Selection Pressure and Adaptation in Ecology
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Selection Pressure and Adaptation in Ecology

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Questions and Answers

What is a selecting agent?

  • A nonliving factor affecting organisms
  • A type of environmental factor that creates a selection pressure (correct)
  • An individual that has a selective advantage
  • An adaptation that improves survival

    • Biotic factors are nonliving factors that affect organisms.

    False

    Define 'selection pressure' in your own words.

    Selection pressure refers to factors that impact an organism's ability to survive and reproduce in a specific environment.

    The introduction of cane toads in Australia was intended to control __________.

    <p>pest beetles</p> Signup and view all the answers

    Match the following examples with their corresponding types of factors:

    <p>Predation = Biotic factor Temperature = Abiotic factor Food availability = Biotic factor Water = Abiotic factor</p> Signup and view all the answers

    Which of the following is a consequence of the high reproductive rate of cane toads?

    <p>Increased competition for food with native frogs</p> Signup and view all the answers

    Cane toads are considered a successful biological control method for pest beetles in Australia.

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

    What selective advantage have cane toads gained in new areas?

    <p>They have evolved longer legs and faster movement to reduce competition for food.</p> Signup and view all the answers

    What is natural selection primarily known as?

    <p>Survival of the fittest</p> Signup and view all the answers

    Microevolution refers to large-scale changes within a species over long periods of time.

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

    What are the five points of natural selection?

    <p>Variation, Overproduction, Competition, Adaptation, Speciation</p> Signup and view all the answers

    The theory that suggests evolution occurs in short bursts followed by long periods of stability is called __________.

    <p>punctuated equilibrium</p> Signup and view all the answers

    Match the types of evolution with their descriptions:

    <p>Divergent evolution = Different species from a common ancestor have different characteristics Convergent evolution = Different species develop similar traits independently Microevolution = Small changes in gene frequency within a population Macroevolution = Evolution of groups larger than an individual species</p> Signup and view all the answers

    Which of the following is NOT a mechanism that drives evolutionary change?

    <p>Genetic cloning</p> Signup and view all the answers

    Darwin and Wallace's theory of evolution explains that species can evolve under identical environmental pressures.

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

    What is the main outcome when advantageous traits are passed on to the next generation?

    <p>Increased proportion of individuals with favorable traits in the population</p> Signup and view all the answers

    In macroevolution, focus is on evolutionary changes at the __________ level.

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

    Which of the following is an example of adaptation?

    <p>Color change for camouflage</p> Signup and view all the answers

    Genetic drift is a mechanism that can change trait frequencies due to chance events.

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

    Give an example of directional selection.

    <p>Evolution of the horse</p> Signup and view all the answers

    In natural selection, an organism's ability to survive and reproduce depends on its __________ to the environment.

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

    What does the term 'overproduction' in natural selection refer to?

    <p>More organisms are produced than can survive</p> Signup and view all the answers

    Which method measures the degree of similarity between DNA from two species using UV light?

    <p>DNA-DNA hybridisation</p> Signup and view all the answers

    Homologous structures are those that evolved independently to perform the same function.

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

    What is comparative anatomy the study of?

    <p>Similarities in the anatomical structure of different species.</p> Signup and view all the answers

    The inner ear bones of mammals are homologous to the ______ bones of reptiles.

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

    Match the following fossil types with their descriptions:

    <p>Mould = Impression of the organism in the sediment Cast = Preserved remains of the organism itself Trace = Marks made by the organism during its lifetime</p> Signup and view all the answers

    What temperature must DNA be heated to in order to separate its strands?

    <p>87°C</p> Signup and view all the answers

    Vestigial structures are features that currently serve a significant function for the species.

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

    What phenomenon demonstrates modern-day evolutionary change in bacteria?

    <p>Antibiotic resistance.</p> Signup and view all the answers

    The ______ arches in mammal embryos are considered homologous to the gill slits of fish.

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

    Match the following dating techniques to their descriptions:

    <p>Relative Dating = Estimates age based on rock strata Index Fossils = Fossils that exist during a specific geological timeframe Absolute Dating = Calculates the actual age of a fossil using radioactive elements</p> Signup and view all the answers

    Which of the following is an example of an analogous structure?

    <p>Bat wings and bird wings</p> Signup and view all the answers

    Cane toads have evolved to travel slower since their introduction to Australia.

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

    How does the presence of vestigial structures support the theory of evolution?

    <p>They indicate common ancestry and evolutionary changes over time.</p> Signup and view all the answers

    What can cane toads affect when predators consume them?

    <p>Heart and nervous system</p> Signup and view all the answers

    Declines in native species such as large goannas and northern quolls are attributed to habitat loss due to cane toads.

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

    What adaptation allows koalas to survive on gum leaves despite their low nutritional value?

    <p>low metabolic rate</p> Signup and view all the answers

    Cactoblastis Cactorum was introduced to control the population of __________ in Australia.

    <p>prickly pear</p> Signup and view all the answers

    Match the following types of adaptations with their definitions:

    <p>Structural adaptation = Physical change in body structure Physiological adaptation = Internal change to regulate homeostasis Behavioral adaptation = Change in behavior for survival Genotypic variation = Differences in DNA within a population</p> Signup and view all the answers

    Which of the following is an example of a structural adaptation?

    <p>A blue whale having blubber</p> Signup and view all the answers

    Charles Darwin's theory of evolution emphasizes that all individuals in a species are genetically identical.

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

    What process did Charles Darwin associate with the survival of species over generations?

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

    The beak shape of finches in the Galapagos Islands serves as an example of an __________ that contributes to their survival.

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

    Match each animal with its adaptation:

    <p>Blue whale = Blubber for insulation Rattlesnake = Venom for immobilizing prey Possum = Nocturnal behavior Fruit bat = Long fingers for wing support</p> Signup and view all the answers

    What was one of the ecological effects of the introduction of prickly pear in Australia?

    <p>Rendered farmland unproductive</p> Signup and view all the answers

    Invasive species like cane toads compete with native animals for resources.

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

    What coupled relationship did Darwin observe between finches and their food sources?

    <p>Their beak shapes adapted to the available food sources.</p> Signup and view all the answers

    The __________ introduced in the 1920s helped to control the prickly pear population in Australia.

    <p>Cactoblastis moth</p> Signup and view all the answers

    Which of the following is not a type of adaptation?

    <p>Cultural adaptation</p> Signup and view all the answers

    Study Notes

    Selection Pressure

    • Selection pressures influence an organism's survival in an environment and can be biotic (living factors) or abiotic (nonliving factors).
    • Examples include predation pressure, which can lead to adaptations such as speed in prey animals and camouflage in predators.
    • A selecting agent is a specific factor prompting selective pressure, such as cheetahs pressuring wildebeest to be faster.

    Biotic and Abiotic Factors

    • Biotic factors include predation, food availability, competition, and disease.
    • Abiotic factors encompass temperature, light intensity, water availability, soil pH, mineral content, and atmospheric gases.

    Cane Toads in Australia

    • Introduced in 1935 for pest control, cane toads have become invasive, spreading significantly and evolving over 50 generations.
    • Long-legged, fast-moving toads at invasion fronts have a selective advantage, facing less competition for resources.
    • Cane toads lay 30,000 eggs at a time and possess poison glands that threaten native predators, leading to species decline (e.g., goannas, northern quolls).

    Prickly Pear Distribution in Australia

    • Introduced from South America, prickly pear became invasive, rendering 40,000 km of farmland unproductive.
    • The introduction of the Cactoblastis moth larvae effectively reduced prickly pear populations, showing biotic selection pressure in action.

    Adaptations

    • An adaptation is a modification that improves survival in specific environments.
    • Structural adaptations involve physical changes, such as blubber in whales for insulation or long fingers in fruit bats for wing support.
    • Physiological adaptations include internal changes, such as koalas' low metabolic rates for digesting low-nutrition gum leaves and rattlesnakes producing venom.
    • Behavioral adaptations are voluntary actions, like bats huddling for warmth or possums being nocturnal to avoid heat.

    Charles Darwin and Evolution

    • Darwin's theory of evolution describes how traits favoring survival become more common over generations ("survival of the fittest").
    • Natural selection is driven by variations in species, leading to increased survival and reproduction of individuals suited to their environments.
    • Finch populations in the Galapagos showcased adaptation through varying beak shapes suited for local resources.

    Theory of Evolution by Natural Selection

    • Variation, overproduction, competition, adaptation, and speciation are key elements in natural selection.
    • Microevolution involves small changes in gene frequencies, while macroevolution encompasses larger evolutionary group changes, often traced through fossils.

    Divergent and Convergent Evolution

    • Divergent evolution occurs when species share a common ancestor but develop different traits due to varying environmental pressures, exemplified by Galapagos finches.
    • Convergent evolution arises when unrelated species evolve similar traits due to similar environmental challenges, as seen in sharks and dolphins.

    Punctuated Equilibrium vs. Gradualism

    • Gradualism proposes a slow, continuous evolution over time with small changes, while punctuated equilibrium suggests rapid changes followed by stability.
    • The fossil record supports both theories, showcasing transitional forms and sudden new species appearances.

    Evidence for Evolution

    • Biochemical, anatomical, embryological, and biogeographic evidence demonstrates evolution.
    • Homologous structures indicate common ancestry through evolutionary modifications (e.g., forelimbs of mammals).
    • Vestigial structures are remnants of ancestral features that are reduced and no longer serve their original function.

    Fossil Dating Techniques

    • Fossils are formed through rapid burial to prevent decomposition and can be classified as impressions, preserved remains, or traces.
    • Relative dating orders fossils chronologically, while absolute dating estimates their actual ages using radioactivity.

    Modern-Day Examples of Evolution

    • Cane toad populations exemplify rapid evolution and adaptation post-introduction.
    • Antibiotic-resistant bacteria demonstrate modern evolutionary change, with resistant strains surviving treatment and proliferating in populations.### Antibiotic Resistance
    • Bacteria can evolve quickly, leading to populations resistant to common antibiotics.
    • The rise of antibiotic-resistant bacteria poses a significant challenge in medical treatment.

    Cane Toad Introduction to Australia

    • Cane toads were introduced to Australia in 1935 and have since proliferated extensively in northeastern Queensland.
    • Their spread is facilitated by several adaptive traits and environmental factors.

    Traits of Invasive Cane Toads

    • Toads at the invasion front typically exhibit straight-line travel and possess longer legs compared to those in established populations.
    • Longer legs contribute to greater endurance and enable faster movement to new areas.

    Factors Supporting Cane Toad Population Growth

    • A lack of natural predators in Australia has contributed to their successful establishment.
    • Availability of abundant food resources enhances their breeding success.
    • Favourable environmental conditions facilitate their survival and reproduction.

    Reproductive Success and Genetic Adaptation

    • Cane toads can lay up to 30,000 eggs at a time, significantly increasing population size.
    • Genetic changes favor individuals that arrive first to new locations, enhancing their competitive advantage over later arrivals.
    • Those who arrive early tend to have access to more resources, leading to higher breeding success due to reduced competition.

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    Description

    Explore the concepts of selection pressure, including biotic and abiotic factors that affect an organism's survival. Understand the role of invasive species like cane toads in Australia and how they adapt to their environments. This quiz will test your knowledge of ecological principles and adaptations.

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