Ecosystems and Biomes Review

Ecosystems

1.1 Ecosystems Overview

  • Definition of an ecosystem: A system composed of living organisms interacting with each other and their physical environment (e.g., soil, air, water).

1.2 Learning Objectives/EK/Skills

Learning Objective

  • ERT-1.A: Explain how the availability of resources influences species interactions.

Suggested Skill

  • 1.A: Concept Explanation: Describe environmental concepts and processes.

Essential Knowledge

  • ERT-1.A.1: In a predator-prey relationship, the predator consumes the prey, affecting the population dynamics and behavior of both species.

  • ERT-1.A.2: Symbiosis refers to long-term interactions between two species. Types include:

    • Mutualism: Both species benefit (e.g., bees and flowers).

    • Commensalism: One species benefits, the other is not significantly affected (e.g., birds nesting in trees).

    • Parasitism: One species benefits at the expense of the other (e.g., tapeworms in mammals).

  • ERT-1.A.3: Competition arises when species vie for limited resources, which may occur intra-specifically (within a species) or inter-specifically (between species). Resource partitioning, wherein species utilize the same resource differently (e.g., in time, place, or manner), can help mitigate competition.

1.3 Ecosystem Basics

  • Individual: A single organism (e.g., one elk).

  • Population: A group of individuals of the same species (e.g., an elk herd).

  • Community: All living organisms in a specific area.

  • Ecosystem: The sum of living and nonliving components in an area (including flora, fauna, rocks, soil, water, air).

  • Biome: A larger ecosystem type characterized by specific climate conditions influencing seed and animal species (e.g., tropical rainforest).

1.4 Organism Interactions

  • Types of Organism Interactions:

    • Mutualism: Both organisms benefit (e.g., coral reefs).

    • Competition: Organisms compete for resources, limiting the population size.

    • Predation: One organism consumes another for energy (e.g., leopards preying on giraffes).

    • Commensalism: One organism benefits without impacting the other (e.g., birds nesting in trees).

1.5 Predation

  • Predation Relationship: Identified as (+/-). Examples:

    • True Predators: Carnivores that kill prey for energy (e.g., leopard and giraffe).

    • Herbivores: Consume plants for energy (e.g., giraffe and trees).

    • Parasites: Derive energy from a host, often without killing the host (e.g., mosquitoes).

    • Parasitoids: Lay eggs in a host; larvae consume host from inside (e.g., parasitic wasps).

1.6 Symbiosis Explained

  • Symbiosis: Derived from the roots "sym" (together) and "bio" (life), indicating close living arrangements.

  • Types of symbiotic relationships:

    • Mutualism (+/+)

    • Commensalism (+/0)

    • Parasitism (+/-)

  • Example of mutualism: Coral providing structure for algae; algae providing sugars for coral energy.

  • Example of lichen: A mutualistic relationship between fungi and algae, where each organism benefits nutritionally.

1.7 Competition and Resource Partitioning

  • Resource partitioning aids in minimizing competition by utilizing resources differently, which can include:

    • Temporal partitioning: Different times of resource use (e.g., wolves vs. coyotes).

    • Spatial partitioning: Different habitat use (e.g., plants with different root depths).

    • Morphological partitioning: Differentiation based on evolved body features affecting resource use.

1.8 Practice Question FRQ 1.1

  • Identify two organisms competing for a shared resource.

  • Explain how resource partitioning could help reduce competition among them.

1.2 Terrestrial Biomes

1.9 Learning Objective

  • ERT-1.B: Describe the global distribution and principal environmental aspects of terrestrial biomes.

Suggested Skill

  • 1.B: Concept Explanation: Explain environmental concepts and processes.

Essential Knowledge

  • ERT-1.B.1: A biome is defined by characteristic plant and animal communities, adapted to its specific climate.

  • ERT-1.B.2: Major terrestrial biomes include:

    • Taiga

    • Temperate rainforests

    • Temperate seasonal forests

    • Tropical rainforests

    • Shrublands

    • Temperate grasslands

    • Savanna

    • Desert

    • Tundra

  • ERT-1.B.3: The distribution of nonmineral terrestrial natural resources, including water and lumber, varies based on climate, geography, latitude, altitude, nutrient availability, and soil quality.

  • ERT-1.B.4: Biome distribution is dynamic, subject to change from climate shifts.

1.10 Biome Characteristics

  • Biomes are influenced by average annual temperature and precipitation, affecting vegetation and animal life (for example: desert and tundra).

  • Latitude affects temperature and precipitation, leading to predictable biome patterns on Earth.

    • Higher latitudes (60°+) typically host tundra and boreal biomes.

    • Mid-latitudes (30°-60°) are home to temperate biomes.

    • Tropic areas by the equator are warmer.

1.11 Nutrient Availability in Biomes

  • Nutrient-poor soils are typical in:

    • Tropical Rainforests: High competition due to various plant species.

    • Boreal Forests: Low decomposition rates lead to nutrient-poor conditions.

  • Nutrient-rich soils often seen in temperate forests due to abundant organic matter decomposition.

1.12 Shifting Biomes

  • Climate change leads to biome shift, for instance, boreal forests shifting northward as permafrost melts.

1.13 Practice Question FRQ 1.2

  • Describe how a specific characteristic of a biome determines its organism community.

1.3 Aquatic Biomes

1.14 Learning Objectives

  • ERT-1.C: Describe the global distribution and principal environmental aspects of aquatic biomes.

Suggested Skill

  • 1.B: Concept Explanation: Explain environmental concepts and processes.

Essential Knowledge

  • ERT-1.C.1: Freshwater biomes encompass streams, rivers, ponds, and lakes, significant for drinking water.

  • ERT-1.C.2: Marine biomes include oceans, coral reefs, marshlands, and estuaries; algae in marine environments contribute to much of Earth’s oxygen.

  • ERT-1.C.3: The global distribution of marine resources, like various fish, is influenced by salinity, depth, turbidity, nutrient availability, and temperature.

1.15 Characteristics of Aquatic Biomes

  • Depth: Affects sunlight penetration for photosynthesis.

  • Temperature: Warmer waters hold less dissolved oxygen.

  • Salinity: Determines species survivability (e.g., freshwater vs. marine).

  • Flow: Influences oxygen availability and aquatic life behaviors.

1.16 Freshwater: Rivers & Lakes

  • Rivers: High oxygenation due to flow, carry nutrients to delta and floodplain regions.

  • Lakes: Defined zones based on depth:

    • Littoral: Shallow water with plants.

    • Limnetic: Well-lit area supporting phytoplankton.

    • Profundal: Deep section lacking light.

    • Benthic: Bottom layer where decomposers inhabit.

1.17 Freshwater: Wetlands

  • Wetland Definition: Area with soil that is submerged or saturated in water for part of the year, supporting emergent plants.

  • Benefits of Wetlands:

    • Reduces flood impact.

    • Recharges groundwater.

    • Filters contaminants in water.

    • Supports diverse plant growth.

1.18 Estuaries

  • Areas where rivers meet oceans, creating high productivity zones due to nutrient deposits.

    • Salt Marsh: Coastal estuary in temperate areas, breeding grounds for fish.

    • Mangrove Swamps: Found in tropics, provide stabilization and habitat.

1.19 Coral Reefs

  • Located in warm, shallow waters, coral reefs are the most diverse marine ecosystems.

  • Demonstrate mutualism between corals and algae, vital for the reef’s health.

1.20 Intertidal Zones

  • Areas along the coastline, home to organisms adapted to varying conditions (e.g., barnacles).

1.21 Open Ocean

  • Generally non-productive; algae and phytoplankton are restricted to the photic zone.

  • The ocean's vast space contributes significantly to oxygen production.

1.4 Carbon Cycle

1.22 Learning Objectives/EK/Skill

  • ERT-1.D: Explain the steps and reservoir interactions in the carbon cycle.

Suggested Skill

  • 2.B: Explain relationships between characteristics of environmental concepts visually.

Essential Knowledge

  • ERT-1.D.1: The carbon cycle refers to carbon's movement between sources and sinks, involving various chemical transformations like (CO2) and glucose (C6H{12}O6).

  • ERT-1.D.2: Reservoirs vary in carbon retention periods; some are short-term, while others like sedimentary rocks are long-term.

  • ERT-1.D.3: Carbon cycling involves crucial processes like photosynthesis and respiration.

  • ERT-1.D.4: Decomposition reinforces carbon storage, while fossil fuel combustion rapidly releases carbon back into the atmosphere.

1.23 Carbon Cycle Overview

  • Flash processes (like combustion) occur quickly while sedimentation and burial are slow.

  • Key reservoirs include:

    • Carbon Sink: Reservoir storing more carbon than it releases (e.g., oceans, plants).

    • Carbon Source: Processes that add carbon to the atmosphere (e.g., combustion of fossil fuels).

1.24 Photosynthesis and Cellular Respiration

  • Photosynthesis: Converts (CO_2) into glucose, utilizing sunlight.

  • Cellular Respiration: Organisms break down glucose, releasing (CO_2).

    • Counteract emissions from human activities and maintain atmospheric balance.

1.25 Ocean and Atmosphere Exchange

  • Carbon exchange occurs between the ocean and atmosphere via direct diffusion.

  • Ocean acidification results from increasing atmospheric carbon influencing marine ecosystems.

1.26 Burial, Extraction & Combustion

  • Process of burial takes a long time, while extraction and combustion are significantly faster, leading to increased atmospheric carbon.

1.27 Feedback Mechanisms in Carbon Cycle

  • Increased atmospheric (CO_2) contributes to climate change and potential ecological impacts over time.

1.28 Practice Question FRQ 1.4

  • Identify a quick and a slow process in the carbon cycle while addressing the fossil fuel impact over the last 250 years.

1.5 Nitrogen Cycle

1.29 Learning Objectives/EK/Skill

  • ERT-1.E: Explain the steps and reservoir interactions in the nitrogen cycle.

Suggested Skill

  • 2.B: Explain relationships visually.

Essential Knowledge

  • ERT-1.E.1: The nitrogen cycle details nitrogen in various forms moving between sources and sinks.

  • ERT-1.E.2: Nitrogen reservoirs are generally short-term holdings.

  • ERT-1.E.3: Nitrogen fixation converts atmospheric nitrogen (N_2) into forms usable by plants.

  • ERT-1.E.4: The atmosphere signifies the major nitrogen reservoir.

1.30 Nitrogen Cycle Overview

  • Nitrogen is crucial for DNA and proteins. However, atmospheric nitrogen's (N_2) form is unusable by most organisms.

1.31 Nitrogen Fixation

  • Includes two processes:

    • Synthetic Fixation: Combustion of fossil fuels converts (N2) into nitrate (NO3^−).

    • Bacterial Fixation: Specific bacteria fix (N2) into ammonia (NH3).

1.32 Steps in Nitrogen Cycle

  • Include nitrification, ammonification, assimilation, and denitrification.

Human Impacts on the Nitrogen Cycle

  • Excessive nitrogen fertilizer usage leads to leaching, eutrophication, climate implications, and pollutes water sources.

1.33 Practice Question 1.5

  • Describe a vital nitrogen cycle transformation and its significance to ecosystems.

1.6 Phosphorus Cycle

1.34 Learning Objectives/EK/Skill

  • ERT-1.F: Explain the steps and reservoir interactions in the phosphorus cycle.

Suggested Skill

  • 2.B: Visual representation relationships.

Essential Knowledge

  • ERT-1.F.1: Phosphorus cycle involves movement between sources and sinks without atmospheric presence.

  • ERT-1.F.2: Major phosphorus reservoirs are found in rocks and sediments.

  • ERT-1.F.3: Phosphorus is limiting in ecosystems, often scarce.

1.35 Phosphorus Cycle Basics

  • Very slow compared to nitrogen and carbon cycles; weathering leads to longer processes.

1.36 Phosphorus Sources and Assimilation

  • Natural phosphorus sources arise from weathered rocks, while synthetic sources result from mining.

1.37 Eutrophication

  • Occurs when excess nutrients from fertilizers stimulate drastic algae growth, depleting oxygen and resulting in ecosystem failures.

1.38 Practice Question 1.6

  • Choose two phosphorus reservoirs and describe their interaction.

1.7 Hydrologic (Water) Cycle

1.39 Learning Objectives/EK/Skill

  • ERT-1.G: Explain the water cycle's steps and reservoir interactions.

Suggested Skill

  • 2.B: Visual representations of relationships.

Essential Knowledge

  • ERT-1.G.1: The hydrologic cycle, powered by energy from the sun, is the movement of water among its various forms.

  • ERT-1.G.2: Oceans serve as Earth's primary water reservoir, with ice caps and groundwater being smaller reservoirs.

1.40 Water Cycle Overview

  • Movement of water (solid, liquid, gas) varies extensively across the environment, chiefly through evaporation and transpiration.

1.41 Key Processes in Water Cycle

  • Evaporation and transpiration return water vapor into the atmosphere, driven by solar energy.

1.42 Runoff and Infiltration

  • Precipitation can either flow over surfaces (runoff) or saturate the ground (infiltration), both crucial for maintaining freshwater supplies.

1.43 Practice Question FRQ 1.7

  • Describe a water cycle process and its effect on water movement.

1.8 Primary Productivity

1.44 Learning Objectives/EK/Skill

  • ENG-1.A: Explain solar energy acquisition and transfer among organisms.

Suggested Skill

  • 1.A: Concept Explanation: Describe environmental concepts and processes.

Essential Knowledge

  • ENG-1.A.1: Primary productivity rate measures solar energy conversion into organic compounds through photosynthesis.

  • ENG-1.A.2: Gross primary productivity (GPP) represents total photosynthesis rate in an area.

  • ENG-1.A.3: Net primary productivity (NPP) accounts for energy loss through respiration.

  • ENG-1.A.4: Productivity measured in energy units (e.g., kcal/m^2/yr).

  • ENG-1.A.5: Light absorption in water impacts aquatic photosynthesis.

1.45 Calculating NPP

  • Formula for NPP: NPP = GPP - RL,
    where RL is respiration loss by plants, representing energy utilizational costs.

1.46 Ecological Efficiency of Biomes

  • Efficiency reflected in the rate of energy transfer, which is estimated at 10% from one level to the next in a trophic structure.

1.47 Trends in Productivity

  • Productivity in ecosystems depends on water, temperature, and nutrient availability, affecting biodiversity levels.

1.48 Practice Question FRQ 1.8

  • Discuss NPP and its relationship to biodiversity.

1.9 Trophic Levels & The 10% Rule

1.49 Learning Objectives/EK/Skill

  • ENG-1.B: Explain energy flow and matter cycling through trophic levels.

1.50 10% Rule in Energy Transfer

  • States that approximately 10% of energy is maintained when moving between trophic levels, while the rest is dissipated as heat.

1.51 Conservation of Matter and Energy

  • Energy is conserved but can change forms, and trophic dynamics illustrate energy availability across ecosystems.

1.52 Trophic Levels Defined

  • Producers: Convert sunlight into energy.

  • Primary Consumers: Herbivores feeding on producers.

  • Secondary and Tertiary Consumers: Carnivores feeding on other consumers.

1.53 Practice Questions FRQs 1.9 & 1.10

  • Assess energy availability in a food chain context.

1.10 Food Chains and Food Webs

1.54 Learning Objectives/EK/Skill

  • ENG-1.D: Describe food chains and webs, including their components by trophic level.

1.55 Understanding Food Webs

  • A food web connects multiple food chains, illustrating the flow of matter and energy.

1.56 Feedback Loops in Ecosystems

  • Organisms' additions or removals affect ecosystem dynamics.

1.57 Practice Question FRQ 1.11

  • Illustrate the effects of population changes in ecosystems on food webs.