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Questions and Answers
Which of the following is NOT a desirable characteristic in offspring due to artificial selection?
Which of the following is NOT a desirable characteristic in offspring due to artificial selection?
Trace fossils include preserved remains of the actual organism.
Trace fossils include preserved remains of the actual organism.
False
List one of the conditions necessary for the formation of fossils.
List one of the conditions necessary for the formation of fossils.
Lack of decomposers
A cast fossil is formed when a mould fossil is filled with __________.
A cast fossil is formed when a mould fossil is filled with __________.
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Match the type of fossil with its description:
Match the type of fossil with its description:
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Which of the following best describes Darwin's concept of variation?
Which of the following best describes Darwin's concept of variation?
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According to Darwin, a higher birth rate than resource availability leads to a decrease in population size.
According to Darwin, a higher birth rate than resource availability leads to a decrease in population size.
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What is the main difference between micro-evolution and macro-evolution?
What is the main difference between micro-evolution and macro-evolution?
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Lamarck's theory of evolution involves the inheritance of acquired traits, such as a giraffe stretching its neck to reach higher leaves causing its offspring to have a longer neck. This is known as ______.
Lamarck's theory of evolution involves the inheritance of acquired traits, such as a giraffe stretching its neck to reach higher leaves causing its offspring to have a longer neck. This is known as ______.
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Match the following key points of allopatric speciation with their descriptions:
Match the following key points of allopatric speciation with their descriptions:
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What is the purpose of artificial selection?
What is the purpose of artificial selection?
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Artificial selection occurs naturally without human intervention.
Artificial selection occurs naturally without human intervention.
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What is the process of accumulation in evolution?
What is the process of accumulation in evolution?
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What is natural selection primarily driven by?
What is natural selection primarily driven by?
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Only mutations in germline cells can be inherited by offspring.
Only mutations in germline cells can be inherited by offspring.
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What is the term for the formation of new species from an existing species?
What is the term for the formation of new species from an existing species?
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A ________ is any feature of the environment that favours one characteristic over another.
A ________ is any feature of the environment that favours one characteristic over another.
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Match the types of mutations with their effects on survival:
Match the types of mutations with their effects on survival:
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Which of the following is NOT a step in allopatric speciation?
Which of the following is NOT a step in allopatric speciation?
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Gene flow can make populations more genetically distinct.
Gene flow can make populations more genetically distinct.
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What kind of mutation positively affects an organism's chances of survival?
What kind of mutation positively affects an organism's chances of survival?
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The ________ is the total sum of all the different types of genes in all individuals of a population.
The ________ is the total sum of all the different types of genes in all individuals of a population.
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What type of reproduction contributes to genetic variation in a population?
What type of reproduction contributes to genetic variation in a population?
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Study Notes
Darwin's Theory of Evolution
- Darwin's theory of evolution has three main ideas: variation, birth rate, and nature's balance.
- Variation exists within all species, with individuals showing a range of traits.
- Birth rates generally exceed the availability of resources, leading to competition for survival.
- Despite high birth rates, population numbers remain relatively constant.
Adaptation over Time
- Environments are constantly changing.
- Organisms with favorable traits are better suited for these changing environments.
- The gene pool of a population changes over time, leading to further evolution.
Micro-evolution vs. Macro-evolution
- Micro-evolution refers to small, gradual genetic changes within a population over short periods.
- Macro-evolution is the accumulation of micro-evolutionary changes over extended periods, potentially leading to new species formation.
Lamarck's Theory of Evolution
- Lamarck believed that acquired traits (changes within an organism's lifetime) could be passed down to offspring.
- This theory is incorrect; acquired traits are not generally heritable.
Allopatric Speciation
- Variation exists within a population.
- A geographic barrier isolates a population, preventing gene flow between subpopulations.
- Different selection pressures act on each isolated subpopulation, leading to independent evolution.
- Over time, the gene pools of the subpopulations diverge, eventually becoming so distinct that they can no longer interbreed to produce fertile offspring.
Artificial Selection
- Humans intentionally breed organisms with desirable traits, hoping to produce offspring with enhanced characteristics.
- This process is repeated over many generations to amplify desired traits.
Variation
- Variation refers to the diversity of traits within a population, encompassing both phenotypic (observable) and genotypic (genetic) differences.
- Variation is influenced by sexual reproduction, mutations, and the environment.
Species
- A species is a group of organisms sharing similar characteristics that can interbreed successfully to produce fertile offspring.
Gene pool
- The gene pool encompasses all the different genes present within a population.
Adaptation
- An adaptation is an inherited trait that increases an organism's chances of survival and reproduction.
Allopatric Speciation Steps
- Variation exists within all populations.
- Isolation occurs when a population splits due to a geographical barrier, hindering gene flow between subpopulations.
- Selection pressures favor different traits in each isolated subpopulation, causing their gene pools to evolve independently.
- Speciation results when the two populations accumulate sufficient genetic differences to become distinct species, unable to interbreed successfully.
Speciation
- Speciation is the formation of two or more new species from a single ancestral species.
Mutation
- Mutations are permanent changes to an organism's DNA sequence.
- Mutations can occur in germline (reproductive) cells, affecting offspring, or in somatic (body) cells, affecting only the individual.
Factors Influencing Phenotype
- An organism's observable characteristics (phenotype) are determined by its genotype (genetic makeup) and interactions with the environment.
Mutagens
- Mutagens are environmental or physical agents that increase the frequency of mutations.
Somatic Cell Mutations
- Mutations in somatic cells affect only the individual and its daughter cells.
Selection Pressures
- Selection pressures are environmental factors that favor certain traits over others, influencing which individuals are more likely to survive and reproduce.
Natural Selection
- Natural selection is the process where organisms with beneficial adaptations for their environment are better able to survive and reproduce, passing on their traits.
How Natural Selection Leads to Evolution
- Variation exists within populations.
- More offspring are produced than can survive, creating competition for resources.
- Individuals with favorable characteristics outcompete those with less favorable traits.
- Survivors reproduce, passing on beneficial characteristics.
- The frequency of favorable alleles increases in the gene pool over generations.
Gene Flow
- Gene flow is the movement of genes between populations through interbreeding.
- It introduces new genes into populations, making them more genetically similar.
Desirable Characteristics in Artificial Selection
- Desired traits in organisms often include disease resistance, faster growth, higher yield, tolerance to adverse conditions, improved product quality, and increased meat production.
Fossils
- Fossils are preserved remains or traces of organisms from over 10,000 years ago.
- Fossil formation requires specific conditions, including the absence of decomposers, oxygen, and water, as well as low temperatures.
Types of Fossils
- Trace fossils capture the activities of organisms (e.g., footprints, burrows).
- True form fossils preserve the actual organism or parts (e.g., insects in amber).
- Mould fossils are impressions formed by an organism that hardens.
- Cast fossils are formed when sediment fills a mould, creating a replica of the organism.
Cast Fossil Formation
- An animal dies and its skeleton settles on the seafloor, becoming buried by sediment.
- Sediment thickens and turns to stone around the skeleton.
- Groundwater dissolves the skeleton, leaving a mould behind.
- Minerals from the groundwater crystallize within the mould, forming a cast.
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Description
Test your understanding of Darwin's theory of evolution, including key concepts like variation, birth rates, and nature's balance. Explore the differences between micro-evolution and macro-evolution, and learn about Lamarck's theory. This quiz will help reinforce your knowledge of evolutionary biology.
