Unit 3 Week 3

Question 1

contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals

Answer 1

relative fitness

Question 2

selection that favors phenotypes at one end of the spectrum of existing variation

Answer 2

directional selection

Question 3

selection that favors two or more distinct phenotypes

Answer 3

diversifying (disruptive) selection

Question 4

selection that favors average phenotypes

Answer 4

stabilizing selection

Question 5

fitness of a phenotype depends on how common it is in the population

Answer 5

frequency dependent selection

Question 6

selection pressure on males and females to obtain matings

Answer 6

sexual selection

Question 7

phenotypic differences between males and females

Answer 7

sexual dimorphisms

Question 8

selection that leads to evolution of traits in males for aggressive interactions with other males over access to females

Answer 8

intrasexual selection

Question 9

selection that occurs when individuals of one sex are choosy when selecting a mate

Answer 9

intersexual selection

Question 10

the general reason why natural selection cannot make perfect organisms

Answer 10

evolution is opportunistic

Question 11

science of naming and classifying organisms into hierarchical classification systems with each organism placed into increasingly more inclusive groupings

Answer 11

taxonomy

Question 12

any group used in classifying organisms

Answer 12

taxon

Question 13

order these in decreasing size: phylum, order, species, kingdom, genus, class, family

Answer 13

kingdom, phylum, class, order, family, genus, species

Question 14

science of resolving evolutionary relationships among organisms

Answer 14

systematics

Question 15

evolutionary history and relationships of an organism or groups of organisms

Answer 15

phylogeny

Question 16

ancestral lineage that gave rise to all organisms on the tree

Answer 16

root

Question 17

where two lineages diverged

Answer 17

branch point or node

Question 18

a lineage that evolved early and remains unbranched

Answer 18

basal taxon

Question 19

when two lineages stem from the same branch point

Answer 19

sister taxa

Question 20

a branch with more than two lineages representing unresolved relationships

Answer 20

polytomy

Question 21

trait in two or more species that is derived from a common ancestor

Answer 21

homology

Question 22

a characteristic that is similar between organisms that evolved through convergent evolution, not due to the same evolutionary path

Answer 22

analogy or homoplasy

Question 23

process by which groups of organisms evolve in diverse directions from a common point

Answer 23

divergent evolution

Question 24

process by which groups of organisms in distant taxa independently evolve to take on similar forms

Answer 24

convergent evolution

Question 25

system used to organize homologous traits to describe phylogenies

Answer 25

cladistics

Question 26

group that includes ancestral species and all its descendants

Answer 26

clad or monophyletic group

Question 27

group that does not contain all descendants from a most recent common ancestor

Answer 27

paraphyletic group

Question 28

the simplest explanation and most likely for a phylogenetic tree

Answer 28

maximum parsimony