Fundamental Principles of Biology

• Biology is the scientific study of life.
• It examines living organisms' structure, function, growth, origin, evolution, and distribution.
• Biology identifies the cell as the fundamental unit of life, genes as the units of heredity, and evolution as the force driving species' creation and extinction.
• Living organisms function as open systems, sustaining themselves by converting energy and reducing their local entropy to maintain a stable condition known as homeostasis.

Core Principles

• Biology contains unifying principles that apply to all living things.

Cell Theory

• All living organisms consist of one or more cells.
• The cell serves as the basic structural and functional unit in organisms.
• All cells develop from pre-existing cells.

Gene Theory

• Traits are passed down through genes.
• Genes reside on chromosomes and consist of DNA.
• Genes carry the instructions for building proteins, which execute most cellular functions.

Evolution

• All life on Earth has evolved from a shared ancestor through descent with modification.
• Natural selection drives evolution, favoring individuals with traits better suited to their environment, increasing their likelihood of survival and reproduction.
• Evolutionary processes result in biodiversity at all degrees of biological organization.

Homeostasis

• Living organisms maintain a stable internal environment despite external changes.
• Homeostasis is achieved through various mechanisms, including feedback loops and regulatory systems.

Thermodynamics

• All living organisms adhere to the laws of thermodynamics.
• Living organisms need energy to sustain their organization and perform their functions.
• Energy moves through ecosystems from producers to consumers.

Branches of Biology

• Biology is a wide-ranging field comprising numerous branches.

Biochemistry

• Biochemistry involves the study of chemical processes within and related to living organisms.
• The focus is on the structure and function of biomolecules like proteins, carbohydrates, lipids, and nucleic acids.
• It investigates the chemical reactions that take place in cells and organisms.

Molecular Biology

• Molecular biology explores the molecular basis of biological activity.
• It emphasizes the structure, function, and interactions of biological molecules, including DNA, RNA, and proteins.
• It also studies the mechanisms of gene expression and regulation.

Cell Biology

• Cell biology is the study of cells, focusing on their structure, function, and behavior.
• It examines various cell types, their organelles, and their interactions with the environment.
• Cell biology also explores cell division, differentiation, and death.

Genetics

• This branch focuses on heredity, genes, and the variation of inherited traits.
• The study includes DNA, chromosomes, gene expression, and mutations.
• It includes the transmission of traits from parents to offspring.

Evolutionary Biology

• It examines the processes that shape the diversity of life on Earth.
• Key concepts include natural selection, adaptation, speciation, and phylogeny.
• Evolutionary biology uses information from fossils, anatomy, and molecular biology to reconstruct the history of life.

Ecology

• Deals with the interactions between organisms and their environment.
• Examines populations, communities, and ecosystems.
• Key concepts include food webs, nutrient cycles, and biodiversity.

Physiology

• Studies the functions and mechanisms within living organisms and their parts.
• Examines processes like respiration, circulation, digestion, and excretion.
• Human physiology focuses on how the human body works.

Anatomy

• Involves the study of the structure of living things.
• Includes the structure of cells, tissues, organs, and organ systems.
• Comparative anatomy compares the structures of different species to understand evolutionary relationships.

Importance of Biology

• Essential for understanding the world and addressing challenges facing humanity.

Medicine

• Provides the basis for understanding human health and disease.
• It informs the development of new diagnostic tools, treatments, and vaccines.
• Crucial for understanding drug action mechanisms and personalized medicine development.

Agriculture

• Underpins modern agricultural practices.
• Helps improve crop yields, develop pest-resistant crops, and reduce agriculture's environmental impact.
• Important for understanding animal nutrition and developing sustainable farming practices.

Environmental Conservation

• Informs understanding of ecosystems and human activities' impact on the environment.
• Helps develop strategies for conserving biodiversity, managing natural resources, and mitigating climate change.
• Critical for understanding the spread of invasive species and pollution's impact on ecosystems.

Biotechnology

• Forms the foundation of biotechnology.
• Enables the development of new technologies for medicine, agriculture, and industry.
• Includes techniques like genetic engineering, cloning, and stem cell research.

Levels of Organization in Biology

• Biology studies life across different organizational levels.

Molecular Level

• Atoms are the basic units of matter.
• Atoms combine to form molecules, like DNA, proteins, and carbohydrates.
• Molecules interact to form cell structures and functions.

Cellular Level

• Cells are the basic unit of life.
• Cells are enclosed by a membrane and contain various organelles.
• The two primary cell types are prokaryotic and eukaryotic.

Tissue Level

• Tissues are groups of similar cells performing specific functions.
• The four primary types are epithelial, connective, muscle, and nervous tissue.
• Tissues organize into organs.

Organ Level

• Organs consist of two or more tissues working together to perform a specific function.
• Examples include the heart, lungs, liver, and kidneys.
• Organs are organized into organ systems.

Organ System Level

• Organ systems are groups of organs that work together to perform major functions.
• Examples: the digestive, respiratory, and circulatory systems.
• Organ systems collaborate to maintain the organism's overall health and function.

Organism Level

• An organism is an individual living entity.
• Organisms can be unicellular or multicellular.
• Organisms interact with each other and their environment.

Population Level

• A population is a group of individuals of the same species in the same area.
• Populations can grow, shrink, or remain stable.
• Populations interact with each other and with other species.

Community Level

• A community includes interacting populations of different species in the same area.
• Communities can be complex and diverse.
• Communities are affected by factors such as climate, resources, and competition.

Ecosystem Level

• An ecosystem is a community of organisms and their physical environment.
• Ecosystems include both living (biotic) and non-living (abiotic) components.
• Ecosystems are characterized by the flow of energy and the cycling of nutrients.

Biosphere Level

• The biosphere is the sum of all ecosystems on Earth.
• It includes all living organisms and their environments.
• The biosphere is a closed system in terms of matter but an open system in terms of energy.