Exam D Terms Glossary
Biology Study Reference Q1 Interim Assessment
15 Essential "D" Biology Terms
Key terms, contextual definitions, and ecosystem applications extracted from the final exam booklet.
Letter D
Part 1: Ecology & Cycles
i
These vocabulary terms appear directly across the Quarter 1 Biology Interim Assessment questions and diagrams. Use this guide to reinforce foundational concepts in food webs, biogeochemical cycles, and ecological competition.
1. Decomposer Q15, Q22
An organism (such as fungi or bacteria) that chemically breaks down dead organic material and waste products.
Exam Role: Recycles nitrogen into ammonium (NH₄⁺) and returns abiotic carbon to soil.
2. Denitrifying Bacteria Q15
Specialized anaerobic soil microbes that convert nitrates (NO₃⁻) back into inert atmospheric nitrogen gas (N₂).
Exam Role: Balances soil nitrogen levels by releasing gas back into the atmosphere in the nitrogen cycle.
3. Diffusion Q3
The net movement of particles from a region of higher concentration to a region of lower concentration along a gradient.
Exam Role: Governs physical gas exchange of CO₂ between Earth's atmosphere and oceanic sinks.
4. Decomposition Q22
The biological decay process where complex organic substances are broken down into simpler mineral matter and inorganic nutrients.
Exam Role: Shown alongside organism death as a critical pathway replenishing fossil and mineral carbon pools.
5. Disruption Q1
An abiotic or biotic disturbance that significantly destabilizes normal trophic relationships and population dynamics.
Exam Role: Evaluated through overfishing of Antarctic cod and cascading effects on seals, krill, and penguins.
6. Density (Population) Q6
The concentration or quantity of individuals of a single species occupying a defined unit of habitat volume or area.
Exam Role: Measured on the y-axis to contrast P. aurelia versus P. caudatum competitive exclusion over time.
7. Dispersal Q8
The transport or scattering of seeds, spores, or individuals away from the parent organism or origin site to colonize new environments.
Exam Role: Wind dispersal carried fluffy seeds to offshore islands, triggering new selection pressures on seed weight.
8. Duckweed Q2
A minute, rapidly reproducing freshwater aquatic macrophyte (genus Lemna) commonly studied in interspecific competition labs.
Exam Role: L. polyrrhiza and L. gibba grown together illustrate overlapping ecological niches.
High School Biology • Quarter 1 IA Study Companion Page 1 of 2
Biology Study Reference Q1 Interim Assessment
15 Essential "D" Biology Terms
Key terms, contextual definitions, and evolution concepts extracted from the final exam booklet.
Letter D
Part 2: Genetics & Evolution
9. DNA Q8, Q15
The double-helical nucleic acid polymer containing genetic instructions required for cellular growth, heredity, and protein synthesis.
Exam Role: Tested as a biomolecule requiring bioavailable nitrogen (NH₄⁺/NO₃⁻) to construct nucleotides.
10. Drought Q26
A prolonged environmental event of severe water scarcity that shifts resource availability and imposes strong natural selection.
Exam Role: The 1977 Daphne Major drought caused small seeds to wither, favoring larger finches with deeper beaks.
11. Depth (Beak Depth) Q26
The vertical top-to-bottom measurement of a bird's bill, an inherited polygenic anatomical trait directly linked to seed-cracking capability.
Exam Role: Tracked over generations to show shifts in mean morphological values following precipitation changes.
12. Distribution Q13
The mathematical or visual spread showing how individual trait values (phenotypes) are represented across a biological population.
Exam Role: Bell curves illustrating stabilizing selection on flower petal length across 20 generations of bee pollination.
13. Decline Q1, Q5, Q11, Q15
A measurable negative change or downward trend in population census size, biomass, or biological activity over time.
Exam Role: Seen when killer whale predation reduces otter abundance, causing kelp collapse via unchecked sea urchins.
14. Data Q2, Q5, Q13, Q26
Empirical qualitative observations and quantitative measurements recorded by scientists during controlled investigations or field studies.
Exam Role: Used repeatedly in prompts asking students to evaluate claims based on graphical evidence (CER framework).
15. Dependent Variable (Dependency) Q5
The observed and measured factor in an experiment that responds to variations or manipulations of the independent variable.
Exam Role: Bacterial concentration in lake sediment was evaluated to determine if its growth rate was directly dependent on changing water temperature.
Key Interim Assessment Themes for "D" Vocabulary
Nutrient Cycles
Decomposers, Denitrifying bacteria, Diffusion, and Decomposition facilitate matter conservation.
Evolution & Selection
Drought and Dispersal drive shifts in inherited traits like beak Depth and phenotypic Distribution.
Scientific Practice
Interpreting Data to measure population Density, track species Decline, and isolate Dependencies.
High School Biology • Quarter 1 IA Study Companion Page 2 of 2
