Descent with Modification: A Darwinian View of Life

Flashcards covering key vocabulary terms related to 'Descent with Modification: A Darwinian View of Life', including pre-Darwinian views, Charles Darwin's theory of natural selection, Lamarck’s ideas, and various lines of evidence for evolution.

Evolution

The mechanism by which the diversity of life on Earth originated, summarized as 'descent with modification'; also defined as the change in the genetic composition of a population over time.

Descent with Modification

The process by which species accumulate differences from their ancestors as they adapt to different environments over time, summarizing evolution.

Aristotle's Scale of Life

A concept that organisms are arranged from simple to complex, with species considered unchanging, which influenced Western thought.

Fixed Species Concept

The idea, proposed by Carolus Linnaeus, that the 'Creator' designed each species for a particular purpose and that species were unchanging.

Carolus Linnaeus

Biologist who proposed the Fixed Species Concept and founded the modern field of Taxonomy.

Taxonomy

The modern field of identifying and classifying species, founded by Carolus Linnaeus.

Georges Cuvier

The founder of Paleontology, who attempted to relate fossils to current life, proposing Catastrophism.

Paleontology

The study of fossils, founded by Georges Cuvier.

Catastrophism

Cuvier's theory that differences in fossil strata are due to catastrophic events that wiped out species, allowing others to move in, opposing evolution.

James Hutton

Proposed Gradualism, explaining Earth's geologic features through gradual mechanisms.

Gradualism

Hutton's idea that Earth's changes were gradual, not catastrophic, such as valleys formed by rivers.

Charles Lyell

Incorporated Hutton’s gradualism into his idea of Uniformitarianism, suggesting geological processes operate at the same rate over Earth’s history.

Uniformitarianism

Lyell's concept that geological processes have operated at the same rate over Earth's history, implying a very old Earth and suggesting slow changes can cause substantial geological changes.

Jean Baptiste Lamarck

Revolutionary scientist who first proposed evolutionary change explains the fossil record, suggesting life changed from simple to complex over time.

Use and Disuse

Lamarck's proposed mechanism of evolution where body parts used to survive become larger and stronger, while unused parts deteriorate.

Acquired Characteristics

Lamarck's proposed mechanism of evolution where modifications acquired throughout an organism's life (due to use/disuse) were passed onto offspring.

Charles Darwin

The father of the modern theory of evolution, known for 'Descent with Modification'.

HMS Beagle Voyage

Darwin's journey (1831-1836) during which he made observations of fossils, earthquakes, and species diversity that contributed to his ideas on Natural Selection.

Adaptations

Inherited characteristics of organisms that enhance their survival and reproduction in specific environments.

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than do other individuals because of those traits.

Alfred Wallace

Published a paper on Natural Selection nearly identical to Darwin's ideas, leading to a joint presentation in 1858.

The Origin of Species

Darwin's foundational book published in 1859, documenting evolution and proposing Natural Selection as its mechanism.

Darwin's Observation #1

Members of a population often vary in their inherited traits.

Darwin's Observation #2

All species can produce more offspring than their environment can support, and many of these offspring fail to survive and reproduce.

Darwin's Inference #1

Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than do other individuals ('Descent with Modification').

Darwin's Inference #2

This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations ('Modification by Means of Natural Selection').

Requirements for Natural Selection

Elements necessary for natural selection to occur: variation within a population and long periods of time.

Units of Evolution

Populations are the units of evolution; individuals do not evolve, only inherited characteristics can lead to species evolution.

Artificial Selection

When humans determine the characteristics that survive and reproduce, resulting in various breeds of animals and plants.

Direct Observation of Evolutionary Changes

Evidence for evolution seen in real-time, such as changes in soapberry bug beak length or the evolution of drug resistance in bacteria.

Fossil Record

Documents the pattern of evolution, showing that past organisms differed from present-day organisms and that many species have become extinct.

Homology (Anatomy)

Evidence for evolution based on underlying similarities in structures (homologous structures) or embryonic development between related species due to common ancestry.

Homologous Structures

Variations on a structural theme that was present in their common ancestor, displaying a common 'building plan' with divergent functions (e.g., mammalian forelimbs).

Vestigial Structures

'Leftover' structures of marginal, if any, importance to the organism; remnants of features that served a function in the organism’s ancestors (e.g., pelvis/leg bones in some snakes and whales).

Homology in Embryos

Anatomical homologies visible in vertebrate embryos, such as pharyngeal arches, which develop into different structures but indicate a common ancestor.

Convergent Evolution

The independent evolution of similar features in different lineages, where unrelated organisms show similar adaptations due to similar environmental pressures.

Analogous Structures

Characteristics present on different species that have a similar function but are anatomically/structurally different, a product of convergent evolution.

Biogeography

Evidence for evolution based on the geographic distribution of species, providing insights into their evolutionary history (e.g., marsupials in Australia).

Island Biogeography

Explains the diversity of species on islands (like Darwin's finches) as a result of a common ancestor migrating to different islands, leading to speciation due to unique selective pressures.

Molecular Evidence

The study of evolution at the DNA or protein level, revealing the relatedness of different species based on similarity in their genetic sequences.