Flashcards in Lecture 16- Marsupials: Koala Deck (39)
What class are the koalas in?
What subclass are the koalas in?
What infraclass are koalas in?
What order are koalas in?
What suborder are koalas in?
Vombatiformes (wombats and koalas)
What family are koalas in?
What is koala's distribution?
-approx. 1 million km squared
-approx. the area of Japan
-koala is not a species most at risk
-coastal East Australia
What is koala habitat like?
-forests, Eucyalyptus woodlands, containing preferred Eucalyptus species
What is ranging behaviour like in koalas?
-adults are sedentary
-have small ranges (in SE Australia)
-larger home ranges in dryer areas in the north
What do koalas eat?
-species depends, can eat more than one
Why is it surprising that koalas are arboreal?
-large body size (males up to 15kg which is the approx. upper limit for arboreals)
How are koalas adapted to arboreal life?
-claws and feet adapted for climbing
-can jump sometimes but not that good at it and dangerous
How did koalas become arboreal?
-wombat and then went up
What is the koala diet?
-specialist folivore, feeds almost exclusively on foliage, from a limited number of (mainly) eucalypt species, these vary regionally
-sometimes feed on peppermint
Why are koalas not very active?
-foliage is poor quality diet, hence not very active
What are the constraints on herbivore digestion?
-structural plant material is hard to digest (cellulose) is difficult to digest
-dependent on bacterial and protist cellulases (diverse protist and bacterial microfauna in the gut-symbiotic microorganism)
-food preparation: fine particles
How do koalas prepare the food they eat?
-cutting molars (4 cusps on each), they cut, chop the leaves, older koalas
-then less efficient digestion (worse surface to area ratio), die of starvation eventually
What are secondary metabolites in plants?
-chemicals that help plants resist herbivores
-vary between species (phenolics=tannins, terpenoids=essential oils)
-secondary= because no know primary function in the plants
===species need to be physiologically specialised to feed successfully on such plants
What are the tactics to deal with plant secondary metabolites (PSMs)?
What is the importance of nitrogen in home ranges?
PSMs limit nitrogen available to animals= low reproductive success and habitat selection
How are PSMs deactivated/detoxified?
-absorption from gut then conjugation in liver (via microsomal enzymes, endoplasmic reticulum), water soluble conjugates are excreted in urine (kidney) or bile (gut)
-urine smells like eucalyptus
When do koalas mate?
-November to March
How long is pregnancy?
How many young per year?
1, (some populations breed more slowly due to chlamydia)
How long is lactation in koalas?
What is the juvenile survival like?
When are koalas sexually mature?
at 2 years of age
How does koala weight change due to lactation?
-weight loss in late lactation due to high energetic load coupled with low quality food
-they carry the baby on their back, costly energetically
-they drive the baby off when new one in the pouch
How do males and females differ?
-males much larger than females
-care of young is maternal only
-males scent mark = chest gland= rub it on trees to mark territory