Notes_for_Finals-Spring_2025

Standard 2A

  • Standard 2A covers carrying capacity and limiting factors in ecosystems.
  • Key aspects include understanding ecological balance, factors influencing carrying capacity, interpreting graphs, assessing human impact, and biodiversity.

Keywords and Definitions

  • Ecology: The study of interactions between living and non-living things at various levels (individual, population, community, ecosystem, biosphere).
  • Organism/Individual: A living thing with organized structure, responses to stimuli, reproduction, growth, adaptation, and homeostasis.
    • Multicellular: Organisms with more than one cell.
    • Unicellular: Organisms with a single cell.
    • Example: An animal, plant, or single-celled life form.
  • Population: Organisms of the same species living in an area at the same time (e.g., all the deer in a forest).
  • Community: A group of populations of different species in a given area (e.g., an algal community).
  • Ecosystem: A community of living things (plants, animals) interacting with their environment; can be small (pond) or large (forest).
  • Biome: A large geographic region with a specific climate, soil type, and dominant plant/animal life (e.g., Tundra, Taiga).
    • Classified based on temperature, precipitation, and vegetation types.
    • Terrestrial biomes (land) and aquatic biomes (water).
  • Biosphere: The region of Earth where life exists, including the surface, above, and below; also known as the ecosphere.
  • Habitat: Specific place where an organism or community lives, with suitable environmental conditions.
  • Predation: One organism (predator) feeding on another (prey); influences population dynamics (e.g., a Lion killing a deer).
  • Climate Conditions: Prevailing weather patterns and environmental factors, including temperature, rainfall, and humidity.
  • Competition: When species or individuals vie for the same resources (food, water, habitat), limiting population growth.
  • Biodiversity: The variety of living things in an area, measuring the richness and complexity of life there.
  • Factor: Any external force, substance, or condition affecting organisms (e.g., temperature).
  • Environment: The sum of all factors (temperature, humidity, wind), forming a complex environmental complex.
  • Adaptation: A feature enabling an organism to exist under its habitat's conditions.

Types of Ecosystems

  • Ecosystems are categorized into terrestrial and aquatic types.
  • Terrestrial Ecosystems: Land-based ecosystems classified by climate, vegetation and precipitation.
    • Forests: Densely populated with trees.
      • Tropical Rainforests: Near the equator, with high temperatures, rainfall, and diverse life (e.g., Amazon Rainforest).
      • Temperate Forests: Moderate temperatures, distinct seasons, deciduous trees (e.g., Olympic National Forest).
      • Coniferous Forests (Taiga): Cold forests with coniferous trees (pine, spruce, fir) in northern regions (e.g., Superior National Forest).
      • Mangrove Forests: Coastal ecosystems with salt-tolerant trees/shrubs in tidal waters (e.g., Everglades National Park).
    • Grasslands: Dominated by grasses, with moderate rainfall in temperate and subtropical regions.
      • Savannas: Open grasslands with scattered trees/shrubs in tropical/subtropical regions, with wet/dry seasons.
      • Prairies: Flat or rolling grasslands in temperate regions, with fertile soil (e.g., American Prairie).
      • Steppes: Semi-arid grasslands with sparse vegetation in dry, temperate climates.
    • Deserts: Extremely dry environments with scarce vegetation and low rainfall (hot: Sahara; cold: Gobi).
    • Tundra: Cold, dry ecosystems with permanently frozen ground (permafrost) and low-growing vegetation in the Arctic and on mountaintops.
  • Aquatic Ecosystems: Water-based ecosystems.
    • Marine Ecosystems: Saltwater ecosystems in oceans/seas with diverse life (plankton to whales); examples: coral reefs, kelp forests.
    • Freshwater Ecosystems: Non-salty water ecosystems in lakes, rivers, streams, ponds, and wetlands.

Biomes

  • Biomes are large geographic regions with a specific climate, soil type, and dominant plant and animal life.
    • Classified based on temperature, precipitation, and vegetation types.
  • Terrestrial Biomes:
    • Tundra: Cold, treeless, with low-growing vegetation.
    • Desert: Dry, with sparse vegetation adapted to conserve water.
    • Grassland: Dominated by grasses, with few trees, found in temperate and tropical regions.
    • Temperate Forest: Experiences four seasons, has deciduous or evergreen trees.
    • Tropical Rainforest: Warm, humid, with high biodiversity.
    • Taiga (Boreal Forest): Cold, dominated by coniferous trees.
  • Aquatic Biomes:
    • Freshwater Biomes: Rivers, lakes, ponds.
    • Marine Biomes: Oceans, coral reefs, estuaries.
  • Each biome supports different ecosystems and biodiversity based on its environmental conditions.
  • Temperature, rainfall, and seasonal variations determine vegetation in terrestrial biomes.
  • Temperature, salinity, depth, and water movement are critical factors for aquatic biomes.

Relationships in Ecosystems

  • Organisms interact in beneficial, harmful, or neutral ways.
  • Symbiotic Relationships: Close, long-term relationships between two species.
    • Mutualism (+/+): Both species benefit.
      • Examples: Bees and flowers.
      • Clownfish and anemone: clownfish find protection in anemone tentacles while anemone gets food from other fish.
    • Commensalism (+/0): One species benefits, the other is unaffected.
      • Examples: barnacles on a whale, Egrets and water buffalos.
    • Parasitism (+/-): One species benefits, the other is harmed.
      • Examples: Ticks on a dog, Varroa mites on bees, and Pinworms in human gut
  • Predator-Prey Relationship: Predators hunt and eat prey; controls population sizes.
    • Example: lion (predator) hunts zebras (prey).
  • Carnivory: predation on animals. Lions eating wolves.
  • Herbivory: predation on plants. Cows eat grass.
  • Omnivory: predation on plants and animals. Humans.
  • Competition: Organisms compete for limited resources.
    • Intraspecific competition: Competition within the same species (e.g., deer fighting for a mate).
    • Interspecific competition: Competition between different species (e.g., lions and hyenas competing for prey).
  • Producer-Consumer Relationships: Energy moves through food chains and webs.
    • Producers (Autotrophs): Make their own food using sunlight (e.g., plants).
    • Consumers (Heterotrophs): Eat other organisms for energy.
      • Primary consumers: Eat plants (herbivores, e.g., rabbits).
      • Secondary consumers: Eat herbivores (carnivores, e.g., snakes).
      • Tertiary consumers: Eat other carnivores (top predators, e.g., hawks).
  • Scavengers: Eat dead animals.
  • Decomposers: Break down dead organisms, returning nutrients to the soil.

Carrying Capacity and Limiting Factors

  • Ecosystems have limits to the number of organisms they can support.
  • Carrying Capacity: Maximum number of individuals an environment can support without resources running out.
    • Example: pond supports 100 frogs.
  • Limiting Factors: Factors that depend on population size and have a greater effect when the population is large.
    • Examples: Food availability, water supply, habitat space, predation, disease, climate conditions.
    • Density-Dependent Limiting Factors:
      • Competition: more individuals compete for resources.
      • Predation: More prey attract more predators.
      • Disease & Parasitism: Spread faster in dense populations.
      • Stress from Overcrowding: Causes aggression, lower birth rates, higher death rates.
    • Density-Independent Limiting Factors:
      • Natural disasters: floods, hurricanes, wildfires, earthquakes.
      • Temperature & Climate: extreme heat, cold, or drought.
      • Human activities: Pollution, deforestation, habitat destruction.
  • Factors Influencing Carrying Capacity:
    • Resource Availability: Food, water, shelter (Fig. 2).
    • Predation: Predators limit prey population size.
    • Climate Conditions: Extreme temperatures, droughts.
    • Competition: Limits population size when species compete for resources.
  • Human Impact:
    • Deforestation, pollution, and overfishing disrupt ecosystems.
  • Examples:
    • African Savanna: Carrying capacity for herbivores depends on grass and water availability; decreases during the dry season.
    • Urban Development: Clearing forests reduces habitat space, lowering carrying capacity.

Energy Flow Through the Ecosystem and the Recycling of Matter

  • Ecosystem: A community of living organisms interacting with their abiotic environment.
  • Energy Flow: The movement of energy through an ecosystem, starting from the sun.
  • Sunlight: The primary energy source for life on Earth.
  • Photosynthesis: Green plants use sunlight to convert water and carbon dioxide into glucose and oxygen.
  • Autotrophs (Producers): Organisms that produce their own food using sunlight or chemical energy.
  • Chemosynthesis: Autotrophic bacteria produce food using chemical reactions instead of sunlight.
  • Heterotrophs (Consumers): Organisms that obtain energy by consuming other organisms.
    • Herbivores: Eat only plants.
    • Carnivores: Eat only other animals.
    • Omnivores: Eat both plants and animals.
    • Detritivores: Feed on dead plant and animal matter.
    • Decomposers: Break down organic matter and recycle nutrients.
  • Food Chain: A linear sequence showing how energy is transferred from one organism to another.
  • Food Web: A complex network of interconnected food chains.
  • Trophic Level: Each step in a food chain representing energy transfer.
  • Primary Producers: The first trophic level, consisting of autotrophs.
  • Primary Consumers: Organisms that consume producers (herbivores).
  • Secondary Consumers: Carnivores that eat primary consumers.
  • Tertiary Consumers: Carnivores that eat secondary consumers.
  • Ecological Pyramid: A diagram representing energy or matter at each trophic level.
  • Gross Primary Productivity (GPP): The total amount of energy captured by producers.
  • Net Primary Productivity (NPP): The energy stored as biomass after producers use some for respiration.
  • Biomass: The total mass of living organic matter in a given area.
  • 10% Rule: Only about 10% of the energy from one trophic level is passed to the next; the rest is lost as heat.
  • Respiration: The process of breaking down glucose to release energy in ATP form.
  • Heat Loss: Energy that is lost to the environment as heat during metabolic processes.
  • Biogeochemical Cycle: Movement of elements and compounds between living and non-living components.
  • Water Cycle: Continuous movement of water through the environment.
  • Carbon Cycle: Movement of carbon through living organisms, the atmosphere, the ocean, and the Earth's crust.
  • Nitrogen Cycle: Movement of nitrogen between the atmosphere, soil, and living organisms.
  • Phosphorus Cycle: Movement of phosphorus through the biosphere.
  • Carbon Fixation: Converting atmospheric carbon dioxide into organic compounds.
  • Cellular Respiration: Organisms break down glucose to release energy, producing carbon dioxide.
  • Decomposition: Breakdown of dead organisms, releasing carbon back into the environment.
  • Fossil Fuels: Carbon-rich energy sources (coal, oil, natural gas) formed from ancient organisms.
  • Greenhouse Effect: Trapping of heat in Earth's atmosphere due to gases like carbon dioxide.
  • Global Warming: Increase in Earth's average temperature due to excessive greenhouse gases.
  • Nitrogen Fixation: Bacteria convert atmospheric nitrogen into ammonia.
  • Ammonification: Decomposers break down organic matter and release nitrogen as ammonia.
  • Nitrification: Conversion of ammonia into nitrates by bacteria.
  • Denitrification: Conversion of nitrates into nitrogen gas, returning it to the atmosphere.
  • Assimilation: Absorption of nitrogen compounds by plants.
  • Nitrogen-fixing Bacteria: Convert atmospheric nitrogen into ammonia.
  • Ammonifying Bacteria: Break down organic matter into ammonia.
  • Nitrifying Bacteria: Convert ammonia into nitrates.

Matter and Energy Flow in Ecosystems

  • Ecosystems consist of living organisms and abiotic factors.
  • Energy is essential for life processes.
  • The sun is the ultimate source of energy; converted and passed through various ecosystem levels.
  • Energy Flow:
    • Sunlight is the main energy source for life on Earth.
      • Less than 1% of sun's energy is used by living organisms for photosynthesis.
      • Photosynthesis converts water and carbon dioxide into glucose and oxygen.
    • Autotrophs: Can use energy from the sun to convert simple inorganic substances into complex organic substances (glucose).
      • Convert carbon dioxide and water into carbohydrates.
      • Green plants, algae, some bacteria, and protists.
    • Heterotrophs: Acquire energy from other organisms.
      • Herbivores eat plants.
      • Carnivores eat other animals.
      • Omnivores eat plants and animals.
      • Detritivores feed on dead matter (vultures, mites, earthworms, snails, crabs).
      • Decomposers break down organic compounds (bacteria and fungi), recycling chemical nutrients.
        *Energy's one-way path passes from the sun to autotrophs, then to heterotrophs, then exits the ecosystem in the form of heat; it cannot be recycled.
        *Food chains & Webs:
        *linear food chain begins with an autotroph and moves up trophic levels.
        *food web = a network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem.
        *Trophic levels:
  • Each level is a step in a food chain. *Primary producers are always first, called autotrophs, *and each subsequent level depends on their lower neighbor for survival.
    *Ecological Productivity: can be gross primary productivity(rate at which producers capture the energy) or net productivity(GPP minus the rate that cells turn glucose into ATP).
    *only about 10% of the total energy from one trophic level gets passed on to the next level.

Ecosystem Recycling

  • Energy moves through an ecosystem in a one-way path.
  • Matter is recycled within and between ecosystems in biogeochemical cycles.
    • Biogeochemical Cycle: A process in which elements pass from one organism to another and from one part of the biosphere to another.
    • Types: water cycle, carbon cycle, nitrogen cycle, phosphorus cycle.

Human Impact on the Carbon Cycle

  • Atmospheric carbon dioxide has risen dramatically in the last 150 years.
  • Burning fossil fuels increases carbon dioxide entering the atmosphere.
  • Increased carbon dioxide enhances the greenhouse effect, leading to global warming.

Standard 2C: Ecosystem Dynamics, Function and Resilience

  • Ecosystem Dynamics: Constant changes and interactions in ecosystems over time.
  • Ecosystem Functioning: Processes within an ecosystem, like nutrient cycling and energy flow.
  • Ecosystem Resilience: The ability of an ecosystem to withstand disturbances and recover to a healthy state.
  • Factors Influencing Ecosystem Resilience:
    • Biodiversity: diverse ecosystems can adapt better to changes.
    • Climate Change: Ecosystems adapt to changing temperatures and weather patterns.
    • Human Impact: Deforestation and pollution can reduce resilience.
  • Disturbances: Events that disrupt the normal balance of an ecosystem (e.g., wildfires, floods, pollution).
  • Ecosystem Health: How well an ecosystem can support life, maintain balance, and recover from stress.
  • Sustainable Practices: Actions to meet human needs while protecting the environment (e.g., reducing waste, conserving water).
  • A stable ecosystem is characterized by a balanced food web, with predator-prey relationships, nutrient cycling, and a constant population of species.
  • Resilience is an ecosystem’s ability to recover after a disturbance..

Ecosystem Resilience (Standard 2C) – Notes & Keywords

  • Definition: The ability of an ecosystem to recover after a disturbance; the system can bounce back and continue to function even after stress or damage.
  • Key Vocabulary:
    • Resilience
    • Disturbance
    • Recovery
    • Biodiversity
    • Stress
    • Adaptation
    • Climate change
    • Coral bleaching
    • Marine protected area (MPA)
    • Restoration
  • What makes an ecosystem resilient?
    • High biodiversity
    • Healthy conditions (clean water, no overfishing)
    • Time to recover between disturbances
    • Support from conservation efforts
  • If reefs are already stressed, they may not survive.

Boom Time for Some Species

  • When the environment changes, some species scramble to find new ways to survive and thrive
  • Evidence: Sudden abundance of food or resources (e.g., surge in insect populations after a forest fire).
    Small changes in inherited traits (like beak size in finches) can give some individuals an advantage in a new environment
  • When Species Can't Keep Up: Extinction
    Sometimes, environmental changes happen too fast, or the change is simply too drastic
  • Deforestation, Overfishing and Climate Change are examples of Real-World Environmental Issues

2C-Ecosystem Dynamics, Function and Resilience

  • Ecological succession is the step-by-step process of change in an ecosystem over time
  • Helps restore ecosystems after natural or human-caused disruptions
  • Sustainable practices can support healthy succession
  • Biodiversity The variety of life in a particular ecosystem or on Earth as a whole-Helps restore ecosystems after natural or human-caused disruptions*Sustainable practices can support healthy succession

Key Vocabulary Definitions

  • Ecosystem A community of living organisms and their physical environment interacting together.
  • Succession The natural, gradual change in the types of species in an ecosystem over time.
  • Pioneer Species The first organisms to grow in a barren or disturbed area (like moss or lichen).
  • Climax Community A stable, mature ecosystem that forms after succession is complete.
  • Resilience An ecosystem's ability to recover after a disturbance.
  • Disturbance A sudden event that changes the environment and affects the ecosystem.
  • Biodiversity The variety of different species living in an ecosystem.
  • Primary Succession Succession that begins in a place without soil (like lava rock or bare ground).
  • Secondary Succession Succession that occurs where soil is present but the area was disturbed (like after fire).
  • Human Impact The ways in which human activities change or affect the environment.
  • Sustainability Using resources in ways that do not harm the environment and allow it to recover.
  • The habitat is unoccupied and starts from scratch in Primary Succession.
  • Happens in areas where there is no previous life and no organic matter.

  • Intense competition happens when life-support resources are scarce, and species have overlapping needs.
  • Lichens release acids that help break down rock, slowly forming the beginnings of soil which then allows mosses and other plants to follow.
  • A sequence of stages in ecological succession leading to a climax community is called Sere.
  • Lithosere - A type of xerosere that starts on bare rock surfaces.