Darwin and Theory of Evolution (2) Flashcards
(32 cards)
Q: What is natural selection, and what are its key conditions for it to occur?
Natural selection is the process by which individuals with advantageous traits survive and reproduce more successfully. It requires: 1) variation in traits, 2) differential survival or reproduction based on those traits, and 3) heritability of traits.
Q: How does variation in a population contribute to evolution by natural selection?
: Variation allows some individuals to have traits that are better suited to the environment, leading to differential survival and reproduction. Over time, favorable traits increase in frequency within the population.
What is the significance of heritability in evolution?
Heritability ensures that advantageous traits are passed down to the next generation. Without heritability, traits favored by natural selection would not be passed on, preventing evolutionary change.
How does the environment influence which traits are advantageous?
Environmental factors determine which traits are beneficial. As environments change, traits that increase an organism’s survival and reproduction in that specific environment become advantageous
Q: Explain the difference between natural selection and artificial selection.
A: Natural selection occurs when environmental pressures favor certain traits for survival, while artificial selection involves human intervention to breed organisms with desired traits, such as in domesticated animals or crops.
How do fossils provide evidence for evolution?
Fossils show a record of species that existed in the past and demonstrate changes in species over time. Transitional fossils, in particular, show intermediate forms between ancient and modern species, supporting gradual change.
How do homologous structures support the theory of evolution?
Homologous structures are body parts that are similar in different species due to shared ancestry. These structures may have different functions but reflect a common evolutionary origin.
Q: What role does differential reproductive success play in natural selection?
A: Individuals with traits that increase their ability to survive and reproduce will leave more offspring, causing those traits to become more common in the population over generations.
Q: How does biogeography provide evidence for evolution?
Biogeography studies the distribution of species across different geographic areas. Similar species found in nearby regions suggest they evolved from a common ancestor and adapted to local conditions.
Q: What is the significance of transitional forms in evolutionary biology?
Transitional forms bridge the gaps between distinct groups of organisms and show how species evolved through intermediate stages, providing direct evidence of descent with modification.
What is the relationship between genetic variation and the process of evolution?
Genetic variation provides the raw material for evolution. Without variation, natural selection would have no differences to act on, and evolution could not occur.
Q: How does environmental change drive evolution in populations?
A: When the environment changes, traits that were once advantageous may no longer be. Populations must adapt through natural selection, where individuals with traits suited to the new environment survive and reproduce.
Q: Explain the concept of fitness in the context of natural selection.
A: Fitness refers to an individual’s ability to survive and reproduce in its environment. Higher fitness means an individual is more likely to pass on its traits to the next generation, influencing the evolutionary process.
Q: What is meant by the phrase “populations evolve, not individuals”?
A: Evolution occurs at the population level as the frequency of certain traits or alleles changes over time. Individuals do not evolve; they either survive and reproduce or do not, based on their traits.
Q: How do vestigial structures provide evidence for common ancestry?
A: Vestigial structures are remnants of organs or structures that had a function in an ancestor but are no longer functional in modern species. Their presence supports the idea that species evolved from common ancestors.
Q: How do changes in allele frequencies lead to evolution?
A: Evolution is defined as the change in allele frequencies in a population over time. As natural selection favors certain alleles, they become more common, leading to evolutionary change.
Q: How does reproductive isolation contribute to the formation of new species?
A: Reproductive isolation prevents gene flow between populations, allowing them to evolve independently. Over time, this can lead to the development of new species as genetic differences accumulate.
Q: What is the difference between stabilizing, directional, and disruptive selection?
A: Stabilizing selection favors the average traits in a population, directional selection favors one extreme, and disruptive selection favors both extremes, leading to increased variation or speciation.
Q: Why is genetic diversity important for the survival of a population?
A: Genetic diversity provides a population with a greater range of traits to adapt to changing environments. Populations with low diversity are more vulnerable to extinction if they cannot adapt.
Q: How can artificial selection lead to unintended consequences in a population?
A: Artificial selection may focus on certain desirable traits while ignoring others, potentially reducing genetic diversity and leading to increased vulnerability to diseases or environmental changes.
: How does uniformitarianism differ from catastrophism in shaping Earth’s history?
Uniformitarianism suggests that Earth’s features are shaped by slow, gradual processes over long periods (e.g., erosion, sedimentation), while catastrophism suggests that Earth’s features result from sudden, large-scale events (e.g., floods, volcanic eruptions).
How did Charles Lyell’s geological findings influence Darwin’s theory of evolution?
Lyell’s work on uniformitarianism suggested that the Earth was much older than previously thought, providing Darwin with the necessary timescale for evolution by natural selection to occur.
What is the significance of Darwin’s finches in the development of the theory of natural selection?
Darwin’s observation of finches on the Galápagos Islands, which had different beak shapes suited to their specific diets, helped him understand how natural selection could lead to the adaptation of species to their environments.
Q: Why are homologous structures considered evidence of common ancestry?
A: Homologous structures are similar body parts in different species that serve different functions, indicating they evolved from a common ancestor. The similarity in structure despite functional differences suggests descent with modification.
