Ch. 14

Question 1

What is speciation? When does it happen?

Answer 1

a “lineage splitting” event that produces two or more species. This happens when there is an interruption of gene flow.

Question 2

What is gene flow?

Answer 2

Exchange of genetic info within or between populations

Question 3

What is the biological species concept? What was Linnaeu’s version of what a species is? How are they different? What are some problems with each method?

Answer 3

Developed by Ernst Mayr developed it- a population, or group of populations, whose members can interbreed and produce fertile offspring.
Linnaeu’s version describes species based solely on their physical appearance.
Problems with the Biological Species Concept:
-excludes asexual reproducers
-only living organisms (excludes extinct species)
-some species can breed in captivity but don’t in the wild (wolf and coyote)
Problems with Linnaeu’s Hierarchical:
-some things can look alike, but aren’t the same

Question 4

Pre- zygotic barriers

Answer 4

They prevent fertilization.

Question 5

Post- zygotic barriers

Answer 5

Prevent viable or fertile offspring (offspring is sterile)

Question 6

What is one example of post-zygotic barriers?

Answer 6

Hybrid issues- they can be interfile or have abnormal genitalia

Question 7

What are some ways in which species can be isolated from one another, creating pre-zygotic barriers?

Answer 7

They can live in different environments at different times, or have different mating seasons or mating calls

Question 8

Allopatric speciation

Answer 8

Reflects geographic barriers

Question 9

Parapatric speciation

Answer 9

adjacent populations that share a border

Question 10

Sympatric speciation

Answer 10

Occurs in a shared habitat

Question 11

Why are there so many fish species in the small amount of fresh water on the planet compared to the large amount of ocean?

Answer 11

There is less interruption of gene flow in the ocean

Question 12

Give a couple of examples of adaptive radiation

Answer 12

Burst of speciation- populations give rise to multiple specialized forms in a relatively short time.
Ex: Anoles, flowering plants, and finches

Question 13

What is the difference between ancestral and derived characters?

Answer 13

Ancestral characteristics are inherited attributes that resemble those of the ancestor of a group.
Derived characteristics are features that are different from those found in the group’s ancestor