Worksheets4.1 Ecosystems Syllabus
Total questions: 138
Worksheet time: 1hrs 9mins
Which term refers to large terrestrial regions characterized by specific climate patterns and distinct communities of plants and animals?
Ecological niche
Terrestrial biome
Food web
Ecosystem service
Primary productivity in an ecosystem is best defined as the rate at which which of the following is produced?
Animal biomass through consumption
Plant and algal biomass via photosynthesis or chemosynthesis
Detritus through decomposition
Minerals through weathering
During ecological succession, which sequence correctly describes the general progression from a newly formed habitat to a mature community?
Climax community → pioneer species → intermediate stages
Pioneer species → intermediate stages → climax community
Intermediate stages → pioneer species → climax community
Pioneer species → climax community → intermediate stages
Ecological pyramids most commonly illustrate which relationship within an ecosystem?
Distribution of genetic variation among species
Energy, biomass, or numbers across trophic levels
Rates of succession stages over time
Spatial arrangement of biomes across continents
Which factor primarily distinguishes one terrestrial biome from another?
Predator–prey ratios
Climate and vegetation patterns
Age of the ecosystem
Amount of geological activity
In primary succession, what is the typical role of pioneer species?
They outcompete climax species to reduce biodiversity
They colonize barren substrates and initiate soil formation
They maintain stable trophic pyramids
They prevent nutrient cycling
Which statement about ecological pyramids is most accurate?
Energy pyramids can be inverted in mature forests
Biomass pyramids are always upright in all ecosystems
Number pyramids may be inverted in ecosystems with few large producers
Energy pyramids are typically upright because energy decreases at higher trophic levels
Which metric would you use to compare how much chemical energy producers capture in different biomes?
Net secondary productivity
Gross primary productivity
Detrital turnover rate
Top-down control index
Which change would most likely occur in an ecosystem’s trophic structure following a disturbance that resets succession?
Increase in the proportion of climax species immediately
Simplification of food webs with dominance of pioneer producers
Immediate rise in apex predator biomass
Elimination of energy transfer losses
Which description best distinguishes secondary succession from primary succession?
Secondary succession begins on surfaces without soil; primary succession begins after fire
Secondary succession follows a disturbance where soil remains; primary succession begins on barren rock or newly exposed substrate
Secondary succession only occurs in aquatic biomes; primary succession only in terrestrial biomes
Secondary succession forms pioneer communities that never reach a climax stage
In an energy pyramid, why is the apex level typically narrow compared to lower levels?
Energy increases as it moves up trophic levels
Only producers exist at the apex
Energy is lost as heat and through metabolic processes at each transfer
Consumers at higher levels photosynthesize less
Which pair correctly matches a concept to its focus within ecosystem study?
Terrestrial biomes—trophic efficiencies
Primary productivity—energy capture by producers
Ecological pyramids—geographic boundaries
Ecological succession—gene flow across populations
Which scenario best exemplifies a transition from early to late succession?
Lichen colonization of volcanic rock followed by soil development and forest establishment
Immediate return of apex predators after a lava flow
Increase in genetic diversity within a single population without habitat change
Formation of deserts from tropical rainforests due to latitude shift
Which component is directly visualized by a biomass pyramid?
Rate of photosynthesis per trophic level
Total mass of living matter at each trophic level
Number of species per biome
Amount of detritus per unit area
Which statement about biomes is correct for global comparisons?
Biomes are defined primarily by latitude alone
Biomes are characterized by climate, typical flora and fauna
Biomes are temporary stages within succession
Biomes only exist on continents with mountains
If net primary productivity (NPP) increases in a grassland after seasonal rains, which immediate effect is most plausible?
Decrease in producer biomass
Increase in available energy for herbivores
Collapse of decomposer communities
Reduction in biodiversity
Which factor would most likely cause an inverted biomass pyramid in an aquatic ecosystem?
Large standing biomass of producers with slow turnover
Producers with low biomass but high turnover rates
Absence of decomposers
High genetic diversity among consumers
Which statement correctly contrasts GPP and NPP in ecosystems?
GPP excludes respiration losses; NPP includes them
GPP is total energy captured by producers; NPP is GPP minus producer respiration
GPP measures consumer energy intake; NPP measures producer biomass only
GPP equals NPP in all biomes
Which outcome is most consistent with late-successional or climax communities?
High dominance of fast-growing, short-lived pioneer species
Complex structure with higher species diversity and stable nutrient cycling
Absence of woody plants and canopy layers
Rapid changes in species composition year to year
Which statement best defines a biome in the context of ecosystems?
A regional community of organisms with similar genetic makeup
A large-scale ecological region characterized by its climate, soil, and typical vegetation
A single habitat type within a national park
An area defined solely by the presence of a keystone predator
Desert biomes are typically characterized by which combination of climate features?
High precipitation and low temperature variability
Low precipitation with high evaporation rates
Moderate rainfall and persistent cloud cover
Frequent storms with high humidity
In deserts, soils are commonly described as which of the following?
Rich in organic matter and deeply developed
Saline, sandy, and low in organic content
Clay-rich with high water retention
Peaty and acidic
Which plant adaptation is most typical of xerophytes found in desert biomes?
Broad, thin leaves with many stomata on both surfaces
Shallow roots and high transpiration rates
Reduced leaf surface area, thick cuticles, and water storage tissues
Seasonal leaf drop to maximize photosynthesis
Which statement accurately describes CAM photosynthesis?
CO2 is fixed during the day into 3-carbon compounds, reducing water loss
Stomata open at night to take in CO2, which is stored and used for photosynthesis during the day
Stomata remain closed both day and night to minimize transpiration
CAM plants rely on high soil moisture and daytime CO2 uptake
Why is CAM photosynthesis advantageous for plants in desert environments?
It increases transpiration to cool the plant during hot days
It synchronizes stomatal opening with peak sunlight for maximum CO2 intake
It reduces water loss by separating CO2 uptake at night from daytime photosynthesis
It allows plants to live only in shaded microhabitats
Which of the following best matches the term xerophyte?
A plant adapted to cold alpine conditions
A plant adapted to low-nutrient aquatic habitats
A plant adapted to arid environments with features that limit water loss
A plant adapted to high-salinity coastal marshes
A desert shrub closes its stomata during the day and opens them at night, storing CO2 as malate. Which pathway is this behavior most consistent with?
C3 photosynthesis
C4 photosynthesis
CAM photosynthesis
Photorespiration
Which characteristic is least likely to be found in typical desert vegetation?
Succulent tissues for water storage
Spines replacing leaves
Extensive shallow root systems
Large, thin leaves with high stomatal density
Consider a desert biome with sparse vegetation and high daytime temperatures. Which management practice would most directly enhance plant survival without irrigation?
Introducing broadleaf mesic forest species
Selecting native xerophytes with CAM metabolism
Increasing soil organic matter using peat from wetlands
Planting species with high transpiration rates
Which sentence correctly links desert climate to vegetation structure?
High rainfall supports dense canopies with large leaves
Low precipitation and intense sunlight favor plants with reduced leaf area and protective cuticles
Frequent fog results in epiphyte-dominated forests
Stable humidity promotes stomata remaining open during the day
In very arid deserts, which combination of traits would most likely be observed together in dominant plants?
Daytime stomatal opening, broad leaves, and high transpiration
Nighttime CO2 uptake, succulent stems, and spines replacing leaves
Thin cuticles, shallow roots, and large leaf area
Aquatic roots, floating leaves, and buoyant tissues
Recall: In CAM plants, when are stomata primarily open to take in CO2?
During midday when light is highest
At night to minimize water loss
Continuously throughout the day and night
Only during early morning dew formation
Skill/Concept: Which statement best describes the initial carbon fixation step in CAM photosynthesis?
CO2 is fixed directly into sugars via the Calvin Cycle in mesophyll cells
CO2 is fixed at night into organic acids (e.g., malate) that are stored in vacuoles
CO2 is fixed during the day into RuBP in bundle sheath cells
CO2 is fixed at night into gaseous oxygen that is later released
Strategic Thinking: A CAM plant is moved from a humid greenhouse to an arid environment with hot daytime temperatures. Which physiological adjustment maintains water-use efficiency while supporting photosynthesis?
Opening stomata wider during the hottest period to increase CO2 uptake
Switching to daytime stomatal opening while storing CO2 as bicarbonate
Keeping stomata closed during the day while decarboxylating stored acids to supply CO2 to the Calvin Cycle
Reducing chlorophyll content to lower light absorption and prevent photorespiration
Skill/Concept: During daylight in CAM plants, which process supplies CO2 to the Calvin Cycle when stomata are closed?
Photorespiration generates CO2 from oxygenation of RuBP
Decarboxylation of nighttime-stored organic acids releases CO2 internally
Direct atmospheric diffusion through cuticle pores provides CO2
Mitochondrial respiration of roots transports CO2 to leaves
Which climate pattern most accurately characterizes grassland biomes?
High precipitation year-round with cool temperatures
Moderate to low precipitation with seasonal temperature extremes
Very high precipitation and consistently warm temperatures
Low precipitation with permanently freezing temperatures
Grassland soils are typically described as which of the following?
Thin, highly acidic, and nutrient-poor
Deep, rich in organic matter, and fertile
Sandy, saline, and nutrient-poor
Shallow, waterlogged, and low in oxygen
What vegetation dominates grassland biomes?
Broadleaf evergreen trees forming dense canopies
Coniferous forests with needle-leaf trees
Grasses and herbaceous plants with few scattered trees
Mosses and lichens forming thick mats
Which plant adaptation is common in grasslands to survive frequent fires and grazing?
Large surface roots that burn easily
Growth from basal meristems near the ground
Leaves with high water content that freeze easily
Tall, single-stem growth with limited regrowth capacity
Animals in grasslands often show which behavioral or physiological adaptation?
Dependence on arboreal nesting to avoid ground predators
Specialized grazing and migratory behavior to track seasonal resources
Reliance on burrowing to escape tidal inundation
Nocturnal hunting adapted to dense forest understory
Savannas are best distinguished from temperate prairies by which feature?
Savannas have dense conifer forests, whereas prairies are treeless
Savannas occur in tropical to subtropical regions with scattered trees; prairies are temperate grasslands
Savannas are polar ecosystems; prairies are tropical rainforests
Savannas have permanent snow cover; prairies have monsoon rainfall
In grasslands, periodic fire typically has which ecological effect?
Eliminates grasses and promotes forest succession
Maintains open habitat by suppressing woody plant encroachment
Destroys soil organic matter and reduces fertility long-term
Creates waterlogged conditions that favor mosses
Which statement best explains why many grassland plants have deep root systems?
To store salt during tidal surges
To access water in dry periods and stabilize nutrient-rich soils
To avoid freezing in permanently cold climates
To support climbing growth into forest canopies
A prairie ecosystem likely experiences which seasonal pattern?
Minimal temperature variation and heavy rainfall year-round
Hot summers, cold winters, and periodic droughts
Persistent monsoon with high humidity and no frost
Cool summers, mild winters, and constant cloud cover
Which animal strategy is most aligned with surviving on grassland prey and avoiding predators?
Camouflage suited to dense leaf litter and tree bark
Long-distance running and herding behavior in open terrain
Specialized climbing skills and prehensile tails
Thick blubber for insulation in marine environments
What is a common consequence if tree encroachment is not controlled in grasslands?
Transition toward forested ecosystems reducing grass-dominated habitats
Expansion of polar ice altering albedo
Increase in coral reef biodiversity
Formation of peat bogs due to constant waterlogging
Which statement correctly pairs a grassland subtype with its region and vegetation structure?
Temperate prairie: tropical region; closed-canopy evergreen forest
Savanna: tropical to subtropical; grasses with scattered drought-tolerant trees
Steppe: polar region; moss mats with permafrost
Chaparral: temperate interior; broadleaf deciduous forest
Recall: Which term describes the process of restoring an area of land to its natural uncultivated state?
Rewilding
Conservation zone
Genetic rescue
National park designation
Recall: In habitat conservation, what defines an extracted reserve?
A fully protected park where human use is prohibited
An area where resources are allocated to a local group or community for its use
A corridor linking fragmented habitats to enable animal movement
A sanctuary created to protect a single endangered species
Skill/Concept: Which action most directly aligns with rewilding as depicted in the image of a field with cattle and natural vegetation?
Planting ornamental gardens with exotic species
Restoring native plant communities and reducing cultivation
Building recreational facilities and picnic areas
Intensive farming to increase crop yields
Recall: The Florida panther population experienced a bottleneck primarily due to which factors?
Overabundance of prey and disease
Hunting and habitat loss
Climate change and invasive plants
Road construction alone
Recall: Approximately how many Florida panthers remain after conservation efforts mentioned?
About 50
About 200
About 500
About 1,000
Skill/Concept: What was the purpose of introducing eight female pumas from Texas to the Florida panther population in 1995?
To replace males lost to hunting
To create a new captive breeding program
To perform a genetic rescue by increasing genetic diversity
To expand the species’ range into Texas
Strategic Thinking: Considering the bottleneck diagram and the curled tail x-ray, which outcome best explains why wildlife corridors could benefit Florida panthers?
Corridors reduce competition by concentrating animals in one area
Corridors increase gene flow between isolated groups, lowering inbreeding-related defects
Corridors eliminate all hunting pressure in the region
Corridors guarantee population sizes will immediately double
Recall: Nature reserves are primarily designed to protect what?
Entire landscapes only
A particular habitat, such as a wildlife sanctuary
Urban green spaces
Agricultural productivity
Recall: National parks are designed to protect which of the following?
Small plots for community resource extraction
Landscapes, wildlife, and natural features of relatively large areas
Only marine fisheries
Endangered species breeding programs only
Skill/Concept: Which policy best matches the definition of conservation zones provided?
Allowing unrestricted fishing throughout a bay
Designating areas where certain uses are prohibited, such as forbidding fishermen from taking their catch in some marine zones
Encouraging open-pit mining near wetlands
Permitting off-road vehicles in all habitats
Strategic Thinking: If a region aims to protect a diverse set of species across a large landscape while also offering visitor access, which tool is most appropriate?
Nature reserve
National park
Extracted reserve
Conservation zone
Strategic Thinking: A coastal community depends on local shellfish but stocks are declining. Based on the definitions, which approach would best balance use with recovery?
Create a national park that covers offshore waters
Establish a conservation zone that restricts shellfish harvesting in key areas
Open an extracted reserve permitting unlimited harvest
Implement rewilding by introducing exotic species to increase yields
Which climatic feature most characterizes tropical rainforest biomes?
Low annual rainfall with long dry seasons
High annual rainfall distributed throughout the year
Cold temperatures with frequent frost
Strong seasonality with monsoon-driven droughts
In tropical rainforests, humidity is typically described as
Low due to rapid drainage
Moderate and variable by season
High because of constant evapotranspiration
High only at night when temperatures drop
Which plant type is most typical of tropical rainforests?
Deciduous needleleaf trees
Broadleaf evergreen plants
Short-grass prairie species
Mediterranean sclerophyll shrubs
Lianas in tropical rainforests are best described as
Ground-dwelling mosses that retain soil moisture
Epiphytic orchids that photosynthesize without soil
Woody vines that climb trees to reach light
Succulent plants adapted to arid understory
Which statement best explains species diversity in tropical rainforests?
It is low because nutrient-poor soils limit plant growth
It is moderate due to periodic fires maintaining open habitats
It is high, supported by stable warm temperatures and abundant moisture
It is declining solely due to natural cycles of drought
Select the location pattern typical of tropical rainforests.
Centered around 30–40° latitude in both hemispheres
Primarily near the equator between the Tropics of Cancer and Capricorn
Restricted to high-altitude mountain ranges globally
Scattered only on western continental coasts
Which factor most directly promotes high humidity in tropical rainforests?
Frequent snowfall increasing albedo
Intense evapotranspiration from dense vegetation
Strong cold fronts bringing moist polar air
Low canopy cover reducing evaporation
Which description best matches rainfall in tropical rainforests?
Seasonal, with a pronounced dry winter
Sparse, often less than 250 mm per year
Heavy and frequent, supporting lush vegetation
Irregular, driven by occasional hurricanes only
A defining structural feature of many tropical rainforest plants is
Thick waxy needles to reduce transpiration
Evergreen broad leaves that remain year-round
Deciduous leaves that fall during summer heat
Tiny leaves adapted to cold climates
Which ecological consequence follows from the climate of tropical rainforests?
Low productivity due to limited sunlight
High net primary productivity and complex food webs
Dominance of wind-pollinated grasses
Persistent permafrost limiting root growth
Which statement about lianas is accurate within the rainforest canopy dynamics?
They compete for water by developing deep taproots exclusively
They use host trees for support, accessing upper light levels
They form independent canopies that shade trees from above
They rely on frost events to trigger flowering
Which combination correctly pairs tropical rainforest traits?
Low humidity, sparse vegetation, and low species diversity
High rainfall, high humidity, and high species diversity
Cold climate, needleleaf evergreens, and low evapotranspiration
Strong seasonality, deciduous broadleaf forests, and frequent frost
Recall: Which statement best describes the typical climate of tropical rainforests?
Low temperatures with seasonal snowfall
Consistently warm with high rainfall throughout the year
Hot days with very cold, dry winters
Mild temperatures with limited precipitation
Skill/Concept: Tropical rainforest soils are often described as nutrient-poor despite luxuriant vegetation. Which explanation best accounts for this observation?
Most nutrients are stored in the deep mineral soil layers
Frequent flooding washes nutrients into rivers
Rapid decomposition and uptake keep nutrients cycling within the biomass rather than in the soil
Volcanic ash continually neutralizes nutrients
Strategic Thinking: The canopy in a tropical rainforest forms multiple layers. Which consequence most directly results from this vertical structure for plant competition?
Understory plants receive abundant direct sunlight all day
Epiphytes and shade-tolerant plants evolve strategies to capture limited light beneath upper layers
Soil temperature becomes too low for root growth
Wind speeds increase dramatically at ground level
Skill/Concept: Which feature is most characteristic of tropical rainforest vegetation?
Sparse leaf area with short-growing seasons
High biodiversity with dense, layered plant communities including a closed canopy
Dominance of conifers adapted to freezing temperatures
Uniform height trees with little understory
Temperate deciduous forests experience distinct seasons. Which statement best describes their typical climate pattern across a year?
Warm summers and cold winters with moderate precipitation spread across seasons
Hot, dry summers and mild, wet winters with minimal annual variability
Consistently warm temperatures and heavy rainfall year-round
Extremely cold temperatures with very low precipitation throughout the year
In temperate deciduous forests, how do trees primarily respond to seasonal changes to conserve resources?
They retain evergreen needles all year to reduce water loss
They shed broad leaves in autumn to lower water loss and metabolic costs
They produce thicker bark in summer to increase photosynthetic rate
They store excess chlorophyll in roots during spring to prevent freezing
Which soil characteristic is commonly associated with temperate deciduous forests and supports diverse plant growth?
Thin, nutrient-poor soils formed from volcanic ash
Deep, fertile soils with rich organic leaf litter
Saline, compacted soils with minimal humus
Permafrost soils with limited decomposition
Mycorrhizae are an important feature of tree root systems in temperate deciduous forests. What is their primary ecological role?
They fix atmospheric nitrogen directly into wood
They form symbiotic associations that increase nutrient and water uptake
They replace roots during winter dormancy
They produce toxins that deter herbivores from feeding on leaves
Which adaptation helps deciduous leaves withstand seasonal variation in light and temperature?
Thick waxy cuticles that prevent all gas exchange
Broad, thin blades that maximize photosynthesis during the growing season
Needle-like leaves that photosynthesize slowly year-round
Spines that reflect excess light and reduce photosynthesis
Nutrient cycling in temperate deciduous forests is strongly influenced by annual leaf fall. What happens during this process?
Leaf litter decomposes, returning nutrients to the soil for reuse by plants
Leaves remain intact and permanently store nutrients on the forest floor
Nutrients are leached into deep aquifers and become unavailable
Decomposition ceases in summer due to low microbial activity
Which scenario best illustrates a DoK 2 application of seasonal knowledge in temperate deciduous forests?
Memorizing that winters are cold
Explaining why trees enter dormancy in winter due to lower temperatures and light
Listing the names of common deciduous tree species
Recalling the term humus
Consider a forest where summers are warm, precipitation is moderate, and winters are cold with snow. Which biome description fits these conditions?
Tropical rainforest
Temperate deciduous forest
Desert
Tundra
If a temperate deciduous forest experiences reduced leaf litter due to heavy autumn winds removing leaves from the site, what is the most likely effect on soil fertility the following spring?
Soil fertility increases because nutrients are stored in tree trunks
Soil fertility decreases because fewer nutrients are returned through decomposition
No change because leaves do not contribute to nutrient cycling
Soil becomes saline due to wind action
A student compares two plots: Plot A with abundant mycorrhizal networks and Plot B where fungi were experimentally reduced. Which outcome is most plausible for Plot B?
Higher tree growth due to reduced competition for nutrients
Lower nutrient uptake and slower tree growth because symbiosis is disrupted
No change because mycorrhizae only affect evergreen species
Increased nitrogen fixation directly by tree roots
Which explanation best uses evidence to justify why deciduous trees shed leaves before winter in this biome?
Leaf shedding reduces transpiration when liquid water is limited and prevents frost damage to photosynthetic tissues
Leaf shedding increases transpiration to keep roots warm
Leaf shedding enhances nitrogen fixation by bark microbes
Leaf shedding is solely to avoid herbivory during winter
A land manager wants to support nutrient cycling in a temperate deciduous forest restoration. Which practice aligns with this goal?
Removing leaf litter each autumn to prevent fungal growth
Leaving leaf litter to decompose and encouraging mycorrhizal associations
Compacting soil to slow decomposition
Applying salt to simulate winter conditions
Recall: Which feature best characterizes the climate of temperate forests described in the summary?
Consistently hot and wet year-round
Moderate temperatures with distinct seasons
Extremely cold with minimal precipitation
Arid conditions with infrequent rainfall
Skill/Concept: Based on the summary, which combination of vegetation types is most typical of temperate forests?
Only broadleaf deciduous trees
A mix of deciduous and evergreen trees
Primarily shrubs with sparse trees
Only coniferous evergreen trees
Strategic Thinking: A land manager is comparing two regions for reforestation. Region A has fertile, well-developed soils and marked seasonal changes; Region B has nutrient-poor soils and minimal seasonal variation. According to the temperate forest summary, which region more closely aligns with temperate forest characteristics, and why?
Region A, because temperate forests have fertile soils and clear seasons
Region A, because temperate forests lack seasonal changes but have poor soils
Region B, because temperate forests have infertile soils and weak seasonality
Region B, because temperate forests require nutrient-poor soils and constant climate
Skill/Concept: Which statement best explains how seasonal variations influence vegetation in temperate forests according to the summary?
Seasonality leads to continuous flowering and fruiting all year
Seasonality supports deciduous leaf drop and evergreen persistence
Seasonality causes trees to remain leafless year-round
Seasonality eliminates the need for evergreen species
Which global biome is characterized by vast coniferous forests, a cold climate, and being the largest terrestrial biome on Earth?
Tropical rainforest
Boreal forest (Taiga)
Temperate grassland
Savanna
Where are boreal forests (Taiga) primarily located on the planet?
Near the equator across multiple continents
In mid-latitudes of both hemispheres
Across high-latitude regions just south of the Arctic circle in the Northern Hemisphere
Almost entirely within Antarctica
Which tree type best represents the dominant vegetation of the boreal forest (Taiga)?
Broadleaf deciduous trees such as oaks and maples
Coniferous trees such as spruce, fir, and pine
Mangrove trees adapted to brackish water
Baobab and acacia trees typical of savannas
What climatic feature most defines the boreal forest (Taiga)?
Year-round warm temperatures and high precipitation
Cold temperatures with long winters and short summers
Monsoonal rainfall with pronounced wet and dry seasons
Extreme aridity with very low annual precipitation
Which statement compares the biodiversity of boreal forests to tropical rainforests most accurately?
Boreal forests generally have higher plant and animal diversity than tropical rainforests
Both biomes have similar levels of biodiversity
Boreal forests have lower biodiversity due to cold climate limiting species variety
Boreal forests lack all animal life
Which adaptation is common among coniferous trees that helps them survive in the Taiga’s cold climate?
Large, thin leaves to maximize transpiration
Needle-like leaves with waxy coatings to reduce water loss
Shallow roots to absorb frequent rainfall
Seasonal leaf drop to avoid herbivory
Which environmental factor most restricts the growth season and productivity in boreal forests?
High soil salinity from ocean spray
Extended periods of freezing temperatures and limited sunlight
Frequent volcanic activity
Persistent flooding from monsoon rains
Among global biomes, which holds the distinction of covering the largest continuous land area?
Temperate deciduous forest
Desert
Boreal forest (Taiga)
Mediterranean shrubland
Recall: Which statement best describes a core characteristic of the tundra biome?
High precipitation and deep fertile soils
Cold temperatures, low precipitation, and thin soils
Tall tree canopy with abundant annual growth
Warm summers with high biodiversity of large mammals
Recall: What is permafrost in tundra ecosystems?
Seasonal layer of water that forms each summer
Permanently frozen ground that persists for years
A surface ice sheet that melts every spring
Loose sand deposited by glacial winds
Skill/Concept: Which plant adaptation is most likely in tundra regions with permafrost and thin soils?
Deep taproots to reach groundwater
Low-growing forms with shallow root systems
Large woody trunks to store water
Broad leaves with high stomatal density
Strategic Thinking: Rising temperatures thaw permafrost. Which ecological consequence aligns with the section’s concepts?
Decreased methane release due to colder soils
Increased methane release from decomposing organic matter
Immediate growth of tall forest species
Rapid increase in precipitation forming lakes everywhere
Recall using the visual: In Antarctica, which human activity is directly linked to heavy losses of whale and seal populations?
Tourism
Overfishing and hunting
Ozone depletion
Protected area designation
Recall using the visual: What concern is raised by a significant decline of krill in Antarctic waters?
Increase in coral reef formation
Collapse of many Antarctic food chains
Expansion of mangrove forests
Improved water clarity and photosynthesis
Skill/Concept using the visual: Why has mineral and oil extraction in Antarctica been limited so far?
Resources are absent in the region
Extraction is difficult and expensive
International laws mandate immediate exploitation
The climate favors easy cleanup of spills
Strategic Thinking using the visual: If mineral reserves dwindle in other regions, what pressure might increase on Antarctica?
Pressure to expand protected areas
Pressure to access mineral resources there
Pressure to stop scientific research
Pressure to increase whale populations
Recall using the visual: According to the slide on human impacts, what is a direct effect of tourism in Antarctica?
Increased ozone formation
Direct pollution
Enhanced krill reproduction
Immediate permafrost formation
Skill/Concept using the visual: How can scientific research activities affect Antarctic ecosystems?
They guarantee habitat expansion for penguins
They cannot influence biodiversity
Their presence can lead to habitat loss and generate waste
They eliminate the need for protected areas
Strategic Thinking using the visual: Ozone depletion is listed as impacting chloroplasts. What downstream ecological effect is most directly related?
Increased photosynthesis rate in algae
Reduced productivity affecting all trophic levels
Immediate decrease in sea ice thickness
Rapid recovery of whale populations
Recall using the visual: Which international agreement governs peaceful use and cooperative scientific investigation in Antarctica?
Kyoto Protocol
Antarctic Treaty (1959)
Paris Agreement
Geneva Convention
Recall using the visual: Under the Antarctic Treaty, which activity is explicitly restricted?
Tourism in all areas
Mining for minerals
Scientific investigation between countries
Observation of wildlife from a distance
Skill/Concept using the visual: What is one purpose of establishing protected areas in Antarctica?
To encourage vehicle access everywhere
To create no-go zones where no activity can occur
To increase annual limits on people entering
To promote introduction of non-native species
Strategic Thinking using the visual: If some protected areas prohibit vehicles and limit visitors annually, what management goal do these rules support?
Maximizing tourism revenue
Reducing disturbance and protecting fragile habitats
Increasing extraction efficiency
Encouraging non-native species colonization
Which statement best defines ecological succession?
The gradual, predictable change in species composition of a community over time
The sudden extinction of all species in an ecosystem
The migration of animals from one biome to another each season
The random introduction of invasive species into a habitat
Primary succession most likely begins in which setting?
On bare rock exposed by a retreating glacier
In a mature forest after a seasonal leaf fall
In a grassland experiencing normal grazing
In a lake during annual turnover
During secondary succession, which condition is present at the start that is typically absent in primary succession?
Existing soil that remains after a disturbance
An absence of sunlight
No living organisms can colonize the area
A permanent lack of water
Which group is most commonly identified as pioneer species in primary succession?
Lichens and mosses that can grow on bare rock
Large hardwood trees requiring deep soil
Top predators requiring established food webs
Aquatic fish species in deep lakes
What is the climax community in the context of ecological succession?
A relatively stable, mature community that has reached dynamic equilibrium
The first colonizers following a disturbance
A temporary stage dominated by annual weeds
A community that excludes all forms of disturbance forever
Which event would most likely initiate secondary succession rather than primary succession?
A forest fire leaving soil intact
Formation of a new volcanic island
Exposure of bedrock after glacial retreat
Lava flows covering previously uninhabited terrain
Why are lichens effective pioneer species in primary succession?
They can secrete acids that help weather rock and contribute to soil formation
They require deep nutrient-rich soils to germinate
They are top-level consumers that regulate prey populations
They disperse only by large seeds carried by mammals
Place the typical stages of primary succession in order from earliest to latest.
Bare rock → lichens/mosses → small plants → shrubs → mature forest
Bare rock → mature forest → shrubs → lichens/mosses
Shrubs → bare rock → small plants → lichens/mosses → mature forest
Mature forest → bare rock → lichens/mosses → shrubs
After a hurricane clears a coastal forest but leaves the soil, what is the most likely first plant stage to appear?
Fast-growing grasses and herbaceous plants
Lichens on exposed bedrock
Large, slow-growing climax trees
Submerged aquatic plants
Which statement correctly contrasts primary and secondary succession?
Primary succession begins on surfaces without soil; secondary succession begins where soil remains after disturbance
Primary succession requires human intervention; secondary succession occurs only without humans
Primary succession is faster than secondary succession in most cases
Primary succession does not involve pioneer species while secondary succession does
In a temperate forest undergoing secondary succession, which change in species composition is most expected over decades?
Early dominance by r-selected species shifting to late dominance by K-selected, shade-tolerant trees
Immediate establishment of top predators followed by herbivores
A permanent dominance by annual weeds without replacement
Replacement of trees by bare rock due to soil loss
Which human action would most likely reset an ecosystem from a late-successional stage to an early-successional stage?
Clear-cut logging that removes most vegetation but leaves soil
Selective removal of a few dead trees
Installation of wildlife cameras
Controlled watering during a drought
Which statement best defines gross primary productivity (GPP) in an ecosystem?
The total rate at which primary producers capture and store energy through photosynthesis
The energy available to consumers after accounting for producer respiration
The total mass of living organisms at all trophic levels
The energy lost as heat during trophic transfers
Net primary productivity (NPP) is most accurately described as:
The energy fixed by producers before any losses
Biomass added to the ecosystem per unit time after producer respiration
Energy transferred from primary consumers to secondary consumers
Total ecosystem respiration across all trophic levels
Which equation correctly relates NPP, GPP, and respiration by producers (R)?
NPP = GPP + R
NPP = GPP − R
GPP = NPP − R
R = NPP + GPP
In ecological terms, biomass refers to:
The number of individuals at each trophic level
The total energy captured by photosynthesis
The mass of living organic matter within a given area or trophic level
The rate of respiration of heterotrophs
Ecosystem productivity primarily depends on which two processes in producers?
Respiration and decomposition
Photosynthesis and respiration
Consumption and excretion
Nitrogen fixation and denitrification
If a forest has a GPP of 2500 g C m⁻² yr⁻¹ and producer respiration (R) of 1800 g C m⁻² yr⁻¹, what is its NPP? Show your reasoning using the NPP formula.
700 g C m⁻² yr⁻¹ because NPP = GPP − R = 2500 − 1800
4300 g C m⁻² yr⁻¹ because NPP = GPP + R = 2500 + 1800
1800 g C m⁻² yr⁻¹ because NPP equals producer respiration
2500 g C m⁻² yr⁻¹ because NPP equals GPP
Which scenario would most likely increase NPP in a grassland?
An increase in producer respiration due to heat stress
A decrease in photosynthetic rate from prolonged shade
Enhanced photosynthesis from adequate water and nutrients
Removal of primary consumers from the ecosystem
Which choice correctly distinguishes GPP from NPP?
GPP excludes respiration losses, NPP includes them
GPP includes respiration losses, NPP excludes them
Both GPP and NPP exclude respiration losses
GPP measures standing biomass, NPP measures energy capture
A lake ecosystem shows high GPP but moderate NPP. What does this imply about producer respiration?
Producer respiration is low, so most energy remains as NPP
Producer respiration is high, reducing the energy available as NPP
Respiration by consumers is high, lowering NPP
Respiration has no effect on NPP in aquatic systems
Which statement about respiration in the NPP equation is correct?
It represents energy lost by producers to metabolic processes
It represents energy stored as biomass and available to consumers
It measures only consumer respiration
It is unrelated to photosynthesis
Two ecosystems have the same GPP, but Ecosystem A has higher NPP than Ecosystem B. Which conclusion is most supported?
Ecosystem A has higher producer respiration than Ecosystem B
Ecosystem B has lower producer respiration than Ecosystem A
Ecosystem A has lower producer respiration than Ecosystem B
Producer respiration is identical in both ecosystems
Which factor directly contributes to biomass accumulation at the producer level?
Higher GPP relative to respiration
Higher respiration relative to GPP
Lower photosynthetic pigment concentration
Greater energy transfer efficiency between consumers
