chapter 9

Question 1

theory of evolution

Answer 1

states that all organisms have developed from previous organismsand that all living things have a common ancestor in some initial form of primitive life.

Question 2

evolution

Answer 2

the process of cumulative, heritable change in a population over many generations

Question 3

mechanisms

Answer 3

cause the basis of evolution; changes in allele frequencies within a gene pool

Question 4

accumulation

Answer 4

The process of certain traits gradually becoming more common over generations

Question 5

adaptation

Answer 5

An inherited trait that allows an individual to survive and reproduce

Question 6

genetic drift

Answer 6

the process of random changes in allele proportions within a population from one generation to the next

Question 7

Adaptive evolution

Answer 7

Changes in a population of organisms that make that population better adapted to its environment over time

Question 8

Adaptive radiation

Answer 8

The process by which a species rapidly diversifies into many taxa with differing adaptations; it can be triggered by many factors, such as the emergence of reproductive barriers within a population, changes in the availability of resources, new challenges or new opportunities; it is a type of divergent evolution

Question 9

Allopatric speciation

Answer 9

Speciation that occurs due to physical or geographic isolation

Question 10

Artificial selection (selective breeding)

Answer 10

The intentional breeding or reproduction by humans of individuals with desirable traits, resulting in changes in allele frequencies in gene pools over time; the traits are beneficial to humans

Question 11

Biological fitness

Answer 11

The capacity of an individual to survive and produce viable, fertile offspring

Question 12

Biological species concept

Answer 12

A definition of species based on whether members can interbreed to produce fertile offspring

Question 13

Bottleneck effect

Answer 13

A random reduction in the size of a population, which can lead to a reduction in the gene pool because of the misrepresented allele proportions; it can occur when a catastrophic event or a period of adverse conditions drastically reduces the size of a population

Question 14

Descent with modification

Answer 14

Darwin’s terminology for the way life today has descended and evolved from common ancestors that were generally different from their modern descendants

Question 15

Divergent evolution

Answer 15

A process whereby related species evolve new traits over time after living in different habitats, becoming increasingly different from their common ancestor and from one another, giving rise to new species

Question 16

Evolution

Answer 16

The process of cumulative, gradual, heritable change in a population of organisms that occurs over many generations and a relatively long time

Question 17

Founder effect

Answer 17

A random reduction in a population that occurs when a few individuals become isolated from a larger population and form a new population that does not carry all the alleles that were present in the original population

Question 18

Gene flow

Answer 18

The transfer of alleles that results from emigration, immigration and migration of individuals between populations

Question 19

Gene pool

Answer 19

A collection of all the alleles for all the genes in the reproducing members of a population at a given time; it is the genetic reservoir from which a population can obtain its traits

Question 20

Genetic drift

Answer 20

A change in the gene pool of a population as a result of chance; it usually occurs more noticeably in small populations

Question 21

Hybrid offspring

Answer 21

Offspring from parents of two different species

Question 22

Inheritable

Answer 22

Capable of being passed on to the next generation

Question 23

Isolating mechanism

Answer 23

A mechanism that prevents organisms from mating or producing viable offspring

Question 24

Macro-evolution

Answer 24

The evolution of new groups of organisms comprising many related species through multiple speciation events; includes adaptive radiations

Question 25

Mass extinction

Answer 25

Extinction of many species over a relatively short (geological) period of time

Question 26

Micro-evolution

Answer 26

Change in the gene pool below species level; any small-scale change in the gene pool of a population

Question 27

Modern synthesis

Answer 27

The theory of evolution incorporating our current understanding of how traits are inherited

Question 28

Morphological species concept

Answer 28

Definition of a species using measurable anatomical criteria and characteristics

Question 29

Mutation

Answer 29

A permanent change in the DNA sequence of a gene; a source of new alleles in a population’s gene pool; the process of generating a mutation

Question 30

Natural selection

Answer 30

Occurs when selection pressures in the environment confer a selective advantage on a specific phenotype that enhances its survival and reproduction. It is a process in which individuals that have certain inherited traits are more likely to survive and reproduce at higher rates than other individuals because of those traits. It can cause changes in a population’s allele frequencies (gene pool) and therefore is a mechanism for evolution

Question 31

Population

Answer 31

A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring

Question 32

Post-reproductive isolating mechanism

Answer 32

A mechanism that prevents fertilisation occurring or an embryo developing into viable offspring if fertilisation does occur

Question 33

Pre-reproductive isolating mechanism

Answer 33

A mechanism that prevents organisms from being able to interact to reproduce habitat isolation, behavioral isolation, temporal isolation, mechanical isolation, and gametic isolation

Question 34

Reproductiveisolation

Answer 34

When a single population becomes two separate populations that are unable to interbreed due to physical, biological or behavioural barriers

Question 35

Selection pressure

Answer 35

A factor that influences the survival of an individual within a population

Question 36

Sexual dimorphism

Answer 36

Different morphologies (often in shape or size) between males and females of a species

Question 37

Sexual selection

Answer 37

A selection process that occurs between males or between females in a population for an inherited trait that assists in copulation or the winning of a mate

Question 38

Speciation

Answer 38

The evolution of one or more new species from an ancestral species. A population is considered a new species when it can no longer interbreed with the ancestral species

Question 39

species

Answer 39

A group of similar organisms capable of breeding and exchanging genes with one another and whose offspring are capable of doing the same

Question 40

Sympatric speciation

Answer 40

Speciation that occurs without physical or geographic isolation A hypothetical example of sympatric speciation is a group of flies from the same species given two different food sources. In the beginning, all of them eat the red apples. However, some flies start to favor green apples over time. Eventually, interactions between the two kinds of flies are so rare that they no longer mate, resulting in genetic divergence Another example is the two kinds of orcas in the Pacific. Although they live in the same region, there is a lack of interaction and mating between these groups. Their behaviors and feeding habits are also different from each other. There is a belief that these factors are the reason for the original species' divergence.

Question 41

Theory of evolution

Answer 41

States that all organisms have developed from previous organisms and that all living things have a common ancestor in some initial form of primitive life. It also states that all organisms are fundamentally similar because their basic chemistry was inherited from this very first organism

Question 42

Variable trait

Answer 42

A trait that varies in the population due to differences in alleles carried by different individuals eg eye colour, weight, height

Question 43

Variation

Answer 43

The diversity of genetic and phenotypic traits within and between populations

Question 44

mechanisms that can lead to change in the gene of a population

Answer 44

by chance in recombination and mating, migration, the bottleneck and founder effects, and differential selection of phenotype of individuals in a population

Question 45

mechanisms leading to isolation of populations

Answer 45

reproductive, geographic, temporal, behavioral, morphological mechanisms

Question 46

allopathic speciation

Answer 46

organisms that could interbreed but don’t because of physical barriers