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Flashcards in lecture 7 - mammals of fraser island Deck (26)
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1

what animals came to australia in the Early jurassic?

> ~200mya
> monotreme ancestors diverged early in 'gondwana' and spread throughout the southern globe, probably

2

what animals came to australia in the early cretaceous?

> ~120mya
> placentals probably split form metatherian ancestors in asia
> placentals also dispersed but few reached australia at this time
> because of land ridges

3

what happened in late cretaceous?

> ~105mya
> passage to australia was getting more difficult because it was separated from gondwana by water

4

what happened in the K/T event

> wiped out the dinosaurs and many other things.
> opened to way for remaining mammals to diversify
> in gondwana, the S.American mixture evolved in isolation
> in Australia, the marsupials radiated
> new cicumpolar currents started to freeze antartica

5

how did the mass extinction event allow for the radiation of marsupials?

> wiped out a lot of animals - thus creating empty niches
> these niches were then filled by the marsupials

6

what happened by the oligocene?

>~35mya
> australia was on its way to warmer and drier climates, shaping the organisms that live here

7

what are prototherians/monotremes?

>neonates hatch from an egg laid in pouch
earliest strain

8

what are metatherians/marsupials?

> neonates born early and develop in pouch attached to teat

9

what are eutherians/placentals?

> neonates born after development supported through a chorioallentoic placenta

10

what sub-class and order is the short-beaked echidna in?

> subclass Prototheria
> order Monotremata

11

what subclass and order is the yellow footed antechinus in?

> Marsupialia
> Dasyuromorphia
- hop
- rat/mice sized
- insectivourous

12

what subclass and order is the common dunnart in?

> marsupialia
> dasyuromorphia
- teeth are pointy for piercing prey

13

what subclass and order are long-nosed bandicoots in?

> marsupialia
> Peramelemorphia
- pointy front teeth, then molars for grinding

14

what order and subclass are northern brown bandicoots in?

> marsupialia
> peramelemorphia

15

what is the subclass and order of the short-eared brushail?

> marsupialia
> Diprotodontia

16

what subclass and order are swamp wallabies in?

> marsupialia
>diprotodontia

17

what happened in the pleistocene?

> ~50,000mya
> the australian plate collided with the asian plate forming an opportunity for new mammals to add to the fauna
> HOWEVER, there is trace evidence of placentals already being here as early as the Eocene (50mya), before the final split from gondwana
> there are a few teeth and jaw fragments from murgon controversially assigned to a placental, plus a fossil bat
> presumably these managed to disperse here from the south, but they didn't persist

18

during which era did multiple waves of invasions ocur

> pliocene

19

what different organisms are in the sub-class Eutheria ad Order - Rodentia

> a mosaic tailed rat whose ancestor arrived after the first 'old endemics' and before the 'new endemics'
>fawn-footed melomys
> bush rat
> have typical rodent dentition

20

what is in the subclass -eutheria and order Chiroptera

> gould's wattled bat
> a micro-chiropteran' that uses echolocation

21

when were all the new endemics present before?

> 1760

22

what sub class and order are black rats in?

> eutheria
> rodentia

23

how do you make abundance estimates?

> mark and recapture
> if you know what proportion of the population you catch, then you know the size of the population, sort of.
> trap initially and mark all the animals you catch.
> trap again and see what proportion are marked
> assume all your marked animals mix into the population in the meantime
> all animals, marked and unmarked are equally likely to be caught
> and the population size has not changed
> of your recaptured animals, the proportion of marked animals in the second event gives an estimate of the proportion you catch in any event
> apply this to the first event to get the original population size

24

what is an example of the mark and recapture technique?

> suppose you trap 30 animals the first time round. you mark and release them.
> suppose you then trap 25 animals, 5 of which are marked
> based on a single estimate so far, your traps successfully retraped 5 in 25, or 1 in 5 animals
> so you assume that your first trapping event successfully trapped 1 in 5 animals, i.e., there were 150 (5x30) animals out there

25

what are some assumptions of the mark and recapture technique?

> animals are equally likely to be trapped each time
- not always the case
- trap happy or trap shy animals

26

how can you improve the precision of mark and recapture?

> increase the number of samples taken
> often its possible to treat multiple trapping events as serial estimates, leading to greater precision
> in any case, its better if you trap heaps of animals, not just a few