Bio Lab 4

Genetic drift

A random change in allele frequencies within a population over time, driven by chance events rather than natural selection. It has a much stronger impact in small populations.

Non-random Mating

Occurs when individuals select mates based on specific phenotypes, genotypes, or proximity, rather than by chance. Examples include inbreeding and sexual selection, which alter genotype frequencies without directly changing allele frequencies.

Speciation

The evolutionary process by which new, distinct biological species arise from a single ancestral lineage. It typically occurs when populations become reproductively isolated through geographic, behavioral, or genetic barriers.

Taxonomy

The branch of biology concerned with naming, describing, and classifying organisms into hierarchical groups (like kingdom, phylum, class, order, family, genus, and species) based on shared characteristics and evolutionary relationships.

domain

The highest and most broad taxonomic rank of organisms, above the kingdom level. The three primary domains of life are Archaea, Bacteria, and Eukarya.

kingdom

The second-highest taxonomic rank, directly below domain. Organisms are grouped into kingdoms (such as Animalia, Plantae, Fungi, and Protista) based on fundamental cell structure, nutrient acquisition, and general body plan.

division/ phylum

A major taxonomic rank below kingdom and above class. "Phylum" is traditionally used for animals, fungi, and protists, while "Division" is often used in botany for plants and algae; both group organisms based on general body plan or structural features.

class

A taxonomic rank below phylum and above order. It groups together related orders of organisms that share a set of major structural or biological characteristics (for example, Mammalia within the phylum Chordata).

order

A taxonomic rank below class and above family. It groups together related families that share specific common traits and biological adaptations (for example, Carnivora within the class Mammalia).

family

A taxonomic rank below order and above genus. It groups together closely related genera that share a distinct set of physical traits and evolutionary lineage (for example, Felidae, the cat family, within the order Carnivora).

genus

A taxonomic rank below family and above species. It groups together species that are structurally similar or closely related through evolution (for example, Panthera, which includes lions, tigers, and jaguars).

species

The most specific basic unit of taxonomic classification, consisting of a group of similar organisms capable of interbreeding and producing fertile offspring in nature (for example, Homo sapiens or Panthera leo).

Binomial

The formal two-part naming system used in taxonomy to identify a species, consisting of the genus name (capitalized) followed by the specific epithet (lowercase), both written in italics or underlined (for example, Homo sapiens or Panthera leo).

Phylogeny

The evolutionary history and relationships among species or groups of organisms, typically illustrated using a branching diagram called a phylogenetic tree.

Phylogenetic tree

A branching diagram that represents the evolutionary relationships among various biological species based on similarities and differences in their physical or genetic characteristics.

leaves (living Taxa)

In a phylogenetic tree, these are the terminal tips or endpoints representing currently existing (extant) species, organisms, or groups being analyzed.

Nodes (hypothetical ancestors

Points on a phylogenetic tree where branches split, representing the common hypothetical ancestor that gave rise to two or more descendant lineages.

Root

The basal (bottom) node or common ancestor at the base of a phylogenetic tree, representing the most recent common ancestor of all the lineages or taxa included in the tree.

Branches (connections)

The lines on a phylogenetic tree that connect nodes and leaves, representing evolutionary lineages and the passage of time or genetic change over generations.

sister Taxa

Two or more lineages (species, genera, or groups) that originate from the same immediate common ancestor on a phylogenetic tree, making them each other's closest evolutionary relatives.

Monophyletic group (Clade)

A taxonomic group that consists of a single common ancestor and all of its lineal descendants, representing a complete branch on a phylogenetic tree (for example, mammals or birds).

non monophyletic

group of organisms that does not include a single common ancestor and all of its descendants. These are classified as either paraphyletic (includes a common ancestor and some, but not all, descendants) or polyphyletic (includes organisms from different evolutionary lineages but omits their most recent common ancestor).

topologies

The structural shapes or branching patterns of phylogenetic trees that define the specific evolutionary relationships and lineage connections among a set of taxa, regardless of branch lengths.[p-