Flashcards
Describe the historical perspective on the hierarchy of life as understood by the Greeks, including the role of God in creation and how this view contrasts with modern classification systems such as that developed by Linnaeus. What implications did this have for the understanding of evolution?
The Greeks viewed life as a Great Chain of Being with a hierarchy from plants to angels, created by God. This contrasts with Linnaeus’s classification system, which is more complex and reflects evolutionary relationships.
How did Charles Darwin’s theory of natural selection change the understanding of species and their relationships? Discuss the implications of his ideas on the common ancestry of organisms and the hierarchy of life.
Darwin’s theory posited that species are not fixed and share a common ancestor, reshaping the hierarchy of life by placing humans among other animals, rather than at the top.
Define the three pillars of Darwinian evolution and provide examples for each. How do these concepts contribute to our understanding of how species evolve over time?
The three pillars are: 1) Species are not immutable (e.g., finch beak variation), 2) Descent with modification (e.g., homologous structures), 3) Natural selection (e.g., survival of the fittest). These concepts explain species change.
Explain the concept of natural selection as a driver of evolution. How does it act on variation within populations, and what are the consequences for species survival and reproduction?
Natural selection favors individuals with advantageous traits, leading to greater survival and reproduction rates, thus driving evolutionary change in populations.
Discuss the process of speciation, including the differences between allopatric and sympatric speciation. What role does reproductive isolation play in the formation of new species?
Speciation occurs through reproductive isolation, with allopatric speciation involving geographic barriers and sympatric speciation occurring without such barriers, leading to distinct species.
How does the concept of descent with modification illustrate the relationship between related species? Provide examples of homologous structures that support this idea.
Descent with modification shows how related species diverge over time. Examples include human arms, seal flippers, and bat wings, which are homologous structures indicating common ancestry.
Describe the concept of macroevolution and its significance in understanding evolutionary changes among large taxonomic groups. What are the key components that macroevolution encompasses, particularly in relation to species origin, diversification, and extinction over extended periods?
Macroevolution explains evolutionary changes above the species level, including the origin, diversification, and extinction of species over long periods.
Define the terms monophyly, polyphyly, and paraphyly in the context of phylogenetic classification. How do these classifications differ in terms of their relationship to common ancestors and their respective descendant groups?
Monophyly includes a common ancestor and all descendants; polyphyly does not include the common ancestor; paraphyly includes the common ancestor but not all descendants.
How do mutations contribute to evolutionary change, and what are the different sources of mutations? Discuss both exogenous and endogenous sources, and explain their roles in introducing genetic variation.
Mutations introduce genetic variation and can arise from exogenous sources like UV radiation and chemical mutagens, or endogenous sources like reactive oxygen species and hydrolysis.
Explain the difference between germline mutations and somatic mutations. How do these types of mutations affect inheritance and the cells they impact?
Germline mutations affect gametes and are heritable, while somatic mutations affect daughter cells of a single cell and are not heritable.
How frequently do mutations occur in the human genome, and what is the estimated mutation rate per nucleotide per generation? Additionally, how many new mutations does a baby typically inherit from its parents?
The mutation rate in humans is about 10^-8 mutations per nucleotide per generation, leading to approximately 50-70 new mutations in a baby.
Discuss the reasons behind the higher contribution of mutations from fathers compared to mothers in human offspring. What biological process accounts for this difference in mutation rates?
Fathers contribute more mutations due to more cell divisions during spermatogenesis, resulting in about four times the mutations compared to mothers.
Describe the concept of genetic drift, including its definition, how it affects allele frequencies in populations, and the significance of population size in its influence. Additionally, explain what a gene pool is and its relevance to genetic variation within a population.
Genetic drift is the random fluctuation of allele frequencies between generations, more impactful in smaller populations. A gene pool is the total genetic information in a population.
Define macroevolution and microevolution, highlighting the differences between the two concepts. Discuss how macroevolution is evidenced through fossil records and phylogenetic transitions, while microevolution can be observed directly in natural populations.
Macroevolution refers to evolution across species over long periods, evidenced by fossil records and phylogenetic changes. Microevolution occurs within species and can be directly observed.
How does natural selection contribute to adaptation in populations? Discuss the role of advantageous and deleterious mutations in this process, and explain how these mutations can influence the traits of organisms over generations.
Natural selection acts on advantageous mutations that enhance survival and reproduction, while deleterious mutations are selected against, shaping adaptive traits in populations.
