Foundations of Biology: Evolution, Chemistry of Life, and Water

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Biology is unified by several major themes that help explain the diversity and complexity of life.

Evolution: The process by which species change over time through natural selection, leading to adaptation and diversity.
Organization: The hierarchical structure of life, from molecules to the biosphere, where structure fits function at all levels.
Information: The storage, transmission, and use of genetic material (DNA) in living organisms.
Energy and Matter: The flow and transformation of energy and matter through living systems.
Interactions: The ways in which organisms interact with each other and their environment.

Life is organized into a hierarchy of levels, each with emergent properties not present at lower levels.

Biosphere: All life on Earth and all places where life exists (land, water, atmosphere).
Ecosystems: Communities of living organisms interacting with their physical environment.
Communities: All organisms inhabiting a particular area.
Populations: Groups of individuals of the same species in a specific area.
Organisms: Individual living things.
Organs and Organ Systems: Body parts with specific functions.
Tissues: Groups of similar cells performing a function.
Cells: Fundamental unit of structure and function in life.
Organelles: Functional components within cells.
Molecules: Chemical structures consisting of two or more atoms.

Emergent Properties: New properties that arise at each level of organization due to interactions among components.
Reductionism: The approach of reducing complex systems to simpler components for study.
Systems Biology: The study of interactions among components of biological systems.

Prokaryotic Cells: Lack a nucleus and membrane-bound organelles (e.g., Bacteria, Archaea).
Eukaryotic Cells: Have a nucleus and membrane-bound organelles (e.g., plants, animals, fungi, protists).

DNA (Deoxyribonucleic Acid): The molecule that stores genetic information.
Genes: Units of inheritance that encode information for building molecules.
Gene Expression: The process by which information from a gene is used to build a functional product (protein).
Genome: The entire set of genetic instructions in an organism.

All living things require energy for growth, reproduction, and cellular activities.
Producers: Organisms that produce their own food (e.g., plants via photosynthesis).
Consumers: Organisms that obtain energy by consuming other organisms.
Decomposers: Organisms that break down dead matter, recycling nutrients.

Explains the unity and diversity of life.
Species accumulate differences from their ancestors as they adapt to different environments.
Natural Selection: The process by which individuals with advantageous traits survive and reproduce more successfully.

All matter is composed of elements, substances that cannot be broken down by chemical means.

Compound: A substance consisting of two or more elements in a fixed ratio.
Essential Elements: Elements required for life (e.g., O, C, H, N make up ~96% of living matter).

Atom: The smallest unit of matter retaining the properties of an element.
Subatomic Particles: Protons (positive), neutrons (neutral), electrons (negative).
Atomic Number: Number of protons in the nucleus.
Mass Number: Total number of protons and neutrons.
Isotopes: Atoms of the same element with different numbers of neutrons.
Radioactive Isotopes: Unstable isotopes that decay, emitting radiation.

Atomic Structure Equations

Valence Electrons: Electrons in the outermost shell, involved in chemical bonding.
Chemical Bonds: Attractions between atoms due to sharing or transferring electrons.
Covalent Bonds: Sharing of electron pairs between atoms (single, double bonds).
Polar Covalent Bonds: Electrons are shared unequally due to differences in electronegativity.
Ionic Bonds: Transfer of electrons from one atom to another, resulting in oppositely charged ions.
Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom.
Van der Waals Interactions: Weak attractions due to transient local partial charges.

Table: Types of Chemical Bonds

Bond Type	Description	Relative Strength
Covalent	Sharing of electron pairs	Strongest
Ionic	Transfer of electrons, attraction between ions	Strong (in dry conditions)
Hydrogen	Attraction between H and electronegative atom	Weak
Van der Waals	Transient attractions due to partial charges	Weakest

Cohesion: Water molecules stick together via hydrogen bonds.
Adhesion: Water molecules stick to other substances.
Surface Tension: Measure of how difficult it is to stretch or break the surface of a liquid.
High Specific Heat: Water resists temperature changes due to hydrogen bonding.
Heat of Vaporization: Amount of energy required to convert water from liquid to gas.
Evaporative Cooling: As water evaporates, it cools the surface.
Ice Floats: Solid water is less dense than liquid water due to hydrogen bonding.

Acid: Substance that increases hydrogen ion (H+) concentration.
Base: Substance that reduces hydrogen ion concentration (accepts H+ or donates OH-).
pH Scale: Measures hydrogen ion concentration; ranges from 0 (acidic) to 14 (basic).
Buffer: Substance that minimizes changes in pH by accepting or donating H+.

pH Equations

Table: Examples of Acids and Bases

Buffers are crucial in biological systems to maintain stable pH, especially in blood and cellular fluids.
Water's unique properties are essential for life, including its role as a solvent, its high heat capacity, and its ability to moderate temperature.