Dinosuars

Question 1

What makes a dinosaur a dinosaur? What isn’t a dinosaur?

Answer 1

3 criteria:
- limbs fully rotated under body
- hole in hip socket
- walks on its toes (mostly)

This means many reptiles, like lizards, aren’t dinosaurs because their limbs are off to the side
Organisms that can swing their legs out to the side also aren’t dinosaurs

Question 2

What were the earliest dinosaurs like?

Answer 2

All bipedal, small, and likely carnivorous

Question 3

What are the 3 kinds of dinosaurs?

Answer 3

Sauropods (long-necks)
Theropods (T-rex)
Ornithischians (triceratops)

Question 4

What features do long-neck dinosaurs have (sauropods)?

Answer 4

Tiny heads, giant bodies, quadrupedal, and herbivorous
Long, dull teeth for stripping leaves from branches

Question 5

Did long-neck dinosaurs chew their food?

Answer 5

No, their teeth weren’t flat enough for grinding
They swallowed leaves whole, then also swallowed rocks to help break down the plants in their stomach as they walk

Question 6

What features do theropods have?

Answer 6

Long/sharp teeth, jaws sutured together for a more powerful bite, hollow bones, bipedal, mostly carnivorous

Question 7

What makes T-rex unusual for a theropod?

Answer 7

Most theropods were small, about the size of a turkey
T-rex was unusually large

Question 8

What evidence suggests that T-rex engaged in both hunting and scavenging?

Answer 8

Super sharp teeth, stress fractures from running, wimpy-sized arms (not useful for combat), big nose (detects the scent of rotting meat), probably had bad vision

Question 9

Why do T-rex have small arms?

Answer 9

Probably just a result of paedomorphism (its a feature retained from their juvenile stage and doesn’t really have much of a purpose)

Question 10

How would you survive a T-rex attack?

Answer 10

T-rex can’t run very fast for very long, so you can definitely escape in a car or run for your goddamn life (preferably with a slower friend)

Don’t run in a zig-zag for the love of god (don’t do it for an alligator either)

Question 11

Could theropods swim?

Answer 11

Probably, we have trave fossils that suggest they could

Question 12

What did velociraptors look like?

Answer 12

Turkey-sized, feathers, likely very smart

Question 13

What was the original purpose of feathers? What were they exapted for? What other exaptation helped with this?

Answer 13

Originally for warmth, but later used for flight
Hollow bones of theropods were also helpful for flight
This is why we see birds evolve from theropods

Question 14

What features did ornithischians have?

Answer 14

Quadrupedal, herbivorous, two types of teeth, special bone for chewing allows jaws to move side to side

Question 15

What adaptations did dinosaurs have (across all types) for eating plants?

Answer 15

Sauropods: long teeth for stripping leaves, large midsections (lots of space needed to break down the material), and swallowing rocks

Theropods (a few): long claws for stripping leaves, no sharp teeth

Ornithischians: sharp teeth for grabbing and duller teeth for grinding, jaws move side to side for grinding, large midsections, strong chewing muscles

Question 16

Why did the triceratops have frills on its head?

Answer 16

To contain very strong chewing muscles

Question 17

Why did the stegosaurus have a row of spines along its back?

Answer 17

They have ridges that contain blood vessels to help keep them warm

Question 18

What is sexual dimorphism? What does it tell us about a species’ mating habits?

Answer 18

The differences between the males and females of a species
The larger the difference between the two, the greater the competition is for mates

We know little about dinosaurs in this regard

Question 19

What adaptations did some dinosaurs have for defense or mating?

Answer 19

A horn that makes noises to communicate with others
A dome on the top of the head made of dense bone

Question 20

What geologic evidence do we have for the K-Pg extinction and what caused it?

Answer 20

Layer or iridium, shocked quartz, tektites, and a crater at the edge of Mexico all point to an extinction caused by an asteroid impact

Question 21

Why would iridium be evidence for an asteroid?

Answer 21

It has a high atomic number, meaning it can only form in a supernova explosion
Most heavy material on earth is in the core, so if found on the crust, we can be pretty certain it came from an extra-terrestrial source

Question 22

What is shocked quartz?

Answer 22

Quartz with unique microstructures, caused when its put under extremely high amounts of pressure

Question 23

What are tektites?

Answer 23

large glass beads with unusual shapes and textures, formed when rock is instantaneously melted, splashed out as big globs, and cools while spinning in the air

Question 24

How did the asteroid impact affect species on earth?

Answer 24

Vaporized anything in a certain range (not natural selection) and caused: forest fires, earthquakes, a mega tsunami, acid rain, little sunlight, and volcanic eruptions

Question 25

How did volcanic eruptions contribute to the P-Kg extinction?

Answer 25

Short term: acid rain, sunlight blocked out by ash (cooling), tsunamis Long term: greenhouse gases caused intense warming

Question 26

What types of plants were more likely to survive the K-Pg?

Answer 26

Plants were heavily affected first because of the lack of sunlight in the weeks following the impact Those most likely to survive were those that reproduce using seeds