Birth, Growth, and Reproduction

Question 1

Amniotic egg

Answer 1

eggs with encapsulating membranes that are water tight

Question 2

Describe some important characteristics amniotic eggs have to support baby development.

Answer 2

• watertight, allowing them to survive in terrestrial enviroments
• membranes are adapted to form toug, lethery, hard shells making them more durable and less vulnerable to small predators
• they have lots of little holes allowing for gas exchange (let O2 in and CO2 out)

Question 3

What groups of animals are amniotes?

Answer 3

Mammals, birds, dinosaurs, and reptiles

Question 4

Why are dino eggs not very large compared to their body size?

Answer 4

As SA and V are increasing, V increases at a faster rate. There is a maximum size an egg can be due to the need for gas exchange (to high of a V would make the rate of gas exchange to slow and the baby would suffacate in the egg due to high amounts of CO2)

Question 5

Lines of Arrested Growth (LAG)

Answer 5

rings formed by the addition of osteons during growth. Sometimes enviromental conditions are not favourable for growth making a distinct ring (LAG).

Question 6

How do we determine how long it took for a dino to become fully grown?

Answer 6

The LAGs

Question 7

WHat are the characteristics of young dino bones?

Answer 7

High vascularity and they have a lamellar texture

Question 8

External Fundemental System (EFS)

Answer 8

A closely spaced series of LAGs formed after growth stops

Question 9

Remodelling

Answer 9

Where the old bone cells were replaced by newer bone cells (Haversian (Secondary) Bone

Question 10

What does the presence of ESF in dino bones mean?

Answer 10

The dino was skelatally mature and has stopped growing

Question 11

Ontogenic changes

Answer 11

Changes in the form of an organism that occur as it matures

Question 12

What are common features of baby dinos?

Answer 12

• Large eye
• Small size
• Shorter relative limb length
• Large head
• Less Prominent facial extrusions

Question 13

Non-isometric Ontogenic Changes (+ example)

Answer 13

Changes in the relative proportions of an animal as it grows that are not simply changes resulting from a general increase in size

Example: changes in the relative length of the horns and frills of cerotopsians

Question 14

Isometric Ontogenic Changes (+ examples)

Answer 14

Changes in the absolute size but not proportions

Example: the length of the tibia relative to the length of the femur in a ceratopsian is nearly the same in proportion to the length of the femur to tibia in an adult

Question 15

Sexual dimorphism

Answer 15

males and females of the same secies are different

Question 16

Medullary Bone

Answer 16

contain concentrations of Ca that are stored prior to eggshell development but not at any other time

Question 17

How can be distiguish the sex of dinosaurs?

Answer 17

• Make inferences based on the conditions in which they were found (if they were found laying on a nest of eggs, found with babies…)
• if they have medullary bones present they are female

Question 18

Where Dinos good parents?

Answer 18

We do not know for sure but it is infered that some where good parents in that they stayed with their eggs and cared for their young while others had a sea tutle approch

Question 19

Predator Satiation

Answer 19

Evolutionary strategy where an organism lays a bunch of eggs and leaves them but the large number of eggs means that only a few need to survive in order to maintain species survival