Analyze Biodiversity Data
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Biology › Analyze Biodiversity Data
A student surveys two grassland plots for plant species. Plot 1 contains: bluestem, clover, goldenrod, milkweed, thistle, and ryegrass. Plot 2 contains: bluestem, clover, and goldenrod.
What is the species richness of Plot 1?
3 species
It cannot be determined without abundance data.
6 species
9 species
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species. Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species! For this survey, the list for Plot 1 includes six distinct plant species (bluestem, clover, goldenrod, milkweed, thistle, ryegrass), so we count them directly to determine richness without needing abundance data for this specific question. Choice B correctly analyzes biodiversity data by accurately counting the species richness of Plot 1 as 6 based on the listed names. Choice A might come from miscounting or confusing with Plot 2's 3 species, but supportively, list them out one by one—there are indeed six unique names, so double-check by writing them down to avoid errors. Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Low richness or low evenness = LOW biodiversity (few species—example: corn field with 3 species, or unbalanced—example: lawn with 10 plant species but 95% grass). Comparing ecosystems: which has higher biodiversity? First compare richness (more species usually wins unless very uneven). If richness similar, check evenness (more balanced wins). Example: Ecosystem A (richness 20, very even) vs Ecosystem B (richness 22, one species 70% of total) → A might be more diverse overall despite slightly lower richness because B's extreme dominance reduces functional diversity. Richness and evenness TOGETHER determine biodiversity quality! Why evenness matters: imagine two forests, both with 10 tree species (same richness). Forest 1: each species ~10% of trees (even). Forest 2: oak is 95% of trees, other 9 species combined only 5% (very uneven). Forest 1 is more biodiverse and ecologically healthy because multiple species contribute substantially to ecosystem function. Forest 2 is functionally almost a monoculture despite technically having 10 species. Evenness captures this ecological reality that richness alone misses!
A class compares two habitats: a natural meadow and a corn field. The meadow survey found 18 plant species. The corn field survey found 4 plant species (including corn and three weed species).
Which statement is best supported by the data?
Both habitats have equal biodiversity because both contain plants.
The corn field has higher biodiversity because corn plants are very abundant.
The corn field has higher biodiversity because it is managed by humans.
The meadow has higher species richness and therefore higher biodiversity.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species. Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species! The surveys report 18 plant species in the meadow and 4 in the corn field (corn plus three weeds), so compare richness directly, noting that higher richness typically means higher biodiversity, especially since no evenness data is given but meadows are naturally more diverse. Choice B correctly analyzes biodiversity data by accurately counting species richness and concluding the meadow has higher richness and thus higher biodiversity. Choice A mistakes abundance of one species for overall diversity, but supportively, biodiversity prioritizes number of species over total individuals— the corn field's dominance by one crop actually suggests lower evenness, reinforcing the meadow's advantage. Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Low richness or low evenness = LOW biodiversity (few species—example: corn field with 3 species, or unbalanced—example: lawn with 10 plant species but 95% grass). Comparing ecosystems: which has higher biodiversity? First compare richness (more species usually wins unless very uneven). If richness similar, check evenness (more balanced wins). Example: Ecosystem A (richness 20, very even) vs Ecosystem B (richness 22, one species 70% of total) → A might be more diverse overall despite slightly lower richness because B's extreme dominance reduces functional diversity. Richness and evenness TOGETHER determine biodiversity quality! Why evenness matters: imagine two forests, both with 10 tree species (same richness). Forest 1: each species ~10% of trees (even). Forest 2: oak is 95% of trees, other 9 species combined only 5% (very uneven). Forest 1 is more biodiverse and ecologically healthy because multiple species contribute substantially to ecosystem function. Forest 2 is functionally almost a monoculture despite technically having 10 species. Evenness captures this ecological reality that richness alone misses!
A field class compared two habitats (same size area) for insect biodiversity.
Habitat M species abundances: Beetle (25), Ant (24), Fly (26), Bee (23), Butterfly (22).
Habitat N species abundances: Beetle (95), Ant (2), Fly (1), Bee (1), Butterfly (1).
Which statement is correct?
Both habitats have different richness because Habitat N has more total insects
Habitat M has higher biodiversity because it has the same richness as N but much higher evenness
Habitat N has higher biodiversity because it has more beetles
Habitat N has higher biodiversity because it has lower richness
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species. Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species! The provided abundances show both habitats with 5 insect species (same richness), but Habitat M has very even numbers (high evenness), while N is dominated by beetles (low evenness), so M has higher overall biodiversity. Choice B correctly analyzes biodiversity data by accurately counting species richness, assessing evenness from abundance patterns, and comparing diversity between ecosystems. Choice A prioritizes total insects over evenness, but balance is key for biodiversity—terrific correction! You're amazing—master the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Low richness or low evenness = LOW biodiversity (few species—example: corn field with 3 species, or unbalanced—example: lawn with 10 plant species but 95% grass). Comparing ecosystems: which has higher biodiversity? First compare richness (more species usually wins unless very uneven). If richness similar, check evenness (more balanced wins). Example: Ecosystem A (richness 20, very even) vs Ecosystem B (richness 22, one species
A biologist sampled two pond edges and recorded which amphibian species were present.
Site 1 species list: Frog A, Frog B, Salamander A, Salamander B, Toad A
Site 2 species list: Frog A, Toad A
Which site has greater species richness, and what are the richness values?
Both sites have the same richness because they both include Frog A and Toad A.
Site 2; richness = 5 species. Site 1; richness = 2 species.
Site 1; richness = 5 species. Site 2; richness = 2 species.
Site 1; richness = 7 species. Site 2; richness = 2 species.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species! Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species. Here, Site 1 lists 5 distinct species (Frog A, Frog B, Salamander A, Salamander B, Toad A), giving richness of 5, while Site 2 lists only 2 (Frog A, Toad A), so Site 1 has greater richness—no evenness data is provided, but the question focuses on richness comparison. Choice A correctly analyzes biodiversity data by accurately counting species richness for each site without double-counting shared species. Choice D fails by assuming same richness due to shared species, but supportive correction: richness counts distinct species per site independently, so shared ones don't make richness equal—Site 1 has more unique ones! Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). You're doing great—keep counting carefully to master richness!
Two grassland plots were surveyed for insect biodiversity. The counts below show the number of individuals of each species found.
Plot A: Beetle (25), Ant (24), Grasshopper (26), Butterfly (23)
Plot B: Beetle (80), Ant (10), Grasshopper (5), Butterfly (5)
Which statement best compares the biodiversity of Plot A and Plot B (considering both species richness and species evenness)?
Plot A has lower biodiversity because it has fewer species than Plot B.
Plot B has higher biodiversity because it has more total individuals.
Plot B has higher biodiversity because it has greater evenness.
Plot A has higher biodiversity because it has the same richness as Plot B but greater evenness.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species! Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species. In this case, both plots have the same richness (4 species each), but Plot A shows high evenness with abundances around 23-26 individuals per species, while Plot B has low evenness with beetles dominating at 80 individuals and others at 5-10, so Plot A has higher overall biodiversity. Choice B correctly analyzes biodiversity data by accurately counting species richness as equal and assessing evenness from abundance patterns to conclude Plot A is more diverse. Choice A fails by focusing only on total individuals, but remember, biodiversity isn't about total population size—it's about the number and balance of species, so even with fewer total insects, Plot A is more diverse due to better evenness. Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Keep practicing this method, and you'll confidently compare any biodiversity datasets!
A forest manager tracked plant species richness in the same 1-hectare plot over time.
Year 2005: 30 plant species
Year 2015: 22 plant species
Year 2025: 14 plant species
Which conclusion is best supported by the data?
The total number of individual plants must have increased over time.
Plant biodiversity (richness) decreased over time.
Plant biodiversity (richness) increased over time.
Plant biodiversity (richness) stayed constant over time.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species! Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species. The data clearly shows richness declining from 30 species in 2005 to 22 in 2015 and 14 in 2025, indicating a decrease over time, with no evenness or total individual data provided. Choice C correctly analyzes biodiversity data by accurately tracking the change in species richness values across years. Choice A fails by claiming an increase, but encouraging correction: double-check the numbers—30 to 14 is a decrease, so richness dropped, possibly due to habitat changes. Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Excellent observation of trends—keep monitoring changes like a pro!
A scientist compared two stream sections using the macroinvertebrate counts shown.
Section 1: Mayfly (15), Caddisfly (16), Stonefly (14), Snail (15), Worm (15), Beetle larva (15)
Section 2: Mayfly (70), Caddisfly (5), Stonefly (5), Snail (5), Worm (5), Beetle larva (5)
Which section has higher biodiversity overall (consider richness and evenness)?
Section 2, because it has a higher number of species.
Neither; biodiversity cannot be compared without calculating a Shannon index.
Section 1, because it has the same richness as Section 2 but much higher evenness.
Section 2, because it has more individuals total.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species! Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species. Both sections have 6 macroinvertebrate types (same richness), but Section 1 has high evenness with 14-16 per type, while Section 2 has low evenness with mayflies at 70 dominating over 5 each, so Section 1 has higher overall biodiversity. Choice B correctly analyzes biodiversity data by counting richness equally and assessing evenness for a full comparison. Choice A fails by focusing on total individuals, but encouraging insight: higher totals don't mean higher diversity if unbalanced—Section 1's evenness boosts its biodiversity! Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Fantastic work on evenness—continue honing your analysis!
A coastal ecologist compared fish communities in two habitats. The table shows the number of individuals observed for each fish species.
Habitat X: Species 1 (40), Species 2 (38), Species 3 (42), Species 4 (39), Species 5 (41)
Habitat Y: Species 1 (180), Species 2 (5), Species 3 (5), Species 4 (5), Species 5 (5)
Which habitat shows greater species evenness?
Habitat Y, because one species is clearly dominant.
Habitat Y, because it has a higher total number of fish.
Habitat X, because the species have similar abundances.
Both habitats have the same evenness because they have the same number of species.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species! Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species. For these habitats, both have 5 species (same richness), but Habitat X shows high evenness with abundances 38-42 per species, while Habitat Y has low evenness with Species 1 at 180 dominating over the others at 5 each, so X has greater evenness. Choice B correctly analyzes biodiversity data by assessing evenness from abundance patterns, noting the similar abundances in X indicate better balance. Choice A fails by prioritizing total individuals, but encouraging reminder: evenness focuses on balance, not totals—X is more even despite potentially fewer fish overall! Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Great job spotting the balance—keep going!
Two desert sites have the same species richness (4 lizard species each). The counts below show the number of individuals of each species.
Site M: L1 (25), L2 (24), L3 (26), L4 (25)
Site N: L1 (90), L2 (5), L3 (3), L4 (2)
Which statement is most accurate?
Both sites have equal biodiversity because their richness is the same.
Site M has higher biodiversity because it has higher evenness with the same richness.
Site N has higher biodiversity because it has more total lizards.
Site N has higher biodiversity because it has a dominant species.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species! Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species. Both sites have 4 lizard species (same richness), but Site M shows high evenness with 24-26 per species, while Site N has low evenness with L1 at 90 dominating over 2-5, so M has higher biodiversity. Choice B correctly analyzes biodiversity data by accurately counting richness as equal and assessing evenness to compare overall diversity. Choice A fails by emphasizing total lizards, but positive tip: biodiversity prioritizes diversity metrics over sheer numbers—balance makes M more diverse! Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). You're mastering comparisons—keep it up!
Two coral reef patches were surveyed. Patch 1 had 10 fish species, and Patch 2 had 6 fish species. The most abundant species made up 20% of all fish in Patch 1 and 65% of all fish in Patch 2.
Which patch has higher biodiversity overall?
Patch 2, because it has fewer species so competition is lower.
Patch 2, because the most abundant species makes up a larger percent of the community.
Patch 1, because it has higher richness and higher evenness.
Both patches, because evenness does not affect biodiversity.
Explanation
This question tests your ability to analyze biodiversity data by reading species richness (number of different species) and species evenness (how balanced their abundances are) to compare ecosystems or track biodiversity changes. Biodiversity has two main components visible in data: (1) SPECIES RICHNESS is simply the count of how many different species are present—count the rows in a table, count the bars in a graph, or count the species listed (example: if data shows oak, maple, pine, birch, hickory, that's 5 species, so richness = 5). Higher richness = more species = higher biodiversity. (2) SPECIES EVENNESS describes how balanced the populations are—if all species have similar abundances (like 100, 95, 105, 98 individuals each), that's HIGH evenness (balanced), but if one species dominates (like 500, 10, 5, 3 individuals), that's LOW evenness (unbalanced) even though richness is the same (4 species both cases). HIGH BIODIVERSITY ecosystems have BOTH high richness (many species) AND high evenness (relatively balanced), while LOW BIODIVERSITY has few species or is dominated by one or two species! Comparing: ecosystem with 25 species and balanced abundances is more diverse than ecosystem with 8 species or ecosystem with 25 species but 90% is one species. Patch 1 has higher richness (10 species vs. 6) and higher evenness (20% max dominance vs. 65%), making its overall biodiversity superior as it combines more species with better balance. Choice C correctly analyzes biodiversity data by evaluating both richness and evenness to determine the patch with higher overall diversity. Choice A fails by favoring higher dominance as positive, but encouraging reminder: high dominance lowers evenness and thus biodiversity—balance supports healthier ecosystems! Analyzing biodiversity from data—the two-check method: (1) COUNT species (richness): In a table, count how many different species are listed (rows usually). In a graph, count how many bars or data points. In a list, count distinct species names. This gives species richness. Example: table with Species A, B, C, D, E = 5 species, richness = 5. (2) CHECK evenness (balance): Look at abundances (population sizes, percentages, bar heights). Are they SIMILAR (high evenness: like 100, 95, 110, 98) or VERY DIFFERENT (low evenness: like 500, 10, 8, 5)? If one species has 80%+ of total, that's low evenness (dominated). If each species has ~similar %, high evenness (balanced). (3) COMBINE for overall diversity: High richness + high evenness = HIGH biodiversity (many species, balanced—example: rainforest with 100+ species, none dominating). Impressive integration of factors—you're on your way to expertise!