Podcast
Questions and Answers
A farmer uses a pesticide that initially kills most of the insect pests in his field. However, after several years, the pesticide becomes ineffective. What evolutionary mechanism best explains this phenomenon?
A farmer uses a pesticide that initially kills most of the insect pests in his field. However, after several years, the pesticide becomes ineffective. What evolutionary mechanism best explains this phenomenon?
- Natural selection favored the survival and reproduction of insects with genes for pesticide resistance. (correct)
- The pesticide directly caused mutations in the insects, making them resistant.
- Gene flow introduced new, resistant insects from other populations.
- Genetic drift randomly eliminated the insects susceptible to the pesticide.
Which of the following best illustrates anatomical homology?
Which of the following best illustrates anatomical homology?
- The similar body shape of sharks and dolphins.
- The presence of a tailbone (coccyx) in humans.
- The bone structure in the forelimbs of bats and humans. (correct)
- The wings of butterflies and birds.
How does the fossil record contribute to the understanding of evolution?
How does the fossil record contribute to the understanding of evolution?
- By providing direct evidence of the genetic relationships between modern organisms.
- By showing a complete and uninterrupted lineage of all organisms that have ever lived.
- By revealing the chronological order in which organisms appeared and how they changed over time. (correct)
- By demonstrating that evolution always progresses towards more complex forms.
Scientists discover that two populations of birds, living on separate islands, are very similar genetically but have different beak shapes suited to their respective food sources. What evolutionary mechanism likely contributed to these differences?
Scientists discover that two populations of birds, living on separate islands, are very similar genetically but have different beak shapes suited to their respective food sources. What evolutionary mechanism likely contributed to these differences?
Which situation would most likely lead to rapid evolutionary change in a small population?
Which situation would most likely lead to rapid evolutionary change in a small population?
What is the evolutionary significance of vestigial structures?
What is the evolutionary significance of vestigial structures?
How does the study of developmental homology support the theory of evolution?
How does the study of developmental homology support the theory of evolution?
Biogeography shows marsupials are found in both Australia and South America. What does this indicate about marsupial evolution?
Biogeography shows marsupials are found in both Australia and South America. What does this indicate about marsupial evolution?
Which of the following statements accurately reflects the relationship between evolution and biological fitness?
Which of the following statements accurately reflects the relationship between evolution and biological fitness?
Gene sequences of two different species are found to be very similar. What does this suggest about their evolutionary relationship?
Gene sequences of two different species are found to be very similar. What does this suggest about their evolutionary relationship?
Flashcards
Biological Evolution
Biological Evolution
Change in a population’s inherited traits over generations; populations, not individuals, evolve.
Gene flow
Gene flow
Genes move between populations, changing the genetic makeup through migration.
Mutations
Mutations
Changes in genetic material that can alter genes; can be harmful, beneficial, or neutral.
Genetic Drift
Genetic Drift
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Natural Selection
Natural Selection
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Molecular Homology
Molecular Homology
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Anatomical Homology
Anatomical Homology
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Analogous Structures
Analogous Structures
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Vestigial Structures
Vestigial Structures
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Developmental Homology
Developmental Homology
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Study Notes
Biological Evolution Definition
- Biological evolution is the change in a population’s inherited traits over generations.
- Populations, not individuals, evolve.
- A population has multiple organisms of the same species with variety in the gene pool.
- Inherited traits in a population are coded for by genes.
Mechanisms of Evolution
- Gene flow involves genes moving between populations, impacting genetic makeup through migration.
- Mutations are changes in genetic material that can alter genes, being harmful, beneficial, or neutral.
- Genetic drift is a change in the genetic makeup of a population due to a random chance event.
- Natural selection is a process where organisms with advantageous traits for their environment survive and reproduce more, passing on those genes.
- Biological fitness relates to number of offspring produced.
- Evolution doesn’t necessarily result in a new species.
Molecular Homology
- Molecular homologies compare DNA relatedness.
- It involves looking at homologous amino acids and characteristics of proteins.
- Molecular evidence supports that animals are more related to each other than they would be to a bacterium.
- Molecular evidence supports that the turkey and emu are more closely related than the turkey and the termite because they share a more recent common ancestor.
Anatomical Homology
- Similarity is due to shared common ancestry.
- Homologous structures like the human arm and dog forelimb have similarity in arrangement and components, inherited from a shared common ancestor, but do not have the same functions.
- Analogous structures, like bird and insect wings, have the same function but are not homologous.
- Vestigial structures are inherited from an ancestor, but the structure has generally lost all or most of its function, like a claw on a chicken wing.
Developmental Homology
- Embryology studies development stages and looks for similarities in development among organisms.
- Animals in the phylum Chordata all have a notochord at least in some developmental stage.
- During embryonic development, organisms in Chordata have similar development structures including pharyngeal slits (or pouches) and a postanal tail.
Fossil Record
- A fossil can be remains, an impression, or a trace of an organism that once lived.
- Fossils reveal how characteristics might have changed in a population over time.
- Fossils build understanding about ancestral organisms that once lived.
- Radiometric dating determines the age of the fossil.
Biogeography
- Biogeography combines biology and geography and looks at how organisms are distributed geographically.
- Populations on an island tend to be the most closely related to the populations nearest them.
- Marsupials in Australia and South America have shared common ancestry.
- During the time of Pangea, the continents were connected.
Evolution Continues
- Evolution is not done.
- Populations of organisms continue to change over generations.
- Antibiotic resistance in bacteria is an example of evolution, since generations do not take long.
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