Evolutionary Patterns

Question 1

How many kinds of dinosaurs were there?

Answer 1

Expected to have ~1844 genera, including undiscovered ones based on graph of how many we have now
Only ~600 genera discovered now
Don’t know actual number of genera

Question 2

Did dinosaurian diversity constantly increase?

Answer 2

Cannot say definitely if there was a constant increase

genera / # rock formation = shows a different pic (not all have a constant increase) compared to the raw data

We got more rocks later on -> so more dinosaurs got preserved

Question 3

Why can’t we trust the raw data when it comes to dinosaur diversity?

Answer 3

Graph has a positive slope so increase in diversity?
(almost) constant increase in diversity over time

Appears (but may not be true) as dinosaur diversity increased w/ time when looking at raw data

Over time, there exists more rock formations
Very close correlation between dinosaur bearing formations and dinosaurs

We got more rocks later on -> so more dinosaurs got preserved

Question 4

What is the correlation between rock formations and number of dinosaur genera found?

Answer 4

There’s a correlation between number of rock formations yielding dinosaurs and the number of dinosaur genera discovered

Over time, there exists more rock formations
Very close correlation between dinosaur bearing formations and dinosaurs

We got more rocks later on -> so more dinosaurs got preserved

Question 5

How do we estimate the body mass of dinosaurs?

Techniques

Answer 5

Physical Models
Regression
3D models

Question 6

Physical models

Answer 6

Made dinosaur scale models

Measured volume in water and multiplied by density of alligator (~0.9 g/cm3) and scaled to actual size

Heaviest weighing was brachiosaurus ~78 tons

Numbers based on physical model

People thought since humans use thigh bones to support our body, then it should be important

Question 7

Regression

Answer 7

fitted to the data of relative stride lengths and dimensionless speeds

Used thigh bones/humerus ONLY (QUADRUPEDAL only) circumference to correlate with bony mass

But this is based on mammals and dinosaurs are reptiles -> large error

Doesn’t work for BIPEDAL animals

Question 8

3D models

Answer 8

Volume

3D models require skeletons but some bones (some wouldn’t even have bones to scan) aren’t accurate

Finds minimal space (hull volume) occupied by animal and actual actual was 10% more

Uses multiple planes to fit all the bones together

Question 9

How did the regression and physical models differ from one another in data of the Brachiosaurus?

Answer 9

the physical model (~78 tons) and regression (29.37 tons) methods were very off from one another

Brachiosaurus was probably 30 tons

Question 10

Which is easier- regression or 3d models?

Answer 10

Regression is easier than 3D models

Question 11

Using different methods to calculate the body mass estimates results in?

Answer 11

Variations in body mass estimates may result from different methods

Question 12

Most likely, the early estimates of heavy dinosaurs are most likely to be ?

Answer 12

Early estimates of heavy dinosaurs are most likely to be FALSE

Question 13

Who is Cope?

Answer 13

Bone War -Edward Drinker Cope (1840-1897)

Question 14

Cope’s Rule?

Answer 14

Hypothesis (not an absolute rule) -body size in a lineage tends to increase over evolutionary time

Question 15

Did dinosaurs evolve larger and larger body sizes through the Mesozoic?

Answer 15

Archosauromorpha got bigger over time BUT
Therapsida (gave rise to mammals) got smaller over time

Changes in body size of dinosaurs are best explained by random changes or stasis

BM - body size did change but due to random change

-> Cope’s rule did not hold

Question 16

Brownian Motion (BM?)

Answer 16

random changes (Brownian Motion or BM)

Question 17

statis

Answer 17

body size stable

Question 18

Why are birds and their relatives exception to the idea that dinosaurs did NOT evolve larger and larger over time?

Answer 18

They started out small, got bigger, but after a certain point, don’t get any bigger

Question 19

What was the general trend for Dinosauria? Does Cope’s Rule hold for Dinosauria?

Answer 19

There was a general increase in size but after a certain part, there was no a correlation/trend - as there was a lot of different sizes

Cope’s rule cannot be established for Dinosauria

Question 20

Size of Herbivorous theropods over time?

Answer 20

Continuous (BM) increase is not observed but there was a rise at the end
Cope’s rule does not apply to Herbivorous theropods either
Did the geographic distribution of dinosaurs change throughout the

Question 21

Did the geographic distribution of dinosaurs change throughout the Mesozoic?

Answer 21

In the beginning dinosaurs were most likely everywhere even Antarctica

Lack of dinosaurs in australia and antarctica
Antarctica b/c there’s so much ice instead of rock

Don’t have rocks from those times in Australia
landmass that was built before the age of dinosaurs.

Much of the rock there is not from the age of dinosaurs
Earliest forms in Argentina