on LearnViz HighSchoolEdu has 150 interactive topics. Each one has a plain-English explanation, a live animation you can control, key ideas to remember and a quick quiz. Biology underpins medicine, farming, conservation and biotechnology.
Cells
1Characteristics of Living ThingsLiving things share seven features: movement, respiration, sensitivity, growth, reproduction, excretion and nutrition.2Cell TheoryAll living things are made of cells, and every cell comes from another cell.3Prokaryotic and Eukaryotic CellsProkaryotes lack a nucleus; eukaryotes have one.4Animal Cell StructureAnimal cells contain membrane-bound organelles.5Plant Cell StructurePlant cells add a cell wall, chloroplasts and a large vacuole.6Cell MembraneThe membrane is a selective phospholipid bilayer.7The NucleusThe nucleus stores DNA and directs cell activity.8MitochondriaMitochondria release energy from food as ATP.9Ribosomes and Endoplasmic ReticulumRibosomes build proteins; ER transports them.10Golgi Apparatus and LysosomesThe Golgi packages proteins; lysosomes digest waste.11CytoskeletonProtein fibres give cells shape and move organelles.12Microscopes and MagnificationMicroscopes enlarge tiny objects.13Levels of OrganisationCells form tissues, organs, organ systems and organisms.14Stem Cells and SpecialisationStem cells can become many cell types.Cell Processes
15DiffusionParticles spread from high to low concentration.16OsmosisWater moves through a membrane from dilute to concentrated solutions.17Active TransportCells use ATP to move substances against a gradient.18Endocytosis and ExocytosisCells engulf or release large particles using vesicles.19EnzymesEnzymes are protein catalysts that speed up reactions.20Enzyme Activity FactorsTemperature, pH and concentration affect enzyme rate.21ATP: The Energy CurrencyATP stores and gives energy in small packets.22PhotosynthesisPlants convert light, water and CO₂ into glucose and oxygen.23Light-Dependent ReactionsLight energy splits water and builds ATP.24The Calvin CycleCO₂ is fixed into sugar using ATP and NADPH.25Cellular RespirationCells break down glucose to release ATP.26Anaerobic Respiration and FermentationWithout oxygen, cells ferment glucose for quick ATP.27The Cell CycleCells grow, copy DNA and divide in a regulated cycle.28MitosisMitosis makes two identical daughter cells.Genetics
29DNA StructureDNA is a double helix of nucleotides held by base pairs.30DNA ReplicationDNA copies itself semi-conservatively.31Genes and ChromosomesGenes sit on chromosomes and code for proteins.32TranscriptionDNA is copied into mRNA in the nucleus.33Translation and the Genetic CodeRibosomes read mRNA codons to build proteins.34MutationsMutations are changes to the DNA sequence.35MeiosisMeiosis makes four genetically different gametes with half the chromosomes.36Mendel's LawsMendel's pea plants showed how traits are inherited.37Punnett SquaresPunnett squares predict offspring genotypes.38Dominant and Recessive AllelesDominant alleles show up when present; recessive only when homozygous.39Incomplete Dominance and CodominanceSome alleles blend or both show.40Sex-Linked TraitsGenes on the X chromosome affect males and females differently.41PedigreesFamily trees trace how traits pass down generations.42Human Genetic DisordersSome disorders are caused by gene or chromosome changes.43Gene Expression and RegulationCells switch genes on and off depending on needs.44Genetic EngineeringScientists move genes between organisms.45CRISPR and Gene EditingCRISPR cuts DNA at chosen sites to edit genes.46DNA FingerprintingDNA profiles identify individuals.Evolution
47Natural SelectionIndividuals with helpful traits survive and reproduce more.48Evidence for EvolutionFossils, anatomy, DNA and embryos support common ancestry.49AdaptationAdaptations help organisms survive in their environments.50SpeciationNew species arise when populations can no longer interbreed.51ExtinctionSpecies disappear when they cannot adapt.52Fossils and Geological TimeFossils are preserved remains that reveal Earth's history.53Human EvolutionHumans share a common ancestor with apes.54Artificial SelectionHumans breed organisms for traits.55Antibiotic ResistanceBacteria evolve resistance when antibiotics are overused.56Classification and TaxonomyOrganisms are grouped from domain to species.57Phylogenetic TreesTrees show evolutionary relationships.58Origin of LifeLife began on Earth about 3.5 billion years ago.The Human Body
59Digestive SystemDigestion breaks food into small molecules that can be absorbed.60Enzymes in DigestionAmylase, protease and lipase digest different foods.61Nutrition and DietA balanced diet supplies carbohydrates, proteins, fats, vitamins, minerals, fibre and water.62The Circulatory SystemThe heart pumps blood around the body.63The HeartThe heart has four chambers and valves to keep blood flowing one way.64BloodBlood carries oxygen, defends against germs and clots wounds.65Blood Groups and TransfusionABO and Rh groups decide compatible blood.66Respiratory SystemLungs exchange oxygen and carbon dioxide.67Breathing MechanicsMuscles change lung volume to move air.68The Nervous SystemNerves carry electrical signals between the brain and body.69Neurons and Nerve ImpulsesNeurons fire action potentials along axons.70The BrainThe brain controls thought, movement and body functions.71Reflex ActionsReflexes are fast automatic responses.72The Eye and VisionThe eye focuses light on the retina.73The Ear and HearingThe ear turns sound waves into nerve signals.74Endocrine System and HormonesHormones are chemical messengers in the blood.75HomeostasisThe body keeps internal conditions steady.76Blood Sugar ControlInsulin lowers blood glucose; glucagon raises it.77The Excretory SystemKidneys filter blood to make urine.78Skin and Temperature ControlSkin protects and helps regulate temperature.79The Skeletal SystemBones support, protect and allow movement.80Muscles and MovementMuscles pull on bones in antagonistic pairs.81Immune SystemThe immune system defends against pathogens.82VaccinationVaccines train the immune system without causing disease.83Reproductive System and DevelopmentGametes fuse in fertilisation and the embryo develops.Plants
84Plant StructureRoots, stems, leaves and flowers perform specific jobs.85Leaf Structure and Gas ExchangeLeaves are built for photosynthesis.86Transpiration and Water TransportWater moves up through xylem pulled by evaporation.87Plant Hormones and TropismsHormones like auxin control plant growth.88Flowers and PollinationFlowers are reproductive organs of flowering plants.89Seed GerminationSeeds sprout when they have water, warmth and oxygen.90Seed DispersalPlants spread seeds by wind, water or animals.91Plant Nutrition and MineralsPlants need nitrogen, phosphorus and potassium.92Factors Affecting PhotosynthesisLight, CO₂ and temperature limit photosynthesis.93Asexual Reproduction in PlantsPlants can clone themselves.94Plant AdaptationsCacti, aquatic and rainforest plants have special adaptations.95Photosynthesis ExperimentsStarch tests and oxygen counts show photosynthesis.Ecology
96Ecosystems and HabitatsAn ecosystem is a community and its environment.97Food Chains and WebsFood chains show the flow of energy from producers up.98Energy PyramidsOnly about 10% of energy passes to the next trophic level.99The Carbon CycleCarbon moves between air, living things and Earth.100The Nitrogen CycleBacteria convert nitrogen into forms plants can use.101The Water CycleWater evaporates, condenses, precipitates and flows back.102Population DynamicsPopulations change with birth, death, immigration and emigration.103Predator–Prey RelationshipsPredator and prey populations rise and fall in linked cycles.104SymbiosisSpecies living closely together can help or harm each other.105Competition and NichesOrganisms compete for limited resources.106BiomesBiomes are large regions with typical climate and life.107SuccessionCommunities change over time after a disturbance.108Human Impact on EcosystemsHumans change habitats through farming, building and pollution.109Climate ChangeRising greenhouse gases are warming the planet.110Conservation and BiodiversityProtecting species keeps ecosystems healthy.111Sampling EcosystemsQuadrats and transects estimate populations.Diversity of Life
112BacteriaBacteria are single-celled prokaryotes found everywhere.113VirusesViruses are non-living particles that hijack cells.114FungiFungi decompose matter and form mushrooms and yeast.115ProtistsProtists are diverse mostly single-celled eukaryotes.116Plants OverviewPlants are multicellular producers.117InvertebratesAnimals without backbones make up most species.118Fish and AmphibiansFish breathe with gills; amphibians live on land and water.119Reptiles and BirdsReptiles have scales; birds have feathers.120MammalsMammals have hair and feed milk to their young.121Animal BehaviourInstincts and learning guide how animals act.122Microorganisms and DiseasePathogens cause infectious diseases.123Biotechnology in FoodMicrobes make bread, yoghurt, cheese and beer.124Sexual vs Asexual ReproductionSexual reproduction mixes genes; asexual makes clones.125Life CyclesOrganisms pass through stages of growth and reproduction.Health and Biotechnology
126Infectious DiseaseGerms spread between people and cause illness.127Non-communicable DiseaseHeart disease, cancer and diabetes aren't infectious.128CancerCancer is uncontrolled cell division.129Drugs and AlcoholDrugs change body chemistry; some are addictive.130Smoking and Lung HealthTobacco damages lungs and heart.131Exercise and FitnessExercise strengthens the heart, muscles and mood.132Sleep and RestSleep restores the body and brain.133Mental HealthMental health is part of overall health.134Medical TechnologyImaging and devices help diagnose and treat.135Biotechnology and EthicsNew biology raises ethical questions.136Genetically Modified CropsGM crops carry added genes for traits like pest resistance.137CloningCloning makes genetically identical copies.138Biomes and Biosphere OverviewThe biosphere is all life on Earth.139Lab Techniques in BiologyCareful method gives reliable results.140Data Analysis in BiologyGraphs and statistics reveal patterns.More Ecology and Body Systems
141Decomposers and Nutrient RecyclingBacteria and fungi break down dead matter and return nutrients to the soil.142BiomagnificationToxins build up as they move up a food chain.143Water Pollution and EutrophicationFertiliser runoff causes algal blooms that starve water of oxygen.144Invasive SpeciesNon-native species can outcompete and harm local wildlife.145Coral Reefs and Marine EcosystemsReefs host a quarter of marine species but are threatened by warming and acidification.146Wetlands and RainforestsWetlands filter water and rainforests store carbon and house biodiversity.147The Lymphatic SystemLymph vessels return fluid to the blood and house immune cells.148Sensory ReceptorsReceptors convert stimuli into nerve impulses.149The Menstrual Cycle and HormonesHormones control the monthly cycle and prepare for pregnancy.150Pregnancy and BirthA fertilised egg develops over about nine months supported by the placenta.No topics match.
Frequently asked questions
What topics are in Biology?
There are 150 topics, including Characteristics of Living Things, Cell Theory, Prokaryotic and Eukaryotic Cells, Animal Cell Structure, Plant Cell Structure, and more.
Who is Biology on LearnViz for?
High school students who want to understand biology visually, teachers who want a quick classroom demonstration, and parents helping with homework.
Do I have to study the topics in order?
No. The list follows the order of the course, but every topic has its own page, so you can start wherever you need help.
How do I track my progress?
Open a topic and press “Mark as learned”. This subject page then shows how many topics you have completed. Progress is saved in your own browser.
How is Biology used in real life?
Biology underpins medicine, farming, conservation and biotechnology.