Lesson 23: Diversity of Animals Flashcards
(28 cards)
what is the largest extant mammal and the largest extant terresterial
blue whale/elephant
therians vs. non therians
eutherians
- placental mammals
metatherians
- marsupeals
the nontherian mammals are these monotremes
DIFFERENCES
- thereians are viviperous
- monotroemes lack nipples
- lumbas ribs are lost in the therian
- have a skeleton that is related to bounding behavior
– involved the evolution of the scapular sling
– all this internal viscera is suspended between the scapula and long muscles
—- helps with shock absorber when you’re bouncing through the grass
- therians have a calcaneal heal
– attachment of achillies tendon
– gives the foot a lot of leverage
- some skull differences
- the shape of the nasal bones being flared vs rectangular (eitheria)
- on average the marsupials differ in the dental formula
- some skull differences
- the shape of the nasal bones being flared vs rectangular (eitheria)
- on average the marsupials differ in the dental formula
diversity of marsupials
- themetatherians actually got originated in asia (we think)
- and then they dispersed to north america in the early cenozoic
- thought to have dispered to australia separated from antartica
- both groups have dog-like, catlike, flying squirrel0like, fasorial herbivores, and digging ant eaters –>examples of convergent evolution
^^^ do not have common ancestor
^^^ their ancestors underwent similar environemental pressures
african originating ungulates
- from the provosciea
- elephants
- there is evidence of the elephant’s kidney that suggest a faily recent quatic ancestor CONCULUDING that elephants were secondarily terresterial
** the first terresterials were aquatic
boroeutheria
- carnivores refer to not only a diet but also to a taxa
- not equivalent
- pangolin is the world’s most poached animal despite having the most protection
viviparity is universal for eutherians as a whole + sexual
- thought to evolve once
- places a big physical change to the mother
- change in the immune system so that they don’t reject their young
- reduced pressure having been descended
- sexual preference of testes being descented
- scrotum is posterior to the penis in most placentals
- metatherians have a cloaca
- process of placentation
process of placentation
- key amniotic membranes
- form different structures that get different kinds of structures names
- correoalentic placenta
ex: kangaroo
- presence of transient appearance of a shell (in marsupeals)
- don’t think of marsupeals as being transiety – it is a pretty derived group
- often enege with well developed lungs and forelimbs, but an underdeveloped neural system
- the motehr kangaroo will not assist the young kangaroo – it has to get out of the birth canal then travel into the pouch (might provide a litmus test)
- in that she hasn’t really invested in her young yet – continue to caring or stop caring and start again
- kangaroos – one of the rare vertebrates that have sibling offsrping that are simulataneously dependent at different stages –> similar to birds and incubation
tusks can develop out of different teeth
- show sex differences
- probably a sexually selected for trait
- rodents are known for gnawing 00 undergo a huge amount of tooth repair
lophodontia
- sharm bladed enamel regions separated by dentene
–> hipsodontia
very large temporalis in carnivores
- not in herbivores, but herbivores have a very strong masseter
- masseter muscles are good at chewing –> narrow gape
- carnivores do a lot of wider gape
only cellulose enzymes can digest cellulose
- plant cell wall
- no known vertebrae that can digest it
- form a asymbiotic reltionship with bacteria
plants and energy
- plants have a lot of energy content per gram compared to meat
- then energy that is available is hard to access
- possible that hindgut digestion is the ancestral trait
hindgut digestion
PROBLEM
– the energy is made accessible to the organism in the hindgut, after it passed through the foregut (absoprtion)
- hindgut fermenters – fractures cell wall – increases surface ara
cow stomach
- gets protein from bacteria
- ^^ cows digest bacteria
- if you have a ton of forge of diffreent types – a hindgut fermenter can digest them very quickly
rabbits
- hindgut fermenters
- eat their own poo for nutrients
- with the elevated surface area to volume raitio – foregut fermenter takes too long – has to be hinggut
hindgut
do with better quality
foregut
starve if low quality but high in quality
morphologies
corsorial limb morphology
- maximizes speed at the expense of power
- tend to be long for coveing distanc e
- musculature restricted to proximal regions – makes the distal regions quite light
HORSE
- most of leg musculature is concentrated close to central body
- restricted to movement in a single plain
forsorial limb morphology
- refers to digging
- maximizes power at the expense of speed
altricial
- monotreme
- marsupial
- eutherian
precocial
eutherian cow
- not fully independant but shortly after birth it is on its legs and thermoregulating
large mammals
- produce less offspring but their young lives longer compared to smaller mammals
large carnivores
- tend to have multiple large altricial young
- while large herbivores tend to produce few precocial young, herbivores would have to face predation so it is better for them to be independent when born
