Comprehensive Biology Review: Climate Change, Scientific Method, and Macromolecules

Flashcards reviewing climate change, scientific method, atomic structure, water chemistry, and biological macromolecules.

Hurricane (Atlantic / NE Pacific)

A rapidly rotating storm system forming over warm tropical oceans with a low-pressure center (eye), strong winds, and heavy rain in the Atlantic or Northeast Pacific Ocean.

Typhoon

A rapidly rotating tropical storm system occurring in the Northwest Pacific Ocean.

Cyclone

A rapidly rotating tropical storm system occurring in the South Pacific or Indian Ocean.

Eye (of a Hurricane)

The low-pressure vortex formed in the center of a rotating hurricane as wind speed increases, where air from above sinks into the center.

Hurricane Energy Source

The evaporation of warm ocean water (at water temperatures of $80^┐\text{F}$ or higher, extending at least $160\,\text{feet}$ down), which condenses into clouds and falls as rain.

US Hurricane Season

The period running from June 1st to November 30th, peaking in September when ocean waters are warmest.

Hurricane Wind Threshold

Sustained wind speeds exceeding $74\,\text{mph}$, which define a rotating tropical storm system as a hurricane.

Storm Surge

Abnormally high tides caused by storm winds and low pressure pushing ocean water onto land, accounting for $90\%$ of fatalities in most storms.

Weather

Short-term atmospheric conditions in a particular location, described in terms of temperature, humidity, precipitation, cloud cover, visibility, wind, and atmospheric pressure.

Climate

The long-term average of weather patterns in a given region over an extended period.

El Nino & La Nina

Periodic short-term changes in ocean currents that temporarily affect global climate patterns for a year or two.

Ice Ages

Cyclical long-term periods of global cooling related to predictable variations in Earth's orbit and axial tilt, as well as shifting continental positions over millions of years.

Bedrock Striations

Grooves or scratches carved into bedrock by advancing glaciers that reveal the historic extent of past glaciation.

Polar Bear Adaptation Constraint

The evolutionary limitation where rapid climate warming melts sea ice before polar bears can adapt their metabolism and gastrointestinal tract to non-seal prey over thousands of years.

Greenhouse Gases

Atmospheric gases, primarily carbon dioxide ($\text{CO}_2$) and methane ($\text{CH}_4$), released by burning fossil fuels and agriculture that trap heat in Earth's atmosphere.

Greenhouse Effect

The warming of Earth's surface and lower atmosphere caused by greenhouse gas molecules absorbing and re-emitting infrared radiation emitted by Earth.

Carbon Cycle

The movement of carbon through Earth's atmosphere, land, and oceans, where photosynthesis is the sole component removing carbon dioxide from the air.

Atmospheric Carbon Dioxide Level

Reached $429\,\text{parts per million (ppm)}$, the highest level measured in modern records and paleoclimatic records dating back $800{,}000\,\text{years}$.

Atmospheric Methane Level

Reached $1938\,\text{parts per billion (ppb)}$, representing a $165\%$ increase above pre-industrial levels.

NOAA

National Oceanic and Atmospheric Administration; the agency tracking climate metrics, greenhouse gas records, and sea surface temperatures.

Ocean Thermal Energy Absorption

The absorption and storage of more than $90\%$ of excess energy trapped in Earth's system by greenhouse gases over the past half-century.

Glacier Fresh Water Reserve

Glaciers store almost three-quarters ($75\%$) of Earth's fresh water, feeding rivers and streams through gradual summer melting.

Ice-Albedo Positive Feedback

A mechanism where melting ice exposes darker surfaces, allowing more heat to be absorbed, which in turn accelerates further ice melting.

Heat Wave Mortality Impact

Extreme heat events kill more people annually than hurricanes, lightning, tornadoes, floods, and earthquakes combined.

June 2021 Pacific Northwest Heatwave

A extreme heat event in Washington, Oregon, and Canada characterized as a 1-in-1000 year occurrence in today's climate that would have been virtually impossible without climate change.

Shared Socio-economic Pathways (SSPs)

Climate projection models built on different potential greenhouse gas emission levels and socio-economic development patterns.

SSP 1-2.6

A scenario where annual greenhouse gas emissions peak by 2020 and decline substantially, reaching net negative emissions after 2070.

SSP 2-4.5

A scenario where greenhouse gas emissions peak around 2040 and then decline.

SSP 3-7.0

A scenario where greenhouse gas emissions continue to rise slowly beyond 2100.

SSP 5-8.5

A scenario where greenhouse gas emissions continue to rise rapidly and remain high beyond 2100.

Carbon Neutral Energy Sources

Energy sources that do not add greenhouse gases to the atmosphere, including solar, wind, hydro, and nuclear power.

Carbon Capture and Storage (CCS)

Technology that removes up to $90\%$ of $\text{CO}_2$ from industrial exhaust, primarily useful for coal-reliant steel and cement production.

Liquid Hydrogen Fuel

A clean transportation fuel alternative that emits water vapor ($\text{H}_2\text{O}$) instead of carbon dioxide ($\text{CO}_2$).

Biology

The study of life and living organisms, all descended from a common ancestor that appeared billions of years ago.

Global Biomass Distribution

The total global distribution of Earth's biomass measured in carbon, where plants account for $82.4\%$ ($450\text{ billion tonnes}$) and bacteria account for $12.8\%$ ($70\text{ billion tonnes}$).

Age of the Earth

Approximately $4.5\text{ billion years}$ ($4{,}500{,}000{,}000\text{ years}$).

First True Cells

Prokaryotes that appeared on Earth approximately $3.9\text{ billion years ago}$.

Cyanobacteria Cell Fossils

$3.5\text{ billion-year-old}$ fossils discovered in Australia representing the first organisms to perform photosynthesis.

First Multicellular Plants and Animals

Organisms that first evolved approximately $500\text{ million years ago}$.

Homo sapiens Emergence

Anatomically modern humans who emerged roughly $200{,}000\text{ years ago}$ ($0.0002\text{ billion years ago}$).

Dinosaur Extinction Event

The mass extinction event $66\text{ million years ago}$ in which all non-avian dinosaurs went extinct.

Avian Dinosaurs

Flying dinosaurs whose direct living descendants are modern birds.

Properties Shared by All Organisms

Common features of life: cellular structure, response to stimuli, reproduction, homeostasis, adaptation, energy processing, and genetic material (DNA).

Stimulus

Anything in the environment that can be detected by an organism, such as light, temperature, moisture, nutrients, chemical signals, or physical touch.

Single-Celled Reproduction

Reproduction achieved by copying DNA and splitting one cell into two genetically identical cells.

Adaptation

The evolutionary process by which organisms become well-suited to their environment through natural selection.

Homeostasis

The maintenance of a steady internal environment, including constant conditions such as pH, chemical concentrations, and temperature.

Metabolism

The sum of all chemical reactions taking place inside the cells of an organism to process energy.

Gene

A segment of DNA that contains instructions (like a recipe) for synthesizing a specific protein.

Scientific Method

An evidence-based approach used by scientists to investigate natural phenomena, involving question asking, research, hypothesis construction, testing, result analysis, and reporting.

Observation

The act of noticing and describing events or processes in a careful, orderly way that prompts a scientific question.

Hypothesis

An educated, testable prediction that offers a potential answer to a scientific question.

Testable Hypothesis

A proposed explanation that can be supported or refuted through experimentation, observation, or data collection.

Independent Variable

The single factor or variable intentionally manipulated or changed by a researcher in an experiment.

Dependent Variable

The measured factor or outcome affected by changes in the independent variable.

Control Group

The group in an experiment that is kept unmanipulated to serve as a baseline comparison for the experimental group.

Experimental Group

The group in an experiment that receives the specific manipulation or treatment being tested.

Statistical Analysis

Mathematical testing applied to experimental data to determine whether differences between groups are due to variable manipulation rather than chance.

Model Organism

A non-human species studied to understand biological processes that are difficult to study directly in target species (e.g., testing human cancer in mice).

Scientific Theory

A comprehensive explanation of the natural world based on a hypothesis that has been rigorously tested by multiple scientists and never rejected.

Peer Review

The process by which scientific experimental results are reviewed and verified by independent field experts before publication in journals.

Virus Biological Status

Non-living entities because they are not composed of cells.

Genomic Characterization

Analyzing and comparing viral or organismal RNA/DNA sequences against known databases to identify novel species or pathogens.

Anthropogenic Climate Change Theory

The rigorously tested scientific theory that human activity is causing current global climate change through greenhouse gas emissions.

Biodiversity

The variety of living species on Earth, providing ecological resilience and potential for agriculture, energy, and medicine.

Atom

The tiny particle that makes up all matter, consisting of a central nucleus of protons and neutrons surrounded by electrons.

Proton

A subatomic particle in the atomic nucleus with a mass of 1 and a positive (+1) charge, determining the atom's identity.

Neutron

A subatomic particle in the atomic nucleus with a mass of 1 and no electrical charge, affecting atomic mass.

Electron

A subatomic particle with a negative (-1) charge and negligible mass that orbits the nucleus and determines bonding behavior.

Atomic Number

The number of protons in an atom, which uniquely identifies the chemical element.

Atomic Mass (Weight)

The mass of an atom determined by adding its number of protons and neutrons.

Element

A substance composed of only one type of atom, exhibiting unique physical and chemical properties.

CHNOPS

The six elements—Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur—that make up $96\%$ of the mass of all living organisms.

Isotope

Atoms of the same element containing the same number of protons but a different number of neutrons (e.g., Carbon-12 vs. Carbon-14).

Radioisotope

An unstable, radioactive isotope of an element.

Orbital

A region outside the nucleus where electrons are located, holding up to 2 electrons per orbital.

Valence Shell

The outermost electron shell of an atom, containing electrons that determine the atom's reactivity and chemical bonding.

Octet Rule

The principle that atoms react to gain, lose, or share electrons until their valence shell contains 8 electrons (or 2 for Hydrogen).

Chemical Bond

Attractive forces that hold atoms together to form molecules and fill their valence shells.

Compound

A molecule consisting of atoms of two or more different elements chemically bonded together (e.g., $\text{CO}_2$, $\text{H}_2\text{O}$).

Ionic Bond

A chemical bond formed between a metal and a nonmetal when one atom transfers (steals) valence electrons to achieve full valence shells, forming charged ions that attract.

Ion

An atom or molecule with an electrical charge due to the loss (donor, positive charge) or gain (recipient, negative charge) of electrons.

Covalent Bond

A strong chemical bond formed between two nonmetals that share one, two, or three pairs of valence electrons.

Electronegativity

A measure of how strongly an atom pulls shared electrons toward itself in a chemical bond.

Nonpolar Covalent Bond

A covalent bond formed between two atoms of identical or near-identical electronegativities, sharing electrons equally with an even charge distribution.

Polar Covalent Bond

A covalent bond between atoms with significantly different electronegativities, causing an unequal sharing of electrons and creating positive and negative poles.

Hydrogen Bond

An attraction between a partially positive hydrogen atom in a polar covalent bond and an electronegative atom (F, O, or N) in another polar molecule.

Hydrophilic

Polar or charged substances that dissolve readily in polar solvents like water.

Hydrophobic

Nonpolar uncharged substances (such as oils) that do not dissolve in water.

Specific Heat of Water

The energy required to raise the temperature of $1\,\text{g}$ of water by $1\,^\circ\text{C}$, which is high because hydrogen bonds must be broken first.

Heat of Vaporization

The energy required for liquid water to change into gas, absorbing heat from the surroundings and creating an evaporative cooling effect.

Cohesion and Adhesion

Cohesion is the attraction between like water molecules via hydrogen bonds; adhesion is the attraction of water molecules to solid surfaces.

Surface Tension

The property of liquid water resisting depression or puncture because surface molecules are tightly hydrogen-bonded to one another.

Macromolecules (Polymers)

Large biological molecules with molecular weights over $1000\,\text{g/mol}$ composed of repeating monomer subunits.

Monomer

A small individual subunit that links covalently to form a polymer.

Functional Groups

Small clusters of atoms covalently attached to biological molecules that determine chemical properties like polarity and charge.

Condensation Reaction

An energy-requiring chemical reaction that covalently links monomers together and releases a water molecule.

Hydrolysis Reaction

An energy-releasing chemical reaction that consumes a water molecule to break covalent bonds between monomers.

Amino Acid

The monomer building block of proteins, featuring a central carbon attached to an amino group, carboxyl group, hydrogen, and unique side chain (R-group).

Primary Structure of a Protein

The linear sequence of amino acids linked by covalent peptide bonds, which dictates the protein's final 3D shape and function.