Terrestrial Australian Mammals Flashcards
What is a species?
Species concept - two organisms should be capable of breeding
Debate is ongoing and essential for designating the endangered list
Mammalian Evolution
- Strong evidence they evolved from reptiles (transitional forms)
Prototheria
Monotremes
Metatheria
Marsupials
Eutheria
“Placentals”
Remaining mammalian groups
Most early mammalian groups are extinct, those remaining are:
Monotremes (Prototheria)
Marsupials (Metatheria)
Placentals (Eutheria)
All living mammals are distinguishable from reptiles by:
Homeothermy
Suckling of young
Body hair
Presence of muscular diaphragm
Australian mammalian origins
Native AUS mammals are derived from at least 2 sources:
- Marsupials and monotremes that were on the continent when it broke free of Antarctica
- Eutherian mammals came by island hopping
What are the two recognised marsupial cohorts
- Australidelphia - found in AUD and PNG
2. Ameridelphia - found in the Americas
Most easily recognisable differences between Australidelphia and Ameridelphia
- Structure of tarsal bones
- Blood proteins, DNA and sperm morphology
Possible evolutionary link between Australidelphia and Ameridelphia
Mountain monkey found in Chile
Relationship with Australidelphia and Ameridelphia is disputed
Four orders of Australidelphia
- Dasyuromorphia
- Peramelemorphia
- Diprotodontia
- Notoryctenorphia
Common morphological features of Marsupials
- Reproductive traits
- Slightly lower body temp & metabolic rate
- Brain usually smaller
- Opposable 1st digit on hind feet
Marsupial morphology
General mammalian features with modifications reflecting function e.g. diet, locomotion
Define polyprotodont
Multiple pairs of lower incisors