Questions and Answers
Define evolution broadly and then give a narrower definition.
Evolution: Descent with modification; the idea that living species are descendants of ancestral species that were different from the present-day ones. It is also defined more narrowly as the change in the genetic composition of a population from generation to generation.
What did Aristotle believe about species and how could they be arranged?
Aristotle viewed species as fixed and recognized 'affinities' among organisms, concluding that life-forms could be arranged on a ladder of increasing complexity called the scala naturae.
What does the Old Testament hold regarding species?
The Old Testament holds that species were individually designed by God and therefore perfect.
What classification system did Carolus Linnaeus adopt?
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Explain the role of fossils in rock strata as a window to life in earlier times.
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How would Georges Cuvier have explained the appearance of the record of life shown in the rock strata?
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What ideas did James Hutton contribute to the understanding of Earth's geology?
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What is the principle of uniformitarianism proposed by Charles Lyell?
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What is the importance of the principle of uniformitarianism?
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What are the two principles of Lamarck's mechanism of evolution?
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What is considered the great importance of Lamarck's ideas?
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What are adaptations, and can you give two examples?
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Explain the process of natural selection.
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Summarize Darwin's observations that drive changes in species over time.
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From Darwin's observations, what two inferences did he make?
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What can differential reproductive success lead to over time?
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Explain the reasoning behind the phrase 'survival of the fittest'.
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What is MRSA?
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How does research on soapberry bugs demonstrate observable evolutionary change?
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How did MRSA become so dangerous?
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Do antibiotics cause bacteria to become resistant?
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List four evidences for evolution.
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How does the fossil record give evidence for evolution?
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What are homologous structures?
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What are vestigial structures?
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What are analogous structures?
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How do homologous structures give evidence for evolution?
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What is summarized in an evolutionary tree?
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Explain convergent evolution and how analogous structures can arise.
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Can you give two examples of convergent evolution?
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What is biogeography?
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Study Notes
Evolution Overview
- Evolution is defined as descent with modification; living species are descendants of different ancestral species.
- A narrower definition focuses on the genetic changes within a population across generations.
Historical Perspectives on Species
- Aristotle viewed species as fixed and created a scala naturae, a hierarchical classification reflecting increasing complexity.
- The Old Testament describes species as individually designed and perfect creations by God.
- Carolus Linnaeus established a nested classification system but attributed species similarities to divine creation rather than evolutionary links.
Fossils and Geological Evidence
- Fossils are often found in sedimentary rocks, providing evidence of past life forms and how they correlated with Earth's layers (strata).
- Georges Cuvier proposed catastrophism, suggesting that species extinctions were caused by sudden, drastic events rather than gradual evolution.
- James Hutton introduced the idea that geological features are the result of gradual processes, influencing Darwin's thoughts on evolution.
- Charles Lyell's principle of uniformitarianism posits that these gradual geological processes occur at a constant rate over time, implying an Earth much older than previously thought.
Early Theories of Evolution
- Jean-Baptiste de Lamarck proposed the mechanisms of use and disuse, suggesting that body parts used frequently develop stronger, while unused ones deteriorate.
- He also introduced the concept of inheritance of acquired characteristics, suggesting modifications can be passed to offspring.
- Lamarck's emphasis on gradual adaptation over special creation laid groundwork for future evolutionary theories.
Natural Selection and Adaptations
- Charles Darwin identified natural selection as the primary mechanism for evolution, driven by adaptations—traits that enhance survival and reproduction.
- Examples of adaptations include a fawn's coloration for camouflage and specialized features of birds of prey for hunting.
- Natural selection operates as individuals with favorable traits are more likely to survive and reproduce, leading to changes in populations over generations.
Observations Driving Evolutionary Change
- Key observations by Darwin include the existence of trait variation, heritability of traits, species overproduction, and competition for resources.
- Inferences from these observations suggest that advantageous traits accumulate in populations over time, leading to evolutionary change.
Differential Reproductive Success
- Differential reproductive success enhances the prevalence of beneficial adaptations, which can lead to the formation of new species.
- The phrase "survival of the fittest" highlights that populations, rather than individuals, undergo evolutionary change over time.
Modern Examples and Evidence of Evolution
- MRSA (methicillin-resistant Staphylococcus aureus) illustrates evolution through antibiotic resistance developed over time from selective pressures.
- Research on soapberry bugs shows how beak length evolved in response to changes in food sources due to introduced plant species.
Evidence Supporting Evolution
- Evolution can be directly observed, exemplified by antibiotic-resistant bacteria.
- Homology demonstrates shared ancestry through structural similarities among different species, such as mammalian forelimbs.
- The fossil record illustrates historical biodiversity and species extinction patterns.
- Biogeography examines species distribution shaped by geological and environmental factors.
Structural Evidence for Evolution
- Homologous structures share a common ancestor, showing structural similarities despite differing functions.
- Vestigial structures, remnants from ancestors, illustrate evolutionary change, such as leg bones in some snake species.
- Analogous structures arise from convergent evolution, where unrelated species develop similar features to solve similar environmental challenges.
Convergent Evolution
- Convergent evolution results in species developing similar traits independently due to adapting to analogous environments, like sugar gliders and flying squirrels, or the wings of bats and birds.
- Biogeography studies how geographic distribution and historical movements, like continental drift, impact species distribution and the presence of endemic species unique to specific regions.
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Description
Test your understanding of evolution with these flashcards from AP Biology Chapter 22. This chapter explores the concept of descent with modification and provides insights into how living species evolve over generations. Use these flashcards to reinforce key definitions and ideas essential to Darwinian evolution.