Descent with Modification and Evidence for Evolution

Vocabulary flashcards covering core concepts, historical contributors, mechanisms of selection, structural similarities, tree thinking, and the definition of scientific theory from the study guide.

Descent with modification

The core idea of evolution stating that life changes over generations, accounting for both the unity (shared features) and diversity (differences) of life.

Evolution (as process and pattern)

Evolution is both a process—the mechanisms that generate change and diversity—and a pattern—the product of those processes visible in living and fossil organisms.

Scala naturae

Aristotle's concept of a linear ladder of complexity with humans at the top, where organismal positions are fixed and unchanging.

Linnaean hierarchy

A taxonomy established by Linnaeus in the 1700s grouping organisms by relatedness into Kingdom → Phylum → Class → Order → Family → Genus → Species, using binomial naming.

Hutton's contribution to biology

The geological idea that the physical world changes slowly and continuously, which was transferred to evolutionary biology.

Malthusian principle in biology

The concept that population growth outstrips resources, applied in biology to show that the environment acts as a limited resource.

Lamarckism

An early hypothesis that catalogued within-population variation and accepted gradual change over generations, but incorrectly asserted that traits acquired in a lifetime are inherited.

Natural selection

A mechanism of evolution where individuals better suited to their environment survive and reproduce more, causing those advantageous traits to become more common over generations.

Artificial selection

A process in which humans grant a reproductive advantage to specific individuals possessing desirable traits, such as breeding wild mustard into cruciferous vegetables.

Polyphenism / phenotypic plasticity

The ability of a single genotype to produce different phenotypes depending on environmental conditions during development.

Homologs

Structures in different species that share the same developmental origin and shared ancestry due to repurposing an existing anatomical structure.

Analogs

Structures across different species that have different developmental origins and arise independently via convergent evolution.

Phylogenetic tree

A diagram depicting evolutionary relationships, where branch lengths reflect time since the last common ancestor.

Node

A point in time on a phylogenetic tree where two lineages last shared a common ancestor.

Out-group

An organism closely related to the group being studied, but not part of it.

Scientific theory

The best available scientific explanation for why things are the way they are, supported by abundant evidence and refined as new findings emerge.