Chapter 26

Question 1

What is the genetic change taking place in a group of organisms?

Answer 1

evolution

Question 2

What is evolution taking place in a single lineage over time?

Answer 2

anagenesis

Question 3

What is the splitting of one lineage into two?

Answer 3

cladogenesis

Question 4

What is the theory that proposes that much molecular variation is adaptively neutral (individuals with different molecular variants have equal fitness)?

Answer 4

neutral-mutation hypothesis

Question 5

What is selection that maintains genetic variation?

Answer 5

balancing selection

Question 6

What are different kinds or types of living organisms?

Answer 6

species

Question 7

What is the widely used definition of a species that states that a species is a group of organisms whose members are capable of interbreeding with each other but are reproductively isolated from the members of other species?

Answer 7

biological species concept

Question 8

What is any biological factor or mechanism that prevents gene exchange?

Answer 8

reproductive isolating mechanism

Question 9

What are mechanisms that prevent gametes from two species from fusing and forming a hybrid zygote?

Answer 9

prezygotic reproductive isolating mechanisms

Question 10

What is the isolation mechanism where species do not encounter one another?

Answer 10

ecological isolation

Question 11

What is the isolation mechanism where species have differences in behavior that prevent interbreeding?

Answer 11

behavioral isolation

Question 12

What is another type of isolation when reproductive activities do not take place concurrently?

Answer 12

temporal isolation

Question 13

What is the isolation caused by anatomical differences?

Answer 13

mechanical isolation

Question 14

What are isolations caused by gametes being unable to form zygotes?

Answer 14

gametic isolation

Question 15

What are isolation mechanisms that see a lack of gene flow after the creation of a viable zygote?

Answer 15

postzygotic reproductive isolating mechanisms

Question 16

What is a form of separation between species where a hybrid cannot complete development?

Answer 16

hybrid inviability

Question 17

What is the form of separation where hybrids develop fully but are sterile?

Answer 17

hybrid sterility

Question 18

What is the form of separation where species can reproduce, but they cannot continue to reproduce (F2 is either inviable or sterile)?

Answer 18

hybrid breakdown

Question 19

What is the process by which new species arise?

Answer 19

speciation

Question 20

What is the form of speciation caused by geographic barriers splitting populations?

Answer 20

allopatric speciation

Question 21

What is the form of speciation that arises in the absence of any external barrier to gene flow?

Answer 21

sympatric speciation

Question 22

What is the evolutionary relationships among a group of organisms?

Answer 22

phylogeny

Question 23

What is a graphical representation of a phylogeny?

Answer 23

phylogenetic tree

Question 24

What are the evolutionary connections in a phylogenetic tree?

Answer 24

branches

Question 25

What are the points where the branches split (representing a common ancestor) in a phylogenetic tree?

Answer 25

nodes

Question 26

What is a description of the phylogenetic tree where one node represents a common ancestor to all other nodes?

Answer 26

rooted

Question 27

What are trees that depict the evolutionary relationships among DNA sequences?

Answer 27

gene tree

Question 28

What is the time deduced from the number of molecular changes that a protein has gone through in a certain amount of time?

Answer 28

molecular clock

Question 29

What is the process where exons of different genes are exchanged?

Answer 29

exon shuffling

Question 30

What are groups of genes that are similar in sequence but encode different products?

Answer 30

multigene families