Unit 7: Speciation, Phylogenetics, and Evidence of Evo.

Question 1

Define

Convergent evolution

Answer 1

Two species that share similar traits due to environmental pressure and not common ancestry

Question 2

Define

Divergent evolution

Answer 2

Two species with traits that differ due to unique selective pressures but share common ancestry

Question 3

Define

Punctuated equilibrium

Answer 3

Periods of genetic equilibrium interspersed by rapid periods of evolutionary change

Question 4

Define

Gradualism

Answer 4

Pattern of slow, continuous evolution

Question 5

Define

Adaptive radiation

Answer 5

Rapid divergent evolution that occurs when one group enters an area that is unoccupied by similar groups

Question 6

Explain the term

Common Ancestry

Answer 6

Two groups that diverged from a single ancestral species;

Ultimately, all species are thought to have arisen from one single common ancestor

Question 7

Define

Phylogeny

Answer 7

Evolutionary history of species

Question 8

List

Three major “branches” on phylogenetic tree of all life

Answer 8

Domains:

- Archaea (Archaebacteria)

- Bacteria (Eubacteria)

- Eukarya

Question 9

Describe

Homologous structures

Answer 9

Physical structures that are similar between species who share a common ancestor, but may have different functions

Question 10

Provide examples of

Homologous structures

Answer 10

Limbs of all tetrapods, which usually have a single long bone, a pair of long bones, many short bones, and digits

Ex: Human arm, cat’s leg, bat’s wing, whale’s fin

Question 11

Define

Analogous structures

Answer 11

Physical structures that share common functions but evolved via convergent evolution (and thus are not due to common ancestry)

Question 12

Provide examples of

Analogous structures

Answer 12

A bird’s, bat’s, and butterfly’s wing

Question 13

Define

Theory

Answer 13

A well-supported explanation of why a particular phenomenon occurs

Question 14

Define and give an example of

Vestigial structures

Answer 14

Structures that have no function but are present because they served a function in the ancestor;

ex: human appendix function is greatly reduced but was used by ancestors for aiding in the digestion of fibrous foods

Question 15

Explain

Fossil Dating

Answer 15

- compare fossil to known age of rock layer

- Carbon-14 dating, where carbon isotopes (C-14) have a known rate of decay and can be measured to approximate age of the organism

Question 16

Describe

Molecular homologies

as a source of evidence for evolution

Answer 16

Groups with most recent common ancestor tend to have fewer differences between their DNA sequences (less time for mutations to accrue)

Comparing DNA or amino acid sequences can be used to determine when two species shared a common ancestor

Question 17

Describe

Embryologic development

as a source of evidence for evolution

Answer 17

Controlled by genes which are shared among descendents of common ancestors.

Closely related organisms undergo very similar embryonic developmental stages.

Similar development also helps account for homologous structures

Question 18

List

Evidence of common ancestry in eukaryotes

Answer 18

-Linear chromosomes

-Membrane-bound organelles

-Genes with introns

Question 19

Define

Biogeography

Answer 19

The geographic distribution of species and fossil evidence of those species’ ancestors

Question 20

How does biogeography support evolution?

Answer 20

Divergence of groups can be traced to movement of Earth’s land masses (techtonic plate movement, changes to terrain);

Groups that diverged most recently are most clustered together, whereas those with distant common ancestors are more widely distributed, because all continents were once joined together

Question 21

Describe how to

Construct a cladogram and/or phylogenetic tree

Answer 21

Compare traits of each group;

Place those with similar traits closest together to maximize parsimony;

Limit the independent emergence of traits in separate lineages

Question 22

Define

Speciation

Answer 22

The divergence of one species into separate species

Question 23

Define

Species

(Biological Species Concept)

Answer 23

A group of organisms that are capable of reproducing and making fertile offspring

Question 24

What is wrong with the biological species concept?

Answer 24

Not very “neat”

-Ring species may exist, where populations A and B can mate, and B and C can mate, but A and C cannot

-Does not apply to extinct species

-Does not apply to species that reproduce asexually

-Difficult to apply to groups that are physically separated but could potentially mate

Question 25

Define

Sympatric speciation

Answer 25

Speciation that occurs without physical separation of the groups

Question 26

Define

Allopatric speciation

Answer 26

Speciation that occurs due to the physical separation of groups

Question 27

What condition is necessary for speciation to occur?

Answer 27

Reproductive isolation

Question 28

State two types of

Reproductive isolation

Answer 28

Pre-zygotic and post-zygotic

Question 29

Define and give examples of

Pre-zygotic isolation

Answer 29

The separation of two groups that prevents the formation of a zygote

Examples: Habitat, temporal, behavioral, mechanical, and gametic isolation

Question 30

Define and give examples of

Post-zygotic isolation

Answer 30

Processes that prevent a hybrid zygote from contributing to the gene pool

Examples: low hybrid viability, hybrid infertility, hybrid break-down

Question 31

Define and provide an example of

Geographic isolation

Answer 31

Reproductive isolation due to physical barriers between species

Example: Squirrels on the north and south ridges of the Grand Canyon

Question 32

Define and provide an example of

Habitat isolation

Answer 32

Reproductive isolation due to different habitats

Example: Lions and tigers, whose habitats differ so they rarely encounter one another

Question 33

Define and provide an example of

Temporal isolation

Answer 33

Reproductive isolation from different mating times / seasons

Example:

Question 34

Define and provide an example of

Behavioral isolation

Answer 34

Answer

Question 35

Define and provide an example of

Mechanical isolation

Answer 35

Answer

Question 36

Define and provide an example of

Gametic isolation

Answer 36

Answer

Question 37

Define and provide an example of

Hybrids

Answer 37

Answer

Question 38

Define and provide an example of

Low hybrid viability

Answer 38

Answer

Question 39

Define and provide an example of

Hybrid infertility

Answer 39

Answer

Question 40

Define and provide an example of

Hybrid breakdown

Answer 40

Answer

Question 41

Command

Term

Answer 41

Answer

Question 42

Command

Term

Answer 42

Answer

Question 43

Command

Term

Answer 43

Answer

Question 44

Command

Term

Answer 44

Answer