learning objectives 3 Flashcards
What is microevolution?
Microevolution refers to changes in the gene pool over short time scales, driven by mutation, gene flow, genetic drift, and natural selection. Examples include antibiotic resistance and changes in beak size in finches.
What is macroevolution?
Macroevolution involves major changes in traits over long time scales, leading to the origin of new species. Examples include the evolution of whales and the adaptive radiation of Galapagos finch species.
How do microevolution and macroevolution differ?
Microevolution occurs over short time scales, focusing on changes within a gene pool, while macroevolution occurs over long time scales, focusing on major trait changes and the origin of new species. However, there is no clear-cut distinction between the two.
What is the principle of stratigraphy?
Stratigraphy is the study of rock layers (strata) and the fossils within them. It is based on the principle that younger rocks are deposited on top of older rocks, meaning younger fossils are found above older fossils.
How does stratigraphy relate to fossil formation?
Fossils form in sedimentary rocks as plant and animal remains are buried by layers of sediment. Over time, these layers accumulate, with younger layers on top, making younger fossils easier to find than older ones
How do extinction and transitional forms in the fossil record provide evidence for evolution?
Extinction and transitional forms show a pattern in the fossil record, where species evolve over time into other species. This pattern, supported by stratigraphy, provides evidence for the theory of evolution.
hat hypothesis were researchers testing when they discovered Tiktaalik?
Researchers were testing the hypothesis that a transitional form between fish and tetrapods would be found in rocks around 375 million years old. Tiktaalik, with features of both fish and tetrapods, confirmed this hypothesis.
How does Tiktaalik resemble both modern tetrapods and fish?
Tiktaalik resembles fish with its specialized fins but resembles tetrapods with its flat head, eyes on top, neck, and ribs, making it a transitional form between the two.
What evidence shows that Archaeopteryx is a transitional form between reptiles and birds?
Archaeopteryx had features of both dinosaurs (toothed beak, winged claws, long bony tail) and birds (feathered wings), indicating it was a transitional form between reptiles and birds.
What are vestigial structures and how do they provide evidence for evolution?
Vestigial structures are reduced, functionless structures in a species that were functional in their ancestors. They provide evidence for evolution by showing that species lose features when there is no selection to maintain them.
Give examples of vestigial structures.
Examples include vestigial eyes in cave-dwelling vertebrates like the Mexican tetra and blind cave salamander, as well as vestigial wings in flightless birds.
What is homology and how does it reveal common evolutionary origins?
Homology refers to similarities in structures, genes, or development across species due to shared ancestry. An example is the similar skeletal structure of tetrapod forelimbs, despite different functions.
What are the different types of homology?
Structural homology refers to similar structures across species, developmental homology refers to inherited similarities during development, and molecular homology refers to similarities at the molecular level, such as genetic code.
Provide an example of a homologous structure in two species.
The forelimbs of humans and bats are homologous, sharing the same basic skeletal structure despite different functions.
Describe an example of evolution that has occurred within the past 50 years in a multicellular species.
One example is the evolution of pesticide resistance in insects, where strong selection for resistant genotypes has occurred due to the overuse of insecticides.
