15 - Speciation And Phylogeny

Question 1

Gene flow is a mechanism of _____ but not _____

Answer 1

Gene flow is a mechanism of microevolution but not speciation.

Question 2

4 ways of defining species

Answer 2

Morphological
Biological
Ecological
Phylogenetic

Question 3

How does the biological perspective define species?

Answer 3

Species is a group of populations who can interbreed and produce fertile offspring.

Question 4

What is the disadvantage of the biological perspective, in terms of defining species? (Ie., the type of organism that it doesn’t apply to)

Answer 4

Cannot be applied to extinct organisms, for example, those found in fossils.
Also cannot be applied to asexual organisms.

Question 5

How does the morphological perspective define species?

Answer 5

Defines species in terms of measurable anatomical criteria.

Question 6

What is the disadvantage of the morphological species concept?

Answer 6

Based on highly subjective criteria.

• needs elaboration; look at textbook

Question 7

How does the ecological perspective define species?

Answer 7

In terms of their ecological niche; their roles.

Question 8

Disadvantage to ecological perspective?

Answer 8

2 different species could inhabit the same niche!

Question 9

How does the phylogenetic concept define species?

Answer 9

The smallest group of organisms that share a common ancestor…ie., one branch in a lineage.

This includes the comparison of both morphology and DNA sequences.

Question 10

Disadvantage of phylogenetic species concept?

Answer 10

Life is so vastly varied. hard to decide how many differences are required to define a separate species?

Question 11

What are reproductive barriers?

Answer 11

Circumstances that isolate gene pools of species, preventing gene flow.

Question 12

What prevents gene flow?

Answer 12

Reproductive barriers!

Question 13

What are the two types of reproductive barriers?

Answer 13

Prezygotic and postzygotic barriers

Question 14

Prezygotic barrier

Answer 14

Prevents mating or fertilization

Question 15

Postzygotic barrier

Answer 15

Occurs after fertilization; prevents formation of VIABLE AND FERTILE offspring.

Question 16

Types of prezygotic barriers (5)

Answer 16

Habitat isolation
Temporal isolation
Behavioural isolation
Mechanical isolation
Gametic isolation

Question 17

Types of postzygotic barriers (3)

Answer 17

Reduced hybrid viability
Reduced hybrid fertility
Hybrid breakdown

Question 18

Temporal isolation is a type of ______ barrier

Answer 18

Prezygotic

Question 19

Mechanical isolation is a type of ____ barrier

Answer 19

Prezygotic

Question 20

Reduced hybrid fertility is a type of _____ barrier

Answer 20

Postzygotic

Question 21

Hybrid breakdown is a type of _____ barrier

Answer 21

Postzygotic

Question 22

Reduced hybrid viability is a type of _____ barrier

Answer 22

Postzygotic

Question 23

Reduced hybrid fertility

Answer 23

When hybrids fail to produce functional gametes.

Question 24

Reduced hybrid viability

Answer 24

When the development or survival of hybrids is impaired.

Question 25

Hybrid breakdown

Answer 25

When offspring of hybrids are feeble or infertile.

Question 26

A horse and a donkey mate. Their offspring is a mule. Mules are sterile. What reproductive barrier is this? Pre/post? And what kind?

Answer 26

Postzygotic; reduced hybrid fertility

Question 27

Hybrid breakdown

Answer 27

Infertility that occurs at or after F2 generation.

Question 28

What are the mechanisms of speciation?

Answer 28

Allopatric speciation and sympatric speciation.

Question 29

What is sympatric speciation?

Answer 29

Emergence of new species, due to barriers that emerge WITHOUT geographic isolation

Question 30

What is allopatric speciation?

Answer 30

Emergence of new species that occurs after reproductive barriers emerge due to geographic isolation.

Question 31

Examples of allopatric speciation

Answer 31

``` Emerging mountain range Partitioning lake Continental drift (plate tectonics!) ```

Question 32

*Reminder to look at fly experiment in textbook*

Answer 32

Do it!

Question 33

Sympatric speciation

Answer 33

Speciation that occurs without geographic isolation! So new species is in same geographic area as parent species!

Question 34

3 mechanisms of sympatric speciation?

Answer 34

Polyploidy Habitat differentiation Sexual selection

Question 35

Polyploidy

Answer 35

An organism having 2+ sets of chromosomes due to accident during cell division

Question 36

2 types of polyploidy?

Answer 36

Autopolyploidy and allopolyploidy

Question 37

Habitat differentiation

Answer 37

Organisms mate with others who are on their preferred resource

Question 38

Sexual selection

Answer 38

Organism mates with others that use the same preferred resource

Question 39

Phylogeny

Answer 39

Evolutionary history of a species

Question 40

Marsupials and eutherians evolved from common ancestor. T F?

Answer 40

F; they’re an example of analogies/convergent evolution

Question 41

Name the structures on your arm

Answer 41

``` Humerus Radius and ulna Carpals Metacarpals Phalanges ```

Question 42

Convergent/divergent: dolphin and puma?

Answer 42

Divergent! Both evolved from mammalian ancestor

Question 43

Convergent/divergent: shark and dolphin?

Answer 43

Convergent! Shark is a chondrichthye. Dolphin is a mammal.

Question 44

Systematics

Answer 44

Biology discipline; classifying organisms, determining evolutionary relationships

Question 45

Taxonomy

Answer 45

System of naming and classifying

Question 46

Claude

Answer 46

Group of species including the ancestor species and /all/ of that ancestor’s descendants

Question 47

Shared ancestral character

Answer 47

Character shared by members of a clade, that originated before the ancestor of that clade

Question 48

Shared derived character

Answer 48

A character that is unique to clade being discussed