Community Ecology Study Guide

Study Guide: Project 2 Test: Community Ecology

1. 10 Principles of Smart Growth

  • Smart growth principles aim to create sustainable communities through responsible planning. Key principles include:
    • Mixed land uses
    • Compact building design
    • Diverse housing opportunities
    • Walkable neighborhoods
    • Distinctive, attractive communities
    • Preserve open spaces, farmland, natural beauty, and critical environmental areas
    • Strengthen and direct development towards existing communities
    • Provide a variety of transportation choices
    • Make development decisions predictable, fair, and cost-effective
    • Encourage community and stakeholder collaboration in development decisions.

2. Biodiversity

  • Biodiversity refers to the variety of life in the world or a specific habitat. Key components include:
    • Species Richness: The number of different species in a given area.
    • Species Evenness: The relative abundance of different species in a given area.
    • Genetic Diversity: The total number of genetic characteristics in the genetic makeup of a species.
    • Species Diversity: The combination of species richness and species evenness in a community.
    • Habitat Diversity: The variety of habitats available in a given area.

3. Population Ecology

  • Focuses on the dynamics of populations in relation to the environment. Key concepts include:
    • Biotic Potential: The maximum reproductive capacity of an organism under optimal environmental conditions.
    • Limiting Factors: Environmental conditions that restrict population growth.
    • Carrying Capacity: The maximum number of individuals in a population that the environment can sustain.
    • Exponential Growth: A population's growth at a constant rate without limiting factors, represented as N(t) = N_0 e^{rt}.
    • Logistic Growth: Population growth that levels off as population size approaches carrying capacity, represented as N(t) = rac{K}{1 + rac{K - N0}{N0} e^{-rt}}.
    • Human Population Growth: The increasing population of humans, currently growing exponentially.

4. Abiotic Factors

  • Non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Examples include:
    • Temperature
    • Water availability
    • Sunlight
    • Soil composition
    • Atmospheric conditions.

5. Biotic Factors

  • Living components of an ecosystem that affect organisms, including:
    • Plants
    • Animals
    • Microorganisms
    • Interactions between these organisms, such as predation, competition, and symbiosis.

6. Generalists vs. Specialists

  • Generalists: Species with a broad ecological niche, able to adapt to various environments and resources.
  • Specialists: Species with a narrow ecological niche, often reliant on specific resources or environments.

7. r-strategists

  • Species that reproduce quickly and in large numbers, often at the cost of raising their young. Characteristics include:
    • High fecundity
    • Short life spans
    • Minimal parental care (e.g., insects, rodents).

8. K-strategists

  • Species that invest significant time and resources into raising fewer young, which are likely to survive. Characteristics include:
    • Lower fecundity
    • Longer life spans
    • High parental care (e.g., elephants, humans).

9. Nonnative Species

  • Species that are introduced to an ecosystem where they do not naturally occur. Potential impacts include:
    • Competition with native species
    • Alteration of habitat and ecosystem dynamics.

10. Characteristics of Endangered Species

  • Species that are at risk of extinction due to:
    • Habitat loss
    • Climate change
    • Overexploitation
    • Predation by nonnative species.
  • Common traits include small populations, specialized habitats, and low reproductive rates.

11. Preventing Extinction

  • Legal frameworks aimed at protecting endangered species, including:
    • Endangered Species Act (ESA): A U.S. law aimed at protecting critically endangered species.
    • Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES): An international agreement to ensure that international trade does not threaten the survival of species.

12. Ecosystem Services

  • Benefits obtained from ecosystems which are categorized as:
    • Provisioning: Products obtained from ecosystems (e.g., food, water).
    • Regulating: Benefits obtained from the regulation of ecosystem processes (e.g., climate regulation).
    • Cultural: Non-material benefits from ecosystems (e.g., spiritual enrichment).
    • Supporting: Services necessary for the production of all other ecosystem services (e.g., nutrient cycling).

13. Doubling Time

  • The time required for a population to double in size, can be estimated using the rule of 70: Doubling ext{ }Time ext{ }(years) = rac{70}{ ext{Growth Rate ext{ }( ext{ extperthousand})}}.

14. Trophic Levels & Food Webs

  • Trophic Levels: The hierarchical levels in an ecosystem, comprising:
    • Producers (1st level)
    • Primary Consumers (2nd level)
    • Secondary Consumers (3rd level)
    • Tertiary Consumers (4th level).
  • Trophic Cascade: A phenomenon where changes in the population of one trophic level cause impacts on the other levels.
  • Food Chains: A linear representation of energy flow through an ecosystem.
  • Food Webs: A complex interconnection of multiple food chains.
  • Laws of Thermodynamics: Principles governing energy transfer and conversion in ecosystems:
    • First Law: Energy cannot be created or destroyed, only transformed.
    • Second Law: Energy transformations are not 100% efficient; some energy is lost as heat.

15. Effects of Urbanization on Water Cycle

  • Urbanization alters natural water cycles through:
    • Increased evaporation and transpiration rates.
    • Enhanced runoff due to impervious surfaces.
    • Reduced groundwater recharge.

16. Federal Lands

  • Types of federal lands include:
    • National Parks: Protected areas established for preservation of natural beauty and ecosystems.
    • National Wildlife Refuges: Areas aimed at protecting wildlife and their habitats.
    • National Forests: Lands managed for multiple uses including conservation, recreation, and resources extraction.
    • National Wilderness Preservation: Areas designated to be untouched by human activity.

17. Protecting Biodiversity

  • Strategies to maintain biodiversity encompass:
    • Habitat preservation
    • Restoration efforts
    • Policy and regulation enforcement.

18. Reserve Design

  • Key considerations for effective reserve planning include:
    • Size: Larger reserves typically support more species.
    • Edge Effect: The difference in species composition at the boundary between two habitats.
    • Corridors: Strips of natural habitat connecting larger reserves to enable wildlife movement.
    • Fragmentation: The division of habitats into smaller, isolated patches.

19. Succession

  • The process through which ecosystems change and develop over time:
    • Primary Succession: The development of an ecosystem in an area where no soil exists (e.g., after a volcanic eruption).
    • Secondary Succession: The recovery of an ecosystem after disturbance that leaves soil intact (e.g., after a forest fire).

20. Mark Recapture Formula

  • Used to estimate wildlife populations:
    • Where:
      M = ext{Number of animals captured and marked in first sample}
      N = ext{Estimated population size}
      m = ext{Number of 'R' that were already marked}
      R = ext{Number of animals captured in all resampling events}
    • The formula is given by:
      N = rac{M imes R}{m}.

21. Biome Characteristics

  • Major biomes are distinguished by factors such as climate, soil types, vegetation, and fauna, examples include:
    • Tropical rainforest: High biodiversity, dense vegetation.
    • Desert: Low precipitation, extreme temperatures.
    • Tundra: Cold, low biodiversity, permafrost layer.

22. Cause of Seasons

  • Seasons are caused by the tilt of the Earth's axis and its orbit around the Sun, leading to varying sunlight intensity and duration throughout the year.

23. Effects on Climate

  • Key factors influencing climate include:
    • Wind Currents: Affect climate patterns and temperature distribution.
    • Ocean Currents: Influence weather and climate across continents.
    • Proximity to Water: Proximity can moderate temperatures.
    • Elevation: Higher elevations generally experience cooler temperatures.
    • Topography: Geographic features influence local climate.

24. Primary Productivity

  • The rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances. It is often measured in terms of biomass per area per time (e.g., g/m^2/yr).

25. Urbanization

  • Urbanization affects environmental conditions, including:
    • Urban Heat Island Effect: Urban areas experience higher temperatures than surrounding rural areas.
    • Urban Sprawl: The uncontrolled expansion of urban areas.
    • Watershed: Areas of land that drain into a common body of water, urbanization can greatly impact watershed health.

26. Sustainable Forestry

  • Management practices aimed at meeting current needs without compromising the health of forest ecosystems for future generations.

27. Clearcutting

  • A logging practice where all trees in an area are cut down. Pros include economic benefits; cons include significant environmental impact.

28. Fire Suppression

  • Practices aimed at controlling or eliminating wildfires which can impact ecosystem health by preventing natural fire cycles.

29. Species Interactions

  • Various ways species interact with each other, examples include:
    • Mutualism: Both species benefit from the interaction (e.g., pollination).
    • Commensalism: One species benefits while the other is unaffected (e.g., barnacles on whales).
    • Parasitism: One species benefits at the expense of the other (e.g., ticks on mammals).
    • Keystone Species: Species that have a disproportionately large effect on their environment relative to their abundance.
    • Foundation Species: Species that create or modify habitats (e.g., corals).
    • Indicator Species: Species whose presence or absence indicates the health of an ecosystem.

Practice Problems

  1. Identify each letter in the provided diagram (context-dependent).
  2. Calculate the doubling time for a population growing at a rate of 3.5% per year using the rule of 70: Doubling ext{ }Time = rac{70}{3.5} = 20 ext{ years}.
  3. Mark-recapture example: 500 piranha captured and tagged, then 10 captured with 2 tagged. Estimate total piranhas:
    N = rac{500 imes 10}{2} = 2500 ext{ piranhas}.
  4. Calculate gross annual primary productivity from net productivity:
    Net = Gross - Respiration
    ightarrow Gross = Net + Respiration
    ightarrow Gross = 9000 + 3000 = 12000 ext{ kcal/m}^2 ext{/yr}.
  5. Calculate the area for 150 male American robin territories:
    Area = 150 ext{ territories} imes 600 ext{ m}^2 = 90000 ext{ m}^2.

AP Classroom Topics

  • Review topics listed in sections 1.1, 1.2, 1.8-1.11, 2.1, 2.2, 2.4-2.7, 3.1-3.5, 3.8, 4.5, 4.7, 4.8, 5.2, 5.10, 5.12, 5.13, 5.17, 7.8, and 9.8-9.10 for complementary understanding and practice.