Branches of Biology and Levels of Organization

Branch of Biology

• Biology is the scientific study of life and living things, including their structure, function, growth, origin, evolution, distribution, and taxonomy.
• Biology encompasses diverse disciplines, from molecular biology to ecology.
• Biologists use a variety of methods, including observation, experimentation, modeling, and computational analysis.
• The study of life ranges from the tiniest molecules to the largest ecosystems.

Levels of Organization in Biology

• Biology studies life at various levels, from the smallest to the largest.
• Atoms combine to form molecules.
• Molecules assemble to form macromolecules.
• Macromolecules combine to form organelles.
• Organelles function together in cells.
• Cells group to form tissues, which form organs.
• Organs work together in organ systems.
• Organ systems make up an organism.
• Populations of a species together form a community.
• Communities and their environment create an ecosystem.
• Related ecosystems are grouped into biomes, which eventually form the biosphere.

Fundamental Themes in Biology

• Biological systems show a hierarchy of complexity and interconnectedness.
• Living organisms need energy for structure and function.
• Energy flows through biological systems, originating from the sun or chemical compounds.
• Information flow is crucial in living things, from DNA replication to nerve impulses.
• Organisms maintain a stable internal environment (homeostasis).
• Biological systems adapt to their environment, driving evolution through natural selection and genetic variation.
• Evolution explains the diversity and unity of life.
• Evolutionary relationships are represented in phylogenetic trees.

Key Concepts

• Cell theory: all living things are composed of cells.
• Inheritance of traits: genetic information is passed down through generations.
• Evolution: populations change over time, leading to adaptation and diversity.
• Homeostasis: organisms maintain a stable internal environment.
• Structure and function are closely linked.
• Biological systems are interconnected at all levels.
• Energy flow is essential to all life.
• Information processing is critical in living organisms.

Branches of Biology Study

• Microbiology: Studies microscopic organisms like bacteria, viruses, and fungi.
• Botany: Studies plants, including their structure, function, and evolution.
• Zoology: Studies animals, covering their diversity, behavior, and development.
• Ecology: Studies the interaction of organisms with their environment.
• Genetics: Studies genes and heredity.
• Physiology: Studies the functions of living systems.
• Molecular Biology: Explores biological activity at the molecular level.
• Biochemistry: Studies the chemistry of living organisms.
• Developmental Biology: Investigates biological processes from fertilized egg to mature organism.