Chapter 8 - Vocabulary

Question 1

Abiogenesis

Answer 1

the origin of life from non-living matter.

Question 2

Adaptive Radiation

Answer 2

the relatively rapid evolution of a single species into many new species, filling a variety of formerly empty ecological niches.

Question 3

Allopatric Speciation

Answer 3

the formation of a new species as a result of evolutionary changes following a period of geographic isolation.

Question 4

Anthropoid

Answer 4

the group of primates that includes monkeys, apes, and humans.

Question 5

Cambrian Explosion

Answer 5

the rapid evolution of most major animal phyla that took place over approximately 40 million years during the Cambrian period.

Question 6

Cladistics

Answer 6

a method of determining evolutionary relationships based on the presence or absence of recently evolved traits.

Question 7

Coevolution

Answer 7

a process in which one species evolves in response to the evolution of another species.

Question 8

Convergent Evolution

Answer 8

the evolution of similar traits in distantly related species.

Question 9

Derived Trait

Answer 9

a trait that has evolved relatively recently with respect to the species or groups being discussed.

Question 10

Disruptive Selection

Answer 10

selection that favours two or more variations of a trait that differ from the current population average.

Question 11

Directional Selection

Answer 11

selection that favours an increase or decrease in the value of a trait from the current population average.

Question 12

Divergent Evolution

Answer 12

the large-scale evolution of a group into many different forms.

Question 13

Founder Effect

Answer 13

genetic drift that results when a small number of individuals separate from their original population and establish a new population.

Question 14

Genetic Bottleneck

Answer 14

a dramatic, often temporary, reduction in population size, usually resulting in significant genetic drift.

Question 15

Genetic Drift

Answer 15

changes to allele frequency as a result of chance; such changes are much more pronounced in small populations.

Question 16

Hardy-Weinberg Principle

Answer 16

in large populations in which only random chance is at work, allele frequencies are expected to remain constant from generation to generation.

Question 17

Hominid

Answer 17

all species descended from the most recent ancestor of chimpanzees and humans that are on the human side of the lineage.

Question 18

Macroevolution

Answer 18

large-scale evolutionary changes including the formation of new species and taxa.

Question 19

Microevolution

Answer 19

changes in gene (allele) frequencies and phenotypic traits within a population and species.

Question 20

Post-zygotic Mechanism

Answer 20

a reproductive isolating mechanism that prevents maturation and reproduction in offspring from interspecies reproduction.

Question 21

Pre-zygotic Mechanism

Answer 21

a reproductive isolating mechanism that prevents interspecies mating and fertilization (for example, ecological isolation, temporal isolation, and behavioural isolation).

Question 22

Primate

Answer 22

a group of relatively large-brained, mostly arboreal mammals that includes prosimians, monkeys, apes, and humans.

Question 23

Prosimian

Answer 23

the group of primates that includes lemurs, lorises, and tarsiers.

Question 24

Reproductive Isolation Mechanism

Answer 24

any behavioural, structural, or biochemical trait that prevents individuals from different species from reproducing successfully together.

Question 25

Sexual Selection

Answer 25

differential reproductive success caused by variation in the ability to obtain mates; results in sexual dimorphism, and mating and courtship behaviours.

Question 26

Speciation

Answer 26

the formation of new species.

Question 27

Stabilizing Selection

Answer 27

selection against individuals exhibiting traits that deviate from the current population average.

Question 28

Sympatric Speciation

Answer 28

the evolution of populations within the same geographic area into separate species.

Question 29

Synapomorphy

Answer 29

a derived trait shared by two or more species or groups.

Question 30

Theory of Gradualism

Answer 30

a theory that attributes large evolutionary changes in species to the accumulation of small and ongoing changes and processes.

Question 31

Theory of Punctuated Equilibrium

Answer 31

a theory that attributes most evolutionary changes to be relatively rapid spurts of change followed by long periods of little or no change.

Question 32

Transitional Form

Answer 32

a fossil or species intermediate in form between two other species in a direct line of descent.