Model Human Activity Biodiversity Effects - Biology

1. What is the typical biodiversity effect of road building through habitat?

   Fragmentation, edge effects, and higher mortality; diversity declines. Roads create barriers and increase wildlife-vehicle collisions.

2. What is selective logging, and how does it differ from clear-cutting in impact?

   Removes some trees; typically less severe than clear-cutting. Maintains canopy cover and some habitat structure.

3. What is overexploitation, and what is its direct effect on biodiversity?

   Harvesting faster than replacement; reduces populations and diversity. Taking more than natural reproduction can replenish.

4. What is the extinction rate, in the context of modeling human impacts?

   Rate at which species disappear from a region or globally. Measures how quickly species are being lost permanently.

5. What is pollution, and how can it reduce biodiversity in aquatic ecosystems?

   Contaminants cause toxicity and habitat degradation; diversity declines. Toxins directly kill organisms and degrade water quality.

6. What is genetic diversity, and why is it important for biodiversity under human change?

   Variation in alleles; increases adaptability and resilience. More genetic variation provides better response to environmental changes.

7. What is desertification, and how can it affect biodiversity in drylands?

   Land degradation to arid conditions; reduces productivity and diversity. Lower rainfall and plant growth support fewer species.

8. What is biomagnification, and why does it threaten top predators?

   Toxin concentration increases up food chains; harms apex species. Each trophic level multiplies toxin concentration from the level below.

9. What is ecological succession, and how can human disturbance alter it?

   Community change over time; disturbance can reset to early stages. Major disturbances restart the process from pioneer species.

10. Which option best describes a point-source pollutant affecting biodiversity?

    A single identifiable discharge location (for example, a pipe). Single source makes pollution easier to identify and control.

11. What is a wildlife corridor, and what biodiversity problem does it address?

    Habitat link between patches; reduces isolation and boosts gene flow. Connects isolated patches to allow movement and breeding.

12. What is carrying capacity $K$, and how can habitat degradation change $K$?

    $K$ is max sustainable population; degradation lowers $K$. Reduced resources support fewer individuals in the population.

13. What is bycatch, and how does it affect biodiversity?

    Non-target capture; increases mortality of many species. Accidental capture kills species that aren't being targeted.

14. Identify the likely biodiversity trend when a habitat is restored and native plants re-established.

    Species richness and evenness generally increase over time. Restoration removes human stressors and allows natural recovery.

15. What is a trophic cascade, often triggered by human removal of predators?

    Food-web changes across trophic levels after predator loss. Effects ripple down from top predators to primary producers.

16. What does the exponent $z$ represent in the species–area model $S=cA^z$?

    How strongly richness increases with area (slope on log-log plot). Higher $z$ values mean richness drops faster with area loss.

17. What is edge effect in fragmented habitats?

    Altered conditions at habitat edges that change species survival. Edges have different light, temperature, and wind patterns.

18. What is overfishing, and what is a common community-level consequence?

    Excess fish harvest; food-web shifts and reduced diversity. Removes key species and disrupts predator-prey relationships.

19. Which option best describes a nonpoint-source pollutant affecting biodiversity?

    Diffuse runoff from many locations (for example, farms and streets). Scattered sources make pollution harder to track and regulate.

20. Identify the predicted effect on $S$ in $S=cA^z$ when habitat area $A$ decreases.

    Species richness $S$ decreases. Smaller areas support fewer species according to the model.

21. What is ecosystem diversity in the context of biodiversity modeling?

    Variety of habitats and ecological processes in a region. Includes diversity of community types and ecological functions.

22. What is thermal pollution, and what is its typical effect on dissolved oxygen?

    Warmer water from discharge; dissolved oxygen decreases. Warm water holds less dissolved oxygen than cool water.

23. What is the species–area relationship formula used in biodiversity modeling?

    $S=cA^z$. Mathematical relationship between habitat size and species count.

24. What is sustainable harvest, and how does it relate to population growth rate?

    Harvest at or below replacement; does not exceed population growth. Harvest rate matches or stays below natural population increase.

25. What is the greenhouse effect, and why does human-enhanced $CO_2$ matter for biodiversity?

    Atmospheric heat trapping; added $CO_2$ drives warming and range shifts. Enhanced greenhouse effect accelerates climate change impacts.

26. What is inbreeding depression in conservation biology?

    Reduced fitness from mating among relatives and harmful recessives. Related individuals share more harmful recessive alleles.

27. What is habitat loss, and how does it typically affect biodiversity?

    Destruction of habitat; usually decreases biodiversity. Removes living space and resources species need to survive.

28. What is bioaccumulation in an organism exposed to pollutants?

    Toxins build up in tissues over time faster than elimination. Organism cannot eliminate toxins as fast as they enter.

29. What is an indicator species, and how is it used to infer biodiversity change?

    Species sensitive to change; signals ecosystem health and diversity. Changes in these species reflect broader ecosystem condition.

30. What is deforestation, and what is its immediate effect on forest biodiversity?

    Forest removal; rapid declines in habitat specialists and richness. Forest-adapted species lose habitat and cannot survive elsewhere.

31. What is the primary biodiversity effect of converting forest to monoculture cropland?

    Lower species richness and evenness due to habitat simplification. Monocultures eliminate habitat complexity and food sources.

32. What is the typical biodiversity effect of urbanization on native species?

    Decreases native diversity; favors generalists and invasives. Urban environments favor adaptable species over specialists.

33. What is climate change, and what is a common biodiversity outcome?

    Long-term warming and shifts; range shifts and extinctions increase. Changing temperatures force species to migrate or face extinction.

34. What is genetic drift, and why is it stronger in small human-isolated populations?

    Random allele frequency change; stronger when population size is small. Random sampling effects are proportionally larger in small populations.

35. What is habitat fragmentation, and what is its typical biodiversity effect?

    Breaking habitat into isolated patches; lowers biodiversity. Small isolated patches support fewer species than large areas.

36. What is species richness in a community biodiversity model?

    The number of different species present. Total count of different species, regardless of abundance.

37. Which variable in $S=cA^z$ represents habitat area, often reduced by humans?

    $A$. Area is the key variable affected by habitat destruction.

38. What is an endemic species, and why is it vulnerable to habitat loss?

    Species restricted to one area; limited range increases extinction risk. Cannot escape to other areas when local habitat is destroyed.

39. What is eutrophication caused by fertilizer runoff?

    Nutrient enrichment that triggers algal blooms and oxygen depletion. Excess nutrients fuel massive algae growth that consumes oxygen.

40. What is species evenness in a community biodiversity model?

    How evenly individuals are distributed among species. Measures if species have similar or unequal abundances.

41. What is biodiversity, as used in ecology when modeling human impacts on ecosystems?

    Variety of life at genetic, species, and ecosystem levels. Encompasses all levels from genes to entire ecosystems.

42. What is the typical biodiversity effect of pesticide use on insect communities?

    Reduces non-target insects and alters food webs; diversity declines. Pesticides kill beneficial insects that support food webs.

43. What is a keystone species in biodiversity models?

    Species with disproportionately large effects on community structure. Their loss causes cascading effects throughout the community.

44. What is an invasive species in models of human-caused biodiversity change?

    Non-native species that spreads and harms native communities. Outcompetes natives and lacks natural predators or diseases.

45. What is bioindicator evidence that acid rain is reducing freshwater biodiversity?

    Declines in sensitive species such as mayflies and some fish. Acid-sensitive species disappear first as pH decreases.

46. What is ocean acidification, and what organisms are especially impacted?

    Lower ocean pH from $CO_2$; harms corals and shell-formers. Dissolved $CO_2$ makes seawater acidic, dissolving calcium structures.

47. What is the Allee effect, and how can it raise extinction risk after habitat loss?

    Low density reduces survival or reproduction; extinction risk increases. Very small populations struggle to find mates and reproduce.

48. What is the typical biodiversity effect of establishing protected areas (reserves)?

    Reduces habitat loss and overharvest; slows declines and extinctions. Protection removes major human threats to species survival.

49. Identify the main genetic risk when small populations become isolated by fragmentation.

    Inbreeding and genetic drift reduce genetic diversity. Small isolated populations lose genetic variation through breeding patterns.

50. What is ecosystem resilience, and how does higher biodiversity affect it?

    Ability to recover after disturbance; higher biodiversity increases it. More species provide more functional redundancy for recovery.

51. What is a biodiversity hotspot, and why is it prioritized for conservation?

    High endemism and high threat; protects many unique species. Conservation efforts here protect maximum species per unit effort.

52. What is hypoxia, and how is it linked to eutrophication and biodiversity loss?

    Low dissolved oxygen; causes die-offs and reduced species richness. Fish and other aquatic organisms cannot survive without adequate oxygen.

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