Introduction to Biology

Introduction to Biology

• Biology is the scientific study of life and living organisms.
• It encompasses the structure, function, growth, origin, evolution, and distribution of living things.
• Branches include botany, zoology, microbiology, genetics, and more.
• Key characteristics of living organisms are organization, response to stimuli, reproduction, adaptation, and homeostasis.

Levels of Biological Organization

• Biological organization arranges biological structures from atoms to the biosphere in a hierarchy.
• Atoms: Fundamental building blocks of matter.
• Molecules: Formed by bonded atoms.
• Cells: Basic units of life, with organelles and structures.
• Tissues: Groups of similar cells.
• Organs: Structures of different tissues with specific functions.
• Organ systems: Groups of organs for common goals.
• Organisms: Individual living beings.
• Populations: Groups of same species in an area.
• Communities: All interacting populations.
• Ecosystems: All living (biotic) and non-living (abiotic) components.
• Biosphere: The global sum of all ecosystems.

Key Biological Principles

• Cell Theory: All life is composed of cells, cells are the basic units, and cells come from preexisting cells.
• Evolution by Natural Selection: Populations change over time due to inherited trait variation; better-suited individuals reproduce more.
• Homeostasis: Living organisms maintain a stable internal environment.
• Molecular Biology: Studies biological molecules like DNA, RNA, and proteins.
• Genetics: Studies heredity, genes, and trait variations.

Branches of Biology

• Botany: Study of plants.
• Zoology: Study of animals.
• Microbiology: Study of microorganisms (bacteria, viruses, fungi, protists).
• Ecology: Study of organism-organism and organism-environment interactions.
• Genetics: Study of heredity and inheritance.
• Physiology: Study of functions of living organisms and their parts.
• Molecular Biology: Studies biological molecules and their interactions.
• Biochemistry: Studies chemical processes in living organisms.

Core Biological Processes

• Metabolism: Sum of all chemical reactions in organisms.
• Photosynthesis: Plants and some organisms use sunlight to synthesize food.
• Cellular Respiration: Organisms break down food to release energy.
• Reproduction: Production of new organisms.
• Growth: Increase in size and complexity.
• Development: Changes from fertilized egg to adult form.

Biological Diversity

• Biodiversity is the variety and variability of life on Earth.
• It encompasses genetic, species, and ecosystem diversity.
• Factors like location, climate, and evolutionary history influence biodiversity.
• Biodiversity is essential for ecosystem health and stability.

Scientific Method

• The scientific method is a systematic way to investigate phenomena, acquire knowledge, or refine prior knowledge.
• Steps include observation, hypothesis formulation, experimentation, data analysis, and conclusions.
• The method aims to test hypotheses empirically.