Animalia Flashcards
What are the 3 subclasses of mamamals?
Monotremes, Metatherians (inc. marsupials) and Eutherians (inc. placentals)
What clade do mammals belong to (starts with S)?
Synapsids
In what period was the origin of pelycosaurs and therapsids?
Permian
In what period was the radiation of Mesozoic mammals?
Middle/ Late Triassic
What are pelycosaurs also known as?
Sail backs
What are the 3 classes on mammalian synapsids?
pelycosaurs, therapsids, cynodont therapsids (in order of derivedness)
Name 3 traits what evolved in synapsids
Dual gait locomotion; teeth specialisation; larger temporal fenestre, diaphragm, heat regulation improved
Name 5 features of the earliest mammals
Tiny; derived skull (larger brain and inner ear); lactation adn suckling; hair; special harderian gland (insulates fur)
What prompted the tertiary radiation of mammals?
potentially extinction of the dinosaurs
Why is high level homeostasis important fro reproduction?
SA:Vol ratio too large and not enough time fro brain development to control systems in juveniles
What is the major advantage of lactation?
Reproduce at any time of year
What did lactation facilitate in terms of teeth?
differentiation of teeth types; shift to diphodonty as don’t need continuous replacement
What is diphodonty?
two successive sets of teeth, initially the “deciduous” set and consecutively the “permanent” set
What did milk likely first evolve for?
Antimicrobial and immunity
What are the 3 main forms of mammalian locomotion?
Non-cursorial, cursorial, fossorial
What is unique about reproduction in monotreme?
Eggs can grow!
What are 3 strange traits of platapus?
1- A genome with good immune system with lots of natural killer receptor proteins
2- Venom- males have venomous spurs on heels of hindlegs
3- Electrolocation
Whats important about marsupalia milk?
Changes composition over time with development
What trait allows marsupialia embryos to suckle during devlopment?
Girdle
What is the name of the mechanoreceptive organs on star nosed mole nose?
Elmers organs; innervated by infraorbital nerve
What is the name for the sensors in harbour seals used to track hydrodynamic fish tracks?
Vibrissae
What adaptation do moths have to bat echolocation?
Some moths can hear clicks of bats and Aartiid moths can produce own sound to disturb the bats radar
How do Aartiid moths produce their own sounds to disrupt the bats radar?
Using tymbal organ on the metathorax
What are the 2 staged=s in Cnideria lifecycle?
Medusa and polyp
What are porifera?
sponges
What are ctenophora?
very diverse
How do placazoa feed?
graze
how do cnideria feed?
predators- sting
What animals belong to anthrozoa?
sea anemones and coral
What symmetry do cnideria and ctenophora have?
radial
Why are bird bones so light?
pneumatized (air filled)
What is vicariance?
an event causing peraration of populations = speciation e.g. godwana break up
Why is bird genome small?
Adaptation to flight- small genome in small cells which have high SA for high metabolism for flight
What are Neognathae
modern birds (99.3% all species)
what type of sex chromosomes do birds have?
female = heterogamy
When did birds likely first evolve-?
cretacious
What did the existence and distribution of ratites help prove?
break up of godwana
what are 5 adaptations of feathers?
1- coiled barbules for water transport (sandgrouse) 2- silent flight in owls 3- structural support - woodpeckers 4- antiicing in penguins 5- sexual display
What are the homologous devlopmental genes of hair, scales and feathers
FGF and Shh
What proportion of bids undergo long distance migration?
25%
What are the 3 trends of migration?
leapfrog, migratory divide and non-adaptive
what is a crown group?
most recent common ancestor together with all of its descendents
what is a stem group?
ancestor and all its descendants, excluding the living representatives of a collection of species.
What are choane?
internal nostrils
When did tetrapods first appear?
early-mid devonian
What are tetrapods?
living amniotes, and amphibians
What is the problem with tracking the origin of amniotes?
Romers gap- gap in fossil record
Where did tetrapod characters evolve?
in water
What was a likely driving selection pressure for tetrapod evolution?
living in high itdal area needing adaptations to move in shallow water and be semi-aquatic
What is interesting about the neck of the Tikaalik tetrapodomorph?
proves neck didnt evolve to support head whilst walking BUT catch food or breath above water instead
Whats a major transition i in the origin of tetrapods?
fins to limbs
What are amniotes?
clade of tetrapods containing reptiles (and dinosaurs, so birds) and mammals
What are present in haplo-diplontic plant lifecyles and not haplontic?
spores
What is included in the archosauria?
birds and crocodiles
what is the sister group to the archosauria?
turtles
What re the 2 great clades of amniota?
Synapsida and diapsida
What clade do all living forms of mammals belong to?
synapsida
What is homeothermy?
stable body temp
What is poikilothermy?
fluctuating body temp
What are the tetrapods?
tetrapod clade
What defines the amniotes?
possession of an amniotic egg
What clade does lepidosauria belong to?
Diapsida in amniota
What are mososaurs the sister group to?
snakes
Are living squamates endothermic or ectothermic
ectothermic
How has ectothermy allowed the evolution of snakes?
more diverse size and shape- high SA:VOL: ratio
How much more efficient is ectotherm biomass conversion tot endotherms?
x10
What are the 2 types of snake venom admission strategies?
strike and release OR strike and hold
what are the paired vomeronasal organs in snakes?
paired auxiliary olfactory (smell) sense organ located in the soft tissue of the nasal septum, in the nasal cavity just above the roof of the mouth (the hard palate).
How do snakes swallow very large prey?
CRANIAL KINESIS (ancestral character of tetrapods)
WHats key about the energetics fo locomotion in ecto and endotherms?
in ectotherms-can reach similar total metabolism BUT for short bursts only
