biogeography and speciation

Question 1

Biogeography

Answer 1

The sicence devoted to dcoumenting spatial patterns of biodiversity

The study of distributions or organisms in both the past and present

of the 1.5 milion names naimals they are less than 20% of extant animals and less than 1% of extinct aniamls

Question 2

Speciation

Answer 2

The process that produces new and distrinct life forms

Evolution can be about speciation, teh engine that generates biodiversity

Question 3

Biological Species Concept

Answer 3

Species are groups of actually or potentially interbreeding populations that are reproductvly isolated from other such groups

reproductive isolation is defining charcteristic of species

The problem with this is hybrids - they interbreed and from viable offpsring but they are usually infertile

Cant always be used beacsue expensive or some species might not breed in the trials

Question 4

Morphospecies concept

Answer 4

Topological species cocnept

Members of the same species usally look alike

Not accurate so we rely on geentic testing

Some things can only be named species through this method like dinosaurs

Consider things like cryptic species which look the same but dont breed with eachother - but have gentic differences

Question 5

Hybrids

Answer 5

Species that are morpholgically distinct form independt populations but can still interbreed would be consideed the same species under the BSC

this presents prob to BSC

Question 6

Other Concepts for species

Answer 6

Biological species concept tells us the mechanism of speciation - reproductive isolation

Species characterized by niche (the range of envirmntal variables occupied by a species)

Two species that coexist in the same location will drive one to extinction is there is too much overlap in their niches due to competition

This led to ecolgical niche concept: a one to one correspondce between a species and niche (not rlly true)

Phylogentic species concept: memebrs of a species all share a common ancestry and common fate - a species is defined as a monophyletic group - no a priori assumptons abt population structure

Question 7

Prezygotic and Post Zygtoic isolation factors

Answer 7

○ Prezygotic factors:
§ Geographic: indivduals are seperated in space
§ Ecolgical: indivduals are separated by habitat or other ecological specilization
§ Temporal: indivduals are reprodcutvly active at diff times
§ Behavioural: indivduals mate with others based on specific corutship rituals, songs or displays
§ Gametic: gametes are infompatble and cant fuse to form a fertalized egg
§ Mechanical: indivduals are unable to mate
○ Postzygotic factors:
§ Hybrid inviability: embry forms but doesn’t fully develop
§ Hybrid sterility: offspring are prodcued but are sterile

Question 8

Allopatric

Answer 8

Speciation can occur through creation of allopatric (diff places) populations - species speciate because they are seperated into two geographic areas - physical seperation of species

Physical sepration doesnt create allopatric populations immediatly - its a gradual process - it can give rise to subspecies where there are distinct traits that have accumulated

Question 9

Vicariance

Answer 9

A geographical speration of a population typically by a physical barrier like a mountain range or river, resulting in a pair of closely related species

ex. ismus of panama and the snapping shrimp - their closest related sister taxa are just across the ismus

Question 10

Dispersal and peripatric speciation

Answer 10

Dispersal - where indivduals colonize a distant place/isaldn is a prominent example - imprtant as a specific kind of allopatric speciation known as peripatric speciation ( a small group of the orgnal poplation founds a new population through dispersal)