Analyze Biodiversity Data - Biology

1. What is the definition of gamma diversity?

   Total diversity across a larger region containing multiple sites. Combined diversity across an entire landscape or region.

2. What does it suggest if a species accumulation curve has reached an asymptote?

   Additional sampling is unlikely to find many new species. Curve flattens when most species are already found.

3. Identify the correct interpretation of an increase in evenness while richness stays constant.

   Diversity increases because individuals are more evenly distributed. More balanced abundance raises diversity measures.

4. What is a common interpretation if sensitive indicator species decline in a dataset?

   Environmental quality is likely worsening (for example, pollution increasing). Declining sensitive species suggests habitat degradation.

5. What is biodiversity in the context of analyzing ecological data?

   Variety of life measured across genetic, species, and ecosystem levels. Includes all forms of life variation across three hierarchical levels.

6. What is a common sampling bias that can reduce observed species richness?

   Insufficient sampling effort or unequal detectability among species. Undersampling misses rare or hard-to-detect species.

7. Which community has higher richness: A has 6 species; B has 4 species. Choose one.

   Community A. Richness is simply the count of species present.

8. Identify the correct conclusion: if richness is constant but $H$ increases, what changed?

   Evenness increased. Higher diversity with constant richness means better evenness.

9. What does a larger Shannon index $H$ generally indicate about a community?

   Higher diversity due to greater richness and or evenness. More species and/or balanced distribution increases index.

10. What is a confounding variable in a biodiversity field study dataset?

    An uncontrolled factor that affects the response and is linked to the predictor. Hidden variable influences both predictor and response.

11. What is a rarefaction approach used for in biodiversity comparisons?

    Standardizing diversity comparisons to equal sample size or effort. Corrects for unequal sampling intensity between studies.

12. What is the edge effect as a factor that can alter biodiversity measurements?

    Changed conditions at habitat edges that can shift species composition. Boundary zones have different conditions affecting species.

13. What is species evenness in biodiversity analysis?

    How evenly individuals are distributed among species. Measures how balanced abundance is across species.

14. What does an invasive species typically do to native biodiversity over time?

    Often reduces native diversity by competition, predation, or disease. Outcompetes natives through various ecological mechanisms.

15. What is species richness as used in biodiversity datasets?

    The number of different species present in a defined area. Simply counts distinct species without considering abundance.

16. What is a species accumulation curve used to evaluate in sampling data?

    Whether sampling effort is sufficient to capture most species. Shows if sampling found most species present.

17. What is a keystone species and why is it important in biodiversity interpretation?

    A species with large ecosystem impact; its loss can reduce diversity. Disproportionate ecological influence maintains community structure.

18. What is the Shannon diversity index formula used in many biology courses?

    $H = -\sum p_i \ln(p_i)$. Natural log version measuring diversity with evenness weighting.

19. What is the definition of alpha diversity?

    Diversity within a single site or local community. Local diversity within one habitat or location.

20. Calculate richness: a site has species counts A:5, B:0, C:2, D:1. What is richness?

    3 species. Count species with abundance greater than zero.

21. What is the most appropriate graph type to show change in diversity over time?

    Line graph. Displays temporal trends and changes over time.

22. What does a larger value of $1 - \sum p_i^2$ generally indicate?

    Higher diversity with lower dominance by any single species. Higher values indicate more even species distribution.

23. Compute Simpson diversity $1-\sum p_i^2$ for $p_1 = 0.5$ and $p_2 = 0.5$.

    $0.5$. Subtract the sum of squared proportions from one.

24. In the formula $p_i = \frac{n_i}{N}$, what does $N$ represent?

    Total number of individuals of all species in the sample. Sum of all individual organisms across species.

25. What is habitat fragmentation and how is it linked to biodiversity data trends?

    Breaking habitat into patches, often lowering richness and increasing extinctions. Smaller patches support fewer species due to isolation.

26. What is the Simpson diversity index (diversity form) commonly used in biodiversity analysis?

    $1 - \sum p_i^2$. Probability-based index measuring species diversity.

27. What is the difference between correlation and causation when analyzing biodiversity data?

    Correlation is association; causation means one factor produces the change. Correlation shows pattern; causation proves mechanism.

28. What is the key assumption when using quadrat sampling to estimate plant diversity?

    Quadrats are representative and placed using an unbiased method. Random placement captures true community diversity patterns.

29. What is the definition of beta diversity?

    Difference in species composition between sites. Measures how species change between different locations.

30. What is dominance in biodiversity data interpretation?

    A pattern where one species has much higher abundance than others. One species overwhelms others in relative abundance.

31. What is the most appropriate graph type to compare species abundances across categories?

    Bar graph. Shows relative abundance differences between categories clearly.

32. Compute $\sum p_i^2$ for $p = 0.8$ and $0.2$ (two species).

    $0.68$. Calculate: $(0.8)^2 + (0.2)^2 = 0.64 + 0.04$.

33. What is relative abundance for species $i$ in a sample?

    $p_i = \frac{n_i}{N}$. Proportion of species $i$ out of total individuals.

34. What is an indicator species in environmental monitoring datasets?

    A species whose presence or abundance reflects environmental conditions. Abundance changes signal environmental health changes.

35. What is an endemic species in biodiversity datasets?

    A species native to and restricted to a specific geographic area. Found only in one specific geographic location.

36. Compute $\sum p_i^2$ for two species with $p_1 = 0.5$ and $p_2 = 0.5$.

    $0.5$. Square each proportion and sum the results.

37. Choose the correct inference: two sites share few species; is beta diversity high or low?

    High beta diversity. Few shared species indicates high species turnover.

38. What is the difference between accuracy and precision in biodiversity measurements?

    Accuracy is closeness to true value; precision is consistency of repeats. Accuracy measures correctness; precision measures repeatability.

39. Find $p_i$: a species has $n_i = 8$ individuals out of $N = 40$. What is $p_i$?

    $0.2$. Divide individual count by total sample size.

40. What is the formula for percent composition of species $i$ in a sample?

    $\% = \frac{n_i}{N} \times 100$. Converts abundance to percentage of total individuals.

41. What does abundance mean in a biodiversity data table?

    The number of individuals of a species in the sample. Raw count of organisms for each species.

42. What is species turnover as interpreted from beta diversity data?

    Replacement of species from one site to another. Different species occupy different sites across landscape.

43. Which option best describes why two communities can have equal richness but different diversity?

    They can differ in evenness despite having the same richness. Evenness affects diversity independently of richness.

44. What is the key assumption when using a transect to compare diversity across a gradient?

    Sampling points are consistently spaced and represent the gradient. Systematic sampling accurately reflects environmental changes.

45. Compute Simpson diversity $1-\sum p_i^2$ for two species with $p = 0.8$ and $0.2$.

    $0.32$. Apply formula: $1 - 0.68 = 0.32$ for diversity.

46. What is the role of replication when comparing biodiversity between two habitats?

    It reduces random error and increases confidence in differences observed. Multiple samples distinguish real patterns from chance.

47. Identify the more even community: A has counts $25,25,25,25$; B has $70,10,10,10$.

    Community A. Equal abundances create maximum evenness.

48. What does the species-area relationship generally state about richness as area increases?

    Species richness tends to increase as sampled area increases. Larger areas support more species through habitat diversity.

49. Calculate percent composition: $n_i = 12$ and $N = 60$. What percent is species $i$?

    $20\%$. Multiply relative abundance by 100 for percentage.

50. What is the most appropriate graph type to show relationship between diversity and area sampled?

    Scatter plot. Reveals correlation between two continuous variables.

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