Ecology & Ecosystems Quiz
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Questions and Answers

What best describes a population in ecological terms?

  • All living organisms within a particular ecosystem
  • A group of different species interacting in an area
  • An interbreeding collection of individuals of the same species in a local area (correct)
  • A collection of ecosystems interacting with one another

    • Which of the following is NOT an attribute of ecosystems?

  • 3D spatial arrangement
  • Diversity of species
  • Increase in soil erosion rates (correct)
  • Interdependence of species

    • What role does dead wood play in an ecosystem?

  • It is the primary energy source for photosynthesis
  • It provides habitat only for large mammals
  • It decomposes rapidly providing nutrients
  • It is an essential part of the ecosystem's structure (correct)

    • What term describes a group of spatially structured individuals interacting via dispersal?

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

    Which of the following is a function of ecosystems?

    <p>Nutrient cycling and retention</p> Signup and view all the answers

    What influences the dynamics of ecosystems over time?

    <p>Changes in biotic interactions and disturbances</p> Signup and view all the answers

    Which spatial pattern in ecosystems is characterized by a uniform distribution of elements?

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

    What process do plants utilize to gain carbon?

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

    What is the primary function of ATP and NADPH in plants?

    <p>Fuel the photosynthesis process</p> Signup and view all the answers

    Which process is essential for converting sugars into usable energy in plants?

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

    What is the light compensation point in photosynthesis?

    <p>The point where photosynthesis equals respiration</p> Signup and view all the answers

    How does temperature affect photosynthesis and respiration?

    <p>It regulates the rates of both photosynthesis and respiration.</p> Signup and view all the answers

    What does an increase in CO2 concentration do to the light saturation point?

    <p>Makes the saturation point higher.</p> Signup and view all the answers

    Which plant species is known for exceptional drought resilience due to stomata regulation?

    <p>Ponderosa Pine</p> Signup and view all the answers

    What is the main factor of soil water potential (SWP)?

    <p>Matric potential</p> Signup and view all the answers

    What is the relationship between photosynthesis and plant growth?

    <p>More photosynthesis than respiration results in growth.</p> Signup and view all the answers

    What process occurs simultaneously with the growth of size in trees due to increased individual demand for resources?

    <p>Competition-based mortality</p> Signup and view all the answers

    In the young old-growth forest stage, what is NOT a characteristic described?

    <p>High canopy closure</p> Signup and view all the answers

    What defines the ancient old growth stage of forests?

    <p>Complex stand structure with few invasive species</p> Signup and view all the answers

    What is the term used to describe the interactions for limited resources that affect plant performance?

    <p>Plant competition</p> Signup and view all the answers

    What does relative density (RD) range from?

    <p>0 to 1</p> Signup and view all the answers

    Which statement about canopy closure is true?

    <p>It occurs at an RD of about 0.15</p> Signup and view all the answers

    Which type of competition involves interactions and access to resources being distance dependent?

    <p>Spatial competition</p> Signup and view all the answers

    What process is mentioned as an important agent of change for stand competition and structure?

    <p>Self thinning</p> Signup and view all the answers

    What role does mortality at the seedling/sapling stage play in forest ecosystems?

    <p>It regulates the pool of potential recruits to fill canopy gaps.</p> Signup and view all the answers

    Which concept describes species interactions that benefit at least one participant without harming either?

    <p>Ecological facilitation</p> Signup and view all the answers

    What is a primary factor that influences the density and distribution of seeds in a forest?

    <p>Reproductive adult density and distribution</p> Signup and view all the answers

    Which fire adaptation allows trees to have a canopy seed bank?

    <p>Serotinous cones</p> Signup and view all the answers

    What is the term for the long-term characteristics of fires at a specific location?

    <p>Fire regime</p> Signup and view all the answers

    Which trait is NOT considered a functional trait that affects plant growth and survival?

    <p>Flower color</p> Signup and view all the answers

    In what kind of environments do ecological facilitation, like nurse logs, commonly occur?

    <p>Older forests in moist sites</p> Signup and view all the answers

    What is the definition of fire intensity?

    <p>The rate of energy released along a unit length of fire line</p> Signup and view all the answers

    What does morphological plasticity in plants refer to?

    <p>Adjustments in leaf structure and inclination based on light conditions</p> Signup and view all the answers

    Which statement best differentiates between shade tolerant and shade obligate plants?

    <p>Shade obligates depend on low light conditions, while shade tolerant plants can survive in both low and high light.</p> Signup and view all the answers

    How is Specific Leaf Area (SLA) calculated?

    <p>The ratio of leaf area to leaf dry mass</p> Signup and view all the answers

    What does the Leaf Area Index (LAI) measure?

    <p>The total one-sided surface area of leaves per unit ground area</p> Signup and view all the answers

    What does the Beer-Lambert Law explain in relation to forest canopies?

    <p>Attenuation of light as it passes through a material</p> Signup and view all the answers

    What is a significant tradeoff for sun leaves in relation to photosynthesis?

    <p>They have a higher photosynthesis rate but also higher respiratory costs.</p> Signup and view all the answers

    What is the primary difference between weather and climate?

    <p>Weather involves short-term atmospheric conditions, while climate is the long-term average of those conditions.</p> Signup and view all the answers

    What primarily influences the variation of leaf morphology within a tree crown?

    <p>Light availability in different areas of the crown</p> Signup and view all the answers

    Study Notes

    Ecology & Ecosystems

    • Ecology is the scientific study of how organisms interact with each other and their environment, influencing distribution and abundance.
    • A population is a group of interbreeding individuals of the same species living in the same area.
    • A metapopulation is a group of populations connected by dispersal.
    • A community is an assemblage of different species interacting in the same location.
    • An ecosystem encompasses a community and its physical environment, known as the habitat.
    • Ecosystem attributes include composition (species present), structure (physical arrangement), and function (processes occurring).
    • Ecosystems are dynamic, changing over time due to drivers like disturbance, biotic interactions, physical template, and species attributes.
    • Disturbances like wildfire, floods, erosion, and debris flows significantly impact ecosystem structure, composition, and function.

    Plant Growth & Photosynthesis

    • Plants gain carbon through photosynthesis, using light energy to create sugars (food).
    • Photosynthesis involves capturing light energy, converting it into high-energy compounds ATP and NADPH, and using these to fix carbon.
    • Most plants use C3 photosynthesis.
    • Respiration is the process where plants use sugars to produce energy for work.
    • Growth occurs when photosynthesis exceeds respiration, while unsustainable growth results when respiration dominates.
    • Temperature, light, and gas exchange (CO2 & H2O) influence photosynthesis.
    • Light compensation point is the light level where photosynthesis equals respiration (net 0).
    • Light saturation point is the light level where photosynthesis reaches its maximum regardless of further light increase.

    Leaf Gas Exchange & Stomata

    • Leaf gas exchange is a tradeoff between CO2 uptake for photosynthesis and water loss through transpiration.
    • Stomata are pores on leaves that regulate gas exchange.
    • Soil water potential (SWP) is a measure of water availability, influenced by matric potential.
    • Ponderosa pine has exceptional drought resilience due to efficient stomata regulation, while Western Larch struggles with it.

    Forest Light Variation & Adaptation

    • Forests have significant light variation, influenced by factors like latitude, season, cloud cover, and canopy density.
    • Forests create their own light environments through biomass production and canopy formation.
    • Morphological plasticity refers to adaptable leaf changes along light gradients, like leaf inclination, stomatal density, and palisade layer thickness.
    • Specific leaf area (SLA) is the ratio of leaf area to leaf dry mass, while leaf mass per area (LMA) is the inverse, both are sensitive to water stress and light environments.

    Canopy Structure & Light Response Curves

    • Light response curves show the relationship between light intensity and net photosynthesis at the leaf scale.
    • Sun leaves have higher photosynthetic rates at high light levels but also higher respiration costs.
    • Canopy structure influences the light profile.
    • Leaf area index (LAI) is the total leaf area per unit ground area, essential for understanding energy and material exchange.
    • The Beer-Lambert law describes light attenuation through a material, applicable to forest canopies.

    Climate, Competition, & Mortality

    • Weather refers to short-term atmospheric conditions, while climate is the long-term average weather pattern.
    • Climate normals are standardized summaries of climate data over 30-year periods.
    • Competition-based mortality occurs as trees grow, leading to increased resource demand, resulting in mortality and size growth.
    • Maturation of dominant trees leads to canopy thinning and understory re-establishment.
    • Agent-cause mortality is caused by factors like insects, diseases, and disturbances.

    Forest Stages & Old-growth

    • Young old-growth forests feature large trees, abundant dead wood, multiple canopy layers, and diverse species.
    • Old-growth forests are later stages with specific characteristics, including large, old trees of long-lived species, complex stand structure, high stand mortality, and few invasive species.
    • Ancient old-growth forests are beyond traditional harvest age and feature high-quality conditions.

    Canopy Closure, Competition, & Regeneration

    • Canopy closure occurs when the density of large trees reaches a point where the site is mostly occupied.
    • Competition for limited resources affects individual plant performance.
    • Types of competition include intraspecific (within a species) and interspecific (between species).
    • Competition is a spatial process where interactions and resource access depend on distance.
    • Relative density (RD) is a measure of stand density, ranging from 0 to 1, used to assess competition levels.
    • Mortality at early stages (seedling/sapling) regulates the pool of potential recruits for canopy gaps.

    Seedling Dynamics & Facilitation

    • Life history stage-based model considers stages from reproductive adults to seedlings, encompassing seed production, dispersal, germination, and seedling density.
    • Ecological facilitation, also called probiosis, occurs when one species benefitting another without harm. It can be mutualistic (both benefit) or commensalistic (one benefits, the other is unaffected).
    • Nurse logs are decaying trees facilitating the growth of certain species.

    Plant Functional Traits & Adaptations

    • Plant functional traits are measurable characteristics influencing performance and function.
    • Fire adaptations include serotinous cones (canopy seed bank), germination response to fire scarification, fruit and flower production, thick fire-resistant bark, self-trimming limbs, and sprouting from adventitious buds.

    Fire Behavior & Regime

    • Fire behavior describes the magnitude, direction, and intensity of fire spread.
    • Fire intensity measures the rate of energy release along a fire line.
    • Fire severity describes the impact of fire on vegetation and soil.
    • Fire regime captures long-term fire characteristics (frequency, magnitude) in a given location.

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    Forest Ecology Notes PDF

    Description

    Test your knowledge on ecology, ecosystems, and the interactions between organisms and their environment. This quiz covers definitions of key terms, ecosystem attributes, and the impact of disturbances on ecological communities. Assess your understanding of population dynamics and plant growth within ecosystems.

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