Chat with AIExam 2: The Pattern of Evolution
Explain the significance of Archaeopteryx as a transitional fossil in our understanding of phylogenetic relationships.
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VerifiedArchaeopteryx shares a common ancestor with both dinosaurs and modern birds,and indicates that birds were derived from dinosaurs.Its phylogenetic position demonstrates that birds evolved feathers first,which was followed by muscular and skeletal modifications that enabled flight in modern birds.
Compare and contrast the processes of microevolution and macroevolution.
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Answered by Examlex AI CopilotMicroevolution and macroevolution are both processes of biological evolution, but they occur on different scales and involve different mechanisms.
Microevolution refers to the changes in allele frequencies within a population over time. This can occur through mechanisms such as natural selection, genetic drift, gene flow, and mutation. These changes are often small and occur within a relatively short period of time. For example, the development of antibiotic resistance in bacteria or the change in beak size in finches due to changes in food availability are examples of microevolution.
On the other hand, macroevolution refers to the large-scale patterns and processes of evolution that occur over long periods of time, leading to the formation of new species, genera, families, and higher taxonomic groups. This can involve the accumulation of many microevolutionary changes over time, as well as other processes such as speciation, extinction, and adaptive radiation. For example, the evolution of whales from land-dwelling mammals or the diversification of flowering plants are examples of macroevolution.
In summary, microevolution involves small-scale changes in allele frequencies within a population, while macroevolution involves large-scale patterns and processes that lead to the formation of new species and higher taxonomic groups. Both processes are important for understanding the diversity of life on Earth and the mechanisms by which it has evolved over time.
On what basic physical principle does radiometric dating rely?
(35) VerifiedUnstable isotopes decay into either other elements or different isotopes of the same element.Each isotope decays at a constant rate,and the resultant half-life can be used to estimate the age of rocks and once-living materials.
The age of the Earth is estimated at 4.6 billion years.When are the first unicellular organisms thought to have evolved on Earth?
(33) After several generations of selectively breeding mice in a laboratory,Ted Garland and his colleagues established populations of mice that voluntarily chose to run great distances on exercise wheels.The process of establishing these populations of mice is termed ________.
(31) Vestigial structures are found in humans,and are thought to be useless or rudimentary body parts that had an important function in ancestral species.Give two examples of vestigial structures in humans.
(31) Large evolutionary changes that result in the placement of related organisms into different genera or higher-level taxa occur via the process of ________.
(36) The transitional fossil Archaeopteryx shows a combination of traits consistent with the hypothesis that it shared a common ancestor with ________.
(32) Explain how microevolution and artificial selection are demonstrated by the wide variety of dog breeds currently in existence.
(26) The biological species concept,formalized by Ernst Mayr in 1942,defined a species as a ________.
(33) The radioactive isotope ________ has a half-life of 5,730 years,and has an effective dating range of 100 to 100,000 years.
(31) What are two features that characterize processed pseudogenes,and how do these arise?
(34) Processed pseudogenes are useful for testing Darwin's theory of descent with modification because they ________.
(39) Nonfunctional copies of normal genes,which lack both introns and promoters,and are important in estimating evolutionary ages of phylogenetic relationships,are ________.
(37) In response to environmental conditions,the average beak size in a population of birds may change between successive generations.This process of change is referred to as ________.
(37) A useless or rudimentary body part that is thought to have been important in ancestral populations but no longer has a known function is termed a(n)________.
(33) The amount of time it takes for a radioactive element to decay to 50% of its daughter isotope is called ________.
(33) Anatomical features that show an underlying structural similarity even though their superficial structure is different are termed ________ structures.
(33) Radioactive dating techniques have demonstrated that Earth was formed approximately ________ years ago.
(32) The coccyx,a tiny tailbone found in humans,is believed to be a ________ structure.
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