Biology Chapter: Properties of Life

Common Properties and Processes of Life

• Life exhibits Order, characterized by complex organization of cells (e.g., elephants composed of organized cells).
• Reproduction is fundamental, allowing organisms to produce offspring resembling themselves (e.g., elephants giving birth to calves).
• Growth and Development follow DNA instructions, ensuring consistent changes (e.g., a baby elephant maturing into an adult).
• Organisms respond to their surroundings, demonstrated by a lizard changing color for camouflage.
• Energy Processing involves obtaining energy from food to sustain life (e.g., caterpillars eat leaves for energy).
• Regulation maintains internal conditions (e.g., iguanas regulate body temperature by basking or seeking shade).
• Evolutionary Adaptation describes organisms evolving features suited to their environment (e.g., pandas evolving to eat bamboo).

Hierarchy of Life's Organizations

• Biosphere encompasses all life and environments on Earth.
• Ecosystem includes living organisms and their physical environment (e.g., coral reefs).
• Community refers to all organisms within an ecosystem.
• Population is a group of individuals of the same species in a location (e.g., human population).
• Organism is a singular living entity.
• Organ System involves collaborative organs for a specific function.
• Organ is made of tissues and performs specific functions for the organism.
• Tissues comprise similar cells working together.
• Cells are the fundamental life unit, capable of division; each exhibits all seven properties of life.
• Organelle is a membrane-bound structure within cells that performs distinct functions.
• Molecule consists of atoms bonded together, with atoms being the basic matter building blocks.

Diversity of Life and Taxonomy

• An estimated 8.7 million species of plants and animals exist, though around 1.2 million have been identified.
• Microorganisms are the most diverse, potentially totaling 1 trillion unidentified microbial species.
• Taxonomy groups organisms by similarities, reflecting their evolutionary relationships.
• Life is classified into three Domains:
  • Bacteria (prokaryotic)
  • Archaea (prokaryotic)
  • Eukarya (eukaryotic)
• Classification hierarchy includes Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Cell Theory and Types of Cells

• Cell Theory states all living things consist of cells and all cells arise from pre-existing cells.
• Two primary cell types exist:
  • Prokaryotic Cells lack membrane-bound organelles and are smaller.
  • Eukaryotic Cells contain membrane-bound organelles including a nucleus and are larger.

Themes in Biology

• Flow of Information: Life relies on information transfer, primarily from DNA to mRNA to proteins.
• Interactions within and between systems emphasize emergent properties at various biological organization levels.
• Energy and Matter transfer and transformation are fundamental for all life activities.
• Structure and Function connectivity is pivotal; a molecule's structure informs its function, applicable from cells to organ systems.
• Evolution is the foundational concept explaining life's unity and diversity.

Flow of Genetic Information

• All cells use DNA for storing genetic information, which consists of nucleotides (A, T, C, G) arranged into genes.
• Gene Expression involves the transformation of DNA to mRNA (transcription) and mRNA to proteins (translation).
• Mutations can alter gene sequences, potentially leading to harmful outcomes like cancer.
• Introducing new DNA or mRNA can enable cells to produce novel proteins (gene therapy).

Energy Flow and Matter Cycling

• Life processes require energy, convertible between forms, while matter is recycled within ecosystems.
• Producers (plants) convert sunlight into chemical energy, forming the basis of the food web.
• Consumers (animals) and Decomposers (bacteria, fungi) play vital roles in matter and energy cycling in ecosystems.

Structure-Function Relationship

• Structure impacts function across all life levels; for instance, human lung architecture optimizes gas exchange.

Emergent Properties in Biological Systems

• New properties appear at each level of biological complexity, resulting from the interactions of systemic components (e.g., Na and Cl forming NaCl).

Core Theme of Evolution

• Evolution underlies the biological diversity observed, facilitating the adaptation and survival of species over generations.