Biology Genetic and Phenotypic Variation
24 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of variation is primarily caused by genetic factors?

  • Discontinuous variation (correct)
  • Mendelian variation
  • Continuous variation
  • Phenotypic variation

    • Phenotypic variation can only be caused by genetic factors.

    False (B)

    What are the two main types of variation in a species?

    Genetic variation and phenotypic variation

    Continuous variation results in a range of phenotypes between two extremes, such as _______ or _______.

    <p>height, weight</p> Signup and view all the answers

    Match the following terms to their definitions:

    <p>Genetic variation = Differences in DNA among organisms Phenotypic variation = Observable characteristics influenced by genetics and environment Discontinuous variation = Limited categories of traits Continuous variation = A range of traits between two extremes</p> Signup and view all the answers

    Which factor can increase the rate of mutation?

    <p>Exposure to ionising radiation (A)</p> Signup and view all the answers

    The potential height of an organism is solely determined by environmental factors.

    <p>False (B)</p> Signup and view all the answers

    What is the role of meiosis in genetic variation?

    <p>Meiosis produces gametes with different sets of alleles.</p> Signup and view all the answers

    Which of the following features is NOT an adaptive feature of xerophytes?

    <p>Large, flat leaves (C)</p> Signup and view all the answers

    Hydrophytes have adaptations that help them minimize water loss.

    <p>False (B)</p> Signup and view all the answers

    What is the primary environment where xerophytes typically thrive?

    <p>Very dry climates</p> Signup and view all the answers

    Xerophytes have a _____ waxy cuticle to prevent water loss.

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

    Which characteristic of hydrophytes promotes water loss?

    <p>Large, flat leaves (A)</p> Signup and view all the answers

    Xerophytes often have small, rolled leaves or spines.

    <p>True (A)</p> Signup and view all the answers

    How do deep roots help xerophytes survive in dry climates?

    <p>They allow plants to absorb water from deeper soil.</p> Signup and view all the answers

    Match the plant type with its adaptation:

    <p>Xerophytes = Thick waxy cuticle Hydrophytes = Shallow root system</p> Signup and view all the answers

    What is the main mechanism for evolution as described in the content?

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

    Antibiotic-resistant bacteria result from environmental changes and external pressures.

    <p>True (A)</p> Signup and view all the answers

    What is selective breeding?

    <p>The process where humans choose plants or animals with desired traits to breed together.</p> Signup and view all the answers

    Natural selection results in organisms with _____ characteristics surviving and reproducing more effectively.

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

    Which of the following is an example of a plant that has been selectively bred?

    <p>Corn (D)</p> Signup and view all the answers

    Negative characteristics in a species are likely to become more common over time due to reproduction.

    <p>False (B)</p> Signup and view all the answers

    What trait was selectively bred for in German Shepherds?

    <p>Intelligence and agility</p> Signup and view all the answers

    Match the following definitions with their terms:

    <p>Natural selection = Process where organisms with favorable traits survive Selective breeding = Human-controlled breeding for desired traits Antibiotic resistance = Bacteria's ability to survive despite antibiotic treatment Mutation = Change in a DNA sequence that may lead to new traits</p> Signup and view all the answers

    Flashcards

    Variation

    Differences between organisms within a species.

    Genetic Variation

    Differences in DNA between organisms.

    Phenotypic Variation

    Observable differences in characteristics (like height).

    Continuous Variation

    A range of phenotypes between two extremes.

    Signup and view all the flashcards

    Discontinuous Variation

    Limited number of phenotypes.

    Signup and view all the flashcards

    Mutation

    Change in DNA sequence.

    Signup and view all the flashcards

    Meiosis

    Cell division creating gametes with different alleles.

    Signup and view all the flashcards

    Allele

    Different forms of a gene.

    Signup and view all the flashcards

    Adaptive Features

    Inherited traits increasing an organism's survival and reproduction in its environment.

    Signup and view all the flashcards

    Xerophytes

    Plants adapted to very dry climates.

    Signup and view all the flashcards

    Fewer Stomata

    Reduced number of stomata on leaves of xerophytes.

    Signup and view all the flashcards

    Stomata in Pits

    Stomata sunken in leaf pits to trap moist air in xerophytes.

    Signup and view all the flashcards

    Small, Rolled Leaves

    Reduced leaf surface area in xerophytes to decrease water loss.

    Signup and view all the flashcards

    Deep Roots

    Roots of xerophytes extending deep into the soil for water absorption.

    Signup and view all the flashcards

    Hydrophytes

    Plants adapted to wet conditions.

    Signup and view all the flashcards

    Large, Flat Leaves

    Leaves of hydrophytes with large surface area to maximize water loss.

    Signup and view all the flashcards

    Natural Selection

    Organisms with favorable traits have a higher chance of surviving and reproducing, passing those traits to their offspring.

    Signup and view all the flashcards

    Favorable Alleles

    Alleles that give an organism an advantage in its environment.

    Signup and view all the flashcards

    Evolution

    Change of heritable characteristics of biological populations over successive generations.

    Signup and view all the flashcards

    Antibiotic Resistance

    When bacteria develop resistance to antibiotics due to a genetic mutation allowing them to survive treatment.

    Signup and view all the flashcards

    Selective Breeding

    Humans choosing organisms with desirable traits to breed, resulting in offspring with those traits.

    Signup and view all the flashcards

    Artificial Selection

    A process where humans choose which organisms reproduce and pass specific traits to their offspring, often for desired characteristics.

    Signup and view all the flashcards

    Desirable Traits

    In selective breeding, traits that are considered beneficial or important and that humans choose to cultivate and enhance.

    Signup and view all the flashcards

    Study Notes

    Variation

    • Variation refers to the differences between organisms within a species.
    • Variation is beneficial, reducing the risk of extinction from diseases.
    • Two types of variation exist: genetic and phenotypic.

    Genetic Variation

    • Genetic variation is caused by differences in DNA.
    • Meiosis, random mating, and random fertilization contribute to genetic variation.
    • Gametes have different alleles (alternate forms of a gene).
    • Gamete fusion creates a new combination of genes.

    Phenotypic Variation

    • Phenotype describes observable characteristics (e.g., height, hair color).
    • Phenotypic variation is influenced by both genetics and the environment.
    • Environmental factors can affect the expression of genetic traits.

    Types of Variation

    • Continuous variation: A range of phenotypes between two extremes (e.g., height, weight).
    • Discontinuous variation: Limited to distinct categories (e.g., blood type, seed shape).
    • Discontinuous variation is mainly determined by genes, while continuous variation is influenced by both genes and the environment.

    Mutations

    • Mutations are random changes in DNA sequences.
    • Mutations can change alleles and lead to new characteristics.
    • Exposure to chemicals or radiation can increase mutations.
    • Mutations at specific alleles can alter their function.

    Adaptive Features

    • Adaptive features enhance an organism's survival and reproduction.
    • They are inherited traits that improve fitness (ability to survive and reproduce).
    • Examples include small ears reducing heat loss and thick fur for insulation.

    Xerophytes

    • Xerophytes are plants adapted to dry climates.
    • Adaptations minimize water loss (e.g., fewer stomata, thick cuticles, deep roots).
    • Examples include cacti and other desert plants.

    Hydrophytes

    • Hydrophytes are plants adapted to wet conditions.
    • Adaptations maximize water uptake (e.g., large, flat leaves, thin cuticles, numerous stomata).
    • Examples include water lilies and other aquatic plants.

    Selection

    • Natural selection favors advantageous traits enabling survival and reproduction.
    • Organisms with favorable alleles have a higher chance of surviving and reproducing.
    • Over time, less favorable traits become less common.
    • Evolution involves adaptation to the environment.

    Antibiotic Resistance

    • Mutations can lead to antibiotic resistance in bacteria.
    • Resistant bacteria survive antibiotic treatment and reproduce.
    • This creates more resistant bacteria over time.

    Selective Breeding

    • Humans select and breed organisms with desirable traits.
    • Repeated breeding across generations amplifies chosen traits.
    • Artificial selection, a controlled process, leads to desired traits in offspring.
    • German Shepherd breeding is an example, emphasizing desirable traits (intelligence and agility).
    • Selective breeding applies to plants too, such as the various banana varieties.

    Natural vs. Artificial Selection

    • Natural selection occurs naturally in the environment.
    • Artificial selection is controlled by humans.
    • Natural selection takes a long time, while artificial selection is faster.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    CAIE Biology IGCSE Variation and Selection Notes PDF

    Description

    Explore the concepts of genetic and phenotypic variation in this quiz. Understand how these variations arise, their benefits, and the different types that exist within a species. Test your knowledge on the factors influencing variation in organisms.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser