Biology
Biology studies life and living systems, from molecules and cells to organisms, ecosystems, evolution, and the shared processes that keep life going.
What biology studies
Biology is the scientific study of life. It asks how living things are built, how they use energy, how they reproduce, how they respond to their environments, and how they change over generations. The scale ranges from molecules inside cells to entire ecosystems and the biosphere.
Cells
Cells are the smallest units that carry out the basic processes of life. Some organisms consist of a single cell, while plants, animals, and fungi are made of many specialized cells working together. Cell biology studies membranes, organelles, signaling, division, and the chemistry that keeps cells alive.
DNA and heredity
DNA stores genetic information used to build and regulate living systems. Genes influence traits by helping cells make RNA and proteins, though traits also depend on environment, development, and interactions among many genes. Genetics studies inheritance, variation, mutation, and how information passes between generations.
Evolution
Evolution describes how populations of organisms change over time. Natural selection, mutation, genetic drift, gene flow, and sexual selection can all shape inherited variation. Evolution helps explain antibiotic resistance, biodiversity, fossils, domestication, and why organisms share both similarities and differences.
Energy and metabolism
Living things need energy and matter to maintain organization. Metabolism is the network of chemical reactions that builds molecules, breaks molecules down, and transfers energy. Photosynthesis, cellular respiration, digestion, and fermentation are examples of biological energy transformations.
Organisms and systems
Multicellular organisms organize cells into tissues, organs, and body systems. Nervous, immune, circulatory, respiratory, and reproductive systems solve different survival problems. Biology studies how these systems develop, coordinate, fail, heal, and adapt to changing conditions.
Ecology
Ecology studies relationships among organisms and their environments. It looks at populations, communities, food webs, nutrient cycles, habitats, and ecosystems. Ecological thinking is essential for understanding conservation, agriculture, disease spread, climate impacts, invasive species, and resource use.
Why it matters
Biology matters because humans are living systems embedded in other living systems. It informs medicine, food production, public health, conservation, biotechnology, climate resilience, and everyday decisions about risk and care. It also gives a way to understand life's unity and astonishing variety.