Dino Scienc e

exhaustedcrumMechanics

Oct 24, 2013 (3 years and 9 months ago)

66 views

Mike Kozina

SASS

July 18, 2012

1

Dino
Scienc
e

What is a dinosaur?

2

That’s right

birds are now dinosaurs!

3

Types of Dinosaurs

4

Sauropods

Theropods

Marginocephalia

Saurischia
: Lizard
-
Hipped

Ornithischia
: Bird
-
Hipped

NBA Players

Thyreophorans

Ornithopods

Dino Sizes

5

Name

Height

Length

Weight

Ankylosaurus (armored lizard) 7 ft. 2.1 m 35 ft. 10.6 m 10,000lbs 4,536kg.

Apatosaurus (deceptive lizard) 15 ft. 4.5 m 75 ft. 22.9 m 66,000lbs 29,937kg.

Argentinosaurus

(Argentina lizard) 70 ft. 21.4 m 120 ft. 36.6 m 220,000lbs 99,792kg

Brachiosaurus (arm lizard) 50 ft. 15.2 m 100 ft. 30.5 m 100,000lbs 45,360kg

Compsognathus (elegant jaw) 2 ft. 0.6 m 3 ft. 0.9 m 8lbs 3.6kg

Corythosaurus (helmet lizard) 16 ft. 4.9 m 30 ft. 9.1 m 8,860lbs 4,019kg

Deinonychus (terrible claw) 5 ft. 1.5 m 9 ft. 2.7 m 175lbs 80kg

Iguanodon (iguana tooth) 18 ft. 5.5 m 30 ft. 9.1 m 10,000lbs 4,536kg

Seismosaurus (tremor lizard) 84 ft. 25.6 m 150 ft. 45.7 m 200,000lbs 90,720kg

Stegosaurus (plated lizard) 11 ft. 3.4 m 30 ft. 9.1 m 6,000lbs 2,722kg

Triceratops (three
-
horned face) 9.5 ft. 2.9 m 26 ft. 7.9 m 14,000lbs 6,350kg

Tyrannosaurus (tyrant lizard) 23 ft. 7.0 m 50 ft. 15.2 m 14,000lbs .6,350kg

Velociraptor (swift robber) 2 ft. 0.6 m 6 ft. 1.8 m 250lbs .113kg

Dino Sizes

6

Name

Height

Length

Weight

Ankylosaurus (armored lizard) 7 ft. 2.1 m 35 ft. 10.6 m 10,000lbs 4,536kg.

Apatosaurus (deceptive lizard) 15 ft. 4.5 m 75 ft. 22.9 m 66,000lbs 29,937kg.

Argentinosaurus

(Argentina lizard) 70 ft. 21.4 m 120 ft. 36.6 m 220,000lbs 99,792kg

Brachiosaurus (arm lizard) 50 ft. 15.2 m 100 ft. 30.5 m 100,000lbs 45,360kg

Compsognathus (elegant jaw) 2 ft. 0.6 m 3 ft. 0.9 m 8lbs 3.6kg

Corythosaurus (helmet lizard) 16 ft. 4.9 m 30 ft. 9.1 m 8,860lbs 4,019kg

Deinonychus

(terrible claw) 5 ft. 1.5 m 9 ft. 2.7 m 175lbs 80kg

Iguanodon (iguana tooth) 18 ft. 5.5 m 30 ft. 9.1 m 10,000lbs 4,536kg

Seismosaurus (tremor lizard) 84 ft. 25.6 m 150 ft. 45.7 m 200,000lbs 90,720kg

Stegosaurus (plated lizard) 11 ft. 3.4 m 30 ft. 9.1 m 6,000lbs 2,722kg

Triceratops (three
-
horned face) 9.5 ft. 2.9 m 26 ft. 7.9 m 14,000lbs 6,350kg

Tyrannosaurus (tyrant lizard) 23 ft. 7.0 m 50 ft. 15.2 m 14,000lbs .6,350kg

Velociraptor

(swift robber) 2 ft. 0.6 m 6 ft. 1.8 m 250lbs .113kg

When did Dinosaurs rule the earth?

7

Dinosaur Motion/Mechanics


How fast did dinosaurs go?



How could they support
such large bodies?



Did land dinosaurs swim?

8

Similarity


Simple scaling does not necessarily reproduce
the same results


9

E.g.: Animal mass ~ bone volume; Bone strength ~ bone cross
section



can’t just scale up

So, how can we relate big to small?

Unitless ratio of relevant physical parameters:

1.
g = acceleration from gravity

2.
v = velocity

3.
L

= linear length scale


Froude Number

(centripetal force/gravitational force):

𝐹
=
𝑣
2
𝑔𝐿

10

Other similarity terms you may have heard


Reynold’s

number

(inertial forces/viscous
forces)

=
𝜌𝑣𝐿
𝜂


Strouhal

number

(oscillation
time/characteristic translation time)

=
𝑣𝜏
𝐿


Prandtl

number

(viscous diffusion rate /
thermal diffusion rate)
𝑃
=
𝜂
𝐶
𝑝
𝑘

11

12

Estimate speed of dinosaurs using:

1.
Stride length (from footprints)

2.
Hip height

3.
Froude number for modern day
mammals


So, how fast?

1.
Sauropods

~ 1m/s

2.
Fastest tracks (from horse
-
sized
biped) ~12m/s


Problems:

1.
Even for mammals scaling fails
for small sizes because
movement pattern very
different

2.
Footprints only tell velocity in
certain types of terrain (those
likely to have tracks saved)

not
representative


How fast could they run, and how do we know?

Other ways to estimate velocity


Relate bone strength to general athleticism


E.g. Triceratops estimated to be in between
elephant and rhino in speed


Computer simulations:


Genetic algorithms search to
extremize

parameters such as energy consumption or speed


Some require knowing motion patterns


Can use constraints to eliminate impossible
orientations

13

Some simulation results

14

Size Problems: How could
Littlefoot

grow so big?

15

What about blood flow?


Open question


Extremely robust hearts?


Possibility that long necks never raised above
~30degrees?

16

Did dinosaurs
swim?

17

Why did they die out?


Hormonal problems leading to thin eggshells


Volcanos put dust in the air blocking the sun


Over predation by
carnosaurs


Slipped disks in vertebral column


Blindness from cataracts


Climate became

1.
Too hot

2.
Too cold

3.
Too wet

4.
Too dry


Constipation


Fluctuations in the gravitational constant, somehow affecting dinosaurs


Radiation from a supernova


Uranium poisoning


18

Really, why did they
die out?


Overwhelming evidence for asteroid
colliding with the earth


Sharp break in fossil type

K/T boundary


High levels of iridium in soil


Large crater in
Chixhulub
, Mexico 65.5 MYA


Estimate size of
asteriod

~10km diameter
(since iridium at K/T found worldwide)


19

More evidence for asteroid impact


Shocked quartz
caused by impact


Microtektites

bits
of glass ejected from
impact site

20

Dino
-
related Research at SLAC


Use synchrotron to pick out different chemicals left in
Archaeopteryx fossil


Can link chemicals to pigment density

21

Selected Bibliography


Dinosaur Diversity


Wang,
PNAS

103

13601
-
13605 (2006)


Dinosaur Biomechanics/Motion


Sellers,
Proc. R. Soc. B
274

2711
-
2716 (2007)


Alexander,
Scientific American
, April 1991


Alexander,
Proc. R. Soc. B
273
1849
-
1855 (2006)


Sauropod

Size Issues


Seymour,
Biol.
Lett
.
5
317
-
319 (2009)


Sander,
Science

322

200
-
201 (2008)


Henderson
Proc. R. Soc.
Lond
. B (Suppl.)

271

S180
-
S183 (2004)


General Dino Stuff (includes all info I used about extinction)


Fastovsky
, D. and
Weishampel
, D.
Dinosaurs: A Concise Natural History
.
Cambridge University Press (2009)


Dino research at SLAC


Bergmann,

PNAS
107

9060
-
9065 (2010)


Similarity in other contexts (non
-
dino
)


Landau, L.D. and
Lifshitz
, E.M.
Fluid Mechanics: Course of Theoretical Physics
Vol. 6
. 2
nd

Ed. Butterworth
-
Heinemann (2010)


http://en.wikipedia.org/wiki/Dimensionless_number


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Thanks for listening!