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Questions and Answers
What is one reason a trait might persist in a population despite the current selective regime?
What is one reason a trait might persist in a population despite the current selective regime?
The adaptationist programme suggests that all traits are adaptations with adaptive significance.
The adaptationist programme suggests that all traits are adaptations with adaptive significance.
True
What term describes a gene that affects more than one trait?
What term describes a gene that affects more than one trait?
Pleiotropy
Traits may have been selected for in a past environment that no longer exists, known as ________.
Traits may have been selected for in a past environment that no longer exists, known as ________.
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Which of the following is a reason traits may persist despite low cost?
Which of the following is a reason traits may persist despite low cost?
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Which of the following methods is NOT used to study adaptation?
Which of the following methods is NOT used to study adaptation?
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What is phenotypic plasticity?
What is phenotypic plasticity?
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Vestigial characters are traits that serve a current useful function in an organism.
Vestigial characters are traits that serve a current useful function in an organism.
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Nucleated red blood cells (RBCs) are characterized by their lack of nuclei.
Nucleated red blood cells (RBCs) are characterized by their lack of nuclei.
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How does the freshwater Mexican cavefish relate to the concepts of adaptation and variation?
How does the freshwater Mexican cavefish relate to the concepts of adaptation and variation?
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Acclimatization and acclimation are the same processes.
Acclimatization and acclimation are the same processes.
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What is a character trait that is considered an adaptation in physiology?
What is a character trait that is considered an adaptation in physiology?
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What is one way biologists can directly observe changes in allele frequencies over generations?
What is one way biologists can directly observe changes in allele frequencies over generations?
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The relationship between _____ and _____ explains how traits are expressed in organisms.
The relationship between _____ and _____ explains how traits are expressed in organisms.
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Adaptation through natural selection leads to an organism whose physiology, anatomy, and behavior are matched to the demands of its __________.
Adaptation through natural selection leads to an organism whose physiology, anatomy, and behavior are matched to the demands of its __________.
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Match the following adaptation study methods with their descriptions:
Match the following adaptation study methods with their descriptions:
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Match the terms with their correct definitions:
Match the terms with their correct definitions:
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Which statement best describes the process of evolution?
Which statement best describes the process of evolution?
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Traits evolve because they serve a specific purpose.
Traits evolve because they serve a specific purpose.
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Explain the difference between acclimation and acclimatization in the context of adaptation.
Explain the difference between acclimation and acclimatization in the context of adaptation.
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What does phylogenetic inertia refer to?
What does phylogenetic inertia refer to?
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Adaptation is solely defined as the mechanism by which an organism survives.
Adaptation is solely defined as the mechanism by which an organism survives.
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What is the adaptive significance of hemoglobin?
What is the adaptive significance of hemoglobin?
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Evolution is described as a ________, not an engineer.
Evolution is described as a ________, not an engineer.
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Why might we not see the best solution to a challenge in evolution?
Why might we not see the best solution to a challenge in evolution?
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The mechanism of a trait and its adaptive significance are the same concept.
The mechanism of a trait and its adaptive significance are the same concept.
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Who shared the Nobel Prize in Physiology or Medicine with Francois Jacob?
Who shared the Nobel Prize in Physiology or Medicine with Francois Jacob?
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What distinctive feature does the Mexican cavefish display due to its adaptation to darkness?
What distinctive feature does the Mexican cavefish display due to its adaptation to darkness?
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Phylogenies can be constructed using only molecular techniques.
Phylogenies can be constructed using only molecular techniques.
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What is the adaptive significance of traits like the loss of pigmentation in cave-dwelling species?
What is the adaptive significance of traits like the loss of pigmentation in cave-dwelling species?
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A _______ provides the history of the evolution of an organism by showing relationships to other organisms.
A _______ provides the history of the evolution of an organism by showing relationships to other organisms.
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Match the following types of red blood cells with their description:
Match the following types of red blood cells with their description:
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Which of the following organisms typically has nucleated red blood cells?
Which of the following organisms typically has nucleated red blood cells?
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The comparative method is important for determining if a trait is an adaptation.
The comparative method is important for determining if a trait is an adaptation.
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What may be a reason for the loss of nucleated red blood cells in mammals?
What may be a reason for the loss of nucleated red blood cells in mammals?
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The ___________ method provides information about evolutionary history.
The ___________ method provides information about evolutionary history.
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What happens to red blood cells as a result of evolutionary adaptations in certain species?
What happens to red blood cells as a result of evolutionary adaptations in certain species?
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Study Notes
Course Information
- Course Title: Biology 3305
- Course Description: Human and Comparative Physiology
Dobzhansky Quote
- "Nothing in biology makes sense except in the light of evolution" - Theodosius Dobzhansky
- Dobzhansky was a Russian-American geneticist and evolutionary biologist
Environmental Adaptation
- Animals are typically matched to their environmental challenges.
- Animals adapt to their environment via phenotypic plasticity which includes acclimation and acclimatization
Meaning of Adaptation
- A short-term compensatory change (phenotypic plasticity)
- Acclimation: A persisting change due to induced exposure to high/low temperature
- Acclimatization: A persisting change due to environmental exposure
- A trait
- Hemoglobin
- A process
- Evolution
Evolutionary Adaptation
- Evolution through natural selection creates a match between an organism's physiology, anatomy, and behavior to their environment
- The process involves allele frequency changes over generations
- Evolution is a slow, irreversible process
- A trait is considered an adaptation only if there is evidence of its selection
Traits and Their Persistence
- Traits are not always selected for a purpose, traits can appear through mutations
- Persistence of a trait is due to selection, and the trait's relative benefit to the bearer
- Phylogenetic inertia: Interaction between ancestral traits and selection in ancestral environments
- Traits may persist due to no detriment or past adaptive value in a no longer existing environment
- Preadaptation or exaptation: A trait selected in a past environment that may not necessarily useful for the current environment
Evolution as a Tinkerer
- "Evolution is a tinkerer, not an engineer" - Francois Jacob
- Jacob received a Nobel Prize for his work in physiology or medicine
Adaptive Significance
- An adaptation is a product of natural selection
- Adaptive significance identifies why a trait or mechanism is beneficial, answering "Why did natural selection favour the trait?"
Adaptive Significance and Mechanism
- Mechanism does not imply adaptive significance, and adaptive significance does not imply mechanism
- E.g. Hemoglobin's mechanism is binding oxygen and transporting it to tissues
- E.g, Hemoglobin's adaptive significance is that animals with hemoglobin can engage in sustained aerobic activity which increases the likelihood of survival
Not All Traits Are Adaptations
- Not all traits are adaptations
- The adaptationist programme is a methodology that suggests that the existence of a trait implies its adaptive significance
- Sometimes a trait may be a product of phylogenetic inertia
- Evidence of selection is needed to deem a trait an adaptation, also known as putative or possibly an adaptation
Reasons for Trait Persistence (Other than Selection)
- Genetic drift
- Genetic linkage and pleiotropy (one gene affects more than one trait)
- A trait persists due to its no harm (or low cost)
- A trait may persist despite being maladaptive in the current environment
- Traits may have been selected in a past environment that no longer exists
- Preadaptation/exaptation: Traits that are selected in the past can be used in a new way
Exaptation Examples (Preadaptation)
- Mexican Cavefish: The cavefish is the same species as the surface-dwelling tetra, but the cavefish has lost its pigmentation and grown skin over its eyes because it adapted to living in complete darkness.
Studying Adaptation
- Biologists cannot directly observe evolution
- Use the comparative method
- Use phylogenetic reconstructions
- Look for independent evolution in different environments
- Use statistically-sound methods analyzing data from closely related species
- Use lab populations to observe changes in allele frequency when subjected to stressors
- Employ single-generation studies of individual genetic variations within a species
- Observe the frequency of alleles within a population in relation to different environmental conditions
- Genetic manipulation through methods like gene substitutions, knockouts to determine the effects
- Use the comparative method
Relationship Between Phenotype and Genotype
- Genotype produces the phenotype
- Phenotype is influenced by random processes, development, biochemistry, physiology, morphology, behavior and the environment
- Natural selection acts upon the phenotype, influencing further biological evolution
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Description
Explore the fundamental concepts of adaptation and evolution in this quiz for Biology 3305. Delve into the mechanisms of environmental adaptation, phenotypic plasticity, and the role of natural selection in shaping species. Test your understanding of these essential physiological processes.
