Explorations Chapter 2

Question 1

Allele

Answer 1

A nonidentical DNA sequence found in the same gene location on a homologous chromosome, or gene copy, that codes for the same trait but produces a different phenotype.

Question 2

Artificial selection

Answer 2

The identification by humans of desirable traits in plants and animals, and the subsequent steps taken to enhance and perpetuate those traits in future generations.

Question 3

Binomial nomenclature

Answer 3

A system of classification in which a species of animal or plant receives a name consisting of two terms: the first identifies the genus to which it belongs, and the second identifies the species.

Question 4

Carrying capacity

Answer 4

The number of living organisms, including animals, crops, and humans, that a geographic area can support without environmental degradation.

Question 5

Catastrophism

Answer 5

The theory that the Earth’s geology has largely been shaped by sudden, short-lived, violent events, possibly worldwide in scope. Compare to uniformitarianism.

Question 6

Comparative anatomy

Answer 6

Georges-Louis Leclerc’s technique of comparing similar anatomical structures across different species.

Question 7

Creationism

Answer 7

The belief that the universe and all living organisms originate from specific acts of divine creation, as in the Biblical account, rather than by natural processes such as evolution.

Question 8

Empiricism

Answer 8

The idea that all learning and knowledge derives from experience and observation. It became prominent in the 17th and 18th centuries in western Europe due to the rise of experimental science.

Question 9

Evolution

Answer 9

In a biological sense, this term refers to cumulative inherited change in a population of organisms through time. More specifically, evolution is defined as a change in allele (gene) frequencies from one generation to the next among members of an interbreeding population.

Question 10

Extant

Answer 10

Still in existence, surviving

Question 11

Extinct

Answer 11

Said of a species, family, or other group of animals or plants that has no living members; no longer in existence.

Question 12

Fixity of Species

Answer 12

The idea that a species, once created, remains unchanged over time.

Question 13

Gene

Answer 13

A sequence of DNA that provides coding information for the construction of proteins.

Question 14

Genetic Drift

Answer 14

Random changes in allele frequencies within a population from one generation to the next.

Question 15

Gene Flow

Answer 15

The introduction of new genetic material into a population through interbreeding between two distinct populations.

Question 16

Gene pool

Answer 16

The entire collection of genetic material in a breeding community that can be passed from one generation to the next.

Question 17

Genotype

Answer 17

The genotype of an organism is its complete set of genetic material—its unique sequence of DNA. Genotype also refers to the alleles or variants an individual carries in a particular gene or genetic location.

Question 18

Hybrid

Answer 18

Offspring of parents that differ in genetically determined traits.

Question 19

Intelligent design

Answer 19

A pseudoscientific set of beliefs based on the notion that life on earth is so complex that it cannot be explained by the scientific theory of evolution and therefore must have been designed by a supernatural entity.

Question 20

Macroevolution

Answer 20

Large and often-complex changes in biological populations, such as species formation.

Question 21

Microevolution

Answer 21

Changes in the frequency of a gene or allele in an interbreeding population.

Question 22

Modern synthesis

Answer 22

The mid–20th century merging of Mendelian genetics with Darwinian evolution that resulted in a unified theory of evolution.

Question 23

Natural selection

Answer 23

The natural process by which the survival and reproductive success of individuals or groups within an interbreeding population that are best adjusted to their environment leads to the perpetuation of genetic qualities best suited to that particular environment at that point in time.

Question 24

phenotype

Answer 24

The detectable or visible expression of an organism’s genotype.

Question 25

Scientific method

Answer 25

A method of procedure that has characterized natural science since the 17th century, consisting of systematic observation, measurement, experimentation, and the formulation, testing, and modification of hypotheses.

Question 26

Speciation

Answer 26

The process by which new genetically distinct species evolve from the main population, usually through geographic isolation or other
barriers to gene flow.

Question 27

Species

Answer 27

A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. The species is the principal
natural taxonomic unit, ranking below a genus and denoted by a Latin binomial (e.g., Homo sapiens).

Question 28

Uniformitarianism

Answer 28

The theory that changes in the earth’s crust during geologic history have resulted from the action of continuous and uniform processes—such as wind, precipitation, evaporation, condensation, erosion, and volcanic action—that continue to act in the present. Compare to catastrophism.