Chapter 22: Descent with Modification: A Darwinian View of Life

Vocabulary flashcards covering key terms from the Darwinian evolution lecture, including natural selection, history, and evidence from fossils, biogeography, and genetics.

Descent with modification

All organisms are related by descent from a common ancestor, with modifications accumulating over time.

Natural selection

A process where individuals with heritable traits that confer survival or reproductive advantages leave more offspring, increasing those traits in the population.

Variation

Differences in traits among individuals in a population; a prerequisite for natural selection.

Heritability

Traits that can be passed from parents to offspring, enabling evolutionary change.

Adaptation

An inherited trait that enhances an organism's survival or reproduction in a specific environment.

Artificial selection

Humans breed individuals with desired traits, shaping populations through human preference rather than environment alone.

Fitness

Relative reproductive success of individuals, often measured by the number of offspring left in the next generation.

Selection pressure

Environmental challenges that determine which traits are favored by natural selection.

Common descent

Idea that all life shares a common ancestor; life shows branching lineages from that ancestor.

Darwin

Charles Darwin (1809–1882), naturalist who proposed natural selection as the mechanism of evolution.

Beagle voyage

Darwin's five-year voyage on the HMS Beagle, which provided key observations leading to evolutionary theory.

Galápagos finches

Different island finch species showing variation that contributed to Darwin's understanding of adaptation.

Binomial nomenclature

Linnaeus' two-part format for naming species (genus and species), e.g., Homo sapiens.

Scala naturae

Aristotle’s idea of a ladder of increasing complexity in living organisms.

Paleontology

The study of fossils and ancient life, foundational to understanding evolutionary history.

Cuvier

Georges Cuvier, a paleontologist who supported catastrophism and helped establish the fossil record’s significance.

Lamarck

Early evolutionist who proposed use/disuse and inheritance of acquired characteristics, though his mechanism was incorrect.

Use and disuse

Lamarck’s idea that body parts used often become larger, unused parts deteriorate.

Inheritance of acquired characteristics

Lamarck’s claim that lifetime modifications could be passed to offspring (not supported by genetics).

Relative dating

Dating method that places fossils in order of age based on strata; older strata are deeper.

Fossil record

Evidence of extinct species, origin of groups, and changes within groups over time.

Biogeography

Study of the geographic distribution of species and its historical patterns, including continental drift.

Homology

Similarity due to shared ancestry, often seen in anatomy, development, and genes.

Vestigial structures

Anatomical features that served a function in ancestors but are reduced or useless now.

Convergent evolution

Independent evolution of similar features in different lineages due to similar selective pressures.

Pax6 gene

A highly conserved gene involved in eye development found across many animals, illustrating deep gene homology.

Post-anal tail and pharyngeal arches

Embryonic vertebrate features that often develop into diverse adult structures, illustrating developmental homology.

Ammonites

Extinct cephalopods used as examples of fossil record and evolutionary history.

La Brea Tar Pits

Pleistocene fossil site illustrating fossil preservation and extinct species.

Theodosius Dobzhansky

Evolutionary biologist who stated that Nothing in Biology Makes Sense Except in the Light of Evolution.

Continental drift

Movement of Earth's continents over time, influencing biogeography and species distribution.

MRSA

Methicillin-resistant Staphylococcus aureus, a drug-resistant bacterial strain arising from antibiotic use.

Antibiotic resistance

Evolution of bacteria to survive antibiotics, often due to misuse or incomplete courses.