Variation, Speciation, and Evolution Practice Flashcards

A set of vocabulary flashcards based on lecture notes covering genetic variation, DNA structure, mechanisms of speciation, natural selection, and evolutionary history.

Heredity

The process by which genetic information is passed from one generation to the next, explaining why offspring resemble their parents.

DNA

A complex molecule consisting of two strands twisted into a double helix, held together by bonds between base pairs, which contains genetic information.

Chromosomes

Thin, coiled structures found in the nucleus of each cell that are composed of DNA.

DNA length in Red Blood Cells

Red blood cells contain none.

DNA length in most cells

Approximately $2\,m$ long.

DNA length in sperm or eggs

Approximately $1\,m$ long.

Mutation

Small changes in DNA that can provide individuals within a species the skills or adaptations to deal with environmental changes.

Species

A group of organisms that are able to interbreed and produce fertile offspring.

Speciation

The development of a new and distinctly different species over a very long period of time from a distant descendant.

Geographic Separation

Speciation caused by physical barriers such as water or mountains that lead to separate habitat and predator pressures.

Behavioural Isolation

A type of isolation occurring when certain members of a species develop different mating calls, rituals, or colors that are not recognized by other members.

Temporal Isolation

Isolation occurring when populations start mating or reproducing at different times, such as different times of day, seasons, or years.

Post-Zygotic Separation

A condition where different species occasionally mate, but their offspring (such as a Mule or Zonkey) is infertile.

Genetic Drift

The change in frequency of an existing gene variant in a population due to random chance, which may cause variants to disappear or become fixed.

Galapagos Islands

A group of islands roughly $1,000\,km$ off the coast of Ecuador where Charles Darwin studied the variations in finches.

Natural Selection

A process by which a species changes over time in response to environmental changes or competition, often described as 'survival of the fittest.'

Evolution

A slow process taking thousands or millions of years in which different species evolve from simpler life forms.

Age of the Earth

Approximately $4.5$ billion years old.

Fossil

The preserved remains of a dead organism from millions of years ago, which can be formed from hard parts, preserved in materials like amber and ice, or left as traces like footprints.