Variation, Heredity and Cell Division – Key Vocabulary

A set of vocabulary flashcards summarising the main terms and ideas about variation and heredity presented in the lecture notes.

Homo sapiens

The scientific name for modern human beings, the single living species of the genus Homo.

Species

A group of similar organisms capable of interbreeding and producing fertile offspring; humans belong to the species Homo sapiens.

Variation

Differences in characteristics among individuals of the same species.

Inherited Variation

Differences passed genetically from parents to offspring, such as eye colour or natural height potential.

Acquired Variation

Differences that arise from environmental influences or life activities, for example suntanned skin or body weight changes due to diet.

Continuous Variation

Variation that shows a full range of values without clear-cut categories, e.g., height or weight.

Discontinuous Variation

Variation with distinct categories and no intermediates, such as blood type, gender, or ability to roll the tongue.

Normal Distribution Curve

A bell-shaped graph that shows most values clustered around the average with few extreme highs or lows; often seen in continuous variation like height.

Frequency Graph

A chart plotting how often particular measurements occur in a sample population, used to visualize variation patterns.

Average (Mean) Height

The central value on a height frequency graph where most individuals’ heights cluster.

Characteristic Features

Distinct traits of a species—shape, structure, or function—that allow recognition and identification.

Tongue Rolling

A discontinuous trait where individuals either can or cannot roll the sides of the tongue upward to form a tube.

Attached vs. Free Earlobes

A classic example of discontinuous variation where earlobes are either connected directly to the head (attached) or hang free.

Gender

A discontinuous characteristic determined genetically, resulting in male or female biological sex in humans.

Evolutionary Advantage of Variation

The idea that diversity in inherited traits increases a species’ ability to adapt and survive over time.