Iterative Evolution: When Species Re-Evolve the Same Traits
Iterative evolution is the repeated emergence of similar traits from the same ancestral lineage at different points in geological time.
Biology and Life Sciences
57 glossary terms
Biology and life sciences cover everything from the molecular machinery inside a single cell to the evolutionary forces that shape whole ecosystems. The terms in this section span genetics, anatomy, microbiology, ecology, and the frontier where biology meets chemistry and computation. Some are classroom staples like the double helix or photosynthesis. Others capture ideas you may never have encountered, from horizontal gene transfer to zygotic gene activation. Together they form the vocabulary scientists use to describe how life works, how it began, and how it continues to surprise us.
Retrovirus Replication Cycle: How RNA Viruses Hijack Cells
The retrovirus replication cycle converts viral RNA to DNA and integrates it into a host cell's genome to produce new virus particles.
Somatic Cell Nuclear Transfer: Cloning Technique Explained
Somatic cell nuclear transfer creates an embryo by moving a body cell's nucleus into an egg cell stripped of its own DNA, enabling mammalian cloning and stem cell research.
Homeostasis: How Living Organisms Maintain Internal Balance
Homeostasis is the set of self-regulating processes by which a living organism maintains stable internal conditions, even as its external environment changes.
Genetic Drift: How Random Chance Reshapes Evolution
Genetic drift is a change in allele frequency within a population caused by random sampling rather than natural selection. It affects every finite population but reshapes small ones fastest, sometimes fixing or eliminating gene variants in just a few generations.
Gut Microbiome Diversity: What It Means for Your Health
Gut microbiome diversity is the range of microbial species in the human gastrointestinal tract, linked to digestion, immunity, and disease prevention.
Endosymbiotic Theory: How Bacteria Became Organelles
Endosymbiotic theory explains how eukaryotic cells acquired mitochondria and chloroplasts by engulfing free-living bacteria that became permanent, integrated organelles.
Epigenetic Inheritance: How Molecular Marks Pass Between Generations
Epigenetic inheritance transmits changes in gene expression across generations without altering the DNA sequence, through DNA methylation, histone modification, and small RNA pathways.
Extremophile: Life That Thrives in Earth's Harshest Environments
An extremophile is an organism that thrives in conditions lethal to most life, including extreme heat, acidity, salinity, and pressure.
Fossilization Process: How Organisms Become Fossils
Fossilization is the set of physical and chemical processes preserving organisms in Earth's crust, typically within sedimentary rock.