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Questions and Answers
Which of the following best describes Darwin's concept of 'descent with modification'?
Which of the following best describes Darwin's concept of 'descent with modification'?
- New species arise independently, with no relation to pre-existing species.
- Species remain unchanged over time, perfectly adapted to their environments.
- Descendants of ancestral organisms spread into diverse habitats and accumulate adaptations. (correct)
- Organisms intentionally modify their traits during their lifetime to better suit their environment.
According to Darwin's theory of natural selection, what role does the environment play in the survival and reproduction of organisms?
According to Darwin's theory of natural selection, what role does the environment play in the survival and reproduction of organisms?
- The environment is a static backdrop that has no influence on an organism's traits.
- The environment only affects the physical characteristics of an organism, not its ability to reproduce.
- The environment provides unlimited resources for all organisms, ensuring equal survival rates.
- The environment acts as a selective force, favoring individuals with advantageous traits and hindering those without. (correct)
What is the fundamental idea presented in Darwin's book, The Origin of Species?
What is the fundamental idea presented in Darwin's book, The Origin of Species?
- Evolution is driven by random mutations with no selective pressure.
- Acquired characteristics during an organism's lifetime can be inherited by its offspring.
- Species are immutable and were created in their present form.
- Species evolve over time through the mechanism of natural selection. (correct)
How did Thomas Malthus's ideas influence Darwin's theory of natural selection?
How did Thomas Malthus's ideas influence Darwin's theory of natural selection?
Which of the followings options describes 'struggle for existence'?
Which of the followings options describes 'struggle for existence'?
Lamarck's theory of evolution differs from Darwin's primarily in its emphasis on what?
Lamarck's theory of evolution differs from Darwin's primarily in its emphasis on what?
Which statement accurately describes the relationship between natural selection and evolution?
Which statement accurately describes the relationship between natural selection and evolution?
A population of birds exhibits variation in beak size. Birds with larger beaks are better at cracking tough seeds during a drought, while birds with smaller beaks are more efficient at consuming small seeds when rainfall is plentiful. Which evolutionary outcome is most likely after several years of alternating droughts and periods of heavy rainfall?
A population of birds exhibits variation in beak size. Birds with larger beaks are better at cracking tough seeds during a drought, while birds with smaller beaks are more efficient at consuming small seeds when rainfall is plentiful. Which evolutionary outcome is most likely after several years of alternating droughts and periods of heavy rainfall?
Which scenario exemplifies how an adaptation beneficial in one environment might be detrimental in another?
Which scenario exemplifies how an adaptation beneficial in one environment might be detrimental in another?
Why is it inaccurate to state that 'species adapt in order to survive'?
Why is it inaccurate to state that 'species adapt in order to survive'?
Why do panda mothers typically raise only one of the two to three offspring they produce?
Why do panda mothers typically raise only one of the two to three offspring they produce?
How does a beneficial variation within a species become more common over generations?
How does a beneficial variation within a species become more common over generations?
What determines which individuals in a species are 'selected' by the environment?
What determines which individuals in a species are 'selected' by the environment?
According to the theory of natural selection, what is the primary factor determining which individuals leave more offspring?
According to the theory of natural selection, what is the primary factor determining which individuals leave more offspring?
What does 'fitness' refer to in the context of 'survival of the fittest'?
What does 'fitness' refer to in the context of 'survival of the fittest'?
Why is 'natural selection' sometimes referred to as 'survival of the fittest'?
Why is 'natural selection' sometimes referred to as 'survival of the fittest'?
In the case study of the peppered moth, what environmental change led to a shift in the moth population's color?
In the case study of the peppered moth, what environmental change led to a shift in the moth population's color?
How did the prevalence of darker-colored peppered moths increase after the industrial revolution?
How did the prevalence of darker-colored peppered moths increase after the industrial revolution?
Flashcards
Darwin's Theory
Darwin's Theory
Darwin's explanation for how evolution occurs, presented with Alfred Wallace.
Evolution
Evolution
Species change over time, descending from ancestral species. In essence, all life is related.
Natural Selection
Natural Selection
The primary mechanism of evolution, where the environment selects for beneficial traits.
Descent with Modification
Descent with Modification
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Struggle for Existence
Struggle for Existence
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Fitness (in evolution)
Fitness (in evolution)
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Variation
Variation
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Populations Evolve!
Populations Evolve!
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Role of Environment
Role of Environment
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Fitness
Fitness
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Survival of the Fittest
Survival of the Fittest
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Genetic Variation Importance
Genetic Variation Importance
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typica
typica
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carbonaria
carbonaria
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Study Notes
- Charles Darwin, with Alfred Wallace, presented his evolution mechanism
- Darwin published "The Origin of Species" in 1859
The Origin of Species
- There are 2 major points:
- All species on Earth today descended from ancestral species
- Species evolve over time
- Natural selection causes species to change over time
Descent with modification
- The major concept is descent with modification
- Definition: descendants of the earliest organisms spread into various habitats over millions of years
- The descendants accumulated different modifications, or adaptations
- The term "evolution" now replaces "descent with modification"
- Descent with modification explains the diversity of life
- Insects with a common ancestor have different adaptations
- Those adaptations allow them to survive in their unique environments (i.e. camouflage patterns)
Natural Selection
- It is based on 3 observations:
- The struggle for existence
- Variation
- The role of the environment
The Struggle for Existence
- Related to Malthus' idea: species produce more offspring than resources available
- Hence, there is a 'struggle for existence' amongst individuals of a population
- In most cases, only a small percentage of offspring survive every generation and reproduce
- Pandas produce 2-3 offspring at a time, usually only one survives
- Limited milk production by the mother causes this
Variation
- Variation: differences among members of the same species
- Sometimes a certain variation is best suited to a specific environment
- Individuals with this heritable variation are more likely to produce the most offspring
- This variation will become more common over many generations
Role of the Environment
- The environment selects individuals suited with variations that are best suited for that environment
Theory of Natural Selection
- Natural Selection: the process by which individuals with inherited characteristics suited to their environment leave more offspring than individuals with adaptations less suited to the environment
Survival of the Fittest
- Fitness: an individual's ability to survive and reproduce in a specific environment
- Survival of the Fittest: individuals with increased fitness will survive and reproduce the most successfully
- Synonym for natural selection
- Natural selection doesn't make organisms better
- An adaptation might work well in an environment but not in another
Case Study: The Peppered Moth
- There must be genetic variation for natural selection to occur
- There are 2 peppered moth forms in England:
- typica
- carbonaria
- The lighter colored moth is more difficult to spot against typical tree bark
- The darker moth stands out and makes easier prey
- At the beginning of the industrial revolution, coal burning produced soot, covering the countryside of some areas
- Now the white moths stand out, while the black moths are hard to see
- The black moths are more likely to survive and pass on the genes for dark color to offspring
- Over time, the black moths became more common than the white moths
Evolution Theories
- Lamarck: Giraffes grew longer necks during their lifetime; this adaptation could be and passed to offspring
- Darwin: Some giraffes were be born with long necks and some with short (variation)
- The environment would have selected giraffes with long necks (higher fitness)
Troubleshooting
- Populations evolve, individuals do not
- Species survive because they adapt, they don't adapt in order to survive
- An adaptation is a characteristic that is heritable
- An adaptation useful in one environment may not be in another
- Natural selection is the mechanism for evolution
- Evolution is not the same as speciation; a population can evolve without creating a totally different species
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Description
Explore the major concepts from Darwin's Origin of Species, including descent with modification (evolution) and natural selection. Learn how species adapt to different environments. Discover the observations that underpin the theory of natural selection.
