Chapter 18, up to 18.2 only

Question 1

Microevolutionary processes do what

Answer 1

alter the pattern and extent of genetic and phenotypic variation

Question 2

SPECIATION:

Answer 2

process of species formation; scientists make inferences about its process

Question 3

What happens when microevolutionary process differ

Answer 3

When these processes differ between populations, the populations will diverge genetically and they may eventually become so different that we recognize them as a distinct species

Question 4

Earth’s biological diversity is packed in

Answer 4

discrete, recognizable units, and not as a continuum

Question 5

Morphological species

Answer 5

Morphological species concept: the idea that all individuals of a species share measurable traits that distinguish them from individuals of other species:

PROS:
Works for fossilized organisms

Helps recognize organisms

CONS:

Individuals of a single species look different in size and colouration (warblers), which may make us think they are different species

Morphology doesn’t help us distinguish closely related species that are nearly identical in appearance
Tells us little about the evolutionary processes that produce new species

Question 6

Biological species concept:

Answer 6

“groups of interbreeding natural populations that are reproductively isolated from other groups [can’t produce fertile offspring]

If the members of two populations interbreed and produce fertile offspring under natural conditions, then they belong to the same species

PROS: helps explain why species look alike, members of the same gene pool share genetic traits that determine their appearance

Question 7

based on Mayr’s definition, how can we think of a species

Answer 7

a large gene pool that can be subdivided into local populations

Question 8

Mayr’s definition of biological species broken down

Answer 8

Defines species in terms of population genetics and evolutionary theory

Mayr looks at genetic cohesiveness of species first, and then looks at populations of the same species experiencing gene flow, from this we can think of a species as one large gene pool that can be subdivided into local populations

The second part is genetic distinctness of each species, since populations are reproductively isolated they can’t exchange genetic information