Lecture 8 - Biogeography

Question 1

What is biogeography?

Answer 1

The study of the distributions of organisms (and genetic diversity) across space and time

Question 2

What is biogeography split into?

Answer 2

Ecological biogeography and historical biogeography

Question 3

Ecological biogeography

Answer 3

Factors that control patterns of distribution in the present

Question 4

Historical biogeography

Answer 4

Tries to understand how these ecological patterns came into existance

Question 5

What are the 3 regional grouping of organisms

Answer 5

Biogeographic realms, biogeographic provinces, Biomes

Question 6

What are the three ways that organisms are distributed?

Answer 6

Cosmopolitan, endemic and disjunct

Question 7

What are the 3 mechanisms involved in distributing organisms?

Answer 7

Vicariance, dispersal and extinction

Question 8

Wallaces Line

Answer 8

Line separating two distinct modern terrestrial faunas that corresponds to a deepwater separation between continental plates

Question 9

Biogeographic realms

Answer 9

Term coined by Wallace

Major geographic regions of earth that have characteristic animal and plant taxa

Question 10

Biomes

Answer 10

Different types of environments suitable for different types of organisms

Question 11

Biogeographic provinces

Answer 11

When biogeographic realms are divided into faunal and floral provinces or regions of endemism

The boundaries are not sharp due to the movement of taxa between realms

Question 12

Cosmopolitan

Answer 12

Found almost anywhere in the world

Question 13

Examples of cosmopolitan

Answer 13

Fruit fly, brown rat, common rock dove, house dust mite

Question 14

Endemic

Answer 14

Restricted to a particular area

Question 15

Examples of endemic

Answer 15

Scottish crossbilss

silverswords

Fossa

Lemurs

Question 16

Disjunct

Answer 16

Distribution with gaps

Question 17

Examples of disjunct

Answer 17

Marsupials, alligators, tapirs, Araucaria pine, camelids

Question 18

Zoogeographic realms

Answer 18

Updated version of biogeographic realms that are split up even more but are still quite similar

Question 19

Where are areas of highest endemism

Answer 19

Australia, Madagascar, South America

Question 20

How do biogeographic maps differ

Answer 20

They differ according to the type of organism considered

Question 21

What are the two types of dispersal?

Answer 21

Range expansion through favorable habitat or jump dispersal across unfavorable habitat

Question 22

What are the 3 dispersal pathways?

Answer 22

Corridors, Filter routes, waif dispersals

Question 23

Filter routes

Answer 23

Corridors that filter organims

Question 24

Waif dispersal

Answer 24

Passive form of dispersal, seeds, rafting

Question 25

Example of dispersal

Answer 25

1883 krakatoa eruption that killed all life on an island, withing 50 years the island was covered in forest inhabitants that came from Java and Sumatra

Question 26

Is the ability to disperse consistant?

Answer 26

No changes between groups: insects, birds and bats are at the top and amphibians and flightless mammals have poor dispersal

Reptiles are better as they can survive longer without food

Question 27

What are two ways of dispersal?

Answer 27

Air currents and oceanic currents

Question 28

What is an example of island biogeography dispersal?

Answer 28

Hawaiian islands formed as tectonic plate moved northwestward over a hotspot, causing formation of volcanic cones

Colonization of Hawaiian islands has proceeded from older to younger islands

Question 29

Vicariance

Answer 29

Splitting of a taxons range

Populations of a widespread species are seperated due to barriers resulting from changes in geology, climate or habitat

LEads to divergences and speciation

Question 30

Example of Vicariance

Answer 30

The breakup of Gondwana in the Mesozoic can explain the distribution of some ancient groups like ratites and marsupials

Question 31

Disjunct distribution of camelids

Answer 31

Evolved in North America

Dispersed via Beringia to Eurasia and Panama to South America

Later became extinct in north America due to climate change in pleistocene

Question 32

Theories of endemic species in madagascar

Answer 32

Thought to be caused by vicariance however the age of species indicates waif dispersal

Question 33

Autochthonous

Answer 33

Evolved within the region

Question 34

Allotochthonous

Answer 34

Originated elsewhere

Question 35

Caenozoic SA mammals vicariance

Answer 35

At the end of the Mesozoic SA was isolated from north America and Africa

Only limited autochthonous mammalian fauna present in south America

Question 36

How did the Caenozoic South American mammals disperse?

Answer 36

Marsupials colonised Antarctica and Australia from South America

Xenarthrans and native ungulates colonised Antarctica from South America

3MYA Isthmus of Panama aros connecting NOrth and South America, this led to the dispersal of previously isolated South American Species into North America and vice versa

Initial symmetry in dispersal but ultimately more NA species in SA than SA in NA

Question 37

What was the extinction of Caenozoic SA mammals like?

Answer 37

South American megafauna (including ungulates) became extinct at the end of the Pleistocene due either hunting by humans or climate change or both

Marsupials, Xenarthrans and native ungulates became extinct in Antarctica due to climate changes