Chapter 22: Descent With Modification Flashcards
What is evolution in biological terms?
Evolution is the change in genetic composition of a population over generations, leading to descent with modification.
What did Darwin mean by ‘descent with modification’?
Darwin proposed that all species are descended from common ancestors and have accumulated adaptations over time, leading to the diversity of life.
What was Aristotle’s view on species?
Aristotle believed species were fixed and arranged in a hierarchy known as the scala naturae.
How did Linnaeus contribute to classification?
Linnaeus developed the binomial nomenclature system and classified organisms into hierarchical categories.
What did Georges Cuvier contribute to paleontology?
Cuvier established the study of fossils and proposed catastrophism, where sudden events shaped Earth’s history.
How did James Hutton and Charles Lyell influence Darwin?
Hutton suggested gradual geological changes (gradualism), and Lyell extended this idea (uniformitarianism), showing Earth was much older than previously thought.
What was Lamarck’s theory of evolution?
Lamarck proposed that traits acquired during an organism’s lifetime (use and disuse) could be inherited by offspring.
Why was Lamarck’s theory incorrect?
Traits acquired during an individual’s lifetime (e.g., muscle growth) are not passed down genetically.
What role did Darwin’s voyage on the HMS Beagle play in his theory?
Darwin observed diverse species, fossils, and geographic variations, leading him to develop his theory of natural selection.
What were Darwin’s key observations that led to his theory?
- Species vary globally (e.g., similar habitats have different species), 2. Species vary locally (e.g., Galápagos finches), 3. Species vary over time (e.g., fossils resemble living species).
What is natural selection?
Natural selection is the process where individuals with advantageous traits are more likely to survive and reproduce, leading to an increase in these traits over generations.
What are the key components of natural selection?
- Variation in traits, 2. Differential survival and reproduction, 3. Heritability of traits, 4. Accumulation of favorable traits over generations.
What are the main types of evidence supporting evolution?
- Fossil record, 2. Biogeography, 3. Comparative anatomy (homologous and vestigial structures), 4. Embryology, 5. Molecular biology.
How do homologous structures provide evidence for evolution?
Homologous structures are anatomical similarities that result from common ancestry, even if their functions differ (e.g., human arm, bat wing, whale flipper).
What is artificial selection?
Artificial selection is the human-driven process of breeding organisms for desired traits, demonstrating how selection can lead to significant changes over time.
How did artificial selection influence Darwin’s thinking?
Darwin recognized that if humans could selectively breed organisms for specific traits, a similar process (natural selection) could shape species in the wild.
What does it mean to call evolution a ‘theory’?
In science, a theory is a well-supported explanation of natural phenomena based on evidence. Evolution is supported by extensive observations and experiments.
How does evolution explain the unity and diversity of life?
Unity is explained by shared ancestry, while diversity arises from adaptations and natural selection in different environments.
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Why was Lamarck’s hypothesis still important despite being incorrect?
Lamarck’s idea that species change over time influenced later scientists, including Darwin, to explore how evolution works.
What was the significance of Charles Lyell’s book Principles of Geology?
Lyell’s book proposed that geological processes happen slowly over long periods, influencing Darwin’s thinking about gradual biological changes.
Why were the Galápagos Islands crucial for Darwin’s theory?
The islands had species that were similar yet uniquely adapted to different environments, suggesting descent with modification.
How did Darwin’s finches support natural selection?
Finches on different islands had distinct beak shapes adapted for specific food sources, showing how selection drives adaptation.
Why do populations evolve, but individuals do not?
Evolution occurs across generations through changes in allele frequencies; individuals cannot change their genetic traits in response to the environment.
