Introduction to Biology

Introduction to Biology

• Biology is the scientific study of life and living organisms.
• It encompasses a vast field, exploring diverse topics like genetics, evolution, ecology, and physiology.
• Biology seeks to understand the structure, function, growth, origin, evolution, and distribution of living organisms.

Branches of Biology

• Genetics: Studies heredity and the mechanisms of inheritance.
• Evolutionary Biology: Examines the processes that have shaped the diversity of life over time.
• Ecology: Focuses on the relationships between organisms and their environment.
• Physiology: Explores the functions of living organisms at different levels.
  • Cellular physiology: studies processes within individual cells.
  • Organismal physiology: examines the integrated functions of organisms.
• Molecular Biology: Investigates the molecular basis of biological activity.
• Biochemistry: Studies the chemical processes within and related to living organisms.
• Botany: Study of plants
• Zoology: Study of animals
• Microbiology: Study of microorganisms (bacteria, viruses, fungi, protists).
• Immunology: Examines the body's defense mechanisms against disease.

Key Concepts in Biology

• Cell Theory: All living organisms are composed of cells. Cells are the basic units of structure and function in living things.
• Evolution: The process by which populations of organisms change over time.
• Natural Selection: The mechanism by which organisms with advantageous traits are more likely to survive and reproduce.
• Homeostasis: The ability of an organism to maintain a stable internal environment.
• Metabolism: The sum of all chemical reactions that occur within an organism.
• Genetics: The study of genes, heredity, and the variation of organisms.
  • DNA (deoxyribonucleic acid): the molecule that carries genetic information.
  • RNA (ribonucleic acid): plays a critical role in protein synthesis.

Biological Diversity

• Species: A group of organisms capable of interbreeding and producing fertile offspring.
• Taxonomy: The science of classifying and naming organisms.
• Phylogenetic Tree: A diagram that depicts the evolutionary relationships among different species.
• Biodiversity: The variety of life on Earth at all its levels, from genes to ecosystems.
  • High biodiversity correlates with ecosystem health.

Levels of Biological Organization

• Atoms: The basic building blocks of matter.
• Molecules: Combinations of atoms.
• Macromolecules: Large, complex molecules (e.g., proteins, carbohydrates, lipids).
• Cells: The basic units of life.
• Tissues: Groups of similar cells performing a specific function.
• Organs: Structures composed of different tissues working together.
• Organ Systems: Groups of organs working together.
• Organisms: An individual living thing.
• Populations: Groups of individuals of the same species in a given area.
• Communities: Interacting populations of different species in a given area.
• Ecosystems: Communities of living organisms and their surrounding environment.
• Biosphere: The global sum of all ecosystems.

Biological Processes

• Photosynthesis: The process by which plants convert light energy into chemical energy.
• Cellular Respiration: The process by which cells break down glucose to release energy.
• Protein Synthesis: The process by which cells create proteins based on the instructions in DNA.
• Reproduction: The process by which organisms create new organisms.
• Meiosis: A type of cell division that produces gametes (sex cells).