Fundamentals of Biology, Genetics, Evolution, and Diversity

Vocabulary flashcards covering core biological topics including research design, biochemistry, cell biology, genetics, evolutionary processes, taxonomy, and eukaryotic diversity.

Hypothesis

A testable and falsifiable explanation for an observed phenomenon.

Theory

A broad, heavily supported explanation of natural phenomena, such as evolution.

Law

A mathematical description of what happens in nature, rather than an explanation of why.

Independent Variable

The specific variable that is manipulated by the experimenter.

Dependent Variable

The variable that is measured in response to changes made to the independent variable.

Controlled Variables

Constants that are held unchanged throughout an experiment to prevent confounding factors.

Experimental Group

The group in a study that receives the independent variable being tested.

Control Group

The group in an experiment that does not receive the treatment and provides a baseline comparison.

Carbohydrates

Biological macromolecules made of monosaccharide monomers that function in short-term energy and structural support (e.g., glucose, cellulose).

Lipids

Biological macromolecules composed of glycerol and fatty acids that function in long-term energy storage and forming cell membranes (e.g., triglycerides, phospholipids).

Proteins

Biological macromolecules composed of amino acid monomers that function as enzymes, transport molecules, and structural support (e.g., hemoglobin, lactase).

Nucleic Acids

Biological macromolecules made of nucleotide monomers that function in storing and transmitting genetic information (e.g., DNA, RNA).

Universal Cell Features

Structures shared by all cells (prokaryotic and eukaryotic): a plasma membrane, cytoplasm, DNA, and ribosomes.

Endosymbiotic Theory

The evolutionary theory stating that mitochondria and chloroplasts originated from free-living bacteria that were engulfed by ancestral eukaryotes.

Homologous Chromosomes

Chromosomes that carry the same genes, consisting of one maternal chromosome and one paternal chromosome.

Sister Chromatids

Identical replicated copies of a chromosome joined together at the centromere.

Genotype

The genetic makeup of an organism (e.g., $PP$, $Pp$, $pp$).

Phenotype

The physical expression or observable trait of an organism.

Monohybrid Cross

A genetic cross between two heterozygotes (e.g., $Pp \times Pp$) yielding a $1:2:1$ genotypic ratio ($PP:Pp:pp$) and a $3:1$ phenotypic ratio.

Incomplete Dominance

A non-Mendelian inheritance pattern where the heterozygote displays a blended phenotype (e.g., Red $\times$ White = Pink).

Codominance

A non-Mendelian inheritance pattern where both alleles are fully expressed simultaneously (e.g., Type AB blood).

Polygenic Traits

Traits controlled by multiple genes, resulting in continuous phenotypic variation (e.g., height).

Epigenetics

The phenomenon in which environmental factors alter gene expression without changing underlying DNA sequences.

Evolution

The change in allele frequencies within a population over time.

Tiktaalik

An example of a transitional fossil that provides physical evidence for evolutionary history.

Genetic Drift

Random changes in allele frequencies over time, which impact small populations most significantly.

Bottleneck Effect

A form of genetic drift that occurs when a population size is drastically reduced by a disaster.

Founder Effect

A form of genetic drift that occurs when a small group colonizes a new location.

Directional Selection

A mode of natural selection that favors one extreme phenotype over others.

Stabilizing Selection

A mode of natural selection that favors intermediate phenotypes and reduces overall phenotypic variation.

Diversifying Selection

A mode of natural selection (also known as disruptive selection) that favors both extreme phenotypes over the intermediate phenotype.

Allopatric Speciation

Speciation that requires physical geographic separation between populations.

Sympatric Speciation

Speciation that occurs within the same geographic location via reproductive barriers.

Sister Taxa

Organisms or lineages on a phylogenetic tree that share an immediate common ancestor.

Domain Bacteria

A domain of single-celled prokaryotes featuring peptidoglycan cell walls.

Domain Archaea

A domain of single-celled prokaryotes that lack peptidoglycan and are often extremophiles.

Domain Eukarya

The domain comprising all organisms built from eukaryotic cells.

Protists

Diverse single- or simple multi-cellular eukaryotes that serve as an evolutionary bridge to complex multicellular kingdoms.

Plants

Autotrophic eukaryotes adapted to land via waxy cuticles/stomata, vascular tissue (xylem/phloem), and seeds/pollen.

Fungi

Heterotrophic absorbers characterized by chitin cell walls and extensive mycelium networks for external digestion.

Animals

Heterotrophic ingestors that are mobile, possessing complex muscular/nervous systems and internal digestive cavities.