Biology Final Flashcards
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Questions and Answers

Which best describes the fossil record?

  • The fossil record is a highly ordered sequence in which fossils are found in layers of sedimentary rock. (correct)
  • The fossil record is random and chaotic.
  • The fossil record does not provide information about extinct species.
  • The fossil record only contains species that lived in water.

    • What is a possible weakness of the fossil record?

    Many species probably did not die in the right place at the right time to be captured in fossils, and many fossils will never be found by paleontologists.

    Whereas some modern whales possess a small and useless __________ pelvis, __________ linking modern whales to their four-legged evolutionary ancestors possess a larger and even functional pelvis.

    vestigial; transitional forms

    What does an evolutionary tree diagram illustrate?

    <p>Evolutionary trees relate species to each other by ancestry.</p> Signup and view all the answers

    The phrase Darwin used to describe his broad theory of evolution is 'descent with ____'.

    <p>modification</p> Signup and view all the answers

    All of life is related through common ancestry, accounting for the ______ of life.

    <p>unity</p> Signup and view all the answers

    The ____ of life arises from the adaptation of species to different habitats over long spans of time.

    <p>diversity</p> Signup and view all the answers

    What did Darwin propose as a mechanism for how evolution occurs?

    <p>natural selection</p> Signup and view all the answers

    Two key observations underlying natural selection are that members of a population vary in their _____ and that all species can produce more offspring than the environment can support.

    <p>inherited traits</p> Signup and view all the answers

    Darwin inferred that those organisms with traits best suited to the environment tend to leave more ________ than other members of a population.

    <p>offspring</p> Signup and view all the answers

    This unequal reproduction in a population leads to the gradual accumulation of ________ to the environment.

    <p>adaptations</p> Signup and view all the answers

    What provides the selective pressure in natural selection?

    <p>The environment</p> Signup and view all the answers

    Which assumptions are part of Charles Darwin's theory of natural selection?

    <ol> <li>Organisms vary in heritable ways 2. Some traits improve the survival and reproduction of individuals who possess them 3. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources 4. Earth and its life are very old</li> </ol> Signup and view all the answers

    All the genes in a population are that population's ____.

    <p>gene pool</p> Signup and view all the answers

    Genetic drift is a process based on _____.

    <p>the role of chance</p> Signup and view all the answers

    A mutation occurs when _____.

    <p>there is a change in the DNA sequence of a gene</p> Signup and view all the answers

    What reduces the probability of genetic drift having an effect on the evolution of humans?

    <p>Modern travel and migration</p> Signup and view all the answers

    The ease with which humans travel across the globe is likely to increase _____.

    <p>gene flow</p> Signup and view all the answers

    Of the choices listed below, which contributes the most to genetic variation among individuals in most prokaryote species?

    <p>Mutation</p> Signup and view all the answers

    Why do mutations play a large role in the microevolution of bacterial populations?

    <p>Bacteria multiply very rapidly and they are haploid, so mutant alleles will immediately have a full effect in the phenotype.</p> Signup and view all the answers

    Which condition would disturb the Hardy-Weinberg equilibrium and cause the gene pool to change?

    <p>Several homozygous recessive individuals leave the population.</p> Signup and view all the answers

    Which of the following are causes of evolutionary change?

    <p>Natural selection</p> Signup and view all the answers

    Generation-to-generation change in allele frequencies in a population is _____.

    <p>microevolution</p> Signup and view all the answers

    Which of the following events could NOT be caused by a population bottleneck?

    <p>Increased population size.</p> Signup and view all the answers

    What is the relationship between natural selection and evolution?

    <p>Natural selection is one of the several mechanisms of evolution.</p> Signup and view all the answers

    What is stabilizing selection?

    <p>Favors intermediate phenotypes selecting against phenotypes at both ends of a range and reducing variations.</p> Signup and view all the answers

    What is disruptive selection?

    <p>Favors phenotypes at both ends of a range over intermediate phenotypes. This type of selection may occur when the habitat is varied.</p> Signup and view all the answers

    What is directional selection?

    <p>Favors phenotypes at one end of a range and is common in periods of environmental change.</p> Signup and view all the answers

    In sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. This often results in ____ differences between the sexes size appearance and behavior.

    <p>sexual dimorphism</p> Signup and view all the answers

    What is intrasexual selection?

    <p>A type of sexual selection in which individuals of one sex (usually male) compete directly for mates.</p> Signup and view all the answers

    In a type of sexual selection often called _______, individuals of one sex (usually females) are choosy in selecting their mates.

    <p>mate choice</p> Signup and view all the answers

    What makes up a community?

    <p>All the populations of organisms living close enough together for potential interaction.</p> Signup and view all the answers

    What is the niche of an animal?

    <p>The way the animal fits into its environment.</p> Signup and view all the answers

    A series of reciprocal evolutionary adaptations in two species is called ____.

    <p>coevolution</p> Signup and view all the answers

    Species richness and relative abundance taken together define the _____ of a community.

    <p>species diversity</p> Signup and view all the answers

    What are keystone species?

    <p>Those species whose absence would cause major disruption in an ecosystem.</p> Signup and view all the answers

    Why are the fifth-level consumers very rare in food webs?

    <p>There is rarely enough available energy to sustain a fifth trophic level.</p> Signup and view all the answers

    _____ are secondary consumers.

    <p>carnivores</p> Signup and view all the answers

    Approximately _____% of the energy at one trophic level is passed on to the next highest trophic level.

    <p>5-10</p> Signup and view all the answers

    10,000 kcal of producer could support approximately _____ kcal of tertiary consumer.

    <p>10</p> Signup and view all the answers

    What is an important consequence of global warming?

    <p>Changes in the distribution of terrestrial biomes.</p> Signup and view all the answers

    What is the new and expanding field that uses ecological principles to develop methods to restore degraded areas to their natural state called?

    <p>Restoration ecology.</p> Signup and view all the answers

    What is the science of facilitating the return of a degraded ecosystem to a more natural condition?

    <p>Restoration ecology.</p> Signup and view all the answers

    Study Notes

    Fossil Record and Evolution

    • The fossil record is arranged in sedimentary rock layers, showcasing a chronological sequence of ancient life.
    • Limitations exist within the fossil record as many species did not leave fossils, and many remain undiscovered.
    • Modern whales exhibit vestigial pelvic bones, whereas transitional forms display functional pelvic structures linking them to four-legged ancestors.

    Evolutionary Concepts

    • An evolutionary tree diagram illustrates species relationships based on common ancestry and homologous traits.
    • Charles Darwin coined the term "descent with modification" to encapsulate his theory of evolution.
    • Unity among all life forms indicates a shared common ancestry, while diversity arises from species adapting to various habitats over time.

    Natural Selection

    • Natural selection, as proposed by Darwin, is a mechanism driving evolution.
    • Key observations of natural selection include variation in inherited traits and the potential for overproduction of offspring.
    • Organisms with advantageous traits tend to leave more offspring, resulting in adaptations over generations.

    Genetic Variation and Population Dynamics

    • The gene pool encompasses all the genes of a population, with genetic drift driven by chance events.
    • Mutations occur due to alterations in DNA sequences, significantly influencing genetic variation.
    • Modern travel enhances gene flow, reducing the effect of genetic drift on human evolution.

    Hardy-Weinberg Equilibrium

    • Disturbances to Hardy-Weinberg equilibrium, such as loss of homozygous recessive individuals, indicate changes in the gene pool.
    • Evolutionary changes arise from gene flow, genetic drift, mutation, and natural selection, contributing to microevolution.

    Selection Types

    • Stabilizing selection favors intermediate phenotypes, reducing variation by selecting against extremes.
    • Disruptive selection promotes both extreme phenotypes over intermediates and may occur in varied habitats.
    • Directional selection selects for phenotypes at one end of the spectrum, often during environmental changes.

    Sexual Selection

    • Sexual dimorphism refers to noticeable differences between sexes in size, appearance, and behavior due to selective mating.
    • Intrasexual selection involves competition among one sex (usually males) for mating opportunities.
    • In mate choice, individuals of one sex (typically females) select mates based on attractive characteristics or behaviors.

    Ecological Principles

    • A community comprises all populations living close enough for potential interaction.
    • An animal’s niche is its role within its environment, encompassing all interactions and adaptations.
    • Coevolution describes reciprocal evolutionary changes between two interacting species.

    Ecosystem Structure

    • Species diversity is defined by species richness and relative abundance in a community.
    • Keystone species play a critical role; their removal can significantly disrupt ecosystem balance.
    • In food webs, fifth trophic level consumers are rare due to insufficient energy transfer from lower levels.

    Energy Transfer in Ecosystems

    • Energy transfer between trophic levels is inefficient, with only about 5-10% of energy passed to the next level.
    • Approximately 10,000 kcal of energy from producers can support around 10 kcal at the tertiary consumer level.

    Environmental Changes and Restoration

    • Global warming impacts terrestrial biomes by altering their distributions.
    • Restoration ecology aims to use ecological principles for rehabilitating degraded ecosystems back to natural states.

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    Prepare for your biology finals with these flashcards covering key concepts such as the fossil record and its limitations. Test your knowledge and improve your understanding of essential biological principles. Ideal for revision before exams.

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