Accelerated Biology Unit 1 Study Guide Review

Vocabulary practice flashcards covering experimental design, biochemistry of water, characteristics of life, taxonomy, cladistics, and natural selection for the Accelerated Biology Unit 1 Test.

Independent Variable

The variable in an experiment that is deliberately changed or manipulated by the experimenter to test its effects.

Dependent Variable

The variable in an experiment that is measured or observed, changing in response to alterations in the independent variable.

Controlled Variables

The conditions and factors that are intentionally kept constant throughout an experiment to ensure a fair test.

Control Group

The standard baseline group in an experiment that does not receive the experimental treatment and is used for comparison.

Experimental Group

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

Atom

The fundamental unit of matter, composed of subatomic particles: protons, neutrons, and electrons.

Isotope

An atom that has the same number of protons as other atoms of the same element, but a different number of neutrons, resulting in a different atomic mass.

Ion

An atom or molecule that carries an electric charge due to the loss or gain of one or more electrons.

Electronegativity

A chemical property that describes the tendency of an atom to attract a shared pair of electrons toward itself.

Nonpolar Covalent Bond

A type of chemical bond formed when electrons are shared equally between two atoms with similar electronegativity values.

Polar Covalent Bond

A chemical bond formed when two atoms share electrons unequally due to a significant difference in their electronegativities, creating partial charges.

Ionic Bond

A chemical bond resulting from the electrostatic attraction between oppositely charged ions, typically formed when electrons are transferred from one atom to another.

Hydrogen Bonding

A weak intermolecular attraction occurring between a partially positive hydrogen atom in one polar molecule and an electronegative atom in another molecule.

Heat Capacity of Water

The ability of water to absorb or release large amounts of heat energy with minimal changes in temperature, driven by its extensive hydrogen bonding.

Cohesion

The intermolecular attraction between molecules of the same substance, such as water molecules sticking to each other via hydrogen bonds.

Adhesion

The attraction between molecules of different substances, such as water molecules binding to plant vessels or container surfaces.

Surface Tension

The cohesive force at the surface of a liquid that causes it to behave as if it were covered by a stretched elastic membrane, resulting from hydrogen bonding.

Heterotroph

An organism that cannot synthesize its own food and must obtain nutrients and energy by consuming other organic substances or organisms.

Asexual Reproduction

A mode of reproduction involving a single parent that produces offspring genetically identical to itself without the fusion of gametes.

Intron

A non-coding segment of DNA or RNA within a gene that is removed during the processing of the precursor messenger RNA.

Motility

The capability of an organism to move independently using metabolic energy; notably, a trait that is not a required characteristic of all living organisms.

Virus

A submicroscopic infectious agent that subverts the traditional characteristics of living organisms by requiring a host cell to replicate and metabolize.

DKPCOFGS

The mnemonic representing the hierarchical taxonomic levels ordered from most inclusive to most specific: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Species

The most specific biological classification level, consisting of individuals capable of interbreeding to produce viable, fertile offspring.

CER Framework

A scientific writing structure comprising a Claim (statement that answers a question), Evidence (scientific data), and Reasoning (justification connecting evidence to the claim).

Cladogram

A branching diagram used in cladistics to illustrate phylogenetic relationships between organisms based on shared derived and ancestral traits.

Monophyletic

A taxonomic group that includes a common ancestor and all of its known descendants (forming a single clade).

Polyphyletic

A group of organisms that does not include the most recent common ancestor of all members, typically grouped by convergent traits.

Ancestral Trait

A characteristic that was present in the common ancestor of a lineage and retained by its descendant lineages.

Derived Trait

A novel morphological or molecular trait that appeared in a lineage after diverging from a common ancestor, distinguishing descendants from ancestral forms.

Outgroup

A distantly related taxon in a cladistic analysis used as an ancestral reference point to determine which traits are ancestral or derived.

Node

A point of branching on a cladogram representing the most recent common ancestor of the diverging descendant lineages.

Clade

A monophyletic group on a phylogenetic tree consisting of a common ancestor and all its descendants.

Natural Selection

The evolutionary mechanism where individuals with traits better suited to their environment survive and reproduce at higher rates, passing favorable traits to the next generation.

Convergent Evolution

The process by which distinct and unrelated evolutionary lineages independently develop similar physical structures or traits due to similar selective pressures.

Divergent Evolution

The process by which related species evolve differing traits and adapt to different ecological niches, accumulating differences from a shared common ancestor.