Ch 6 - Geography of Evolution

Question 2

Realms

Answer 2

Some related ones divided by continental drift; after that very little exchange between them

Question 3

Smaller realms

Answer 3

provinces of flora and fauna shaped by long term weather patterns

Question 4

Cape York Peninsula in Australia

Answer 4

Mega diverse area in NE Oz

Question 5

Hardy-Weinburg math and criteria

Answer 5

For Diploid, (p + q)(p + q) = 1; no mutation, no gene flow, no inbreeding, no selection, very large population

Question 6

Wright

Answer 6

We move away from Hardy-Weinburg; assume inbreeding occurs; Hsj = probability alleles are different; F statistics,

Question 7

Disjunct distributions

Answer 7

Closely related species found on different continents, evidence of common ancestor that was then separated by continents (ex. cichlids, gators, some pines)

Question 8

Human influences

Answer 8

European starling: 100 released in New York in 1896. Expands to cover most of NA by 1970.

Question 9

Saxifrage example. Why at certain disconnected high elevations?

Answer 9

Would have been pushed South by glaciers. Would have died out at lower altitudes as glaciers receded, so they remained at high elevations and in Arctic

Question 10

How do lineages diverge?

Answer 10

Food source changes (common in insects); geographic dispersal or migration, vicariance (a barrier like a mountain range or climate); behavioural;

Question 11

Breakup of Gondwanaland*

Answer 11

Break off of antartica; first India and Madagascar which then split; South America last 35 Mya

Question 12

Hawaiian cricket species

Answer 12

Spread from one island to another as they emerged; don’t go backwards, no extinctions

Question 13

Lemurs

Answer 13

Phylogenetic analysis shows that they stemmed from African monkeys and then colonized Madagascar after it had already split off. Neat.

Question 14

Allochthonous

Answer 14

Taxa that originated elsewhere, arrive by dispersal (eg Hawaii)

Question 15

Autochthonous

Answer 15

Evolved within an area (flightless birds of SA, Africa, NZ, Oz; Lungfish of SA and Africa)

Question 16

Basal group (fig 6.13)

Answer 16

A branch that diverges earlier, usually show place of origin

Question 17

Phylogeography

Answer 17

processes (ie dispersal)that govern geographic distribution of gene linages, esp. within a species or closely related ones; ex. grasshoppers in Balkans, Italy and Spain, spread to rest of Europe from Balkans

Question 18

Gene duplications

Answer 18

Can allow for a lot of mutational freedom, since one can still perform the normal function, while the other can mutation however it likes

Question 19

Multiregional hypothesis

Answer 19

Homo erectus and neanderthal spread from Africa and then became sapien in Africa, Asia, and Europe, and gene flow followed

Question 20

Out of Africa hypothesis

Answer 20

one wave of homo erectus spread from Africa, then diverged, then was replaced with second wave (sapiens)

Question 21

Founder effect

Answer 21

Change in allele frequencies due to rare colonization event; often lose rare alleles; need to reach equilibrium before we can do analysis like Fst

Question 22

Niche conservatism

Answer 22

Similar species maintain similar requirements; helps us understand distribution

Question 23

Why doesn’t a species keep adapting to new environments?

Answer 23

Lack genetic diversity; attack of genes from species in favourable environments prevent recipients from adapting (counteracts natural selection)