Principles of Life and Evolution Practice Flashcards

This set of 50 flashcards covers key vocabulary from Biology Chapter 1, 2, 13, 14, and 16, focusing on the principles of life, chemistry of water, and mechanisms of evolution.

Biology

The scientific study of living things or organisms.

Organism

Any individual living entity.

Single common ancestor

The shared ancestral cell from which all modern life descended.

Nucleic acid

Molecules such as DNA or RNA that store and transmit genetic data via a universal code.

Prokaryote

An organism that lacks a nucleus and membrane-enclosed organelles, including the domains Bacteria and Archaea.

Eukaryote

An organism characterized by cells possessing a membrane-enclosed nucleus and organelles.

Photosynthesis

The process that transforms environmental light into chemical energy while releasing $O_2$.

Cyanobacteria

Early photosynthetic prokaryotes responsible for the oxygenation of Earth's atmosphere.

Stromatolites

Layered rock structures formed by fossilized mats of cyanobacteria.

Endosymbiosis

The origin theory that eukaryotic mitochondria and chloroplasts evolved from engulfed prokaryotes.

Organelle

A membrane-enclosed internal compartment within a cell.

Genome

The complete set of genetic information (DNA) contained within an organism.

Mutation

A permanent structural change in genetic material that occurs at random.

Binomial nomenclature

The two-part species naming system consisting of Genus and species.

Phylogenetic tree

A diagrammatic reconstruction of evolutionary histories among lineages.

Model biological system

A representative species, such as E. coli, studied in laboratories to discover general biological principles.

Homeostasis

The preservation of a stable internal environment within a living system.

Negative feedback

A control mechanism that slows or inhibits a pathway to stabilize it.

Positive feedback

A control mechanism that accelerates or amplifies a process away from a baseline.

Evolution

Changes in allele frequencies in a population over time.

Natural selection

An evolutionary mechanism driven by environmental fitness where traits increasing survival/reproduction are favored.

Adaptation

A heritable trait that increases an organism's chances of survival and reproduction.

Controlled experiment

A scientific study where subjects are split into an experimental group and a control group to isolate confounding factors.

Independent variable

The specific factor that is manipulated in a scientific experiment.

Dependent variable

The measured response or outcome in a scientific experiment.

Atom

The smallest unit of matter.

Atomic number

The total number of protons in an atom's nucleus, which defines the element.

Isotope

Forms of an element that have the same number of protons but a different number of neutrons.

Valence shell

The outermost electron shell of an atom which determines its chemical reactivity.

Electronegativity

The nuclear pulling force that an atom exerts on shared electrons within a chemical bond.

Covalent bond

A strong chemical bond formed by the sharing of electron pairs between atoms.

Ionic bond

The electrostatic attraction between a positive cation and a negative anion.

Hydrogen bond

An electrostatic attraction between a $\text{δ}+$ Hydrogen and a $\text{δ}-$ electronegative atom such as Oxygen or Nitrogen.

Van der Waals interactions

Weak, transient attractions between non-polar molecules resulting from shifting electron densities.

Entropy

A measure of randomness or disorder in a system, which increases during energy transfers.

Hydrolysis

A chemical reaction that breaks polymers into monomers by consuming water.

Condensation reaction

A chemical reaction that links monomers into polymers while releasing water.

Exergonic reaction

A chemical reaction that releases free energy.

Endergonic reaction

A chemical reaction that requires an input of free energy to proceed.

Specific heat

The amount of heat required to raise the temperature of $1\,g$ of a substance by $1\,^{\circ}\text{C}$.

Cohesion

The property of water molecules sticking to other water molecules.

Adhesion

The property of water molecules sticking to polar surfaces.

Amphipathic

A molecule that possesses both polar (hydrophilic) and non-polar (hydrophobic) regions.

Functional group

A cluster of atoms with consistent chemical properties and reactivities regardless of the molecule they are in.

Gene flow

The movement of alleles between populations via migration or the transfer of gametes.

Genetic drift

Changes in allele frequencies due to random chance, which are most severe in small populations.

Population bottleneck

An event where a random disaster leaves only a few unrepresentative survivors, reducing genetic diversity.

Founder effect

A type of genetic drift occurring when a few individuals colonize a new area with a subset of the original population's genetic diversity.

Synapomorphy

A shared derived trait that is unique to a specific clade.

Speciation

The divergence of biological lineages and the emergence of reproductive isolation between them.