Exam 2 PPTs - 2

Question 1

how many different species are living on Earth?

• slightly over … species of animals, plants, fungi and protists have been described thus far
• conservative estimates propose that the total number of described and undescribed species is about …
• some analyses suggest that it could be as high as …

Answer 1

1.9 million;
9 million;
100 million

Question 2

understanding what species are and how they form is central to efforts to …

Answer 2

preserve biodiversity

Question 3

what is a species and how are they formed? 
species concepts: 
1. ... 
2. ... 
3. ...

Answer 3

the morphospecies concept;
the phylogenetic species concept;
the biological species concept

Question 4

how species are formed:

allopatric: start with original population
- initial step of speciation: ….
- evolution of reproductive isolation occurs in …
- new distinct species after …

Answer 4

barrier formation;
isolation;
equilibration of new ranges

Question 5

how species are formed:

peripatric:
- initial step of speciation: …
- evolution of reproductive isolation: …
- new distinct species after equilibration of new ranges

Answer 5

new niche entered;

in isolated niche

Question 6

how species are formed:

parapatric:
- initial step of speciation: …
- evolution of reproductive isolation: …
- new distinct species after equilibration of new ranges

Answer 6

new niche entered;

in adjacent niche

Question 7

how species are formed:

sympatric:
- initial step of speciation: …
- evolution of reproductive isolation: …
- new distinct species after equilibration of new range

Answer 7

genetic polymorphism;

within the population

Question 8

how species are formed:
classically, speciation has been hypothesized to be a three-stage process:
1. …
2. … such as mating system or habitat use
3. …

Answer 8

isolation;
divergence in traits;
reproductive isolation

Question 9

how species are formed:

• classically, speciation has been hypothesized to be a three-stage process: isolation, divergence in traits, reproductive isolation
• speciation via this process is widespread in nature. However, in some instances, speciation can follow a different path. Stages 1 and 2 can occur … and in the … In many speciation events stage 3 …
• nevertheless, this hypothesis provides a useful framework for analyzing how speciation tasks place

Answer 9

at the same time;
same place;
never occurs

Question 10

mechanisms of isolation:

• isolation is … between two populations
• commonly occurs as a result of … factors that cause populations to become …

Answer 10

reduction in gene flow;
geographic factors;
physically separated

Question 11

mechanisms of isolation:

• gene flow tends to … gene frequencies and reduce the … of populations
• once gene flow is dramatically reduced or ceases, … begins and … may take place

Answer 11

homogenize;
differentiation;
evolutionary independence;
speciation

Question 12

mechanisms of isolation:

- the allopatric model: the essence of allopatric speciation is that … creates an effective barrier to …

Answer 12

physical isolation;

gene flow

Question 13

mechanisms of isolation:
geographic isolation through dispersal and colonization in Hawaiian Drosophila species
- the dispersal and colonization hypothesis make two predictions:
1. closely related species should be found on …
2. the sequence of … events should correspond to the sequence of …

Answer 13

adjacent islands;
branching events;
island formation

Question 14

mechanisms of isolation:

- geographic isolation through …

Answer 14

vicariance;

Question 15

mechanisms of divergence:
- adaptation to different …: when populations of a single species occupy multiple habitats with differing …, a frequent outcome is … and …, which can lead to …

Answer 15

habitats;
selection pressures;
phenotypic; genetic divergence;
speciation

Question 16

mechanisms of divergence:

- selection in the seedcracking finch based on bill width and seedcracking performance - … selection

Answer 16

disruptive

Question 17

hybridization and gene flow between species:

• what keeps two sympatric species separate?
  1. … isolation: …. are never formed, usually bc … between species does not take place

Answer 17

prezygotic;
hybrid offspring (zygotes);
mating

Question 18

hybridization and gene flow between species:

• what keeps two sympatric species separate?
  2. … isolation: hybrid offspring suffer from …, … or …

Answer 18

postzygotic;
inviability;
sterility;
reduced fitness

Question 19

hybridization and gene flow between species:
when species do interbreed, possible evolutionary outcomes include:
1. …
2. …
3. …

Answer 19

reinforcement of prezygotic isolation;
hybrid speciation;
stable hybrid zones

Question 20

hybridization and gene flow between species:
when species do interbreed
1. reinforcement of prezygotic isolation and/or …, selection against …

Answer 20

genetic incompatibility;

hybrids

Question 21

hybridization and gene flow between species:
when species do interbreed:
2. hybrid speciation –> selection favors hybrids in … not …

Answer 21

novel habitat;

occupied by parental species

Question 22

hybridization and gene flow between species:
when species do interbreed:
3. hybrid zones: selection favors hybrids in …

Answer 22

transitional habitats

Question 23

Morphospecies concept:

• the great advantage of the morphospecies concept is that it is …
• morphospecies can be identified in individuals that are … or ….

Answer 23

widely applicable;
extinct;
living

Question 24

Morphospecies concept:
problems;
- difficult to applying groups like …, … and many … that are small and have few measurable … characters

Answer 24

bacteria;
archaea;
fungi;
morphological

Question 25

Morphospecies concept:
problems
- fossil species that differed in … or the anatomy of … cannot be distinguished
- populations that are similar in … but were strongly divergent in … (…)

Answer 25

color; 
soft tissues; 
morphology; 
other traits; 
cryptic species

Question 26

Morphospecies concept:

problems:
- it does not work for cryptic species, for groups that are actually … of one another but appear to be … based on …

Answer 26

independent of one another;
members of the same species;
morphological similarity

Question 27

The phylogenetic species concept (PSC):

• … is the criterion for identifying species
• monophyletic groups are defined as lineages that contain all of the …. of a …

Answer 27

monophyly;
known descendants;
single common ancestor

Question 28

The phylogenetic species concept (PSC):
- the rationale behind the phylogenetic species concept is that traits can distinguish populations on a phylogeny only if the populations have been … in terms of … and have …., and possibly … as well

Answer 28

isolated;
gene flow;
diverged genetically;
morphologically

Question 29

The phylogenetic species concept (PSC):

- the appeals of this approach are that it can be applied to … - including … and …- and that it is …

Answer 29

any type of organism;
asexual;
fossils;
testable

Question 30

The phylogenetic species concept (PSC):
- the appeals of this approach are that it can be applied to any type of organism - including asexual and fossils - and that it is testable: species are named on the basis of … in the traits used to estimate the phylogeny

Answer 30

statistically significant differences;

Question 31

The phylogenetic species concept (PSC):

• different sources of information can lead to differing phylogenies, resulting in … under the PSC
• instituting the phylogenetic species concept could easily double the number of … and might create a great deal of confusion if traditional names and species identities are changed. proponents of the concept argue that this is not if it is a better representation of reality

Answer 31

conflicting species designations;

named species

Question 32

The phylogenetic species concept (PSC):

• recent analyses have found that the PSC often distinguishes multiple … in populations that were formerly considered a single species
• for organisms such as …, the PSC has been immensely useful in identifying possible … that can then be further explored experimentally

Answer 32

cryptic species;
fungi;
species boundaries

Question 33

The biological species concept (BSC):

• the criterion for identifying evolutionary independence is …
• species should be different: if populations of organisms do not … in nature, if they fail to produce … when they do …

Answer 33

reproductive isolation;
hybridize regularly;
fertile offspring;
hybridize

Question 34

The biological species concept (BSC):

• has been widely accepted since Ernst Mayr championed it in 1942. it is used in practice by many biologists and is the legal definition employed in the endangered species act of 1973, the flagship … legislation in the US
• the great strength of the BSC is that reproductive isolation is a meaningful criterion for identifying species because it confirms …
• although this criterion is compelling in concept and useful in some situations, it is often difficult to apply

Answer 34

biodiversity;

lack of gene flow;

Question 35

The biological species concept (BSC):

- there are several examples of species that are …

Answer 35

not reproductively isolated