Podcast
Questions and Answers
Feathers either play a role, or may have played a role, in _____.
Feathers either play a role, or may have played a role, in _____.
all of these
_____ is rapid speciation under conditions in which there is little competition.
_____ is rapid speciation under conditions in which there is little competition.
Adaptive radiation
Mass extinctions create conditions that promote _____.
Mass extinctions create conditions that promote _____.
adaptive radiation
The appearance of an evolutionary novelty promotes _____.
The appearance of an evolutionary novelty promotes _____.
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The different finch species found on the Galápagos Islands probably arose as a result of _____.
The different finch species found on the Galápagos Islands probably arose as a result of _____.
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Classifying Reproductive Barriers:
Classifying Reproductive Barriers:
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According to the ______ species concept, a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.
According to the ______ species concept, a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.
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The separation between species is maintained by _______ isolation, which prevents gene flow between species.
The separation between species is maintained by _______ isolation, which prevents gene flow between species.
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But in some cases, distinct species can occasionally interbreed, producing ________ offspring.
But in some cases, distinct species can occasionally interbreed, producing ________ offspring.
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Alternatively, the _______ species concept identifies species based on physical traits or body form.
Alternatively, the _______ species concept identifies species based on physical traits or body form.
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This species concept can be applied to ________ species, and it is the way most of the 1.8 million named species have been identified.
This species concept can be applied to ________ species, and it is the way most of the 1.8 million named species have been identified.
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In the _______ species concept, species are defined by their niche--the role they play in the environment.
In the _______ species concept, species are defined by their niche--the role they play in the environment.
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The ________ species concept defines species as the smallest group of individuals that share a common ancestor and form one branch on the tree of life.
The ________ species concept defines species as the smallest group of individuals that share a common ancestor and form one branch on the tree of life.
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In ________, a population isolated by a geographic barrier becomes a new species as it accumulates changes by natural selection or genetic drift.
In ________, a population isolated by a geographic barrier becomes a new species as it accumulates changes by natural selection or genetic drift.
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In ________, a new species may arise as mating and gene flow are reduced between populations that share the same area.
In ________, a new species may arise as mating and gene flow are reduced between populations that share the same area.
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Many plant species have formed by _______, in which accidents in cell division result in extra sets of chromosomes.
Many plant species have formed by _______, in which accidents in cell division result in extra sets of chromosomes.
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Both allopatric speciation and sympatric speciation depend on the establishment of ________, which prevent(s) gene flow between a new species and its parent species.
Both allopatric speciation and sympatric speciation depend on the establishment of ________, which prevent(s) gene flow between a new species and its parent species.
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________ occur(s) when a species gives rise to many new species after colonizing a region with diverse habitats.
________ occur(s) when a species gives rise to many new species after colonizing a region with diverse habitats.
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Connecting the Concepts: Species and Speciation:
Connecting the Concepts: Species and Speciation:
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Humans are diploid and have 46 chromosomes. How many sets of chromosomes are found in each human gamete?
Humans are diploid and have 46 chromosomes. How many sets of chromosomes are found in each human gamete?
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Humans are diploid and have 46 chromosomes. How many chromosomes are found in each human gamete?
Humans are diploid and have 46 chromosomes. How many chromosomes are found in each human gamete?
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_____ is the process by which haploid gametes form a diploid zygote.
_____ is the process by which haploid gametes form a diploid zygote.
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A particular diploid plant species has 48 chromosomes, or two sets. A mutation occurs and gametes with 48 chromosomes are produced. If self-fertilization occurs, the zygote will have _____ set(s) of chromosomes.
A particular diploid plant species has 48 chromosomes, or two sets. A mutation occurs and gametes with 48 chromosomes are produced. If self-fertilization occurs, the zygote will have _____ set(s) of chromosomes.
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Which of these terms applies to an organism with extra sets of chromosomes?
Which of these terms applies to an organism with extra sets of chromosomes?
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Mutant tetraploid plants _____.
Mutant tetraploid plants _____.
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Most polyploid plants arise as a result of _____.
Most polyploid plants arise as a result of _____.
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How do the skulls of adult chimpanzees and humans differ?
How do the skulls of adult chimpanzees and humans differ?
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The differences between chimpanzee and human observed in these animations is attributable to differences in ____.
The differences between chimpanzee and human observed in these animations is attributable to differences in ____.
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What accounts for human infants having large heads on small bodies?
What accounts for human infants having large heads on small bodies?
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Variations in allometric growth patterns demonstrate how _____.
Variations in allometric growth patterns demonstrate how _____.
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Which of these is a difference between the skull of an adult chimpanzee and the skull of an adult human?
Which of these is a difference between the skull of an adult chimpanzee and the skull of an adult human?
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Which of the following statements about reinforcement is true?
Which of the following statements about reinforcement is true?
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A subset of a population of birds leaves its habitat and colonizes a nearby island. After many generations, the island sinks and the population of birds living on the island returns to its original habitat. Which of the following statements most accurately describes the two bird populations?
A subset of a population of birds leaves its habitat and colonizes a nearby island. After many generations, the island sinks and the population of birds living on the island returns to its original habitat. Which of the following statements most accurately describes the two bird populations?
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A biologist spends her summer break collecting frogs from a remote jungle in Peru. She discovers two distinct color forms that could be variants of a single species or two different species. What would be the most direct test of their species status under the biological species concept?
A biologist spends her summer break collecting frogs from a remote jungle in Peru. She discovers two distinct color forms that could be variants of a single species or two different species. What would be the most direct test of their species status under the biological species concept?
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In _____ isolation, it is physically impossible for two species to mate with each other, often because their genitalia do not fit together properly.
In _____ isolation, it is physically impossible for two species to mate with each other, often because their genitalia do not fit together properly.
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Eastern and western spotted skunks breed at different times of the year. Therefore, they are prevented from interbreeding by _____ isolation.
Eastern and western spotted skunks breed at different times of the year. Therefore, they are prevented from interbreeding by _____ isolation.
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The process of speciation starts with a single species. It often involves the following steps: (1) two populations become physically separated from one another by a barrier to dispersal and stop exchanging genes; (2) the populations experience independent evolutionary changes; (3) changes in one or both populations result in the development of reproductive isolating mechanisms that prevent interbreeding; further changes in geography may bring the groups back into contact. When do you officially have two separate species?
The process of speciation starts with a single species. It often involves the following steps: (1) two populations become physically separated from one another by a barrier to dispersal and stop exchanging genes; (2) the populations experience independent evolutionary changes; (3) changes in one or both populations result in the development of reproductive isolating mechanisms that prevent interbreeding; further changes in geography may bring the groups back into contact. When do you officially have two separate species?
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Darwin thought that significant evolution was much too slow to be witnessed in a human lifetime. Recent experiments by biologists have _____.
Darwin thought that significant evolution was much too slow to be witnessed in a human lifetime. Recent experiments by biologists have _____.
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Of the 59 matings in the experimental groups, how many were between like-adapted flies (flies adapted to the same medium)?
Of the 59 matings in the experimental groups, how many were between like-adapted flies (flies adapted to the same medium)?
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Which of the following statements is best supported by the data on matings in the experimental groups?
Which of the following statements is best supported by the data on matings in the experimental groups?
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Which of the following statements is supported by the data from the control group matings?
Which of the following statements is supported by the data from the control group matings?
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A similar control experiment was performed with flies adapted to maltose, and similar results were obtained. What were these control experiments testing?
A similar control experiment was performed with flies adapted to maltose, and similar results were obtained. What were these control experiments testing?
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Current best estimates suggest that life has been on Earth for how long?
Current best estimates suggest that life has been on Earth for how long?
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If life exists or originated on another planet, most scientists today believe that it is which of the following planets?
If life exists or originated on another planet, most scientists today believe that it is which of the following planets?
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Which of the following is true regarding current scientific thought?
Which of the following is true regarding current scientific thought?
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You discover a new means of energy transfer by organisms living in hydrothermal vents in the ocean. Who is most likely to be interested in funding your research?
You discover a new means of energy transfer by organisms living in hydrothermal vents in the ocean. Who is most likely to be interested in funding your research?
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Which of the following scientists is closest to creating life?
Which of the following scientists is closest to creating life?
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According to most paleoanthropologists, which of the following is true?
According to most paleoanthropologists, which of the following is true?
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If your pituitary gland isn't functioning properly, which of the following will be affected?
If your pituitary gland isn't functioning properly, which of the following will be affected?
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You are a paleoanthropologist studying Neanderthals. Where should you look for their fossils?
You are a paleoanthropologist studying Neanderthals. Where should you look for their fossils?
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What do paleoanthropologists generally believe about genetic findings?
What do paleoanthropologists generally believe about genetic findings?
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How do genomes of species change?
How do genomes of species change?
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Study Notes
Evolution and Speciation
- Feathers have various roles, possibly in thermoregulation, display, and flight.
- Adaptive radiation occurs rapidly in low-competition environments, often during mass extinctions and after the appearance of evolutionary novelties.
- The Galápagos finches exemplify adaptive radiation, having evolved differently due to varying ecological niches.
Reproductive Barriers
- Reproductive barriers are classified as prezygotic (before fertilization) and postzygotic (after fertilization).
- Examples include:
- Behavioral isolation: Differences in mating rituals prevent interbreeding.
- Mechanical isolation: Physical reproductive parts are incompatible.
- Temporal isolation: Species breed at different times.
- Gametic isolation: Sperm and eggs of different species cannot fuse.
- Reduced hybrid fertility: Hybrids are often sterile or have lower fitness.
Species Concepts
- Biological species concept: Defines species based on reproductive isolation and potential to produce viable offspring.
- Morphological species concept: Identifies species by physical traits, applicable to both extinct and asexual species.
- Ecological species concept: Defines species through their ecological niche.
- Phylogenetic species concept: Defines species as groups sharing a common ancestor.
Speciation Mechanisms
- Allopatric speciation: Occurs when populations are geographically isolated, leading to genetic divergence.
- Sympatric speciation: New species arise in overlapping geographic areas, often due to behavioral changes.
- Polyploid speciation: Common in plants, results from errors in cell division leading to extra chromosome sets.
Chromosomal Insights
- Humans are diploid with 46 chromosomes; gametes contain 23 chromosomes.
- Polyploidy in plants often results from hybridization, creating organisms with extra chromosome sets.
Developmental Biology
- Allometric growth explains the size difference between human infants and adults, illustrating how small genetic changes can lead to significant phenotypic variation.
- Adult chimpanzees have prominent brow ridges compared to humans, reflecting allometric differences.
Reinforcement and Isolation
- Reinforcement strengthens reproductive barriers, facilitating natural selection.
- The process of speciation involves physical separation, independent evolutionary changes, and the development of reproductive isolating mechanisms.
Current Scientific Concepts
- Life on Earth has existed for approximately 3.5 billion years, with Mars being a likely candidate for extraterrestrial life origins.
- RNA is considered to precede DNA in evolutionary history.
Paleoanthropology Insights
- When modern humans arose, archaic humans likely vanished in Africa.
- Neanderthal fossils can predominantly be found in Europe, supporting genetic findings that require fossil evidence for validation.
Genetic Changes
- Species’ genomes change through mutations, affecting their evolutionary trajectory.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge with flashcards covering essential concepts from Chapter 14 of Mastering Biology. This chapter focuses on evolutionary biology, including speciation and the role of mass extinctions in shaping biodiversity. Perfect for students looking to reinforce their understanding of these fundamental topics.
