NCEA Level 3 Biology flashcards
NCEA Level 3 Biology · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Independent variable
- The factor the investigator deliberately changes between treatment groups so that its effect on the measured outcome can be observed.
- Validity in investigation
- The extent to which a method actually measures the intended variable, achieved through controls, appropriate sampling, and elimination of confounding variables.
- Reliability of data
- The consistency of repeated measurements, indicated by a small range or standard deviation; increased by taking repeats and using a standardised procedure.
- Chi-square test use
- A statistical test comparing observed and expected frequencies in categories to decide whether a difference is larger than chance alone would produce.
- Socio-scientific issue
- A real-world problem with a biological basis whose resolution also depends on economic, ethical, cultural, or political considerations and competing stakeholder interests.
- Hazard versus risk
- A hazard is anything with the potential to cause harm; risk is the probability of that harm occurring under a specified level of exposure.
- Precautionary principle
- A decision rule that allows action to prevent serious or irreversible harm even when the scientific evidence is incomplete or uncertain.
- Selection pressure and resistance
- An environmental factor such as an antibiotic that reduces survival of susceptible individuals, allowing pre-existing resistant variants to increase in frequency.
- Phototropism
- Directional growth of a plant shoot toward light, caused by auxin accumulating on the shaded side and promoting greater cell elongation there.
- Gravitropism in roots
- Directional growth of roots toward gravity, produced by auxin accumulating on the lower side where high concentration inhibits cell elongation.
- Nastic response
- A non-directional, reversible plant movement such as Mimosa leaf folding, driven by changes in turgor pressure rather than growth.
- Circadian rhythm
- An endogenous biological cycle of about twenty-four hours that persists under constant conditions and is entrained by zeitgebers such as light.
- Kinesis versus taxis
- A kinesis is a non-directional change in activity rate in response to stimulus intensity; a taxis is directional movement toward or away from a stimulus.
- Photoperiodism
- The flowering response of plants to the length of the dark period, detected through phytochrome interconversion between red and far-red absorbing forms.
- Negative feedback
- A control mechanism in which the response to a deviation from the set point reverses that deviation, restoring the internal condition toward its normal value.
- Insulin action
- A hormone from pancreatic beta cells that lowers blood glucose by increasing cellular uptake, promoting glycogenesis, and stimulating fat synthesis.
- Glucagon action
- A hormone from pancreatic alpha cells that raises blood glucose by stimulating glycogen breakdown in the liver and gluconeogenesis from amino acids.
- ADH and osmoregulation
- Antidiuretic hormone released when osmoreceptors detect high plasma solute; it increases collecting duct aquaporins, so more water is reabsorbed and urine concentrates.
- Endotherm versus ectotherm
- An endotherm generates most body heat metabolically and regulates it; an ectotherm relies mainly on behaviour and environmental heat, giving variable body temperature.
- Type 1 diabetes
- An autoimmune condition destroying pancreatic beta cells, so insulin is not produced and blood glucose rises unless insulin is supplied externally.
- Genetic drift
- Random change in allele frequencies between generations due to chance, with strongest effects in small populations and no necessary link to fitness.
- Founder effect
- Reduced genetic diversity in a new population established by a small number of individuals, whose allele frequencies may differ from the source population.
- Allopatric speciation
- Speciation in which a geographic barrier separates populations, blocking gene flow so that independent mutation, drift, and selection produce reproductive isolation.
- Sympatric speciation
- Speciation without geographic separation, often through polyploidy in plants or through habitat, temporal, or behavioural isolation within one area.
- Prezygotic barrier
- A reproductive isolating mechanism that prevents fertilisation, such as habitat, temporal, behavioural, or mechanical isolation or gamete incompatibility.
- Postzygotic barrier
- A reproductive isolating mechanism acting after fertilisation, producing hybrid inviability, hybrid sterility, or hybrid breakdown in later generations.
- Bipedalism indicators
- Skeletal features showing habitual upright walking: forward-placed foramen magnum, S-shaped spine, bowl-shaped pelvis, valgus knee, and non-opposable big toe.
- Cranial capacity trend
- The increase in hominin brain size over time, from roughly 400-500 cubic centimetres in Australopithecus to about 1300-1400 in Homo sapiens.
- Prognathism reduction
- The evolutionary trend toward a flatter human face with reduced brow ridges, smaller jaws and molars, and a more parabolic dental arcade.
- Cultural evolution
- Change in knowledge, tools, and behaviour transmitted by learning rather than genes, which can buffer environmental selection pressure on human populations.
- CRISPR-Cas9 mechanism
- A guide RNA directs the Cas9 nuclease to a complementary DNA sequence, where it cuts; repair then knocks out or corrects the target gene.
- Recombinant DNA steps
- Cut vector and insert with restriction enzymes, join with DNA ligase, transform into a host cell, then select successful transformants using a marker gene.