Practice Qs Flashcards
Using diagrams, show the main patterns of skull fenestration in aminotes and give an example for each.
Anapsid - Turtle
Synapsid - Human
Diapsid - Lizard
What are pharyngeal jaws? Give an example
- Second set of jaws within an animals pharynx
- Branchial arches modified
- E.g Moray Eel has highly specialised raptorial jaws
Other than the aminotic egg, what are some dervied features of the aminotes?
- Thick, waterproof skin
- Costal ventilation (by ribs and diaphram)
- Temporal fenestration
- Skin elaborations (Scales, hair, feathers,
How do cartilaginous fish sense their prey?
- Mechanoreceptors: neuromast cells detect vibrations
- Chemoreceptors: Olfactory bulbs, acute sense of smell
- Electroreceptors: electric impulses sensed by ampullary organs
- Vision: low light
Key features of mammals
- Diaphragm
- Mammary glands = lactation
- Hair
- Lower jaw made from single bone (Dentary) - strong articulation
- Endothermy
Illustrate covergent evolution in marsupial and placental mammals
Flying squirrel (placental) and flying phalanger (marsupial)
Or
Marsupial mole and placental mole
How and why did the jaw evolve?
- Muscularised pharynx (branchial arches) - formed jaw
- Mandibular arch
- Gnathostomes were able to suck in prey - selected jaw to be large for feeding
- Duplication of Hox gene complex
What features distinguish the vertebrates from the invertebrate chordates?
- Vertebrae (replaces notochord)
- Endoskeleton made from cartilage or bone
- Invert chordates have 1 hox gene complex, verts have 2
- Larger brain with 3 parts (fore,mid, hind)
Why is Tiktaalik considered a transitional form between the early
tetrapodomorph fishes and the early tetrapods?
Fish like features:
- Scales
- Fins
- Gills
Tetrapod features:
- Neck
- Flattened head with eyes on top
- Lungs!
Explain why Archaeopteryx can be considered as an intermediate
between birds and dinosaurs.
Reptillian features:
- Strong thick bones
- No fusion of vertebrae
- Toothed Jaw
Bird features:
- Well developed feathers
- Reduction in digits (3)
- S shaped neck
Discuss the importance of hip structure in the phylogeny of Dinosauria.
Semi-erect to erect posture
- Open hip socket (acetabulum)
Divides into clades: Saurischians, Ornithischians:
- Saurischians ‘lizard hipped’ bone points down and forwards (modern birds)
- Orthiischians ‘bird hipped’ bone points down and backwards
What are the main hypotheses explaining the evolution of flight? Discuss
using examples.
- Arboreal ‘tree down’ e.g Extant Hoatzin chicks use claw to help climb trees
- Cursorial ‘ground up’ e.g Archaeopteryx may have used wings for balance while running
- WAIR ‘wing assisted incline running
- Pouncing Proavis
Briefly detail the unique features of marsupial reproduction and discuss
the associated costs and benefits
- 2 vaginas and bifuricate penis! so preg can follow immediately after one another
- Short gestation
- Extended lactation & development
Benefits
- Less gestation risk for mother
- Rapid repro cycle
- Post-birth flexibility
Costs:
- Low fitness of young
- High parental care
Providing one example, discuss the diversity of sociality in primates.
Very diverse:
- Male transfer
- Female transfer
- Monogamy
- E.g organutans are solitary but due to undefendable ranges display scramble competition polygyny
