Midterm #2

Question 1

What is allopatric (“other country”) speciation

Answer 1

gene flow is interrupted when a population is divided into geography isolated subpopulations.

e.g. Snapping Shrimp : The isthmus of panama formed about 3 mil years ago, separating snapping shrimp species on each side. (separated due to the Isthmus’ land bridge that basically divided North and South America)

Question 2

What is another allopatric speciation example that is more close to us in the genes?

Answer 2

Chimpanzee and Bonobo monkeys split by the Congo river circa 2 million years ago
- bonobo’s inclined to deeper forests
- chimpanzees can live in varied environments.

Question 3

What is parapatric speciation?

Answer 3

there is no physical barrier, but it’s covering the range of the species. Usually original species is covering in a large area.

Where there is some kind of different natural selection going on in different areas, and you get a hybrid zone in between as the speciation process is ongoing.

Question 4

What is an example of parapatric speciation?

Answer 4

European crows: Corvus Corone and Corvus Cornix

Question 5

what is sympatric (“same country”) speciation?

Answer 5

speciation occurs in populations that live in the same geographical area.

Question 6

if gene flow is reduced by such factors as polyploidy, sexual selection, and habitat differentiation, what speciation can occur?

Answer 6

sympatric speciation

Question 7

What is an example of sympatric speciation?

Answer 7

Anolis lizards

Question 8

what is the definition of a polyploidy?

Answer 8

A condition where species may originate from an accident during cell division that results in extra sets of chromosomes.

“an unusual occurrence during meiosis can sometimes cause a high number of chromosomes (usually double, from 2n to 4n)

Question 9

what is the result of polyploidy individuals only limited to interbreeding with other polyploidy individuals (though plants self-polinate)?

Answer 9

reproductive isolation

Question 10

what is an example of polyploidy?

Answer 10

[common in plants, rare in animals]
the common gray tree frog (4n, double in chromosomes) and the southern (cope’s) gray tree-frog (2n)

Question 11

what is a phylogenetic tree?

Answer 11

A phylogenetic tree is a diagram that represents evolutionary relationships among organisms.

phylogenetic trees are hypotheses, not definitive facts.

the pattern of branching in a phylogenetic tree reflects how species or other groups evolved from a series of common ancestors.

Question 12

what is the definition of phylogenetics?

Answer 12

the science of figuring out relationships between organisms.

Question 13

what is phylogeny?

Answer 13

the evolutionary history of a group of related species/ populations.

Question 14

what is the definition of systematics?

Answer 14

the science of classifying organisms based on their characteristics/ relationships, taxonomy: part of of systematics concerned with naming organisms.

Question 15

what is cladistics (phylogenetic systematics)?

Answer 15

classification of organisms based on their order of branching on an evolutionary tree.

Question 16

what is Linnaeus known for?

Answer 16

Linnaeus: 18th century taxonomy

Question 17

Linnaeus’: 18th century taxonomy includes two part format for scientific names, what are the names?

Answer 17

Binomial nomenclature and hierarchal classification system (e.g. Kingdom, Phylum, Class, Order, Family, Genus, Species)

Question 18

Is the Linnaeus’ 18th century taxonomy still in use today?

Answer 18

yes, although Domain has been added as the most inclusive hierarchal category.

Question 19

Today, when is the Linnaean System used?

Answer 19

The Linnaean System is used assuming the named taxa show some sort of relationship (usually monophyletic)

Question 20

Taxonomic Tips: what word obtains both the singular and plural form?

Answer 20

‘species’, there is no such thing as ‘specie’

Question 21

Taxonomic Tips: if ‘genus’ is singular, then what is it’s plural form?

Answer 21

‘genera’

Question 22

Taxonomic Tips: In a binomial species name, the first letter of the genus only is capitalized, what example is given?

Answer 22

Homo sapiens, not Homo Sapiens (and the ‘s’ is not plural)

Question 23

Taxonomic Tips: what is italicized, or less commonly uderlined?

Answer 23

The entire binomial.

Question 24

(a) Monophyletic Taxon (Clade), what are the key take aways? [referring to the diagram]

Answer 24

in group 1: ancestor + descendants
- the school of cladistics in systematics emphasize only monophyletic groups in taxonomy

Question 25

what are the key take aways from the Paraphyletic Taxon?

Answer 25

Some paraphyletic groups are still used in naming taxa. The descendant is not included in group 2.

Question 26

what are the key take aways from the Polyphyletic Taxon?

Answer 26

ancestor is not included in group 3
- polyphyletic groups are avoided in modern taxonomy

Question 27

The class of Reptilia is paraphyletic (as traditionally defined)

Answer 27

LTCARD
Lepidosauria, Tetrodines, Crocodylia, Archosauna, Reptilia, Diaspora

Question 28

systematists are known as what?

Answer 28

polyphyletic, ‘warm blooded animals’
- mammalian + aves

Question 29

What is thing to be noted about nodes?

Answer 29

Branches can be rotated around nodes.

Question 30

what can be inferred from morphological and molecular homologies?

Answer 30

phylogenies

Question 31

what does homologies show due to shared ancestry?

Answer 31

developmental, phenotypic, and genetic similarities.

Question 32

caution: what can convergent evolution lead to?

Answer 32

analogous (homoplastic) traits:
- similar, analogous, trait that evolved independently in each lineage (homoplasy)
- brought on by natural selection due to similar environment rather than shared ancestry

Question 33

caution: what is the given example of “convergent evolution leading to analogous traits”?

Answer 33

Howler Monkeys + Colobus monkeys: Most monkeys eat fruit, but Howler monkeys and Colobus monkeys have independently evolved complex stomachs to handle a folivorous diet.

Question 34

What is homoplasy?

Answer 34

Analogous (or convergent) characteristics

Question 35

what is the given example for homoplasy?

Answer 35

Marsupial mole, Australia + Golden mole, Africa
- not related at all except for being mammals

Question 36

in a phylogenetic analysis, analogous morphologies or molecular sequences that evolved independently are called what?

Answer 36

homoplasies (homoplastic characters)

Question 37

what is the given example of of homoplasies (homoplastic characteristics)?

Answer 37

e.g. Taxon A and D are both black, but the last common ancestor… and Taxa A and D share a trait not because their common ancestor possessed that trait, but because they each have independently converged on the trait.

Question 38

what is molecular homoplasy?

Answer 38

statistical tools have been developed to determine whether DNA sequences that share a certain fraction of their bases do so because they are homologous or homoplastic.

Question 39

what can phylogenies be inferred from?

Answer 39

morphological and molecular homologies.

Question 40

what do homologies show?

Answer 40

developmental, phenotypic, and genetic similarities due to shared ancestry.

Question 41

what is the example given as to how homologies show developmental, phenotypic, and genetic similarities due to shared ancestry.

Answer 41

human, cat, whale, bat
- in short the bone + structure in the arm are the same
- this is the same genes that are expressed in making up the radius
- strong evidence in homology