Science passages — particularly biology and natural science — are a staple of the GRE Reading Comprehension section. These passages present specific challenges: they use technical vocabulary, they present arguments built on empirical evidence, and they often describe complex causal relationships that must be tracked precisely to answer inference questions correctly.
This guide covers the science and biology vocabulary most likely to appear in GRE passages, organized by the types of passages and scientific reasoning they support. You don't need a science background — you need the vocabulary and reading strategies to handle science text confidently.
How Science Passages Work on the GRE
GRE science passages typically follow one of four structures:
- Discovery narrative: Scientists believed X; new evidence suggests Y; the implications are Z
- Competing theories: Theory A explains phenomenon; Theory B offers an alternative; evidence favors one
- Mechanism description: Here is how process X works at the biological/chemical/physical level
- Controversy: The accepted view is contested; here are the arguments on each side
Recognizing the structure early lets you predict what the questions will ask — and directs your attention to the most critical parts of the passage (the evidence, the turning points, the nuances).
Category 1: General Scientific Method Vocabulary
| Word | Definition | Example Sentence |
|---|---|---|
| Empirical | Based on observation and experiment, not theory | The empirical evidence for the drug's efficacy came from three randomized controlled trials. |
| Hypothesis | A proposed explanation requiring testing | The hypothesis that gut bacteria influence mood has gained significant empirical support. |
| Paradigm | A framework of assumptions; a typical example | The discovery challenged the paradigm that had guided evolutionary biology for decades. |
| Replication | Reproducing an experiment to verify results | The finding gained credibility only after independent replication by three separate laboratories. |
| Confound | A variable that influences both the independent and dependent variable | The study's conclusions were weakened by the confound of socioeconomic status. |
| Correlation | A statistical relationship between two variables | The correlation between sleep deprivation and poor memory was strong but did not establish causation. |
| Causation | The relationship where one event causes another | Determining causation required a longitudinal study, not merely cross-sectional correlation data. |
| Variable | A factor that may change in an experiment | Temperature was the sole independent variable; all other conditions were held constant. |
| Taxonomy | The classification of organisms into groups | Modern molecular biology has revised the taxonomy of many species originally classified by morphology. |
| Extrapolate | To extend conclusions beyond the known data | The researchers cautioned against extrapolating from mouse models to human outcomes. |
Category 2: Biology-Specific Vocabulary
Biology passages often involve evolution, genetics, ecology, and cell biology. These are the vocabulary domains most likely to appear on the GRE.
Evolution and Natural Selection
Adaptation: A characteristic that has evolved because it increases reproductive fitness. Selection pressure: An environmental force that determines which traits are advantageous. Fitness (in biology): Reproductive success — the ability to survive and reproduce, not physical health. Niche: The role an organism plays in its ecosystem, including the resources it uses. Speciation: The process by which new species evolve from existing ones. Convergent evolution: When unrelated species independently evolve similar traits in response to similar environments.
Genetics Vocabulary
Phenotype: The observable characteristics of an organism (what it looks and acts like). Genotype: The genetic makeup of an organism. Allele: One version of a gene. Dominant: An allele whose effect is expressed even when only one copy is present. Recessive: An allele whose effect is only expressed when two copies are present. Epigenetics: The study of changes in gene expression that do not involve changes to the DNA sequence itself — an increasingly important concept in GRE science passages.
Category 3: Ecology and Environment Vocabulary
| Word | Definition | Example Sentence |
|---|---|---|
| Biodiversity | The variety of life in an area or ecosystem | Researchers found that higher biodiversity increased the ecosystem's resilience to drought. |
| Biomass | The total mass of living organisms in a given area | Deforestation reduced the region's biomass by an estimated 40% within a decade. |
| Carrying capacity | The maximum population size an environment can sustain | The island's carrying capacity for deer was exceeded when predators were removed. |
| Ecosystem | A community of organisms and their physical environment | The wetland ecosystem provided natural flood control that reduced downstream damage. |
| Mutualism | A relationship where both species benefit | The relationship between the clownfish and sea anemone is a classic example of mutualism. |
| Parasitism | A relationship where one organism benefits at the other's expense | The parasite's evolutionary success depends on keeping its host alive long enough to reproduce. |
| Succession | The process by which an ecosystem changes over time | The abandoned farmland underwent ecological succession, progressing from grasses to shrubs to forest. |
| Trophic level | A position in a food chain | Energy is lost at each trophic level — only about 10% is transferred from prey to predator. |
Category 4: Neuroscience and Psychology Vocabulary
GRE passages increasingly draw on cognitive science and neuroscience research. Key vocabulary:
Neuroplasticity: The brain's ability to form new neural connections throughout life. Cognitive bias: A systematic error in thinking that affects judgments and decisions. Confirmation bias: The tendency to seek information that confirms existing beliefs. Heuristic: A mental shortcut that allows quick judgments (often accurate but sometimes wrong). Working memory: The part of memory used for conscious processing — limited in capacity. Long-term potentiation: A biological mechanism underlying the formation of lasting memories — appears in advanced biology passages.
Handling Unfamiliar Scientific Terms on Test Day
When a GRE science passage uses a term you don't know, apply the following approach:
- Look for an in-text definition: Scientific passages often define technical terms when they first appear, especially unusual ones
- Look for examples: The passage may illustrate the term with a specific example that reveals its meaning
- Apply root knowledge: Many scientific terms have Latin/Greek roots — see our guide on Greek origin words for the most common scientific roots
- Use process of elimination: Even if you can't define the term, you may be able to determine whether it's being described positively or negatively, whether it's an entity or a process, and whether it increases or decreases something
FAQ
How much science background do I need for GRE reading comprehension?
None beyond high school level. GRE passages are written for educated general readers. However, comfort with scientific reasoning (hypothesis testing, the difference between correlation and causation, the role of controls in experiments) is valuable and develops with practice.
What types of science appear most often in GRE reading passages?
Biology (particularly evolution, ecology, and neuroscience) appears most frequently, followed by earth science, physics, and chemistry. Pure mathematics rarely appears in verbal passages. Social science passages (psychology, economics, sociology) are also common and use many of the same vocabulary conventions as natural science passages.
What is the difference between a "hypothesis" and a "theory" on the GRE?
In scientific usage (as used on the GRE), a hypothesis is an untested or partially tested explanation, while a theory is a well-substantiated explanation supported by extensive evidence. In everyday language, "theory" means a guess — but in science passages, a theory (like evolutionary theory or germ theory) is robust and well-supported. Confusing the everyday and scientific meanings of "theory" will mislead you on GRE passages.
How do I improve my reading speed for dense science passages?
Practice reading science journalism (magazines, science sections of quality newspapers) and scientific abstracts. These genres use the same vocabulary and reasoning patterns as GRE passages but are shorter and self-contained. Thirty minutes of this kind of reading per day for four to six weeks significantly improves both speed and comprehension.
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