Introduction to Biology

Introduction to Biology

• Biology is the scientific study of life, encompassing all living organisms and their interactions.
• It explores the complexities of life at various levels, from molecules to ecosystems.
• Core concepts in biology include evolution, heredity, metabolism, and ecology.

Characteristics of Living Organisms

• Living organisms exhibit shared characteristics:
  • Organization: Cells are the basic unit of life.
  • Metabolism: Chemical reactions that build up and break down molecules.
  • Growth and Development: Increase in size and complexity
  • Adaptation: Evolution and adjustment to the environment.
  • Response to Stimuli: External or internal changes.
  • Reproduction: Creating new organisms of the same kind.
  • Homeostasis: Maintaining stable internal conditions.

Levels of Biological Organization

• From smallest to largest: molecules, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and biosphere.
• Each level builds upon the one below it, with emergent properties arising at higher levels.

The Scientific Method

• A systematic approach to understanding the natural world.
• Steps include: observation, hypothesis formation, prediction, experimentation, data analysis, and conclusion.
• Includes the crucial concepts of control groups, variables (independent and dependent), and repeatable trials.

Cell Biology

• Cells are the fundamental units of life.
• Two main types: prokaryotic (without a nucleus) and eukaryotic (with a nucleus).
• Cellular structures and organelles: include the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and ribosomes.
• Cell membrane and transport: Regulates what enters and exits the cell.

Genetics

• Heredity: Transmission of traits from parents to offspring.
• DNA: Deoxyribonucleic acid, the molecule that carries genetic information.
• Genes: Segments of DNA that code for specific proteins.
• Chromosomes: Structures composed of DNA and proteins that organize genetic material.
• Mutations: Changes in DNA sequence.

Evolution

• Natural selection: The process by which organisms with heritable traits better suited to their environment tend to survive and reproduce more successfully.
• Adaptations: Traits that enhance survival and reproduction in a specific environment.
• Common ancestry: All organisms share a common ancestor and have evolved from it.
• Classification and taxonomy: the grouping and naming of organisms based on shared characteristics and evolutionary relationships.

Ecology

• The study of interactions between organisms and their environment.
• Ecosystems: Communities of organisms interacting with each other and their physical environment.
• Energy flow: Movement of energy through an ecosystem; often in the form of food chains or webs.
• Nutrient Cycling: Recycling of vital elements for growth and development throughout ecosystems.

Biodiversity

• The variety of life on Earth at all levels, from genes to ecosystems.
• Importance: Ecosystem services, medicine, agriculture.
• Threats: Habitat loss, pollution, climate change, overexploitation.

Microbiology

• The study of microbes (bacteria, viruses, archaea, fungi)
• Importance: Decomposition, disease, biotechnology (e.g., genetic engineering).

Physiology

• The study of how living things function.
• Includes processes like respiration, circulation, digestion, and excretion.

Biochemistry

• The study of chemical processes in living organisms.
• Includes topics such as metabolism, enzyme function, and cellular signaling.