Biology Dictionary
Our Biology Dictionary is the largest dictionary of Biology terms and definitions in the world. Learn various topics, concepts, and principles in Biology by searching the definitions and essential details of 70,000+ Biology terms.
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A
- A Band
- Abdomen
- Abiogenesis
- Abiotic
- Abiotic factor
- Abscission
- Absolute fitness
- Absorption
- Accessory pigment
- Acellular
- Acid
- Acidophile
- Acoelomate
- Action potential
- Active transport
- Adaptation
- Adaptive evolution
- Adaptive radiation
- Adaptive trait
- Adaptive zone
- Adenine
- Adenosine diphosphate
- Adenosine triphosphate
- Adhesion
- Adventitious root
- Aerial root
- Aerobic
- Aerobic bacteria
- Aerotolerant
- Afferent Nerve
- Agar
- Agglutination
- Agonist muscle
- Agriculture
- Akinetes
- Algae
- Algal bloom
- Alkaliphile
- Allele
- Alloimmunity
- Allopatric speciation
- Allopolyploidy
- Amino acid
- Amino acid sequence
- Ammonification
- Amnion
- Amniote
- Amoeboid movement
- Amoebozoa
- Amphimixis
- Amylase
- Amyloplast
- Anabolic pathway
- Anabolism
- Anaerobic
- Anaerobic process
- Anaerobic respiration
- Analogous
- Analogous structures
- Analogy
- Anaphase
- Anaphase I
- Anaphase II
- Anastomosis
- Anatomy
- Anemia
- Angiosperm
- Animal
- Animal Kingdom
- Animal testing
- Antagonism
- Antagonistic Muscle
- Anther
- Antibiotic
- Antibody
- Anticodon
- Antigen
- Apical bud
- Apical Dominance
- Apical meristem
- Apicomplexa
- Apoenzyme
- Apomixis
- Apomorphy
- Apoptosis
- Apparent competition
- Appendage
- Appositional growth
- Archaea
- Archaebacteria
- Archaeplastida
- Arthropod
- Asexual reproduction
- Assay
- Assimilation
- Aster
- Atom
- ATP synthase
- Atria
- Atrium
- Atrophy
- Autecology
- Autocrine signaling
- Autophagy
- Autopolyploidy
- Autosome
- Autotroph
- Aves
- Axon
- Axon hillock
B
- B lymphocyte
- Backbone
- Bacteria
- Bacteriophage
- Balanced diet
- Barophile
- Basal metabolic rate
- Base pair
- Base pair substitution
- Base pairing
- Benign
- Betaproteobacteria
- Bicoid
- Bidirectional replication
- Bilateral symmetry
- Bile
- Binary fission
- Binomial nomenclature
- BIOACCUMULATION
- Biochemistry
- Biodiversity
- Biogenesis
- Biogeography
- Biological system
- Biology
- Biomass
- Biome
- Biomolecule
- Biosphere
- Biosynthesis
- Biota
- Biotic
- Biotic factor
- Biotic potential
- Bipennate muscle
- Birth Rate
- Bivalent
- Blade
- Blastula
- Blastulation
- Blood
- Blood vessel
- Body cavity
- Bone matrix
- Bone tissue
- Botany
- Branches of biology
- Branching tree
- Buccal cavity
- Budding
- Buffer
C
- C3 plant
- C4 plant
- Caecum
- Calvin cycle
- CAM
- CAM plant
- Canaliculus
- Cancer
- Capillary action
- Capping
- Capsid
- Capsule
- Carbohydrate
- Carbon
- Carbon cycle
- Carbon dioxide
- Carbon fixation
- Cardiovascular system
- Carnivore
- Carotenoid
- Carrier
- Carrier protein
- Carrying capacity
- Cartilage
- Cartilage cell
- Cartilaginous joint
- Catabolic pathway
- Catabolism
- Cell
- Cell adhesion
- Cell culture
- Cell cycle
- Cell death
- Cell determination
- Cell differentiation
- Cell division
- Cell growth
- Cell junction
- Cell line
- Cell locomotion
- Cell matrix
- Cell membrane
- Cell membrane permeability
- Cell morphology
- Cell plate
- Cell recognition
- Cell sap
- Cell theory
- Cell wall
- Cellular
- Cellular respiration
- Cellulose
- Centromere
- Centrosome
- Chamber
- Channel
- Chemiosmosis
- Chemiosmotic theory
- Chemoautotroph
- Chemoheterotroph
- Chemolithotroph
- Chemoreceptor
- Chemosynthesis
- Chemotaxis
- Chemotroph
- Chemotropism
- Chiasma
- Chimera
- Chitin
- Chlorophyll
- Chlorophyll a
- Chlorophyta
- Chloroplast
- Cholesterol
- Chondrichthyes
- Chondroblast
- Chordata
- Chromatid
- Chromatids
- Chromatin
- Chromoplast
- Chromosomal crossover
- Chromosomal mutation
- Chromosome
- Cilia
- Ciliate
- Cilium
- Circular muscles
- Circulation
- Circulatory system
- Cisterna
- Citric Acid Cycle
- Class
- Classification
- Cleavage
- Clone
- Cloning
- Closed circulatory system
- Cnidocyte
- CNS
- Coated pits
- Codominance
- Codominant trait
- Codon
- Coelom
- Coenzyme
- Cofactor
- Cohesion Tension Theory
- Colcemid
- Collagen fiber
- Colony
- Commensalism
- Compact bone
- Competition
- Complementary base pairing
- Complementary strands
- Complete dominance
- Compound
- Concentration
- Concentration gradient
- Condyloid joint
- Cone
- Conjugation
- Connective tissue
- Conservation
- Conserved sequence
- Conspecific
- Consumer
- Consumption
- Contamination
- Contractile vacuole
- Control
- Convergence
- Convergent evolution
- Copulation
- Cork
- Cornification
- Cotransport
- Cotyledon
- Covalent bond
- Crenation
- Cristae
- Crop
- Cross
- Crossbreeding
- Cuticle
- Cyanobacteria
- Cyclic adenosine monophosphate
- Cyclins
- Cytokinesis
- Cytolysis
- Cytoplasm
- Cytoplasmic matrix
- Cytosine
- Cytosol
D
- Dark reaction
- Dark respiration
- Darwinian fitness
- De novo
- Decatenation
- Decomposer
- Decomposition
- Dedifferentiation
- Definitive host
- Degradation
- Deletion
- Deletion mutation
- Deltaproteobacteria
- Denitrification
- Dense connective tissue
- Dense irregular connective tissue
- Dense regular connective tissue
- Density
- Density dependent limiting factor
- Deoxyribonucleic acid
- Deoxyribose
- Depolarization
- Desert
- Desiccation
- Detritivore
- Development
- Diarthrodial joint
- Diatom
- Dichotomous
- Dichotomous key
- Dicot
- Differentiation
- Diffusion
- Diffusion equilibrium
- Digestion
- Digestive system
- Dimorphism
- Diploblastic
- Diploid
- Diploidy
- Disaccharide
- Discoidal cleavage
- Disease
- Disjunction
- Dithecous
- Diurnal rhythm
- Divergence
- Divergent evolution
- Diversity
- Division
- Dizygotic twins
- DNA
- DNA polymerase
- DNA polymerase II
- DNA replication
- Dogma
- Domain
- Dominance
- Dominant
- Dominant species
- Dominant trait
- Dormancy
- Dorsal spine
- Double circulation
- Double stranded DNA virus
- Drupe
- Duplication mutation
E
- Ecological pyramid
- Ecological succession
- Ecosystem
- Ecosystem diversity
- Ectoparasite
- Ectoplasm
- Egestion
- Egg
- Ejaculation
- Elastic cartilage
- Elastic tissue
- Electron acceptor
- Electron carriers
- Electron transport chain
- Electron transport phosphorylation
- Element
- Elongation
- Embryo
- Embryology
- Emigration
- Endangered species
- Endemic
- Endocrine system
- Endocytosis
- Endomembrane system
- Endoparasite
- Endoplasmic reticulum
- Endosome
- Endosymbiosis
- Endosymbiotic theory
- Endothelial cells
- Energy
- Energy Flow
- Enteric bacteria
- Enterobacteriaceae
- Entomology
- Environment
- Enzyme
- Enzyme activation
- Enzymes
- Epidermis
- Epimastigote
- Epistasis
- Epithelium
- Epoch
- Equilibrium
- Erythrocyte
- Eubacteria
- Euchromatin
- Eucoelomate
- Eukarya
- Eukaryote
- Eukaryotic cells
- Euploidy
- Evolution
- Ex vivo
- Exocytosis
- Exon
- Exotic species
- Exploitation competition
- Expression
- Extinction
- Extracellular
- Extracellular digestion
- Extracellular fluid
- Extracellular matrix
- Extrinsic muscles
- Exudate
F
- F-factor
- Facilitated diffusion
- Facultative anaerobe
- Facultative mutualism
- Facultative parasite
- Family
- Family traits
- Fastidious organism
- Fat
- Fatty acid
- Fecundity
- Feedback mechanism
- Feedback regulation
- Female
- Fermentation
- Fertilization
- Fertilization membrane
- Fetus
- Fiber
- Fibre
- Fibrinous exudate
- Fibrocartilage
- Fibrous tissue
- Fight or flight reaction
- Filament
- Filial generation
- Filtration
- Fimbria
- First filial generation
- Flaccid
- Flagellate
- Flagellum
- Flatworm
- Flavin adenine dinucleotide
- Flower
- Fluid
- Fluid mosaic model
- Fluorescence
- Food
- Food chain
- Food web
- Fossil
- Fossil record
- Fragmentation
- Frameshift mutation
- Fructose
- Fruit
- Fundamental niche
- Fusiform muscle
- Fusion
G
- Gamete
- Gametogenesis
- Ganglia
- Gap 1 phase
- Gap 2 phase
- Gap junction
- Gastric juice
- Gastrulation
- Gdp
- Gene
- Gene flow
- Gene pool
- Gene transfer
- Genera
- Generation
- Generation time
- Generic name
- Genetic code
- Genetic disorder
- Genetic diversity
- Genetic drift
- Genetic equilibrium
- Genetic locus
- Genetic material
- Genetic mutations
- Genetic recombination
- Genetic screening
- Genetic variation
- Genetics
- Genome
- Genomic dna
- Genomic imprinting
- Genotype
- Genotypic ratio
- Genus
- GERL
- Germination
- Giemsa stain
- Global warming
- Gluconeogenesis
- Glucose
- Glycerol
- Glycogen
- Glycogenesis
- Glycogenolysis
- Glycolipid
- Glycolysis
- Glycoprotein
- Golgi apparatus
- Gram staining
- Gram-positive
- Granum
- Grass
- Gravitaxis
- Gravitropism
- Gross photosynthesis
- Ground meristem
- Growth
- Growth rate
- Guanine
- Gut
- Gymnosperm
H
- H antigen
- Habitat
- Haemocoel
- Haemolysis
- Halophile
- Haploid
- Hardy-Weinberg equilibrium
- Hatch
- Heart valve
- Heat
- Heat-labile
- Helicase
- Hemidesmosome
- Hemizygosity
- Hemizygote
- Hemizygous
- Hemoglobin
- Hemolysis
- Hepatocyte
- Heptose
- Herbivore
- Heredity
- Hermaphrodite
- Heterochromatin
- Heterogeneity
- Heterospecific
- Heterotroph
- Heterozygote
- Heterozygous
- Hierarchy
- Histone
- HnRNA
- Holoblastic cleavage
- Holocrine gland
- Homeostasis
- Homeostatic equilibrium
- Homo
- Homo sapiens
- Homo sapiens sapiens
- Homogenate
- Homolog
- Homologous chromosome
- Homologous structures
- Homologue
- Homology
- Homoplasy
- Homozygous
- Hormone
- Host
- Host cell
- Housekeeping gene
- Hox gene
- Human
- Humor
- Humoral immunity
- Hyaline cartilage
- Hyaloplasm
- Hybrid
- Hybrid Sterility
- Hybridization
- Hydrogen
- Hydrolysis
- Hydrolytic cleavage
- Hydrolytic enzyme
- Hydrophilic
- Hydrophobic
- Hydrostatic pressure
- Hydrotropism
- Hyperosmotic
- Hyperpolarization
- Hyperthermophile
- Hypertonic
- Hypertonic solution
- Hyphae
- Hypomorphic mutation
- Hyposmotic
- Hypothesis
- Hypotonic solution
I
- Ichthyology
- Immovable joint
- Immune system
- Immunity
- Immunoglobulin
- Imperfect flower
- Imprinting
- In situ
- In vitro
- In vivo
- Inbreeding
- Incipient Species
- Incomplete dominance
- Incomplete penetrance
- Incubation
- Independent variable
- Indeterminate cleavage
- Indirect life cycle
- Induced fit model
- Infection
- Inflammatory response
- Ingestion
- Inheritance
- Inherited trait
- Initiation
- Inner cell mass
- Inoculating loop
- Inoculation
- Inoculum
- Inorganic salt
- Inspiration
- Insulin
- Integral membrane protein
- Integral protein
- Integument
- Interbreed
- Intercalary meristem
- Interference competition
- Interkinesis
- Intermediate host
- INTERMEDIATE PHENOTYPE
- Internal environment
- Interneuron
- Interphase
- Interspecific competition
- Interspecific hybridization
- Interstitial fluid
- Intracellular
- Intracellular digestion
- Intraspecific competition
- Intron
- Invagination
- Invasive species
- Inversion
- Invertebrate
- Involuntary muscle
- Involuntary Response
- Involution
- Ion
- Ion Pump
- Irritability
- Isoenzyme
- Isopeptide bond
- Isotonic
- Isotonicity
L
- Lacrimation
- Lactic acid
- Lactic acid fermentation
- Lactose
- Lacuna
- Lagging strand
- Lamellae
- Lanugo
- Latency
- Law of Dominance
- Law of Independent Assortment
- Law of Independent Assortment
- Law of Segregation
- Law of the minimum
- Legumes
- Lenticel
- Leucoplast
- Leukocytosis
- Life
- Life cycle
- Ligand
- Ligase
- Light
- Light reactions
- Lignin
- Liliopsida
- Lineage
- Linkage
- Linkage map
- Linked genes
- Lipid
- Liver
- Living things
- Loci
- Lock-and-key model
- Locomotion
- Longitudinal section
- Loose connective tissue
- Lumen
- Lung capacity
- Lymph
- Lymph nodes
- Lymphocyte
- Lymphoid cell
- Lysis
- Lysogenic conversion
- Lysogenic cycle
- Lysosome
- Lytic cycle
M
- Macroevolution
- Macromolecule
- Macroorganism
- Magnification
- Male
- Malic acid
- Maltose
- Mammal
- Mantle
- Mass
- Mass extinction
- Maternal inheritance
- Matrix
- Maturation
- Mature mRNA
- Medicinal plant
- Medusa
- Meiosis
- Meiosis I
- Meiosis II
- Meiotic spindle
- Membrane
- Membrane protein
- Membrane Transport Protein
- Memory cell
- Mendelian Genetics
- Mendelian inheritance
- Menstruation
- Meristem
- Meroblastic cleavage
- Mesophile
- Mesophyll
- Metabolic pathway
- Metabolic rate
- Metabolic Water
- Metabolism
- Metabolite
- Metachromatic granules
- Metamerism
- Metamorphosis
- Metaphase
- Metaphase I
- Metaphase II
- Metaphase plate
- Metastasis
- Microaerophile
- Microbe
- Microbiology
- Microevolution
- Microfibril
- Microfilament
- Microhabitat
- Micrometer
- Micromolecule
- Microorganism
- Microscope
- Microsphere
- Microspore
- Microtubule
- Microtubule organizing center
- Microvilli
- Migration
- Milk
- Mimicry
- Missense mutation
- Mitochondrial inheritance
- Mitochondrion
- Mitogen
- Mitosis
- Mitotic phase
- Mitotic spindle
- Mixotroph
- Modification
- Moiety
- Mole
- Molecule
- Monocot
- Monogenic inheritance
- Monogenic trait
- Monohybrid
- Monohybrid cross
- Monophyletic
- Monoploid
- Monosaccharide
- Monozygotic twins
- Morphology
- Mortality
- Mosaic
- Motility
- Mouth
- MRNA
- Mucus
- Multicellularity
- Multipennate muscle
- Multiple alleles
- Multipotent
- Muscle
- Muscle cell
- Muscle contraction
- Muscle fatigue
- Muscle tone
- Muscle tonus
- Muscular system
- Mutagen
- Mutant
- Mutation
- Mutualism
- Mutualistic symbiosis
- Mycelium
- Myelinated neuron
- Myoblast
- Myocardium
N
- NADH
- Natural active immunity
- Natural environment
- Natural passive immunity
- Natural selection
- Naturally acquired passive immunity
- Nature
- Negative feedback
- Nematocyte
- Nephron
- Nerve
- Nerve impulse
- Nervous system
- Nervous tissue
- Net photosynthesis
- Net primary productivity
- Neurilemma
- Neuroglia
- Neutral mutation
- Nicotinamide adenine dinucleotide phosphate
- Nitrates
- Nitrification
- Nitrogen Cycle
- Nitrogen fixation
- Non Random Mating
- Non-Mendelian inheritance
- Nondisjunction
- Nonsense mutation
- Nuclear division
- Nuclear envelope
- Nuclear membrane
- Nuclear pore
- Nuclear pore complex
- Nuclease
- Nucleic acid
- Nucleoid
- Nucleolus
- Nucleotide
- Nucleus
- Null hypothesis
- Nullisomy
- Nutrient
O
- O antigen
- Obligate aerobe
- Obligate anaerobe
- Obligate mutualism
- Obligate parasite
- Offspring
- Oil
- Okazaki fragment
- Oligopeptide
- Oligosaccharide
- Omnivore
- Oncogene
- Oocyte
- Open circulatory system
- Operator
- Operon
- Opportunistic pathogen
- Orbits
- Order
- Organ
- Organelle
- Organic catalyst
- Organic compound
- Organic molecule
- Organism
- Origin
- Osmoregulation
- Osmosis
- Osmotic lysis
- Osmotic Potential
- Osmotic pressure
- Osmotrophy
- Osteoblast
- Osteocyte
- Outbreeding
- Ovum
- Oxidation
- Oxidative phosphorylation
- Oxygen
- Oxyhemoglobin
P
- P680
- Pancreatic juice
- Paracrine
- Paracrine signaling
- Parallel evolution
- Parapatric speciation
- Paraphyletic
- Parasite
- Parasitism
- Paratenic host
- Parent cell
- Parental generation
- Parthenogenesis
- Particulate inheritance
- Passive immunity
- Passive transport
- Pathogen
- Pathogenicity
- Pedigree
- Penetrate
- Pentadactyl Limb
- Pentose
- PEP carboxylase
- Peptidoglycan
- Perception
- Perfect flower
- Perinuclear space
- Peripatric speciation
- Peristalsis
- Peritoneum
- Permeability
- Perturbation
- PGA
- PH scale
- Phagocyte
- Phagocytosis
- Phagotrophy
- Phelloderm
- Phenotype
- Phenotype frequency
- Phenotypic ratio
- Pheomelanin
- Phloem
- Phosphate
- Phosphate group
- Phospholipid
- Phospholipid bilayer
- Phosphorylation
- Photoautotroph
- Photoheterotroph
- Photorespiration
- Photosynthesis
- Photosystem
- Photosystem I
- Photosystem II
- Phototaxis
- Phototroph
- Phototropism
- Phyletic gradualism
- Phyllode
- Phylogeny
- Phylum
- Physiological processes
- Physiology
- Phytochrome
- Phytoplankton
- Pili
- Pilus
- Pinocytosis
- Pit
- Plankton
- Plant
- Plantae
- Plaque assay
- Plasma
- Plasma B cell
- Plasmid
- Plasmodesmata
- Plasmolysis
- Plastid
- Pleiotropy
- Ploidy
- Plumule
- Pluripotent
- Pneumatophore
- Point mutation
- Polar compound
- Polar molecule
- Polarity
- Polarization
- Pollen Grain
- Poly a tail
- Polycythemia
- Polygene
- Polygenic inheritance
- Polygenic trait
- Polymer
- Polymerization
- Polymorphism
- Polynucleotide
- Polypeptide
- Polyphyletic
- Polyploid
- Polyploidy
- Polyprotein
- Polysaccharide
- Population density
- Positive feedback
- Postsynaptic cell
- Potency
- Precursor
- Predation
- Predator
- Predator-prey relationship
- Presynaptic cell
- Presynaptic terminals
- Prey
- Primary cell wall
- Primary consumer
- Primary meristem
- Primary oocyte
- Primary phloem
- Primary productivity
- Primary succession
- Primary xylem
- Primate
- Primer
- Prion
- Producer
- Progeny
- Prokaryote
- Prokaryotic
- Prokaryotic cell
- Proliferation
- Promastigote
- Prometaphase
- Promoter
- Promoter gene
- Prophase
- Prophase I
- Prophase II
- Proplastid
- Proprioceptor
- Protein
- Protein domain
- Protein pump
- Protein synthesis
- Proteoglycan
- Proteome
- Protist
- Protista
- Proto-oncogene
- Protocell
- Protoderm
- Proton donor
- Proton gradient
- Proton-motive force
- Protoplasm
- Protozoa
- Pseudodominance
- Pseudopodia
- Pseudostratified columnar epithelium
- Pulmonary ventilation
- Pulse
- Punctuated equilibrium
- Punnett Square
- Purebred
- Purine
- Pyramid of Productivity
- Pyrimidine
- Pyruvate
R
- Race
- Radial symmetry
- Reading frame
- Realized niche
- Reannealing
- Receptor
- Recessive
- Recessive trait
- Recombinant DNA
- Recombination
- Reduction Division
- Reflex
- Regeneration
- Regulation
- Relative fitness
- Relay neuron
- Replication
- Repolarization
- Reproduction
- Reproductive isolation
- Reservoir host
- Residual air
- Respiration
- Respiratory system
- Resting potential
- Restriction enzyme
- Reticular connective tissue
- Reticular fiber
- Retrovirus
- Reverse transcription
- Rhizoids
- Rhizome
- Ribonucleic acid
- Ribose
- Ribosome
- Ribosomes
- Ribozyme
- Rivet Hypothesis
- RNA virus
- Root
- Root cap
- Root Hair
- Rostrum
- Rough endoplasmic reticulum
- Roughage
- Rubisco
- Runner
S
- Saccharide
- Sample
- Saprophyte
- Saprophytic
- Sarcolemma
- Sarcomere
- Sarcoplasmic reticulum
- Saturated fat
- Scavenger
- Schizogony
- Science
- Scientific method
- Scientific name
- Secondary cell wall
- Secondary meristem
- Secondary oocyte
- Secondary succession
- Secondary xylem
- Secretion
- Seed
- Segmentation
- Segregation
- Selective permeability
- Selectively-permeable membrane
- Self
- Self antigen
- Semipermeable membrane
- Sensory neuron
- Sensu lato
- Septa
- Sex
- Sex chromosome
- Sex hormone
- Sex linkage
- Sex pili
- Sex-linked
- Sex-linked trait
- Sexual reproduction
- Sexual selection
- Sieve plate
- Signal peptide
- Signal sequence
- Signal transduction
- Silent mutation
- Simple columnar epithelium
- Simple cuboidal epithelium
- Simple diffusion
- Simple epithelium
- Simple fruit
- Sinew
- Single stranded dna
- Single stranded DNA virus
- Siphonophore
- Sister chromatids
- Slime layer
- Smooth endoplasmic reticulum
- Smooth muscle
- Solute
- Solution
- Somatic cells
- Somatosensation
- Speciation
- Speciation event
- Species
- Species Richness
- Specific epithet
- Specificity
- Sperm cell
- Spermatogenesis
- Spermatophyta
- Spermiogenesis
- Sphenopalatine ganglioneuralgia
- Spindle
- Spindle apparatus
- Spindle fiber
- Splicing
- Spongy bone
- Spontaneous generation
- Spontaneous Mutation
- Spore
- Sporophyte
- Sporozoa
- Sporozoan
- Standard deviation
- Starch
- Starlings law
- Statistics
- Statolith
- Stem
- Stem cell
- Sterile
- Steroid
- Sterol
- Sticky end
- Stigma
- Stimulus
- Stock
- Stoma
- Stomate
- Storage
- Strain
- Strata
- Stratified columnar epithelium
- Stratified epithelium
- Stratified squamous epithelium
- Stratum germinativum
- Striated muscle
- Stroma
- Style
- Subcellular
- Submetacentric chromosome
- Subspecies
- Substitution mutation
- Substrate
- Substrate-level phosphorylation
- Substratum
- Succession
- Sucrose
- Sugar
- Sugar-phosphate backbone
- Survival of the fittest
- Sustainability
- Symbiont
- Symbiosis
- Symmetry
- Sympathetic nervous system
- Sympatric speciation
- Symport
- Synapomorphy
- Synapse
- Synaptonemal complex
- Syncytium
- Synecology
- Synergy
- Syngamy
- Synthesis
- Synthesis phase
- Systematics
T
- Tactile sense
- Taxa
- Taxis
- Taxon
- Taxonomy
- Telophase
- Telophase I
- Telophase II
- Temperate phage
- Temperate virus
- Terminal electron acceptor
- Terminal web
- Termination
- Terrestrial
- Terrestrial animal
- Terrestrial plant
- Tertiary consumer
- Test cross
- Theory
- Thermophile
- Thermotropism
- Thigmotropism
- Thin filament
- Thoracic duct
- Threatened species
- Thymine
- Tight junction
- Tissue
- Tissue perfusion
- Tonicity
- Tonoplast
- Topology
- Totipotent
- Totipotent cell
- Toxin
- Tracheary elements
- Tracheid
- Tracheophyte
- Traits
- Transcellular fluid
- Transducer
- Transfection
- Transferase
- Transformation
- Transgene
- Transgenic organisms
- Translation
- Translocation
- Transmembrane proteins
- Transmission
- Transmutation
- Transmutation of species
- Transpiration
- Transport
- Transposition
- Transposon
- Trigger
- Triglyceride
- Triploblastic
- Trophic
- Trophic level
- Tropic
- Tropism
- Tropomyosin
- True breeding
- Tubule
- Tumor
- Turgidity
- Turgor pressure
V
- Vaccination
- Vacuolization
- Variance
- Variation
- Variety
- Vascular bundle
- Vascular plants
- Vascular tissue
- Vector
- Vegetable
- Vegetative Cell
- Vegetative propagation
- Vegetative reproduction
- Ventilation
- Vertex
- Vertical gene transfer
- Vesicle
- Vestigial
- Vicariance
- Vicariant speciation
- Virulent virus
- Virus
- Vitamin
- Vitreous humor
- Voluntary muscle
- Vulnerable species