Campbell Biology, 12th Ed. – Chapter 22: Descent with Modification

These vocabulary flashcards capture the major terms, people, concepts, and examples from Chapter 22, providing concise definitions to reinforce understanding of Darwinian evolution, natural selection, supporting evidence, and key historical contributions.

Evolution

The process by which species accumulate differences from their ancestors over time, adapting to different environments.

Descent with Modification

Darwin’s phrase summarizing evolution: all organisms share a common ancestor and diversify through accumulated changes.

Natural Selection

Process in which individuals with advantageous heritable traits survive and reproduce more successfully, increasing those traits’ frequency.

Adaptation

Inherited characteristic that enhances an organism’s survival and reproduction in a specific environment.

Pattern of Evolution

Observable evidence (fossils, homology, biogeography, etc.) showing that life has changed over time.

Process of Evolution

Mechanisms—chiefly natural selection—that produce the observed pattern of evolutionary change.

Scala Naturae

Aristotle’s ladder-like arrangement of organisms from simple to complex, assuming species are fixed.

Binomial Nomenclature

Linnaeus’s two-part scientific naming system for species (e.g., Homo sapiens).

Nested Classification

Linnaeus’s hierarchical grouping of similar species into increasingly inclusive categories (genus, family, etc.).

Fossil

Remains or traces of ancient organisms, often found in sedimentary rock strata.

Strata

Layers of sedimentary rock that record chronological sequences of fossils.

Paleontology

Scientific study of fossils; largely founded by Georges Cuvier.

Catastrophism

Cuvier’s idea that strata boundaries reflect sudden, short-term, catastrophic events causing extinctions.

Gradualism

Hutton’s view that Earth’s geologic features formed slowly through cumulative processes (e.g., river erosion).

Uniformitarianism

Lyell’s principle that the same geologic processes operate today as in the past at the same rate.

Use and Disuse

Lamarck’s incorrect principle that body parts used extensively become larger while unused parts deteriorate.

Inheritance of Acquired Characteristics

Lamarck’s unsupported idea that traits acquired during an organism’s life are passed to offspring.

Artificial Selection

Human-directed breeding of organisms to produce desired traits (e.g., crop varieties from wild mustard).

Thomas Malthus

Economist who argued populations grow faster than resources; influenced Darwin’s thinking on overproduction.

Fitness

Relative reproductive success of an individual in a given environment.

Soapberry Bug Study

Direct observation showing beak length evolution in response to introduced plant species with different fruit sizes.

MRSA (Methicillin-Resistant Staphylococcus aureus)

Pathogenic bacterial strains that evolved resistance to methicillin and other antibiotics.

Antibiotic Resistance

Evolutionary process where bacteria possessing genes for drug resistance survive and proliferate under antibiotic use.

Teixobactin

New antibiotic (discovered 2015) effective against some multidrug-resistant pathogens.

Homology

Similarity due to common ancestry; can be anatomical, embryological, or molecular.

Homologous Structures

Body parts that share underlying anatomy but may differ in function (e.g., mammalian forelimbs).

Vestigial Structures

Remnants of ancestral features that no longer serve their original function (e.g., snake pelvic bones).

Comparative Embryology

Study revealing developmental homologies like post-anal tails and pharyngeal arches in vertebrate embryos.

Molecular Homology

Genetic similarities (e.g., shared genes, universal genetic code) indicating descent from a common ancestor.

Evolutionary Tree

Diagram hypothesizing relationships among species; branching indicates common ancestry and divergence.

Tetrapod

Vertebrate with limbs bearing digits; a nested homology within vertebrates.

Convergent Evolution

Independent evolution of similar features (analogous traits) in distantly related lineages (e.g., sugar glider vs. flying squirrel).

Analogous Structures

Features that are similar in function but evolved independently, not from common ancestry.

Fossil Record

Chronological collection of fossils providing evidence for extinction, origin of groups, and transitional forms.

Cetacean Transition

Fossil series documenting the evolution of whales from land-dwelling even-toed ungulate ancestors.

Biogeography

Study of species’ geographic distributions as evidence for evolution (e.g., Galápagos finches, Galaxiid fish).

Continental Drift

Movement of Earth’s landmasses over time; explains patterns of species distribution.

Pangaea

Supercontinent that existed ~250 million years ago before breaking apart, influencing evolutionary lineages.

Direct Observation

Real-time studies of evolutionary change, such as antibiotic resistance or soapberry bug beak evolution.

Unity of Life

Observation that diverse organisms share many characteristics, explained by common ancestry.

Diversity of Life

Vast variety of living organisms resulting from evolutionary divergence over time.

Common Ancestor

An ancestral species from which two or more descendant species evolved.

Key Features of Natural Selection

1) Individuals vary; 2) traits are heritable; 3) more offspring are produced than survive; 4) differential survival leads to accumulation of favorable traits.

Population (in Evolution)

Group of interbreeding individuals of one species; the unit that evolves over generations, not the individual.

Tree Thinking

Interpreting evolutionary relationships using branching diagrams and nested homologies.

Pattern vs. Process

Evolutionary biology distinguishes the evidence showing change (pattern) from mechanisms driving change (process).