Lecture 7: morphology

Question 1

ancestral condition

Answer 1

when the anatomy of one of the oldest dinosaurs (ex: Eoraptor) gave us an insight into what the first dinosaurs looked like
- Earliest dinosaurs had 5 fingers on their hands (tetrapods)

Question 2

convergent evolution

Answer 2

when a similar morphological trait evolved independently in two or more clades
- Ex: evolving “bird hips”, Effigia

Question 3

descendant with modification aka Darwinian evolution

Answer 3

• Scientific theory of common descent: all living things are connected through a series of common ancestors
• Variation w/n populations results in differential success => if variation is heritable then favorable traits (adaptations) spread through the population
  
  • Population becomes more different from each other
• Differences in populations as they adapt to their local environment & with enough time, populations no longer reproduce with each other (become biological species)

Question 4

anterior

Answer 4

around head area

Question 5

dorsal

Answer 5

from back to belly

Question 6

illium, ischium, pubis

Answer 6

bones that make up the pelvis
- Acetabulum: a hole in the pelvis that allows the femur to lock in place and gave dinos an upright stance like birds and mammals

Question 7

mandibular fenestra

Answer 7

socket in jaw

Question 8

naris

Answer 8

nose

Question 9

orbit

Answer 9

eye socket

Question 10

posterior

Answer 10

tail end

Question 11

ventral

Answer 11

front of the body

Question 12

postorbital fenestrae

Answer 12

2 sockets behind the eye socket

Question 13

saurischia

Answer 13

lizard, hip joint

Question 14

ornithischia

Answer 14

bird, hip joint
- & Saurischia’s hip joint is a synapomorphy that separates the 2 major clades of dinosaurs

Question 15

theory of evolution

Answer 15

species can change over time, that new species come from pre-existing species, and that all species share a common ancestor