Practice Test Geeks(CES) Certified Environmental Scientist Practice Test
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Ecological Risk Assessment & Biodiversity Flashcards

7 cards from real CES practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. Which biodiversity metric accounts for both species richness and the evenness of species distribution?

    Answer: Shannon-Wiener diversity index (H')

    The Shannon-Wiener index (H' = -Σpi ln pi) incorporates both the number of species (richness) and their relative abundances (evenness).

  2. The 'insurance hypothesis' in biodiversity-ecosystem function research predicts that:

    Answer: Biodiversity buffers ecosystem functioning against environmental variability

    The insurance hypothesis posits that high biodiversity reduces variance in ecosystem function because different species respond differently to environmental fluctuations.

  3. In the Species Sensitivity Distribution (SSD) approach, the HC5 value represents:

    Answer: Both A and B — they describe the same metric

    HC5 (hazardous concentration to 5% of species) is both the 5th percentile of the SSD and the concentration predicted to affect 5% of species.

  4. A 'trophic cascade' occurs when:

    Answer: Changes in a top predator population propagate effects through lower trophic levels

    Trophic cascades are indirect effects in which predator removal releases prey populations, which then overexploit their own food resources.

  5. Which of the following is an example of 'secondary poisoning' in ecological risk assessment?

    Answer: A hawk dying after eating rodents that consumed rodenticide bait

    Secondary poisoning occurs when a predator or scavenger is poisoned by consuming prey that has accumulated a toxic substance.

  6. The International Union for Conservation of Nature (IUCN) Red List category 'Vulnerable (VU)' requires that a taxon meets thresholds for:

    Answer: Greater than 30% population reduction over 10 years or 3 generations

    VU requires ≥30% population reduction (Criterion A), whereas EN requires ≥50% and CR requires ≥80% reduction under the same criterion.

  7. Which of the following best characterizes 'compensatory mortality' as it relates to wildlife population management?

    Answer: Harvest mortality that replaces natural mortality without reducing population size

    Compensatory mortality occurs when harvest-induced deaths replace natural deaths (e.g., starvation), leaving total mortality and population size unchanged.